Anatomical Context: Understanding heart disorders requires a review of the heart layers (found on page 363 of the clinical text). The nomenclature of these conditions is derived directly from the specific layer of the heart that is affected.
Infective Endocarditis (IE):
* Definition: An infection or inflammation of the internal lining of the heart (the endocardium) and the heart valves. Since the endocardium is the innermost layer, this inflammation affects every surface that comes into direct contact with blood.
* Etiology and Risk Factors:
* Secondary infection: Often originates from an infection elsewhere in the body.
* Rheumatic Fever: A common precursor following specific bacterial infections.
* Streptococcal Infections: Primarily "Strep throat" or other systemic strep infections.
* Intravenous (IV) Drug Use: A significant risk factor for introducing pathogens directly into the bloodstream.
* Invasive Procedures: Can occur after dental work (e.g., root canals) or other invasive surgeries. Anything introduced into the oral cavity has a direct pathway to the heart.
* Prophylaxis: Antibiotics are often administered prophylactically (preventatively) a few days before dental or invasive procedures for at-risk patients.
Clinical Manifestations and Treatment of Endocarditis
General Signs of Infection:
* Fever.
* Localized and systemic inflammation.
* Laboratory Findings: Elevated White Blood Cell (WBC) count.
Physical Assessment Findings:
* Splinter Hemorrhages: Small, longitudinal brown streaks in the nail beds that look like a pin was used to draw a line. While these are a classic sign of endocarditis, they can also be caused by minor trauma to the nail.
* Petechiae: Small, pinpoint purple or pink "polka dot" hemorrhages on the skin caused by minor bleeds.
* Heart Murmurs: Caused by the inflammation preventing valves from opening and closing properly, leading to the backflow (regurgitation) of blood.
* Muscle Aches: Systemic discomfort associated with the inflammatory process.
Medical Management:
* Antibiotics: Primarily treated with a course of antibiotics to target the bacterial cause.
* Surgical Intervention: In cases of severe damage to the inner lining or valves, heart valve replacements may be necessary.
Complications: Vegetations and Emboli:
* Inflammation leads to the formation of "vegetations" (clumps of bacteria, platelets, and fibrin) on the heart valves.
* Embolization: These vegetations can break loose and become emboli, traveling through the bloodstream to other organs.
* Patient Sensation (The Aura): Patients may experience a sense of impending doom or extreme anxiety right before a clot embolizes (specifically seen in Pulmonary Embolism). This is often described as an "aura."
Pericarditis and Pericardial Effusion
Definition: Inflammation of the pericardium, which is the fluid-filled sac surrounding the heart that allows it to move and contract without friction.
Pericardial Effusion:
* The "Two Fs" Rule: Effusion stands for "lots of Fluid."
* It is the accumulation of excess fluid within the pericardial sac, often accompanying pericarditis.
Etiology:
* Infections elsewhere in the body.
* Post-Myocardial Infarction (MI): Pericarditis can occur as a complication following a heart attack.
Symptoms:
* Angina: Chest pain described as sharp or grating.
* Positional Relief: Pain is often relieved when the patient sits up and leans forward, as this changes how the heart hangs within the sac.
* Pericardial Friction Rub: A distinct sound heard during auscultation that sounds like leather rubbing together. It occurs because the inflamed layers of the sac are touching the heart.
Complication: Cardiac Tamponade:
* Occurs when there is so much fluid in the pericardial sac that it restricts the heart's movement.
* The heart becomes unable to contract properly.
* Signs: Muffled heart sounds; the heart sounds like it is "underwater."
* Hemodynamic Impact: Arrhythmias (dysrhythmias), pulse discrepancies, and decreased oxygen saturation (O2) due to poor cardiac output.
Treatment:
* Treating the underlying infection (Antibiotics).
* Bed Rest: To minimize cardiac workload.
* Pericardiocentesis: A procedure using a large-bore needle to aspirate (pull back) fluid from the pericardial sac. Often performed using ultrasound guidance and heart/pressure monitors.
* Medications: Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) like Ibuprofen and Steroids are used to reduce inflammation.
* Diagnostics: Primarily diagnosed via Echocardiogram (Echo).
Myocarditis and Cardiac Trauma
Definition: Inflammation of the myocardium, the middle muscular layer of the heart.
Anatomy: The myocardium is thickest around the left ventricle to facilitate pumping blood to the entire body.
Etiology: Though rare, it typically follows a viral infection. Notably, it was seen as a complication of COVID−19 and occasionally associated with vaccinations.
Symptoms: Initially vague (fever, fatigue) but can rapidly become severe.
* Respiratory: Dyspnea (shortness of breath).
* Cardiac: Palpitations and, in extreme cases, sudden death.
Management: Supportive care, bed rest, oxygen, and antivirals (if viral) or antibiotics (if bacterial).
Related Conditions: Cardiac trauma, Cardiomyopathy, and Cardiomegaly (enlarged heart).
Venous Disorders and Thromboembolism
Venous Thromboembolism (VTE): Includes Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE).
Thrombophlebitis: Inflammation of a vein caused by a clot (thrombus).
Risk Factors:
* Immobility (bed-bound patients).
* Post-Surgical status (prolonged time on the operating table).
* Dehydration.
* Prolonged sitting (e.g., students in class for 6 hours).
* Obesity.
Assessment of DVT:
* Symptoms: Aching pain, edema (swelling), redness (sometimes streaking), and warmth.
* Pulse Note: Pulses are typically normal because a DVT is in a vein, not an artery; however, pulses may be hard to palpate if edema is severe.
* Homan's Sign: The patient is positioned supine; the nurse places a hand under the knee and instructs the patient to push "toes to the nose" (dorsiflexion). Pain during this maneuver suggests a DVT.
* Controversy: Many facilities discourage Homan's sign because the mechanical force of stretching the muscle against the vein could potentially dislodge the clot, causing it to embolize.
* Leg Circumference: Measuring the legs to check for asymmetrical swelling (e.g., one leg being an inch larger than the other).
Prevention:
* Leg exercises and pumps.
* Early ambulation.
* Anti-embolism stockings (TED hose) and Sequential Compression Devices (SCDs).
* Vena Cava Filters: A physical filter placed in the vena cava to catch and break up clots before they reach the heart and lungs.
Pharmacological Management: Anticoagulants and Antiplatelets
Mechanism of Action:
* Anticoagulants: Interrupt the "clotting cascade" (the multi-step process involving fibrinogen and fibrin). They stop the process of clot formation.
* Antiplatelets: (e.g., Aspirin). These make platelets "less sticky" so they do not clump together. They do not affect the clotting cascade directly.
Specific Medications and Lab Monitoring:
* Warfarin (Coumadin):
* Monitored via PT/INR (Prothrombin Time / International Normalized Ratio).
* Providers focus primarily on the INR value.
* High risk of bleeding compared to newer drugs.
* Heparin:
* Monitored via PTT (Partial Thromboplastin Time).
* Mnemonic: A capital "H" can be formed by the two "T"s in PTT (H=PTT).
* Action: Heparin does NOT break up an existing clot; it only prevents the clot from getting larger while the body naturally dissolves it.
* Enoxaparin (Lovenox): A Low Molecular Weight Heparin (LMWH). Safer than standard Heparin, often given as a subcutaneous injection in the abdomen. Used prophylactically in hospitals.
* Apixaban (Eliquis): A newer anticoagulant that does not require the same intensive lab monitoring of clotting times as Warfarin.
Additional Labs:
* D-dimer: A specific lab test used to identify the presence of a blood clot, often drawn when a Pulmonary Embolism is suspected.
Patient Education: Patients on these medications should carry a medical alert card or wear a bracelet to inform emergency personnel of their bleeding risk.