Cardiomyopathy PDF

Cardiomyopathy • Diverse heart muscle disorder that affects myocardial systolic/diastolic function • Types: o Dilated: systolic dysfunction o Hypertrophic: diastolic dysfunction o Restrictive: diastolic dysfunction o Arrhythmogenic o Unclassified CM (LV noncompaction, stress-induced, cirrhotic) o Id...

Cardiomyopathy • Diverse heart muscle disorder that affects myocardial systolic/diastolic function • Types: o Dilated: systolic dysfunction o Hypertrophic: diastolic dysfunction o Restrictive: diastolic dysfunction o Arrhythmogenic o Unclassified CM (LV noncompaction, stress-induced, cirrhotic) o Idiopathic CM= No pathogenesis Anatomic Appearances of CMs • Dilated CM -> LV enlargement with mild hypertrophy: Bigger chamber, thin walls • Hypertrophic CM -> LV hypertrophy (asymmetrical), thick muscles, small chambers • Restrictive CM -> infiltration or fibrosis of ventricles w/o chamber enlargement (no size change) Dilated Cardiomyopathy (DCM): (Most common CM) • Systolic dysfunction • Results in dysfunction of ventricular contraction (Systolic Heart Failure (EF < 40%) • Ventricle volume increases in diastole • Atrial volume increases with time • ALL chambers are enlarged and dilated with possible mural thrombi • Histology: o Myocyte hypertrophy o Interstitial fibrosis • Signs and symptoms of heart failure (HF) develop o Shortness of breath o Edema (Pulmonary and Peripheral o Fatigue o Tachycardia/Tachypnea o Hypertension or hypotension Causes of DCM • Genetic: o Mutation in TTN (encodes for titin) o Mutations in genes that code for cardiac cytoskeletal, myofibrillar, and nuclear membrane proteins. • Myocarditis: Coxsackievirus, influenza, hepatitis, HIV • Toxins: Alcohol, cocaine, doxorubicin, chemo • Pregnancy/peripartum CM • Secondary to other CVD: Ischemia, HTN, valvular disease, diabetes, hyperthyroidism, hypothyroidism • Idiopathic: Many cases of DCM are unexplained DCM Diagnosis • History and Physical Exam o Family History o Toxin Intake (Alcohol, Cocaine, etc.) o Risk Factors for Coronary Artery Disease (CAD) o Various Symptoms of Heart Failure (HF) • Complete blood cell (anemia) • B-type natriuretic peptide (BNP): Increased BNP (Normal BNP < 100 pg/ml) • Electrocardiogram (ECG) • Chest X-ray: Cardiomegaly, pulmonary edema • Echocardiogram o Systolic Dysfunction (EF Less than or equal to 40%) o Chamber dilation (LV and LV hypokinesis) Treatment of DCM • Low sodium diet • Medications o Diuretics o Beta-blocker o Digoxin o Vasodilator (ACE inhibitor, ARBs) CONTRAINDICATED in pregnancy o Anticoagulation (prevent thromboembolic event) • Devices: Pacemaker and Implantable cardioverter defibrillator (ICD) • Procedures: Heart Transplant DCM: Alcohol Cardiomyopathy • Assc with biventricular dysfunction and dilation of chambers • Common occurs in: o Heavy alcohol consumers > 10 yrs o Increased risk if more than 90 gram of alcohol daily for more than 5 yrs DCM: Peripartum Cardiomyopathy (PPCM) • Occurs during last or first few months of pregnancy • Enlarged heart (weakened pump) • Risk factors: o Advanced age of mother o Multiple pregnancies o Family hx o HTN o Obesity o Drug use • 70% women recover in 1 year if EF reaches 50-55% • Complications: o Acute decompensated heart failure o Sudden cardiac death o Arrhythmia Hypertrophic Cardiomyopathy (HCM) • Heritable autosomal dominant disease • Myocardial hypertrophy with NO dilation o Myofibril disarray o Small LV chamber o Myocyte hypertrophy o Interstitial and replacement fibrosis • Asymmetric septal hypertrophy (most common) • In 10% of cases, hypertrophy is symmetrical • Genetic: Most common mutations are in myosin-binding gene (MYBP and MYH7) Pathophysiology of HCM • Endocardial thickening in LV tract and mitral valve leaflet thickening due to: o Impaired diastolic LV relaxation: impaired filling o Mitral valve leaflet adjoining the septum causes transient LV outflow tract obstruction during midsystole Clinical Presentation of HCM • Majority are asymptomatic • Physical exam: Harsh systolic crescendo-decrescendo murmur at left lower sternal border due to turbulent flow from LV outflow obstruction OR Holosystolic blowing murmur at apex from mitral regurgitation Diagnosing HCM • History and Physical Exam o Family History o Various Symptoms of Heart Failure (HF): Syncope, Shortness of breath o Murmur: Systolic Ejection Murmur • Electrocardiogram (ECG): LV hypertrophy • Chest X-ray: Cardiomegaly • Echocardiogram (ECHO): Diastolic Dysfunction (EF greater than 50%, mostly normal) o Increased Septum to LV wall thickness (greater than 1.3:1) o Mitral regurgitation • Genetic Tests • Cardiac Muscle Biopsy to see Myofibril disarray Complications of HCM • Sudden Cardiac Death (SCD): Seen in athletes, individuals who exercise/sports CONTRAINDICATED • Heart Failure (HF): extensive LV remodeling w systolic and diastolic dysfunction • Atrial Fibrillation (AF) • Syncope • Infective Mitral Endocarditis Treatment of HCM • Meds (Beta blockers, Ca blockers) • Devices: o Pacemaker o Implanted cardioverter-defibrillator (ICD) o Cardiac Resynchronization therapy (CRT) • Procedures o Septal Myectomy: removes portion of the septum o Alcohol Septal Ablation o Heart Transplant Restrictive Cardiomyopathy (RCM) • impaired ventricular filling, with normal or decreased diastolic volume of either or both ventricles • No change in ejection fraction • Ventricle size is normal • Heart is always constricting • Causes: o Fibrosis § Radiation § Idiopathic o Infiltration § Amlyloidosis § Sarcoidosis § Metabolic disorders § Hemochromatosis § Scleroderma • Diastolic Failure: Decreased ventricular compliance Pathophysiology of RCM • Elevated ventricular diastolic pressures and • Decreased ventricular filling • Congo red stain is the gold standard for the demonstration of amyloid in tissue sections has an apple green birefringence polarized light. • Electrocardiogram (ECG): Low Voltage (QRS) • Chest X-ray: NO cardiomegaly; Pulmonary congestion • Echocardiogram (ECHO): Diastolic dysfunction (EF greater than 50%=normal) • Cardiac Muscle Biopsy Treatment of RCM • RCM typically has poor prognosis • A lot of arrhythmia • Salt restriction • Diuretics • ACE inhibitors • Anticoagulant (thromboembolism event) • Pacemaker implantation Arrhythmogenic RV Cardiomyopathy (ARVD/ARVC) • CM affecting the RV with pathologic hallmarks of o myocardial thinning with fibrofatty deposits o Aneurysm formation • Ejection fraction is normal • Fat deposit distracts the signal from spreading • Myocyte necrosis • Apoptosis • Repair w fibrofatty replacement Unclassified CM – Takotsubo Cardiomyopathy “stress induced CM” / “Broken Heart Syndrome” • Assc with severe emotional or physical events • Symptoms: o Chest pain (similar to ischemia and MI) o ST elevation o no significant coronary artery stenosis (no obstruction in vessels) Practice A 76-year-old woman with multiple myeloma (bone marrow cancer of plasma cells) presents with dyspnea and lower extremity edema. Her ECG demonstrates low-voltage QRS complexes in each lead. Echocardiography shows markedly increased ventricular thickness, enlargement of both atria and a normal left ventricular ejection fraction. What is the most likely diagnosis? a. Hypertrophic CM b. Arrhythmogenic right ventricular CM c. Dilated CM d. Cardiac amyloidosis causing restrictive CM D Which of the following is not a recognized primary cause of dilated CM? a. Alcohol b. Mitral stenosis c. Chemotherapy d. Viral myocarditis B