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11. Cardiomyopathies, myocarditis, pericardititis, endocarditis
Cardiomyopathies encompass a group of diseases that primarily affect the structure and function of the heart muscle. These conditions can lead to significant mechanical and electrical dysfunction, impacting the heart’s ability to pump blood effectively. Here's a breakdown of the essential concepts related to cardiomyopathies:
Overview of Cardiomyopathies
Definition: Cardiomyopathies are disorders of the heart muscle, involving changes in the myocardial wall thickness and the size of the heart chambers.
Primary vs. Secondary:
Primary cardiomyopathies are intrinsic to the heart muscle and are not related to other systemic diseases.
Secondary cardiomyopathies are part of a broader systemic disorder but are distinct from heart issues caused by ischemic disease, valvular abnormalities, or hypertension.
Classification
Cardiomyopathies are typically classified based on their structural and functional impacts on the heart:
Dilated Cardiomyopathy (DCM)
Hypertrophic Cardiomyopathy (HCM)
Restrictive Cardiomyopathy (RCM)
Arrhythmogenic Right Ventricular Dysplasia (ARVD)
DILATED CARDIOMYOPATHY (DCM)
Incidence and Prevalence: It is the most common type, with an incidence of 6 per 100,000 people per year, showing a male predominance.
Characteristics: Marked by progressive dilation of the ventricles often accompanied by ventricular hypertrophy.
Functional Impact: Leads to systolic dysfunction, where the dilated heart struggles to pump blood efficiently.
Causes of Dilated Cardiomyopathy:
Idiopathic: In about 50% of cases, no specific cause is identified.
Secondary Causes: Can include viral myocarditis (e.g., Coxsackie virus), exposure to toxins such as alcohol, cocaine, and anthracyclines (e.g., doxorubicin, daunorubicin), nutritional deficiencies like thiamine deficiency (beriberi), malnutrition, genetic factors, and peripartum cardiomyopathy.
Pathophysiology of Dilated Cardiomyopathy
Structural Damage: Initial damage to the myocardium triggers compensatory mechanisms aimed at maintaining cardiac output.
Compensatory Mechanisms:
Frank-Starling Law: Initially, the myocardium responds by increasing the left ventricular end-diastolic volume (preload) and developing eccentric hypertrophy. This helps to temporarily maintain stroke volume and cardiac output.
Progression to Dilation: Over time, as the heart's capacity for hypertrophy is exceeded, it begins to dilate. Dilation increases the distance between myofibrils, which reduces myocardial contractility.
Outcome: The progressive decrease in contractility leads to a reduction in ejection fraction, culminating in heart failure.
Left ventricular failure (LVF) leads to:
Left ventricular failure (LVF) is a serious condition that arises when the left ventricle of the heart is unable to pump blood effectively. This can lead to a variety of clinical consequences, categorized into forward failure, backward failure, and secondary right heart failure. Each type of failure reflects different aspects of the deteriorating function and effects on the body. Here’s a detailed explanation of each:
Forward Failure
Definition: Occurs when the left ventricle fails to pump sufficient blood into the systemic circulation.
Consequences: Diminished blood flow results in reduced perfusion of vital organs. This manifests as:
Renal Dysfunction: Poor kidney perfusion can lead to acute kidney injury and chronic kidney disease.
Cerebral Dysfunction: Reduced cerebral perfusion may cause symptoms ranging from dizziness and confusion to more severe cognitive impairments.
Cold Extremities: Due to decreased blood flow to peripheral areas of the body, resulting in feelings of coldness, especially in the hands and feet.
Backward Failure
Definition: This occurs due to the inability of the left ventricle to receive and eject the blood coming from the lungs, leading to a buildup or "backup" of blood in the pulmonary circulation.
Consequences: The increased pressure in the pulmonary circulation leads to:
Pulmonary Congestion and Edema: Fluid leaks into the alveolar and interstitial spaces, impairing gas exchange and leading to symptoms such as shortness of breath, orthopnea, and paroxysmal nocturnal dyspnea.
Right Heart Failure
Definition: Often a secondary consequence of chronic left ventricular failure, where the increased pressure in the pulmonary circulation (caused by the backward failure) places a strain on the right ventricle.
Consequences: The right ventricle struggles to pump blood effectively into the overloaded pulmonary arteries, leading to:
Systemic Circulation Congestion: Manifests as peripheral edema (swelling of ankles and feet), abdominal edema (ascites), and other signs of fluid overload such as jugular venous distention.
Pathological and Clinical Features of Dilated Cardiomyopathy
Heart Enlargement: The heart is typically enlarged, often 2-3 times heavier than normal, primarily due to the dilation of all chambers.
Valvular Changes: There are usually no primary valvular diseases; however, valvular regurgitation (especially mitral regurgitation) may occur secondary to the dilation of the heart.
Coronary Arteries: Generally free from significant atherosclerosis if the cause is non-ischemic cardiomyopathy.
Ventricular Changes: Eccentric hypertrophy of the left ventricle occurs, characterized by an increase in the size of the ventricular cavity with normal or decreased wall thickness.
Microscopic Changes: Enlarged muscle cells with atypical nuclei, signs of interstitial and endocardial fibrosis, and absence of inflammatory infiltrate. Mural thrombi may form due to stasis of blood in the dilated chambers, posing a risk for embolic events such as stroke.
Clinical Symptoms of DCM
Early Signs: Include exertional dyspnea, palpitations, and chest pressure.
Late Signs: As the condition progresses, symptoms such as fatigue, angina pectoris (due to increased cardiac workload and oxygen demand), and signs of fluid overload (ankle edema, ascites) become more pronounced.
Physical Examination of DCM
Mitral or Tricuspid Valve Regurgitation: Detected as a systolic murmur during auscultation. This occurs due to dilation of the ventricles, which can lead to improper closure of the valves.
S3 Gallop: This is a low-frequency sound heard shortly after S2 (the "dub" of "lub-dub") during the rapid filling phase of the ventricle and is indicative of increased ventricular filling pressures, often associated with heart failure.
Left Ventricular Impulse Displacement: A laterally displaced point of maximal impulse (PMI) can indicate left ventricular hypertrophy or dilation.
Jugular Venous Distention (JVD): Suggestive of elevated right atrial pressure, commonly seen in heart failure.
Rales (Crackles): Heard over both lung fields, indicating fluid accumulation within the lung interstitium, a sign of pulmonary edema.
Palpitations: Patients may report feeling their heart beating irregularly or rapidly.
Peripheral and Abdominal Edema: Fluid accumulation in the extremities and abdomen, indicating systemic congestion often seen in right heart failure.
Diagnostics of DCM
Laboratory Tests:
BNP (Brain Natriuretic Peptide): Elevated levels are indicative of heart failure as BNP is released in response to ventricular volume expansion and pressure overload.
Troponins and CK-MB: These markers of myocardial injury should not be significantly elevated unless there is concurrent myocardial infarction.
Electrocardiogram (ECG):
Conduction Disorders: Such as atrioventricular (AV) block or left bundle branch block, which might suggest a genetic or inflammatory etiology and generally carry a poorer prognosis.
Arrhythmias: Including atrial fibrillation, which may arise due to tissue fibrosis and abnormal electrical re-entry.
Reduced QRS Amplitude: Indicates decreased contractile cardiac tissue mass.
Axis Changes: Deviations in the cardiac axis can occur due to structural changes in the heart from dilation.
Echocardiography:
Ventricular and Atrial Dilation: Direct visualization of chamber sizes.
Decreased Ejection Fraction: Quantifies the reduction in the left ventricular pumping capacity.
Wall Motion Abnormalities: Such as hypokinesis, which indicates reduced wall movement during the cardiac cycle.
Chest X-Ray:
Cardiomegaly: General enlargement of the heart, particularly of the left side, often with a balloon-like appearance.
Pulmonary Edema: Fluid in the alveolar and interstitial lung spaces, indicative of left-sided heart failure decompensation.
Treatment Strategies for DCM
Lifestyle Modifications:
Avoid Alcohol and Cardiotoxic Agents: These substances can exacerbate myocardial damage and should be avoided to prevent further deterioration of cardiac function.
Manage Infections: Prompt treatment of infections to avoid additional stress on the heart.
Heart Failure Management:
Sodium Restriction: Helps to reduce fluid retention and manage blood pressure.
ACE Inhibitors: Aid in vasodilation, reducing the heart's workload and improving survival.
Beta-Blockers: Decrease heart rate and blood pressure, reducing the heart's oxygen demand and also beneficial in arrhythmia control.
Diuretics: Used to remove excess fluid from the body, relieving symptoms such as swelling and shortness of breath.
Digoxin: Helps strengthen heart muscle contractions and can control heart rate.
Aldosterone Receptor Antagonists: Reduce fluid retention and provide cardioprotective effects.
Anticoagulation:
Warfarin or Other Anticoagulants: Necessary in cases of intraventricular thrombus or atrial fibrillation to prevent thromboembolic events such as stroke.
Device Implantation:
Implantable Cardioverter Defibrillator (ICD): Recommended for patients with an ejection fraction of less than 35% to prevent sudden cardiac death due to life-threatening arrhythmias like ventricular fibrillation.
Heart Transplantation:
Considered when all other treatments have failed and the patient’s condition continues to deteriorate, or in young patients with severe disease.
Complications of DCM
Progressive Left Ventricular Failure:
Can lead to cor bilaterale (bilateral heart failure), where both the left and right sides of the heart fail.
Systemic Thromboembolism:
May cause stroke, pulmonary embolism, or acute mesenteric ischemia due to blood clots traveling to different parts of the body.
Arrhythmias:
Ventricular Tachycardia and Ventricular Fibrillation: Severe types of arrhythmia that can lead to sudden cardiac death if not promptly treated.
Sudden Cardiac Death:
A significant risk in patients with cardiomyopathy, particularly those with severe left ventricular dysfunction and arrhythmias.
Prognosis:
Approximately 50% of patients may die within two years of diagnosis, primarily due to progressive cardiac failure or arrhythmias.
HYPERTROPHIC CARDIOMYOPATHY
Hypertrophic cardiomyopathy (HCM) is a complex heart condition characterized by excessive thickening of the heart muscle, particularly the ventricles, without an obvious cause such as high blood pressure or aortic stenosis. It is a significant health concern due to its implications, including sudden cardiac death, especially in young athletes. Here’s a detailed look at the etiology, pathophysiology, and pathological changes associated with HCM:
Etiology of Hypertrophic Cardiomyopathy
Primary Hypertrophic Cardiomyopathy:
It is the most common hereditary heart disease, following an autosomal dominant pattern of inheritance with variable penetrance.
The genetic mutations responsible are typically found in the genes that encode sarcomeric proteins, which are crucial for muscle contraction. Commonly involved proteins include myosin heavy chain, myosin binding protein C, cardiac troponins, and tropomyosins.
Approximately 60-90% of cases are primary, with no other underlying cardiovascular condition.
Secondary Causes:
These include conditions that traditionally cause cardiac hypertrophy such as chronic hypertension and aortic stenosis. Other systemic diseases like Fabry disease and amyloidosis can also lead to hypertrophic changes in the heart muscle.
Pathophysiology
Concentric Hypertrophy:
HCM is most often characterized by concentric hypertrophy, particularly of the left ventricular septum. This abnormal thickening can lead to a reduction in the size of the ventricular cavity.
The septal hypertrophy can cause mechanical obstruction to blood flow out of the heart (left ventricular outflow tract obstruction), especially during systole.
Diastolic Dysfunction:
The hypertrophied muscle is stiffer and less compliant, which impairs the left ventricle’s ability to relax and fill properly during diastole (the phase of the heart cycle when the heart fills with blood). This results in inadequate filling and reduced stroke volume, which can lead to compensatory tachycardia (increased heart rate).
Left Ventricular Outflow Tract Obstruction:
In cases where there is left ventricular outflow obstruction, this can exacerbate the condition by increasing the pressure load on the left ventricle, prolonging ventricular relaxation, and further elevating diastolic pressure. The obstruction is often due to the systolic anterior motion of the mitral valve or due to the hypertrophied septum itself.
Pathological Changes
Macroscopic Changes:
The hearts in HCM are often markedly thick-walled and heavy, with significant hypertrophy often centered around the septum. The ventricular shape may be altered, resembling a banana due to the inward bulge of the hypertrophied septum.
Microscopic Changes:
There is notable disarray of the myocardial fibers and sarcomeres (myofiber disarray), a hallmark of HCM. Myocytes are significantly hypertrophied, much larger than normal, accompanied by both interstitial and replacement fibrosis. This fibrosis can follow myocardial necrosis and contributes to the risk of arrhythmias and sudden cardiac death.
Clinical Symptoms
Asymptomatic: Especially in the non-obstructive type of HCM, many individuals do not experience noticeable symptoms.
Exertional Dyspnea: Difficulty breathing during physical activity is common due to the decreased filling capacity and reduced cardiac output resulting from left ventricular hypertrophy.
Angina Pectoris: Chest pain not necessarily related to coronary artery disease but due to increased myocardial oxygen demand and decreased coronary perfusion during diastole.
Dizziness and Syncope: These symptoms can occur due to arrhythmias or inadequate cardiac output during exertion.
Palpitations and Arrhythmias: Irregular heartbeats are common and can be due to atrial fibrillation, ventricular tachycardia, or other rhythm disturbances.
Sudden Cardiac Death: Although relatively rare, this is a significant risk, particularly in young athletes or during intense physical activity.
Physical Examination Findings
Systolic Ejection Murmur: A crescendo-decrescendo murmur best heard at the left sternal border; this murmur is typically due to the turbulent flow across the left ventricular outflow tract. It increases with maneuvers that decrease venous return to the heart like the Valsalva maneuver or standing up, and decreases with maneuvers that increase venous return like squatting or lying down.
Mitral Regurgitation: A holosystolic murmur can sometimes be heard due to the systolic anterior motion of the mitral valve, which affects its ability to close properly.
Sustained Apex Beat: A laterally displaced apex beat that is powerful and sustained, indicative of significant myocardial hypertrophy.
S4 Gallop: An additional sound in the heart rhythm that occurs just before the normal two beats (S1 and S2), associated with the forceful atrial contraction pushing blood into a stiff ventricle.
Paradoxical Split of S2: This abnormal finding during the cardiac cycle occurs when the closure of the aortic valve is delayed, making it audible during expiration.
Pulsus Bisferiens: A double-peaked pulse that is palpable during each cardiac cycle, indicative of significant outflow obstruction.
Impact of Activities and Medications
Symptoms of HCM can worsen under certain conditions:
Exercise: Increases symptoms due to higher cardiac output demand and reduced filling time.
Dehydration and Diuretics: Can exacerbate outflow tract obstruction by decreasing blood volume.
ACE Inhibitors and Digoxin: These medications can potentially worsen the obstruction or negatively affect the contractility and rhythm of the hypertrophied heart muscle.
Diagnostics
Electrocardiogram (ECG)
Left Ventricular Hypertrophy: Indicated by high voltage QRS complexes, a common sign in HCM due to thickened heart muscle.
Deep Q-Waves: Particularly in the inferior and lateral leads, suggesting septal hypertrophy.
Giant Inverted T-Waves: Typically seen in the precordial leads, indicative of apical or mid-ventricular hypertrophy.
P-Wave Changes: Such as a bifid P wave with a broad terminal negative component in lead V1 (P-mitrale), suggesting left atrial enlargement due to increased atrial pressure and volume.
Left Bundle Branch Block: May occur due to extensive myocardial fibrosis.
Arrhythmias: Detection of ventricular tachycardia, atrial flutter, or fibrillation is common and significant due to the risk of sudden cardiac death.
Echocardiography
Primary Diagnostic Tool: Echocardiography is the best initial and confirmatory test for HCM.
Ventricular Wall Thickness: Asymmetric hypertrophy of the left ventricular wall, typically >15 mm, most pronounced in the septum. A wall thickness >30 mm is associated with a higher risk of sudden cardiac death.
Outflow Tract Abnormalities: Includes systolic anterior motion of the mitral valve leaflet, mitral regurgitation, and a high left ventricular outflow tract pressure gradient, detectable with Doppler imaging.
Left Atrial Enlargement: Can be secondary to mitral regurgitation or diastolic dysfunction.
Systolic and Diastolic Function: While systolic function is usually preserved (normal ejection fraction), diastolic dysfunction is evident due to increased myocardial stiffness and reduced ventricular compliance.
Chest X-Ray
Indications: Useful if there is dyspnea or chest pain of unknown origin; can show cardiomegaly, signs of pulmonary congestion, and left atrial enlargement.
Exercise Testing
Purpose: Useful in patients who exhibit symptoms only during physical activity. Exercise testing allows for the monitoring of cardiac performance and symptom reproduction under controlled conditions.
Cardiac MRI
Utility: Employed when echocardiographic findings are inconclusive or to obtain more detailed anatomical and functional information, including precise measurement of myocardial thickness, identification of fibrosis, and more accurate assessment of ventricular volumes and mass.
Lifestyle Modifications
Avoid Strenuous Exercise: Patients are advised to avoid intense physical activities that could trigger cardiac events.
Limit Alcohol Intake: Excessive alcohol can exacerbate the condition.
Avoid Dehydration: Maintaining proper hydration helps manage blood volume and pressure, reducing cardiac stress.
Healthy Body Weight: Keeping a healthy weight reduces the strain on the heart and helps control associated cardiovascular risk factors.
Pharmacotherapy
Beta-Blockers: Such as propranolol, are the first line of treatment; they reduce heart rate, decrease myocardial oxygen demand, and alleviate outflow tract obstruction.
Nondihydropyridine Calcium Channel Blockers: Such as verapamil, used as a second-line treatment, help to relax the heart muscle and improve filling by reducing the rate of contraction and slightly decreasing the degree of outflow obstruction.
Device Therapy
Automated Implantable Cardioverter Defibrillator (AICD): Recommended for patients at high risk of sudden cardiac death, especially those with a history of serious ventricular arrhythmias, syncope of unknown origin, or severe myocardial hypertrophy (ventricular wall thickness >30 mm).
Invasive Therapies
Surgical Septal Myectomy: A procedure where a portion of the thickened septal wall is surgically removed. This is often considered for patients with severe symptomatic obstruction not responsive to medications.
Transcoronary Ablation of Septal Hypertrophy (TASH): Also known as alcohol septal ablation, this procedure involves the injection of alcohol into the septal artery to induce a controlled myocardial infarction in the hypertrophied area, reducing its thickness and the associated obstruction.
Pacemaker
For patients who cannot undergo septal reduction therapy, pacemaker implantation can help manage heart rhythm disorders and improve symptoms in some cases of HCM, particularly those involving disrupted electrical signaling.
Heart Transplant
Considered a last resort for patients with end-stage hypertrophic cardiomyopathy who have significant systolic dysfunction (ejection fraction <50%) and are refractory to other treatments.
Complications
Hypotension: Can occur, particularly in the setting of outflow tract obstruction and after interventions.
Heart Failure: Both systolic and diastolic dysfunction can lead to heart failure in HCM patients.
Atrial Fibrillation: Common due to atrial enlargement and fibrosis, increasing the risk of stroke.
Ventricular Arrhythmias: Pose a risk for sudden cardiac death, particularly in severe cases with extensive myocardial fibrosis.
RESTRICTIVE CARDIOMYOPATHY
Restrictive cardiomyopathy (RCM) is a form of heart muscle disease that is characterized by the heart being restricted from stretching and filling properly. It is the least common type of cardiomyopathy and is primarily defined by its functional impairment—poor ventricular filling with normal ejection fraction. Here’s a detailed explanation of the etiology, pathophysiology, and microscopic findings associated with RCM:
Etiology of Restrictive Cardiomyopathy
Idiopathic: In many cases, the exact cause of RCM is not identified.
Löffler Endocarditis: This is a rare form of endocarditis featuring an eosinophilic infiltrate that damages the endomyocardium, often associated with peripheral eosinophilia. It releases major basic protein, which is toxic to tissues and particularly harmful to the heart.
Endocardial Fibroelastosis: Mainly seen in young children, this condition involves diffuse thickening of the left ventricular endocardium due to the proliferation of fibrous and elastic tissue. The cause remains largely unknown.
Endomyocardial Fibrosis: Predominantly affects children in tropical regions; characterized by thickening of the endocardium, starting from the apex of the heart and potentially spreading upwards. The exact cause is unknown, but it leads to significant cardiac dysfunction.
Systemic Diseases:
Amyloidosis: The most common systemic disease causing RCM, where misfolded proteins accumulate in the heart tissue, leading to stiffness.
Sarcoidosis: Features granulomatous inflammation that can stiffen the myocardium.
Hemochromatosis: Iron overload in the heart leads to tissue damage and fibrosis.
Systemic Sclerosis: Connective tissue disease that leads to widespread fibrosis, including in the heart.
Iatrogenic Causes: Certain medical treatments, such as chemotherapy, radiation therapy, and surgery, can lead to RCM.
Pathophysiology
Connective Tissue Proliferation: The heart becomes stiffer due to the proliferation of connective tissue within the myocardium. This stiffness markedly impairs the ventricles' ability to fill properly during diastole (the heart's relaxation phase).
Impaired Diastolic Filling: Due to the reduced compliance of the ventricular walls, the heart cannot fill adequately, leading to decreased cardiac output despite a normal ejection fraction.
Atrial and Systemic Venous Congestion: The increased stiffness and poor filling of the ventricles lead to a backup of blood into the atria, causing their enlargement and eventually leading to systemic venous congestion.
Microscopic Findings
Interstitial Fibrosis: There can be patchy or diffuse fibrosis within the myocardium, which contributes to the overall stiffness and decreased compliance of the heart. This fibrotic change can vary widely in its presentation and extent.
Clinical Features
Symptoms of Left Heart Failure: Dyspnea is a prominent symptom due to impaired filling and elevated left atrial pressures, which can lead to pulmonary congestion.
Symptoms of Right Heart Failure: As the disease progresses, it often affects the right heart, leading to jugular venous distention, peripheral edema, ascites, and hepatomegaly due to systemic venous congestion.
S4 Heart Sound: An atrial gallop occurs due to the atria contracting forcefully to overcome the increased stiffness of the ventricles.
Diagnostics
Echocardiography: The most useful diagnostic tool for RCM. It typically shows:
Atrial enlargement due to increased filling pressures.
Normal or decreased ventricular volumes with biatrial enlargement.
Reduced diastolic filling and possibly symmetric wall thickening without significant ventricular dilation.
ECG: May show left bundle branch block or non-specific abnormalities. Low voltage signals are characteristic in cases of amyloidosis due to the infiltrative nature of the disease.
Chest X-Ray: Useful for identifying secondary complications such as pulmonary edema or pleural effusions and may show signs of sarcoidosis like hilar lymphadenopathy.
Cardiac Catheterization: Can measure direct hemodynamic parameters, showing high atrial pressures and characteristic dip-and-plateau or "square root sign" in ventricular pressure recordings.
Biopsy: Performed if other tests are inconclusive; can confirm the presence of myocardial fibrosis or infiltrative diseases like amyloidosis or sarcoidosis.
Treatment
Managing Underlying Conditions: Specific treatments depending on the cause, such as chelation for hemochromatosis or immunomodulatory drugs for sarcoidosis.
Symptomatic Treatment:
Beta-Blockers: Used to maintain sinus rhythm and manage arrhythmias, though must be used cautiously as they can exacerbate the diastolic dysfunction.
Cardioselective Calcium Channel Blockers: Such as verapamil, which can help increase ventricular filling time by slowing down the heart rate.
ACE Inhibitors: Generally used to decrease preload and afterload, though their benefit in RCM can be limited by their potential to reduce cardiac output further in patients with severe diastolic dysfunction.
Anticoagulation: Important for preventing thromboembolic complications, especially in patients with atrial fibrillation.
Heart Transplant: Considered for patients with refractory symptoms who do not respond to other treatments, representing an end-stage option.
ARRYTHMOGENIC RIGHT VENTRICULAR CARDIOMYOPATHY (ARVC)
Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) is a genetic cardiac disorder characterized primarily by changes in the structure and function of the right ventricle. Here's an overview of ARVC, including its clinical features, diagnostic methods, and treatment options:
Clinical Features
Variable Presentation: Many patients may be asymptomatic, especially in the early stages of the disease.
Angina Pectoris and Dyspnea: Chest pain and difficulty breathing due to decreased cardiac output as the disease progresses.
Peripheral Edema, Ascites, Hepatic Congestion: These symptoms occur due to right-sided heart failure as the right ventricle fails to pump effectively.
Palpitations and Syncope: Caused by arrhythmias, which are common in ARVC.
Sudden Cardiac Death: Particularly during physical exertion, due to severe ventricular arrhythmias.
Diagnostics
Family History: A significant number of cases are familial, with a history of sudden cardiac death being a critical clue.
ECG: Shows repolarization disturbances, prolonged QRS duration especially in right precordial leads, episodes of ventricular tachycardia, and frequent ventricular extrasystoles.
Echocardiography: Reveals enlargement of the right ventricle, wall motion abnormalities, decreased right ventricular ejection fraction, and possible right ventricular aneurysms.
Endomyocardial Biopsy: Demonstrates fibrous and fatty replacement of the myocardium, which is pathognomonic for ARVC.
Genetic Testing: Identifies mutations related to desmosomal proteins, helping to confirm the diagnosis especially in familial cases.
Treatment
Activity Modification: Patients are advised to avoid intense physical exertion to reduce the risk of arrhythmias and sudden cardiac death.
Anti-arrhythmic Medications:
Beta-blockers: Used to manage arrhythmias and protect against sudden cardiac death.
Amiodarone and Calcium Channel Blockers: Effective in controlling heart rate and maintaining rhythm.
Invasive Procedures:
Implantable Cardioverter Defibrillator (ICD): Recommended for patients at high risk of sudden death to detect and correct dangerous arrhythmias automatically.
Radiofrequency Ablation: Used to treat recurrent ventricular tachycardia by destroying the abnormal electrical pathways in the heart.
Heart Transplant: Considered in severe cases that are resistant to other forms of treatment and where there is significant risk of fatal arrhythmias.
TAKOTSUBO CARDIOMYOPATHY
Takotsubo cardiomyopathy, also known as stress-induced cardiomyopathy or "broken heart syndrome," is a temporary condition where your heart's left ventricle (the main pumping chamber) becomes suddenly weakened and balloons outwards. This condition mimics symptoms of an acute coronary syndrome but occurs in the absence of significant coronary artery obstruction. It predominantly affects postmenopausal women and can be triggered by acute emotional or physical stress. Here's a detailed overview of the clinical features, diagnostics, and insights into Takotsubo cardiomyopathy:
Clinical Features
Chest Pain: Retrosternal chest pain resembling angina, often precipitated by severe stress.
Dyspnea: Difficulty breathing, a common symptom in heart conditions, reflecting reduced heart function.
Syncope: Episodes of fainting or near-fainting due to inadequate cerebral perfusion.
Arrhythmia: Irregular heartbeats can occur, contributing to the feeling of palpitations or chaotic heart rhythm.
Heart Failure/Cardiogenic Shock: In severe cases, the dysfunction of the heart muscle can lead to signs of heart failure or even cardiogenic shock, characterized by low blood pressure and severe circulatory failure.
Diagnostics
Laboratory Tests:
Troponins and CK-MB: Elevated levels similar to those seen in myocardial infarction, despite no coronary blockage.
BNP (B-type Natriuretic Peptide): Often elevated, indicating cardiac stress or heart failure.
Electrocardiogram (ECG):
ST-Elevations: Typically observed in the precordial leads (V1-V3, aVR), although ST depressions and diffuse T-wave inversions can also be present.
Prolonged QT-Interval: A sign of electrical instability in the heart.
Echocardiography:
Reveals characteristic patterns such as apical ballooning or dyskinesis of the apex of the left ventricle.
Decreased ejection fraction, reflecting impaired pumping efficiency.
Coronary Angiography:
Performed to rule out acute coronary syndrome as the cause of symptoms by confirming the absence of significant coronary artery blockage.
Cardiac MRI:
Provides detailed images of the heart structure and function, better visualizing the extent of myocardial damage and helping to exclude other cardiac pathologies.
Pathophysiology
The pathophysiology of Takotsubo cardiomyopathy involves a surge of catecholamines that leads to cardiotoxic effects on the heart muscle, particularly the apex of the left ventricle. This surge can cause transient spasms in the coronary arteries and direct myocardial stunning, leading to the characteristic ballooning of the apex during systole (contraction).
Management
The management of Takotsubo cardiomyopathy typically involves supportive care:
Monitoring: In-hospital monitoring of cardiac function and symptoms is crucial.
Medications: Use of beta-blockers, ACE inhibitors, or diuretics to manage symptoms and prevent recurrence.
Stress Management: Addressing and managing the triggers of stress can help prevent future episodes.
Follow-up: Regular follow-up with echocardiography to monitor recovery, as the left ventricular function often returns to normal within weeks.
Treatment of Takotsubo Cardiomyopathy
Underlying Cause: Identification and management of any triggers or underlying causes, particularly emotional or physical stressors, are crucial.
ACE Inhibitors: Used to manage symptoms by reducing the heart's workload and improving survival rates.
Low-dose Beta-Blockers: Help to reduce the effects of stress hormones on the heart and prevent recurrence of symptoms.
LEFT VENTRICULAR NON COMPACTION CARDIOMYOPATHY
Avoid Physical Exertion: Patients with LVNC should avoid strenuous activities to reduce the risk of heart failure and arrhythmias.
Symptomatic Management: Treatment focuses on managing symptoms of heart failure using standard heart failure medications.
Prevention of Thromboembolism: Due to the structure of the myocardium in LVNC, there is an increased risk of thrombus formation within the trabeculations. Anticoagulation therapy may be recommended to reduce the risk of thromboembolic events.
ARRYTHMIA INDUCED CARDIOMYOPATHY
Beta-Blockers: Used to control heart rate and manage symptoms associated with arrhythmias.
Antiarrhythmics: Drugs like amiodarone are prescribed to control and prevent arrhythmic episodes.
Catheter Ablation: This procedure is used to treat the arrhythmias by destroying the area of heart tissue that is causing irregular electrical signals. This can help restore normal heart function and potentially reverse the cardiomyopathy.
MYOCARDITIS
Myocarditis is an inflammation of the heart muscle (myocardium) that can significantly affect the heart's ability to function and its electrical rhythm. This condition can be caused by a variety of infectious and non-infectious factors and is a significant cause of sudden cardiac death, particularly in young individuals. Here’s an overview of the etiology, pathological features, and microscopic characteristics of myocarditis:
Etiology of Myocarditis
Viral Infections: The most common cause of myocarditis. Viruses such as Coxsackie B, parvovirus B19, adenovirus, and human herpesvirus 6 are frequently implicated.
Bacterial Infections: Less common but includes organisms such as Borrelia burgdorferi (responsible for Lyme disease). Historically, bacteria like those causing diphtheria and tuberculosis were also common causes.
Parasitic Infections: Trypanosoma cruzi, the causative agent of Chagas disease, is a significant cause in South America.
Autoimmune Conditions: Diseases like systemic lupus erythematosus (SLE), rheumatic fever, and polymyositis can trigger myocarditis as part of their systemic impact.
Hypersensitivity Reactions: Can occur due to adverse reactions to medications such as antibiotics, diuretics, or antihypertensives.
Toxins: Exposure to substances like alcohol, cocaine, certain chemotherapeutic agents (anthracyclines), and radiation can lead to toxic myocarditis.
Transplant Rejection: Myocarditis can develop as a part of the rejection process in heart transplant recipients.
Pathology and Microscopy
Macroscopic Appearance: The affected myocardium often appears soft and flabby, which may display pale or hemorrhagic areas indicative of inflammation and damage.
Microscopic Findings: The inflammatory response is typically marked by:
Lymphocytic Infiltration: Common in viral myocarditis, where lymphocytes predominate the cellular infiltrate.
Eosinophilia: Seen in hypersensitivity-induced myocarditis, where eosinophils are more prevalent.
Parasitic Infiltration: In cases like Chagas disease, parasites can be seen within the tissue.
Giant Cells and Multinucleated Cells: These can appear in more severe cases or specific types of myocarditis (e.g., giant cell myocarditis), often associated with a worse prognosis.
Clinical Features of Myocarditis:
Myocarditis often presents with a range of symptoms, varying from none to severe, depending on the extent and severity of myocardial involvement:
Asymptomatic: In many cases, especially early on, individuals may not exhibit any symptoms.
Flu-like Symptoms: Commonly, symptoms such as fatigue, fever, malaise, and muscle aches occur 1-2 weeks before more overt cardiac symptoms, suggesting a viral etiology.
Fatigue, Weakness, Dyspnea, Nausea, Vomiting: These are typical symptoms of general malaise and can escalate as the heart's function diminishes.
Cardiac Arrhythmias: Manifestations can range from mild sinus tachycardia and palpitations to severe arrhythmias like ventricular extrasystoles, syncope, and even complete heart block.
Chest Pain: Can indicate involvement of the pericardium (the fibrous sac surrounding the heart), suggesting a complication such as pericarditis.
Heart Failure and Cardiogenic Shock: As the disease progresses, symptoms of heart failure (such as edema and worsening dyspnea) or even acute cardiogenic shock may occur due to the weakening of the heart muscle.
Sudden Cardiac Death: Although rare, severe myocarditis can lead to sudden cardiac death, especially if significant arrhythmias develop.
Diagnostics of Myocarditis:
Diagnosing myocarditis involves a combination of clinical evaluation, imaging, and laboratory tests to assess heart function and identify the presence of inflammation:
Auscultation: May reveal abnormal heart sounds, such as brief systolic murmurs, or gallop rhythms like S3 and S4 in heart failure cases, and pericardial friction rub if pericarditis is present.
ECG: Typically shows non-specific changes which can include sinus tachycardia, ectopic beats, and repolarization abnormalities (variations in ST-segments and T-waves). Signs of AV block or bundle branch block may indicate specific etiologies like Lyme disease.
Laboratory Tests:
Cardiac Enzymes: Elevated levels of creatine kinase (CK), CK-MB, and troponin T suggest myocardial damage.
Inflammatory Markers: Increased erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and leukocytosis indicate an ongoing inflammatory process.
BNP: Elevated in cases of heart failure.
Viral Serology: Helpful to identify specific viral etiologies.
Chest X-Ray: May show signs of cardiac enlargement and features consistent with heart failure such as pulmonary congestion and pleural effusions.
Echocardiography: Can show a range of findings from unremarkable to more severe changes such as ventricular dilation, diffuse hypokinesia, reduced ejection fraction, impaired contractility, and pericardial effusion.
Endomyocardial Biopsy: This is a definitive diagnostic tool used in cases where the diagnosis is unclear, severe arrhythmias are present, or there is resistance to conventional treatment. It can show inflammation, necrosis, and, in viral myocarditis, possibly the viral genome.
Treatment of Myocarditis
Treatment strategies for myocarditis are tailored based on the severity and etiology of the condition:
Supportive Care: This includes cardiac monitoring in a hospital setting, administration of oxygen to relieve hypoxia, fluid management to balance input and output, and restriction of physical activity to reduce cardiac workload. Analgesics may be used to manage chest pain associated with myocarditis.
Antibiotics: If myocarditis is due to a bacterial infection, specific antibiotics are used to target the causative organism.
Treatment of Complications: Management strategies may include:
Heart Failure: Use of medications such as ACE inhibitors, beta-blockers, diuretics, and sometimes inotropes.
Arrhythmias: Depending on the type and severity, treatment might include antiarrhythmic drugs, pacemaker placement, or even an implantable cardioverter-defibrillator (ICD) for severe cases.
Heart Transplantation: Considered in severe cases where conventional treatments fail and the heart's function is irreversibly compromised.
Complications of Myocarditis
The course of myocarditis can lead to several serious complications:
Progression to Dilated Cardiomyopathy: Occurs in approximately 15% of cases, where chronic inflammation leads to persistent cardiac dilation and impaired contractile function.
Concurrent Pericarditis: This can lead to complications such as cardiac tamponade, a life-threatening condition where fluid accumulates in the pericardium (the sac around the heart), exerting pressure on the heart and hindering its ability to pump effectively.
Arrhythmias and Atrioventricular Block: Can range from minor irregularities to severe disturbances that affect the heart's electrical system.
Intracardiac Thrombi Formation: The risk of thrombus formation increases due to altered blood flow and heart muscle injury, leading to potential embolization and stroke or other ischemic events.
Heart Failure: Myocarditis can weaken the heart muscle, leading to heart failure with symptoms of fluid overload, such as shortness of breath and swelling.
Sudden Cardiac Death: Particularly in younger adults, severe myocarditis can cause fatal arrhythmias such as ventricular tachycardia or fibrillation.
Prognosis of Myocarditis
Viral Myocarditis: Most adults recover completely, although the prognosis varies based on the viral etiology and the initial severity of the condition. Children and infants have a higher risk of severe outcomes, with reported lethality rates of 25% in children and up to 75% in infants.
Markers for Poor Prognosis: These include poor ventricular function at presentation, presence of a left bundle branch block on ECG, low ejection fraction, persistent detection of the viral genome indicating ongoing viral activity, and chronic inflammation detected on biopsy.
PERICARDITIS
Pericarditis involves the inflammation of the pericardium, the fibrous sac that surrounds and protects the heart. It can manifest in either acute or chronic forms, affecting the heart's function differently based on the severity and duration of the inflammation.
Classification of Pericarditis:
Acute Pericarditis: This form of pericarditis involves short-term inflammation of the pericardium and can occur alone or alongside myocarditis. It is characterized by sudden and severe symptoms.
Chronic Pericarditis: Inflammation lasting longer than three months. Chronic pericarditis can be further divided into:
Constrictive Pericarditis: Where the fibrous pericardium thickens and becomes rigid, constricting the heart and impairing its ability to pump blood effectively.
Effusive Pericarditis: Involves pericardial effusion, where fluid accumulates in the pericardial cavity, in addition to fibrosis. This condition can progress to cardiac tamponade, a critical condition where fluid pressure in the pericardium adversely affects heart function.
Causes of Pericarditis:
Idiopathic: In many cases, the cause of pericarditis remains unknown.
Infectious Agents:
Viral: Commonly caused by Coxsackie B virus, among other viruses.
Bacterial: Includes pathogens such as Staphylococcus aureus, Streptococcus pneumoniae, and Mycobacterium tuberculosis.
Fungal and Parasitic: Less common, involves organisms like Toxoplasma.
Myocardial Infarction:
Acute Pericarditis: Can occur 1-3 days post-MI, known as fibrinous pericarditis.
Dressler Syndrome: A delayed form of pericarditis that develops weeks to months after a myocardial infarction.
Postopericardiotomy Syndrome: Following cardiac surgery, inflammation of the pericardium can occur, thought to be an immune-mediated response.
Uremia: In patients with renal failure, accumulated waste products can lead to pericardial inflammation.
Radiation: Exposure to therapeutic radiation for chest or heart cancers can induce pericarditis.
Neoplasm: Metastasis from other parts of the body to the pericardium.
Autoimmune Connective Tissue Disease: Conditions like systemic lupus erythematosus (SLE), rheumatoid arthritis, and scleroderma can involve the pericardium as part of systemic inflammation.
ACUTE PERICARDITIS
Acute pericarditis is an inflammation of the pericardium that often presents suddenly and can involve various types of exudates, each indicating different potential causes and implications for treatment. Here's a detailed explanation based on the classification of exudates and clinical features associated with acute pericarditis:
Classification by Exudate
Serous Pericarditis:
Cause: Typically viral infections.
Exudate Characteristics: Clear, serous fluid within the pericardial space.
Fibrinous Pericarditis:
Cause: Common in autoimmune conditions such as rheumatic fever and systemic lupus erythematosus (SLE).
Exudate Characteristics: Thick fibrin deposits, leading to a "bread-and-butter" appearance of the pericardium.
Purulent Pericarditis:
Cause: Usually secondary to bacterial infections, such as pneumonia or sepsis.
Exudate Characteristics: Pus within the pericardial space, indicating a severe infection.
Hemorrhagic Pericarditis:
Cause: Often seen post-cardiac surgery or in severe bacterial infections.
Exudate Characteristics: Presence of blood mixed with a fibrinous or purulent effusion.
Clinical Features
Pleuritic Chest Pain:
Description: Sharp, acute pain located retrosternally.
Aggravation: Pain typically worsens with coughing, swallowing, or deep inspiration.
Alleviation: Improves when sitting up and leaning forward.
Pericardial Friction Rub:
Description: A high-pitched, scratchy sound heard on auscultation.
Timing: Occurs during both atrial and ventricular systole as well as early diastole.
Best Detected: Over the left sternal border during expiration while the patient is in a sitting and forward-leaning position.
Pericardial Effusion:
Signs: Muffled heart sounds, indicating fluid accumulation in the pericardial sac.
Ewart Sign: Dullness at the base of the lungs, increased vocal fremitus, and bronchial breathing due to compression of lung tissue by a large effusion.
Flu-like Symptoms:
Common Symptoms: Include low-grade intermittent fever, tachypnea, dyspnea, and a non-productive cough.
Etiology: These symptoms are typical for a viral infection, which is a common cause of serous pericarditis.
Diagnostics of Acute Pericarditis
Diagnosing acute pericarditis involves identifying a combination of clinical, laboratory, and imaging findings. According to the guidelines, a diagnosis can be confirmed if at least two of the following four criteria are met:
Characteristic Chest Pain:
Sharp and pleuritic pain, typically worsened by lying down and alleviated by sitting up and leaning forward.
Pericardial Friction Rub:
A scratchy or squeaking sound heard best at the left sternal border with the patient leaning forward, occurring due to the rubbing of the pericardial layers.
ECG Changes:
Divided into four stages reflecting the progression of the disease:
Stage 1: Diffuse ST-elevation and PR-segment depression across multiple leads, representing acute inflammation.
Stage 2: Normalization of the ST segments, usually within a week.
Stage 3: Inversion of T-waves, which may persist as the condition evolves.
Stage 4: ECG returns to baseline, which can take weeks to months.
New or Worsening Pericardial Effusion:
Identified via imaging techniques like echocardiography, indicating fluid accumulation within the pericardial space.
Additional Diagnostic Tools:
Echocardiography: Crucial for visualizing pericardial effusion and excluding other cardiac conditions such as heart valve diseases or ventricular dysfunction.
Cardiac MRI and CT: These are more advanced imaging modalities that can be utilized to assess pericardial thickness and the presence of pericardial effusion, especially when the diagnosis is uncertain.
Laboratory Tests:
Troponin I: May be elevated, particularly when there is concurrent myocarditis.
ESR and CRP: Typically elevated, indicating inflammation.
Creatine Kinase: Can be slightly elevated.
Leukocytosis: An increase in white blood cell count, often seen in inflammatory conditions.
Chronic Pericarditis
Chronic pericarditis is defined as pericardial inflammation lasting longer than three months and can manifest in various forms:
Effusive Chronic Pericarditis:
Characterized by the continued presence of serous fluid within the pericardial cavity.
Adhesive Chronic Pericarditis:
Occurs when fibrous adhesions develop from the healing of the serous layer, potentially leading to restricted heart movement.
Fibrotic Chronic Pericarditis:
Involves extensive scarring and potential calcification, often a sequel of severe exudative pericarditis. This type is particularly common in tuberculosis-related pericarditis.
Constrictive Pericarditis:
The most severe form, where thick fibrosis and calcification of the pericardium severely restrict diastolic filling of the heart. This leads to symptoms of congestive heart failure without the typical findings of ventricular hypertrophy.
Clinical Features of Chronic Pericarditis:
Fluid Overload:
Jugular Vein Distention: Visible bulging of the jugular veins in the neck, indicating increased central venous pressure.
Kussmaul's Sign: An increase, rather than the normal decrease, in jugular venous pressure during inhalation.
Hepatic Vein Congestion: Leads to liver enlargement and dysfunction.
Peripheral Edema: Swelling of legs and ankles due to fluid accumulation.
Abdominal Discomfort: Can occur due to fluid accumulation and enlarged liver.
Reduced Cardiac Output:
Fatigue and Dyspnea on Exertion: Due to decreased heart performance.
Tachycardia: An abnormally fast heart rate as the body attempts to maintain adequate blood flow.
Pericardial Knock: A sound heard during auscultation at the left sternal border caused by sudden cessation of ventricular filling in early diastole.
Pulsus Paradoxus: A significant drop in blood pressure during inhalation by more than 10 mmHg.
Effusions:
Asymptomatic in Small or Slow-Growing Effusions: These do not generally produce symptoms unless they are large.
Large Effusions: Can lead to cardiac tamponade, which is a severe compression of the heart due to fluid in the pericardium, evident from hypotension, muffled heart sounds, and distended neck veins (Beck's triad). There might also be dullness at the lung base due to fluid displacement.
Pathophysiology Insight:
Normally, during inspiration, intrathoracic pressure decreases, allowing the right ventricle to expand. In constrictive pericarditis, the rigidity of the pericardium restricts this expansion, causing a further increase in jugular venous pressure during inhalation instead of the expected decrease.
Diagnostics of Chronic Pericarditis:
Echocardiography: Most effective non-invasive tool for diagnosing pericarditis. It can detect abnormal ventricular filling, variation in filling with inspiration, and biatrial enlargement.
CT/MRI: Useful for detailed imaging of pericardial thickening (more than 2mm), presence of calcifications, maintaining a normal cardiac silhouette, and identifying pericardial effusions.
ECG: May show generalised flat or inverted T-waves and low QRS voltage, which are nonspecific but suggestive of pericardial involvement.
Cardiac Catheterisation: Employed when non-invasive methods are inconclusive. It measures pressures within the heart chambers, differentiating between constrictive and effusive types of pericarditis based on the pressure profiles observed.
Therapy for Chronic Pericarditis
Symptomatic Treatment for Acute Episodes:
Nonsteroidal Anti-Inflammatory Drugs (NSAIDs): Used to manage pain and inflammation. This is often the first line of treatment for acute pericarditis and can help in the chronic phase for flare-ups.
Chronic Management:
Anti-inflammatory Agents: Aspirin and corticosteroids like prednisone are commonly prescribed to reduce inflammation.
Treatment of Underlying Causes: Depending on the cause of pericarditis, specific treatments may be required:
Antibiotics: For bacterial infections.
Immunosuppressants: For autoimmune-related pericarditis.
Dialysis: In cases where pericarditis is related to uremia (excess urea in the blood typically due to kidney dysfunction).
Lifestyle Adjustments:
Avoid Physical Activity: Patients are advised to limit physical exertion until their symptoms have resolved and diagnostic markers such as ECG and C-reactive protein (CRP) levels return to normal.
Invasive Procedures:
Pericardiocentesis: This procedure involves the extraction of fluid from the pericardial sac and is necessary in cases of cardiac tamponade or significant pericardial effusion to relieve pressure on the heart.
Pericardiectomy: The surgical removal of part or all of the pericardium, recommended for patients with persistent symptoms of heart failure (class III-IV), particularly when other treatments have failed.
Complications of Chronic Pericarditis
Progression from Acute to Chronic: Acute pericarditis can evolve into a chronic condition if not adequately treated or due to underlying health issues.
Cardiac Tamponade: A critical condition where fluid accumulation exerts excessive pressure on the heart, impeding its ability to pump effectively.
Overview of Infective Endocarditis
Infective endocarditis is a serious condition involving inflammation of the heart valves due to infection. It's crucial to understand its causes, especially in patients with chronic pericarditis, as they may be at increased risk for cardiac complications.
Common Pathogens:
Staphylococcus aureus: Most prevalent in acute cases; can infect healthy valves and is life-threatening if untreated.
Streptococcus viridans: Often linked with subacute cases, typically following dental procedures.
Staphylococcus epidermidis: Associated with infections in prosthetic valves or in patients with intravascular devices.
Enterococcus species: These infections are often hospital-acquired and resistant to many antibiotics.
Gram-negative bacteria: Include organisms like Haemophilus, often connected with poor dental hygiene.
Fungal pathogens (Candida, Aspergillus): Seen in immunocompromised individuals or those with intravenous drug use.
Infective endocarditis (IE) is a complex disease where bacteria enter the bloodstream, colonize the heart valves (particularly those that are already damaged), and lead to the formation of vegetations. These vegetations are masses of platelets, fibrin, microorganisms, and inflammatory cells. The disease has distinct clinical manifestations depending on how rapidly it progresses and the type of valve involved:
Clinical Course and Manifestations of Infective Endocarditis:
Acute Infective Endocarditis:
Onset and Progression: Rapid development, with severe symptoms manifesting within days to weeks.
Symptoms: High fever is common.
Common Causes: Staphylococcus aureus, typically affecting native valves that were previously healthy.
Complications:
Valve Insufficiency: The valve fails to close properly, causing blood to flow backward.
Septic Embolic Infarcts: Pieces of the vegetation break off and travel to other parts of the body, blocking blood vessels and causing tissue death.
Tendinous Cord Rupture: The chords that hold the valve leaflets in place can snap due to the strain from the infected vegetations.
Subacute Infective Endocarditis:
Onset and Progression: Gradual onset, with symptoms developing over weeks to months.
Symptoms: Low-grade fever or no fever at all.
Common Causes: Viridans streptococci, usually affecting valves that are already damaged.
Complications: Can lead to chronic valve insufficiency (where the valve does not close tightly) or stenosis (narrowing of the valve).
Prosthetic Valve Endocarditis:
Pathogens: Commonly caused by Staphylococcus aureus or Staphylococcus epidermidis.
Challenges: Diagnosis and treatment can be more difficult than with native valve endocarditis due to the involvement of artificial materials.
Cardiac Manifestations:
New or Changing Heart Murmurs: An audible sign of turbulent blood flow across a damaged valve. This is often the first clue in diagnosis.
Valve Regurgitations:
Mitral Regurgitation: Presents as a holosystolic murmur, heard throughout the entirety of systole (heart contraction).
Tricuspid Regurgitation: Also holosystolic, typically louder at the left sternal border and commonly seen in intravenous drug users and immunocompromised patients.
Aortic Valve Regurgitation: Characterized by an early diastolic murmur, also loudest at the left sternal border.
Signs of Heart Failure and Cardiac Decompensation: As the disease progresses, symptoms of heart failure such as dyspnea, fatigue, and edema may develop.
Arrhythmias: Often a result of a perivalvular abscess which can affect the electrical conduction pathways of the heart.
Extra-cardiac Manifestations of Infective Endocarditis:
Petechiae: Small, pinpoint hemorrhages typically seen on the skin, often a result of septic microemboli.
Janeway Lesions: Non-tender, flat, red spots found on the palms and soles, caused by microabscesses in the capillaries due to septic emboli.
Osler Nodes: Painful, raised lesions found on the fingers and toes, thought to be due to immune complexes depositing in the tissues.
Roth Spots: Round or oval retinal hemorrhages with pale centers, which can be observed during eye examination.
Systemic Effects:
Acute Renal Injury: Can occur due to embolic events or immune complex deposition affecting the kidneys.
Splenomegaly: Enlargement of the spleen, which may occur due to arterial occlusion or abscess formation.
Neurological Manifestations: Including stroke or meningitis, can result from emboli dislodging from the heart and traveling to the brain.
Pulmonary Embolism: Although less common, vegetations can embolize to the lungs.
Arthritis: Particularly in subacute cases, joint pain and swelling can occur, typically due to immune complex deposition.
Diagnostics for Infective Endocarditis:
Blood Culture: Critical for identifying the causative organism. Positive results guide antibiotic therapy.
Signs of Inflammation: Elevated markers like C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR).
Echocardiography: The most important imaging test for IE, capable of visualizing vegetations on the valves, any valve regurgitation, and the presence of cardiac abscesses.
Treatment of Infective Endocarditis:
Antibiotic Therapy:
Vancomycin: Used empirically for suspected Staphylococcus aureus infections, especially in cases of acute IE or when MRSA is suspected.
Penicillin: Effective against Streptococcus viridans and other penicillin-sensitive organisms.
Duration of Treatment:
Native Valve Infections: Typically require at least 4 weeks of antibiotic therapy.
Prosthetic Valve Infections: Often require a longer duration, generally 6 weeks, due to the challenges in eradicating bacteria from foreign materials.
Prophylaxis:
Oral Amoxicillin: Recommended before certain dental or surgical procedures for patients at high risk of IE, to prevent the introduction of bacteria into the bloodstream.
Non-Infective Endocarditis
Non-infective endocarditis, also known as sterile or nonbacterial thrombotic endocarditis (NBTE), involves the formation of sterile vegetations on heart valves. Unlike infective endocarditis, these vegetations are not due to an infectious pathogen but rather to the aggregation of platelets and fibrin. This condition can occur on any of the heart valves, though it most commonly affects the mitral and aortic valves.
Aetiology of Non-Infective Endocarditis
Trauma: Damage to the heart or valves can lead to clot formation.
Malignancy: Certain cancers can create a hypercoagulable state, increasing the risk of clot formation.
Hypercoagulable States: Conditions such as thrombophilia where the blood has a propensity to clot excessively.
Previous Rheumatic Fever: Can cause scarring and deformity of the valves, making them more susceptible to thrombus formation.
Chronic Infections or Autoimmune Diseases: Such as systemic lupus erythematosus (SLE), where inflammation can lead to clot formation on the valves.
Specific Forms of Non-Infective Endocarditis
Libman-Sacks Endocarditis: A form of non-infective endocarditis seen in patients with systemic lupus erythematosus (SLE). It is characterized by small, sterile, verrucous (or warty) vegetations that typically appear on both sides of the valve.
Clinical Features
Valve Function: In non-infective endocarditis, heart valve function is rarely impaired initially, unlike in bacterial forms where damage and deterioration can occur rapidly.
Embolization Risk: Although the valves function relatively normally, the risk of embolization (where parts of the vegetation break off and travel through the bloodstream to block distant blood vessels) is higher than in infectious endocarditis. This can lead to serious complications, such as stroke or pulmonary embolism.
Diagnostics
Blood Cultures: Typically negative, helping to differentiate it from bacterial endocarditis.
Echocardiography: Can reveal vegetations on the valves. These vegetations are usually smaller and less destructive than those seen in infective endocarditis but are crucial for diagnosis.
Treatment
Anticoagulation: The primary treatment involves anticoagulation to prevent further thrombus formation and to reduce the risk of embolization. Heparin is commonly used initially, possibly followed by longer-term anticoagulation depending on the patient's risk factors and underlying conditions.
Managing Underlying Conditions: Treatment also focuses on addressing any underlying disorders contributing to the hypercoagulable state, such as managing autoimmune conditions with immunosuppressants or treating cancer.