Ch 14 Heart

Key Words

• Angina Pectoris: Chest pain due to reduced blood flow to the heart.

• Angioplasty: Procedure to open narrowed or blocked blood vessels.

• Aorta: The largest artery in the body which carries oxygenated blood from the left ventricle.

• Arrhythmia: Irregular heartbeat or abnormal heart rhythm.

• Atrial Fibrillation: A disorganized electrical rhythm leading to uncoordinated atrial contractions.

• Cardiac Arrest: Sudden loss of heart function.

• Cardiopulmonary Resuscitation (CPR): Emergency procedure to restore normal heart rhythm.

• Coronary Artery Disease (CAD): Narrowing of coronary arteries due to plaque buildup.

• Myocardial Infarction (Heart Attack): Damage to heart muscle due to insufficient blood flow.

• Heart Failure: Condition where the heart is unable to pump blood effectively.

Functions of the Circulatory System

• Circulatory Efficiency: Over 60,000 miles of blood vessels in an adult body.

• Key Functions:

  1. Circulate oxygenated blood throughout the body.

  2. Transport deoxygenated blood back to the heart and lungs for oxygenation.

  3. Deliver hormones and nutrients to cells, while removing waste products.

  4. Lymphatic system functions alongside, returning excess fluid to circulation.

Structure of the Heart

• General Characteristics:

  • Size of a closed fist, approximately 5 inches long and 3.5 inches wide.

  • Weighs about 12 to 13 ounces.

  • Located between the lungs in the thoracic cavity, apex points left.

• Cardiac Anatomy:

  • Pericardium: Double-layered membrane surrounding the heart, with:

    • Visceral (serous) Pericardium: Inner layer covering the heart.

    • Parietal (fibrous) Pericardium: Outer tough layer; contains pericardial fluid.

  • Myocardium: Thick muscular layer responsible for heart contractions.

  • Endocardium: Smooth inner lining of the heart and valves.

Chambers and Valves

• The heart has four chambers:

  • Atria: Right and Left.

  • Ventricles: Right and Left.

• Valves:

  • Atrioventricular (AV) Valves:

    • Tricuspid Valve: Between right atrium and right ventricle.

    • Bicuspid (Mitral) Valve: Between left atrium and left ventricle.

  • Semilunar Valves:

    • Pulmonary Semilunar Valve: At opening of pulmonary arteries from the right ventricle.

    • Aortic Semilunar Valve: At opening of aorta from the left ventricle.

Circulation and Physiology of the Heart

• Double Pump Mechanism:

  • Right Heart: Deoxygenated blood received from the body through the superior/inferior vena cava to the right atrium, pumped through tricuspid valve into right ventricle, sent to lungs via pulmonary arteries.

  • Left Heart: Oxygenated blood flows from lungs through pulmonary veins into left atrium, pumped through bicuspid valve into left ventricle, distributed to body via aorta.

• Heart Rate:

  • Normal resting heart rate: 72-80 beats per minute, with a stroke volume of 60-80 mL.

  • Cardiac output: Stroke volume x heart rate (average 4800 mL/min).

Conduction System of the Heart

• Electrical Activity:

  • Sinoatrial (SA) Node: Pacemaker of the heart; initiates electrical impulses causing atrial contraction.

  • Atrioventricular (AV) Node: Transmits impulses to the ventricles.

  • Bundle of His & Purkinje Fibers: Conduct impulses throughout the ventricles leading to contraction.

Heart Sounds and Diagnostics

• Normal Heart Sounds:

  • "Lubb" sound: Closure of AV valves.

  • "Dupp" sound: Closure of semilunar valves.

• Electrocardiogram (ECG): Records electrical activity and can identify abnormalities.

Heart Disease and Conditions

• Heart diseases can be congenital or acquired.

• Symptoms: Chest pain, arrhythmia, fatigue, shortness of breath.

• Diagnosis and Treatment Options:

  • Lifestyle changes, medications, surgical procedures (e.g., angioplasty, valve replacements).

  • Regular screenings for early identification of cardiovascular issues.

Prevention and Management of Heart Disease

• Key Preventative Measures:

  1. Maintain healthy cholesterol levels.

  2. Control blood pressure and diabetes.

  3. Avoid tobacco and limit alcohol intake.

  4. Regular exercise and balanced diet.

• Awareness of Symptoms: Recognizing signs like angina or arrhythmia for early intervention.

Important Procedures

• Cardiac Surgical Procedures:

  • Angioplasty & Stenting: Unblocking arteries to restore blood flow.

  • Coronary Bypass: Redirect blood around blocked arteries.

  • Heart Transplant: Replacement of damaged heart.

Cardiopulmonary Resuscitation (CPR)

• should be performed when an individual shows signs of cardiac arrest

  • includes unresponsiveness

  • absence of breathing or normal breathing (like gasping)

• CPR helps maintain blood flow to the brain & other vital organs until professional medical help arrives

• Significantly increases the chances of survival.

• A vital emergency procedure that can restore normal heart rhythm if done quickly and effectively.

Pathway of Blood Through the Heart

1. Deoxygenated Blood Flow

   • Superior/Inferior Vena Cava: Deoxygenated blood from the body enters the right atrium.

2. Right Atrium

   • Blood flows from the right atrium through the tricuspid valve into the right ventricle.

3. Right Ventricle

   • Blood is pumped from the right ventricle through the pulmonary semilunar valve into the pulmonary arteries.

4. Lungs

   • In the lungs, blood receives oxygen and releases carbon dioxide.

5. Oxygenated Blood Flow

   • Pulmonary Veins: Oxygenated blood returns from the lungs to the left atrium.

6. Left Atrium

   • Blood flows from the left atrium through the bicuspid (mitral) valve into the left ventricle.

7. Left Ventricle

   • Blood is pumped from the left ventricle through the aortic semilunar valve into the aorta.

8. Aorta

   • Oxygenated blood is distributed throughout the body.

Oxygenated Blood vs Deoxygenated Blood

• Oxygenated Blood

  • Carries oxygen from the lungs to the body.

  • Appears bright red due to the high oxygen content.

  • Enters the heart through the pulmonary veins into the left atrium, then flows into the left ventricle before being pumped into the aorta and distributed throughout the body.

• Deoxygenated Blood

  • Carries carbon dioxide from the body back to the lungs for exhalation.

  • Appears dark red due to the lower oxygen content.

  • Enters the heart through the superior and inferior vena cava into the right atrium, then flows into the right ventricle before being pumped to the lungs via the pulmonary arteries for oxygenation.

Blood Supply to the Heart

1. Coronary Arteries: The heart receives its oxygenated blood supply mainly from the coronary arteries. These arteries branch off from the aorta just above the aortic semilunar valve.

   • Right Coronary Artery: Supplies blood to the right atrium, right ventricle, and the inferior part of the left ventricle.

   • Left Coronary Artery: Further divides into two main branches:

     • Left Anterior Descending (LAD) Artery: Supplies blood to the anterior portion of the septum and left ventricle.

     • Circumflex Artery: Supplies blood to the lateral aspect of the left ventricle and atrium.

2. Cardiac Veins: Deoxygenated blood from the heart muscle is drained by cardiac veins. They typically converge into the coronary sinus, which empties into the right atrium.

3. Coronary Bypass: This surgical procedure can be done if coronary arteries are significantly blocked, redirecting blood flow to ensure cardiac tissues receive adequate oxygen and nutrients.

Conduction System of the Heart

1. Electrical Activity: The heart's conduction system is essential for maintaining a rhythmic heartbeat.

   • Sinoatrial (SA) Node: Known as the pacemaker of the heart, it initiates electrical impulses that cause atrial contraction.

   • Atrioventricular (AV) Node: It transmits impulses from the atria to the ventricles, ensuring that the ventricles contract after the atria have emptied.

   • Bundle of His & Purkinje Fibers: These structures conduct impulses throughout the ventricles, leading to contractions that pump blood out of the heart.

P wave

• Component of an electrocardiogram (ECG or EKG)

• Represents the electrical activity associated with the depolarization of the atria, which leads to atrial contraction.

• It is the first waveform seen in the electrical cycle of the heart, indicating the start of the heart's cycle as the atria prepare to pump blood into the ventricles.

Electrocardiogram (ECG or EKG)

• Test records the electrical activity of the heart over a period of time

  • Provides information about the heart's rhythm

  • The size and position of the heart chambers, and any electrical conduction issues.

Importance of an ECG:

1. Diagnosis of Heart Conditions: It helps identify various cardiac conditions such as arrhythmias, heart attacks, and other heart diseases.

2. Monitoring Heart Health: ECGs can be used to monitor heart health in patients with existing heart conditions and assess the effectiveness of treatments.

3. Preoperative Assessments: An ECG is often performed before surgeries to evaluate the heart's condition and ensure it can handle the stress of surgery.

4. Identifying Structural Changes: It can detect changes in the electrical conduction system due to conditions like myocardial infarction (heart attacks) or cardiomyopathy.

QRS complex

• A component of an electrocardiogram (ECG or EKG) that represents the electrical activity associated with the depolarization of the ventricles, which leads to ventricular contraction.

• It is a critical part of the heart's electrical cycle, appearing after the P wave and is typically characterized by three distinct waves: the Q wave (downward deflection), the R wave (upward deflection), and the S wave (downward deflection following the R wave).

• The QRS complex allows for the assessment of ventricular size and function.

T wave

• A component of an electrocardiogram (ECG or EKG) that represents the electrical activity associated with the repolarization of the ventricles, which occurs after ventricular contraction.

• It indicates the recovery phase of the ventricles as they prepare for the next heartbeat.

Heart disease

• Refers to various types of conditions that affect the heart's structure and function.

• It can be congenital (present at birth) or acquired over time.

• Common forms of heart disease include coronary artery disease (CAD), heart failure, arrhythmias, and heart defects.

• Symptoms may include chest pain, shortness of breath, fatigue, and irregular heartbeats.

Risk factors for heart disease include:

1. High Blood Pressure: Can damage arteries and lead to heart disease.

2. High Cholesterol Levels: Elevated low-density lipoprotein (LDL) cholesterol can lead to plaque buildup in arteries.

3. Smoking: Tobacco use significantly increases the risk of heart disease.

4. Obesity: Excess weight can lead to high blood pressure, high cholesterol, and diabetes, all of which increase heart disease risk.

5. Physical Inactivity: Lack of exercise contributes to weight gain and increases heart disease risk.

6. Diabetes: High blood sugar levels can damage blood vessels and the nerves that control the heart.

7. Unhealthy Diet: A diet high in saturated fats, trans fats, sodium, and sugar can increase heart disease risk.

8. Age: Risk increases with age; men over 45 and women over 55 are at higher risk.

9. Family History: A family history of heart disease can increase your risk.

10. Stress: Chronic stress may contribute to heart disease, often leading to poor habits like unhealthy eating and smoking.

LDL

• Stands for Low-Density Lipoprotein.

• Often referred to as "bad" cholesterol because high levels of LDL cholesterol in the blood can lead to the buildup of plaque in the arteries, which increases the risk of cardiovascular diseases like heart attack and stroke.

• Managing LDL levels is crucial for maintaining heart health.

VLDL

• Stands for Very Low-Density Lipoprotein.

• It is a type of lipoprotein that carries triglycerides, a form of fat, in the bloodstream.

• VLDL is often considered "bad" cholesterol because high levels of it can contribute to the buildup of plaque in the arteries, increasing the risk of cardiovascular diseases.

• VLDL is produced by the liver and helps transport triglycerides to various tissues in the body.

HDL

• Stands for High-Density Lipoprotein.

• Often referred to as "good" cholesterol because it helps remove other forms of cholesterol from the bloodstream

• Higher levels of HDL cholesterol are associated with a lower risk of heart disease, as it transports cholesterol to the liver for elimination from the body, preventing the buildup of plaque in the arteries

Atherosclerosis

• Condition characterized by the buildup of plaque within the arterial walls, which can lead to narrowing and hardening of the arteries.

• This condition is a major contributor to coronary artery disease (CAD) and increases the risk of heart attack and stroke.

• Risk factors include high cholesterol levels, high blood pressure, smoking, diabetes, obesity, and a sedentary lifestyle.

• Prevention includes maintaining a healthy diet, regular exercise, and monitoring cardiovascular health.

Prevention and Management of Heart Disease

Key Preventative Measures:

• Maintain healthy cholesterol levels.

• Control blood pressure and diabetes.

• Avoid tobacco and limit alcohol intake.

• Engage in regular exercise and maintain a balanced diet.

• Be aware of symptoms and recognize signs like angina or arrhythmia for early intervention.

Angiography

• A medical imaging technique used to visualize the interior of blood vessels and organs of the body, particularly the heart and blood vessels, through the use of a contrast agent that is injected into the vascular system.

• The procedure allows for the diagnosis of various conditions such as coronary artery disease (CAD) by identifying blockages or aneurysms.

• It is often performed in conjunction with other procedures like angioplasty to treat narrowed or blocked arteries.

Echocardiography

• A diagnostic imaging technique that uses ultrasound waves to create images of the heart.

• It allows healthcare providers to assess the heart's size, shape, and function, as well as to visualize the heart valves and blood flow.

• Key uses include diagnosing heart diseases, evaluating heart function, and monitoring the effectiveness of treatments. It is a non-invasive procedure and does not involve the use of radiation, making it a safe option for patients.

Stress

• Can significantly affect heart health.

• Chronic stress may contribute to heart disease by prompting poor habits such as unhealthy eating, smoking, and physical inactivity.

• It can also lead to elevated blood pressure and heart rate, increasing the risk of heart-related issues.

• Managing stress through techniques like exercise, relaxation, and mindfulness can help mitigate these risks.

Cardiac catheterization

• A medical procedure used to diagnose and treat certain cardiovascular conditions It involves inserting a long, thin tube (catheter) into a blood vessel and guiding it to the heart.

• This procedure allows healthcare providers to measure the pressures within the heart chambers, visualize the heart's arteries using contrast dye (often performed as part of an angiography), and assess the overall function of the heart.

• Cardiac catheterization can also be used for therapeutic purposes, such as angioplasty, to open blocked arteries and improve blood flow.

Trans-esophageal echocardiography (TEE)

• A specialized type of echocardiography that involves the insertion of a flexible ultrasound probe into the esophagus to obtain detailed images of the heart

• This method provides clearer images of the heart's structure and function, as the esophagus is close to the heart and allows for better visualization than traditional transthoracic echocardiography.

• TEE is particularly useful for diagnosing conditions such as heart valve disorders, atrial septal defects, and to visualize blood clots that may not be clearly seen with other echocardiography techniques

BNP

• Stands for B-type Natriuretic Peptide

• A hormone produced by the heart's ventricles in response to excessive stretching of heart muscle cells

• BNP levels are often measured to help diagnose and assess the severity of heart failure

• Elevated levels of BNP can indicate heart failure and provide insight into the heart's ability to pump blood effectively

Cardiac Troponin T (cTnT)

• A protein released into the bloodstream when the heart muscle is damaged, often associated with heart attacks or other forms of heart injury

• Used as a biomarker in diagnosing acute coronary syndromes and assessing heart damage

• Elevated levels of Cardiac Troponin T in the blood can indicate myocardial infarction (heart attack) and help evaluate the severity of heart conditions.

Arrhythmia

• An irregular heartbeat or abnormal heart rhythm

• Can occur when the electrical impulses that coordinate the heart's beats do not function properly, leading to either a slow or fast heartbeat

• Some arrhythmias may be harmless

• While others can pose serious health risks, including increased risk of stroke or cardiac arrest

Symptoms of arrhythmia can vary depending on the type and severity, but common signs may include:

• Palpitations: A feeling of rapid, fluttering, or pounding heartbeat.

• Dizziness or lightheadedness: Often accompanied by fainting or near-fainting spells.

• Shortness of breath: Difficulty in breathing, which may occur during physical activity or while resting.

• Chest pain or discomfort: May feel like pressure, tightness, or pain in the chest.

• Fatigue: Unusual tiredness or lack of energy even without exertion.

If someone experiences these symptoms, it is crucial to seek medical attention, as they may indicate a serious underlying condition.

Bradycardia

• A slower than normal heart rate

• Typically fewer than 60 beats per minute

• Can be a sign of an underlying health problem or due to the heart's natural response to certain situations such as sleep or relaxation

Symptoms of Bradycardia may include:

• Fatigue: Unusual tiredness or lack of energy.

• Dizziness or lightheadedness: Especially upon standing or exertion.

• Fainting or near-fainting: A sudden loss of consciousness due to insufficient blood flow to the brain.

• Shortness of breath: Difficulty in breathing, particularly during physical activity.

• Chest pain or discomfort: May feel like pressure or tightness in the chest.

*If bradycardia leads to severe symptoms or is caused by serious health issues, medical evaluation and intervention may be necessary*

Tachycardia

• An abnormally fast heart rate

• Typically exceeding 100 beats per minute in adults

• Can occur as a physiological response to exercise or stress, but it can also indicate health issues

Symptoms of Tachycardia may include:

• Palpitations: A sensation of a rapid or pounding heartbeat.

• Dizziness or lightheadedness: Feeling faint or weak.

• Shortness of breath: Difficulty breathing, especially during rest or minimal exertion.

• Chest pain or discomfort: Can feel like pressure or tightness in the chest.

• Fatigue: An unusual lack of energy or exhaustion.

If tachycardia is accompanied by severe symptoms, it is important to seek medical attention, as it can lead to more serious complications.

Heart Murmur:

• An unusual sound heard during a heartbeat

• Often described as a whooshing or swishing noise

• Murmurs are caused by turbulent blood flow in the heart or blood vessels

• Occur due to various reasons such as heart valve problems, congenital heart defects, or increased blood flow due to conditions like fever or anemia

Symptoms of a Heart Murmur may include:

• Typically, heart murmurs are asymptomatic and may not cause noticeable symptoms.

• In some cases, if a murmur is associated with an underlying heart condition, symptoms could include:

  • Shortness of breath, especially during exertion.

  • Fatigue or weakness.

  • Chest pain or discomfort.

  • Swelling in the ankles, feet, or abdomen.

  • Dizziness or fainting.

If there are any concerns regarding a heart murmur, it is essential to seek medical evaluation to determine the underlying cause and whether treatment is necessary.

Mitral valve prolapse (MVP)

• Condition in which the mitral valve, located between the left atrium and left ventricle of the heart

  • It does not close properly during heartbeats

  • Instead of lying flat, the valve flaps bulge (prolapse) backward into the left atrium

  • This can lead to abnormal blood flow and a variety of symptoms

Symptoms of Mitral Valve Prolapse may include:

• Palpitations: Noticeable heartbeats that may feel fast or irregular.

• Chest pain: Discomfort or pain in the chest that is not caused by coronary artery disease.

• Shortness of breath: Difficulty in breathing that may occur during exertion or when lying down.

• Fatigue: Unusual tiredness or lack of energy.

• Dizziness or lightheadedness: Feelings of dizziness, especially upon standing or during physical activity.

In many cases, mitral valve prolapse may be asymptomatic and does not require treatment. However, if symptoms are present, they should be evaluated by a healthcare professional.

Coronary Artery Disease (CAD): A condition characterized by the narrowing of coronary arteries due to plaque buildup, which can restrict blood flow to the heart muscle.

Symptoms of CAD:

• Chest pain or discomfort (angina), which may feel like pressure or tightness.

• Shortness of breath, especially during exertion.

• Fatigue or unusual tiredness.

• Heart palpitations or irregular heartbeats.

• Symptoms may sometimes be absent, especially in the early stages.

Angina Pectoris: Chest pain due to reduced blood flow to the heart.

Symptoms of Angina Pectoris:

• Chest pain or discomfort that may feel like pressure, squeezing, fullness, or pain.

• Pain may also radiate to the shoulders, neck, arms, back, teeth, or jaw.

• Episodes often triggered by physical exertion, stress, or heavy meals.

• Symptoms typically last a few minutes and subside with rest or medication.

Myocardial Infarction (Heart Attack): Damage to heart muscle due to insufficient blood flow.

Symptoms of Myocardial Infarction:

• Chest pain or discomfort, often described as pressure, squeezing, or fullness.

• Pain may radiate to the arms, back, neck, jaw, or stomach.

• Shortness of breath, which may occur with or without chest discomfort.

• Cold sweat, nausea, or lightheadedness.

• Women may experience atypical symptoms, such as fatigue or indigestion.

Cardiotonic Drugs: These are medications used to improve the contractility of the heart muscle, enhancing its ability to pump blood. They are primarily used in the treatment of conditions such as heart failure and atrial fibrillation.

Common Types of Cardiotonic Drugs:

• Digoxin: Increases the force of heart contractions and slows heart rate.

• Dobutamine: Increases cardiac output by enhancing myocardial contractility, often used in acute heart failure.

• Dopamine: In low doses, it dilates blood vessels; in higher doses, it increases heart rate and contractility.

Mechanism of Action: Cardiotonic drugs work by increasing intracellular calcium concentrations, leading to stronger cardiac contractions. This helps in improving the heart's efficiency in pumping blood.

Indications:

• Heart failure (to enhance cardiac output)

• Atrial fibrillation (to control heart rate)

• Severe hypotension

Side Effects: Potential side effects can include nausea, vomiting, dizziness, and increased risk of arrhythmias. Monitoring is essential when using these medications.

Diuretics: Medications that promote the excretion of water and electrolytes through urine. They are commonly used to treat conditions such as hypertension (high blood pressure), heart failure, and edema (swelling due to fluid accumulation).

Types of Diuretics:

• Thiazide Diuretics: Often used to treat high blood pressure and mild fluid retention. Examples include hydrochlorothiazide and chlorthalidone.

• Loop Diuretics: More potent and often used for more severe fluid retention, such as in heart failure. Examples include furosemide (Lasix) and bumetanide.

• Potassium-Sparing Diuretics: Help retain potassium while promoting water excretion, used to prevent hypokalemia (low potassium levels). Examples include spironolactone and amiloride.

Mechanism of Action: Diuretics work by affecting different parts of the kidneys (nephrons) to inhibit the reabsorption of sodium and chloride. This leads to increased urine production and the removal of excess fluid from the body.

Indications:

• Management of hypertension.

• Treatment of heart failure to decrease preload.

• Relief of edema due to liver cirrhosis or kidney disorders.

Side Effects: Possible side effects can include dehydration, electrolyte imbalances (such as low potassium or sodium levels), dizziness, and increased urination.

**Pericarditis**: Inflammation of the pericardium, the double-layered membrane surrounding the heart.

**Myocarditis**: Inflammation of the heart muscle (myocardium) that can affect the heart's ability to pump blood and cause irregular heartbeats.

**Endocarditis**: Inflammation of the inner lining of the heart chambers and heart valves (endocardium), often caused by an infection. It can lead to serious complications, such as heart valve damage or heart failure.

Rheumatic Heart Disease: A condition resulting from rheumatic fever, which is caused by untreated or poorly treated strep throat infection. It leads to inflammation of the heart valves, the heart muscle, and the lining of the heart, potentially causing permanent damage to the heart structures.

Symptoms of Rheumatic Heart Disease:

• Chest pain or discomfort.

• Shortness of breath, especially when exerting oneself or lying down.

• Fatigue or unusual tiredness.

• Heart palpitations or irregular heartbeats.

• Swelling in the legs, abdomen, or feet due to fluid retention.

• Symptoms of rheumatic fever in the past, such as fever, joint pain, and skin rashes.

Rheumatic heart disease can lead to serious complications and requires medical evaluation and management.

Heart Failure: A condition where the heart is unable to pump blood effectively.

Symptoms of Heart Failure:

• Shortness of breath, especially during exertion or when lying down.

• Fatigue or unusual tiredness.

• Swelling in the legs, ankles, or abdomen due to fluid retention.

• Rapid or irregular heartbeat.

• Persistent cough or wheezing, often with white or pink blood-tinged mucus.

• Difficulty concentrating or decreased alertness.

Heart failure can result from various underlying causes, including coronary artery disease, high blood pressure, and previous heart attacks. It requires ongoing medical management and lifestyle adjustments to improve quality of life and reduce symptoms.

Conduction Defects: Abnormalities in the electrical conduction system of the heart that can lead to various heart rhythm disorders. These defects may affect the heart's ability to contract effectively, leading to symptoms such as irregular heartbeats, dizziness, and fainting.

Types of Conduction Defects:

• Atrioventricular (AV) Block: Involves a delay or complete block in the electrical signals traveling from the atria to the ventricles.

• Bundle Branch Block: A disruption in the electrical signals traveling through the right or left bundle branches, affecting ventricular contraction timing.

• Sick Sinus Syndrome: An issue with the sinoatrial (SA) node, which can result in intermittent bradycardia and tachycardia.

Symptoms of Conduction Defects:

• Palpitations: A sensation of rapid or irregular heartbeats.

• Dizziness or lightheadedness: These symptoms may occur, especially during physical activity or exertion.

• Syncope: A temporary loss of consciousness or fainting due to reduced blood flow to the brain.

• Fatigue: Unusual tiredness or lack of energy.

Diagnosis and Treatment: Diagnosis typically involves an electrocardiogram (ECG) to identify the specific type of conduction defect. Treatment options may include lifestyle changes, medications, or the implantation of a pacemaker to regulate heart rhythm if necessary.

**Atrial Fibrillation**: A disorganized electrical rhythm in the heart that leads to uncoordinated contractions of the atria. **Why It Is Bad**: Atrial fibrillation can increase the risk of stroke due to the potential for blood clots to form in the atria, as blood may pool and not be effectively pumped out. Additionally, it may lead to complications such as heart failure and other heart-related issues due to the increased workload on the heart and the irregularity of the heart's rhythm.

Premature Ventricular Contractions (PVCs): Abnormal heartbeats originating in the ventricles that disrupt the regular rhythm of the heart.

Causes: PVCs can be triggered by various factors including stress, caffeine, alcohol, smoking, and certain medications. They can occur in healthy individuals as well as those with underlying heart conditions.

Symptoms: Many people with PVCs may not experience any symptoms, but common sensations can include:

• Palpitations: A feeling of a skipped heartbeat or an extra heartbeat.

• Dizziness or lightheadedness: May occur, particularly if PVCs are frequent.

• Fatigue: Unusual tiredness may be reported by some individuals.

Management: In most cases, PVCs are not harmful and do not require treatment. However, if they occur frequently or cause significant symptoms, a healthcare provider may recommend lifestyle changes, medications, or further evaluation to assess any underlying heart issues.

**Ventricular Fibrillation (VF)**: A serious heart condition where the ventricles quiver ineffectively instead of contracting in a coordinated manner, preventing the heart from pumping blood effectively. **Causes**: VF can be triggered by various heart issues such as a heart attack, cardiomyopathy, or other heart diseases, as well as electrical disturbances or imbalances in the body. **Symptoms**: VF typically leads to loss of consciousness, lack of pulse, and cessation of breathing. It is a medical emergency that can quickly result in cardiac arrest. **Why It Is Bad**: Ventricular fibrillation is life-threatening because it disrupts the normal rhythm of the heart, leading to a significant drop in blood flow to vital organs. Without immediate treatment, such as cardiopulmonary resuscitation (CPR) and defibrillation, it can lead to death within minutes.

Importance of a Defibrillator: A defibrillator is a vital medical device used to treat life-threatening cardiac arrhythmias, specifically ventricular fibrillation and pulseless ventricular tachycardia.

Key Points:

1. Restores Normal Heart Rhythm: A defibrillator delivers an electric shock to the heart, which can interrupt the chaotic electrical activity and restore a normal heartbeat, allowing the heart to pump blood effectively again.

2. Increases Survival Rates: Immediate defibrillation is crucial during cardiac arrest, significantly increasing the chances of survival. Studies show that the sooner defibrillation is administered after cardiac arrest, the better the outcomes are for the patient.

3. Easy to Use: Modern defibrillators, especially Automated External Defibrillators (AEDs), are designed for layperson use. They provide clear instructions and automatically analyze the heart's rhythm to determine if a shock is needed, making them accessible in emergency situations.

4. Widespread Availability: Defibrillators are increasingly found in public places, such as airports, shopping malls, and sports venues, making them readily accessible in case of an emergency.

5. Part of CPR Protocol: Defibrillation is an essential component of the cardiopulmonary resuscitation (CPR) protocol. When combined with CPR, it enhances the chances of saving a life during a cardiac emergency.

Angioplasty: A medical procedure used to open narrowed or blocked blood vessels, often performed in coronary arteries to improve blood flow to the heart.

Goals of Angioplasty:

• Restore blood flow to the heart by clearing obstructions in coronary arteries.

• Relieve symptoms of angina (chest pain) and improve exercise capacity.

• Reduce the risk of heart attack and other serious complications

Cardiac Stents: Small, tube-like devices inserted into narrowed or blocked coronary arteries during angioplasty to keep the artery open and improve blood flow to the heart.

Goals of Cardiac Stents:

• Maintain open coronary arteries post-angioplasty to prevent re-narrowing (restenosis).

• Reduce symptoms of coronary artery disease, such as chest pain (angina).

• Lower the risk of heart attack by ensuring adequate blood supply to the heart muscle.

Coronary Bypass: A surgical procedure that redirects blood around blocked arteries to improve blood flow and oxygen supply to the heart. This is typically done using a healthy blood vessel from another part of the body.

Goals of Coronary Bypass:

• Restore blood flow to heart muscle that is deprived due to blocked or narrowed coronary arteries.

• Relieve symptoms of angina (chest pain) and improve quality of life.

• Reduce the risk of heart attack by ensuring adequate blood flow to the

Transmyocardial Laser Revascularization (TMR): A surgical procedure that uses laser technology to create channels in the heart muscle (myocardium) to improve blood flow to areas of the heart that are not receiving sufficient blood supply, often due to coronary artery disease.

Goals of TMR:

• Enhance blood flow to areas of the heart muscle that are ischemic (lacking oxygen) to relieve angina (chest pain).

• Improve heart function and overall quality of life for patients with chronic angina who are not suitable candidates for traditional bypass or angioplasty procedures.

• Promote the formation of new blood vessels (angiogenesis) in the heart, potentially improving oxygen delivery to affected areas.

Heart Transplant: A surgical procedure that involves replacing a severely diseased or damaged heart with a healthy heart from a donor.

Goals of Heart Transplant:

• Restore normal heart function in patients with end-stage heart disease

• Improve quality of life and increase life expectancy for recipients

• Alleviate symptoms associated with heart failure, such as shortness of breath and fatigue

• Enable the patient to return to daily activities and improve overall physical capacity.

Histocompatibility:

• Crucial in organ transplantation and tissue grafting, it refers to the compatibility between the tissue of a donor and that of a recipient

1. Immune Response Prevention: Ensuring histocompatibility helps prevent the recipient's immune system from recognizing the donor tissue as foreign. If the tissue is deemed foreign, the recipient's body might mount an immune response against it, leading to transplant rejection.

2. Organ Graft Survival: High levels of histocompatibility increase the likelihood that the transplanted organ or tissue will survive and function properly in the recipient's body over time.

3. Reduced Complications: Better histocompatibility minimizes the need for immunosuppressive drugs, which come with side effects and risks, including increased susceptibility to infections and other complications.

4. Matching Donor and Recipient: Histocompatibility is assessed through tests that evaluate human leukocyte antigens (HLA), which play a significant role in the immune response. The closer the match between donor and recipient HLAs, the better the chances of successful transplantation.

Importance of Immunosuppressants: Immunosuppressants are medications that inhibit or prevent activity of the immune system. They are critical in various medical contexts, especially in organ transplantation and autoimmune diseases. Their importance can be summarized as follows:

1. Preventing Rejection in Organ Transplants: After an organ transplant, the recipient's immune system may recognize the new organ as foreign and attack it. Immunosuppressants help suppress this immune response, increasing the likelihood of the transplant being successful and functioning properly.

2. Managing Autoimmune Diseases: In conditions where the immune system mistakenly attacks the body's own tissues (such as rheumatoid arthritis, lupus, etc.), immunosuppressants can help reduce inflammation and prevent further damage.

3. Controlling Allergic Reactions: They can also help manage severe allergies by suppressing the immune response that causes allergic reactions, providing patients with relief from symptoms.

4. Reducing Inflammation: Immunosuppressants play a role in reducing inflammation in various diseases, leading to improved symptoms and quality of life for affected patients.

5. Enabling Chemotherapy: In some cases, immunosuppressants are used to support patients undergoing chemotherapy, as they help manage the immune response to counteract the side effects of the treatment.