Summary This document provides a comprehensive overview of various cardiac conditions, including cardiomyopathies, pericardial diseases, congenital heart defect
Summary This document provides a comprehensive overview of various cardiac conditions, including cardiomyopathies, pericardial diseases, congenital heart defects, and cardiac tumors. It delves into their definitions, causes, pathophysiology, gross and microscopic pathology, clinical features, and key diagnostic points, often using mnemonics and comparison tables for clarity. Key Points - Cardiomyopathies are categorized into Dilated (DCM), Hypertrophic (HCM), and Restrictive (RCM), each with distinct causes, pathophysiology, and clinical presentations. - Pericardial diseases include pericarditis, pericardial effusion, cardiac tamponade, and constrictive pericarditis, differentiated by their acute vs. chronic nature and specific diagnostic findings. - Congenital heart defects are broadly classified into acyanotic (left-to-right shunts) and cyanotic (right-to-left shunts), with specific conditions like VSD, ASD, PDA, TOF, TGA, and coarctation of the aorta detailed. - Cardiac tumors, though rare, are discussed, with myxoma being the most common primary tumor in adults and rhabdomyoma in children, each presenting with unique clinical scenarios. Detailed Notes --- PART 1: CARDIOMYOPATHIES Definition Disease of the heart muscle itself — NOT caused by coronary artery disease, hypertension, or valvular disease There Are 3 Types — Remember "DHR" - D ilated Cardiomyopathy - H ypertrophic Cardiomyopathy - R estrictive Cardiomyopathy --- 1A. DILATED CARDIOMYOPATHY (DCM) Definition All 4 chambers dilate + systolic dysfunction → heart cannot CONTRACT properly Causes — Remember "ABCDE" - A lcohol (most common toxic cause) - B eri-beri (Thiamine/B1 deficiency) - C oxsackievirus B (viral myocarditis → DCM) - D rugs (Doxorubicin/adriamycin — chemotherapy) - E clampsia/pregnancy (Peripartum cardiomyopathy) Other Important Causes Cause Notes --- --- Idiopathic Most common overall (50%) Genetic 25-35% — mutations in cytoskeletal proteins Chagas disease Trypanosoma cruzi — South America Hemochromatosis Iron deposition in myocardium Sarcoidosis Granulomas in myocardium Thyroid disease Hypothyroidism or hyperthyroidism Cocaine Toxic cardiomyopathy Pathophysiology Gross Pathology Microscopic Pathology Clinical Features Feature Details --- --- Age Any age, peak 20-60 Symptoms Progressive heart failure — dyspnea, fatigue, orthopnea Signs S3 gallop, displaced apex beat, JVP raised CXR Massive cardiomegaly — "globular heart" Echo Dilated all chambers, reduced EF Arrhythmias Common — AF, VT, sudden death Emboli Stroke from mural thrombus Key MCQ Facts - Most common cardiomyopathy overall - Systolic dysfunction — problem with CONTRACTION - All 4 chambers dilate - Alcohol → DCM → stop alcohol → can RECOVER - Doxorubicin (adriamycin) → dose-dependent cardiotoxicity → DCM - Peripartum cardiomyopathy → last month of pregnancy or 5 months postpartum - Worst prognosis of all cardiomyopathies --- 1B. HYPERTROPHIC CARDIOMYOPATHY (HCM) Definition Massive hypertrophy of the LEFT VENTRICLE (especially septum) WITHOUT dilation → diastolic dysfunction Key Feature Asymmetric Septal Hypertrophy (ASH) — interventricular septum thicker than LV free wall Cause Autosomal dominant genetic mutation — mutations in sarcomere proteins Most common: Beta-myosin heavy chain or myosin binding protein C mutations Pathophysiology Systolic Anterior Motion (SAM) Gross Pathology Microscopic Pathology — PATHOGNOMONIC Myofiber disarray = diagnostic of HCM Clinical Features Feature Details --- --- Age Young adults, athletes Symptoms Dyspnea, angina, syncope on exertion Murmur Harsh systolic murmur — INCREASES with Valsalva/standing, DECREASES with squatting Pulse Jerky, bifid pulse Sudden death Exercise-triggered VF The Murmur Trick — High Yield Key MCQ Facts - Most common cause of sudden cardiac death in young athletes - Autosomal dominant — always ask about family history - Diastolic dysfunction — problem with RELAXATION not contraction - EF is NORMAL or HIGH (squeezes well, can't relax) - Small LV cavity (opposite of DCM) - Myofiber disarray = pathognomonic on microscopy - Treatment: Beta-blockers (slow heart, improve filling) - Avoid: nitrates, digoxin, diuretics (reduce preload → worsen obstruction) --- 1C. RESTRICTIVE CARDIOMYOPATHY (RCM) Definition Heart muscle becomes STIFF and cannot relax → diastolic dysfunction → impaired filling Walls are NOT thickened, NOT dilated — but rigid and non-compliant Causes — Remember "HASSI" - H emochromatosis (iron deposition) - A myloidosis (most common cause overall) - S arcoidosis (granulomas) - S cleroderma (fibrosis) - I diopathic / Endomyocardial fibrosis (Loeffler) Most Important Causes Cause Notes --- --- Amyloidosis Most common — amyloid deposits stiffen heart Hemochromatosis Iron overload — deposits in myocardium Sarcoidosis Non-caseating granulomas Loeffler endocarditis Hypereosinophilia → endomyocardial fibrosis Radiation Post-radiation fibrosis Glycogen storage diseases Pompe disease Pathophysiology Key Features Feature Details --- --- Systolic function NORMAL (EF preserved) Diastolic function SEVERELY impaired Ventricular size Normal (not dilated) Wall thickness Normal or slightly increased Atria Massively dilated (blood backs up) Symptoms Right heart failure predominates Amyloidosis — Special Focus Key MCQ Facts - Least common cardiomyopathy - Diastolic dysfunction with NORMAL systolic function - Amyloidosis = most common cause - Congo red stain → apple-green birefringence = amyloid - Massive atrial dilation — diagnostic clue - Hardest to treat — no specific therapy for most causes --- CARDIOMYOPATHY COMPARISON TABLE Feature DCM HCM RCM --- --- --- --- Chamber size All dilated LV small, thick Normal Wall thickness Thin Massively thick Normal/slightly thick Dysfunction Systolic Diastolic Diastolic EF Reduced ( 50mL) Types of Fluid Type Cause --- --- Transudate Heart failure, hypoalbuminemia Exudate Infection, malignancy, autoimmune Hemorrhagic Trauma, aortic dissection, malignancy Chylous Lymphatic obstruction Key Point The RATE of accumulation matters MORE than the volume --- 2C. CARDIAC TAMPONADE Definition Life-threatening compression of the heart by pericardial fluid → impaired cardiac filling → reduced cardiac output Causes Trauma, aortic dissection, MI rupture, malignancy, TB, post-cardiac surgery Pathophysiology Beck's Triad — MUST KNOW 1. HYPOTENSION — reduced cardiac output 2. RAISED JVP (distended neck veins) — backed up venous blood 3. MUFFLED HEART SOUNDS — fluid dampens sounds Pulsus Paradoxus Normal: BP drops slightly ( 10mmHg during inspiration Why? During inspiration → right ventricle expands → Pushes septum LEFT (constrained by tamponade) → LV fills less → BP drops significantly Pulsus paradoxus 10mmHg = hallmark of cardiac tamponade ECG Findings - Low voltage complexes (fluid insulates) - Electrical alternans — QRS complex alternates in height (Heart swinging back and forth in fluid) - Sinus tachycardia Treatment PERICARDIOCENTESIS — emergency needle drainage of pericardial fluid Needle inserted at left xiphocostal angle --- 2D. CONSTRICTIVE PERICARDITIS Definition Chronic fibrosis and calcification of pericardium → forms rigid shell around heart → impairs filling Causes Cause Notes --- --- TB Most common worldwide Viral pericarditis After healing Radiation Post-radiotherapy Cardiac surgery Post-operative Purulent pericarditis After bacterial infection Pathophysiology Key Features - Kussmaul's sign: JVP RISES on inspiration (opposite of normal) - Pericardial knock: early diastolic sound - CXR: pericardial calcification - Features of RIGHT heart failure: JVP raised, hepatomegaly, ascites, edema - Quiet, non-displaced apex beat Tamponade vs Constrictive Pericarditis Feature Tamponade Constrictive Pericarditis --- --- --- Cause Fluid accumulation Fibrosis/calcification Onset Acute Chronic Pulsus paradoxus YES — prominent Mild or absent Kussmaul's sign Absent YES CXR Enlarged cardiac silhouette Pericardial calcification Treatment Pericardiocente