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CARDIOMYOPATHY. (OVERVIEW,TYPES AND DILATED CARDIOMYOPATHY) Oyindamola Alabi 701. Introduction.
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CARDIOMYOPATHY (OVERVIEW,TYPES AND DILATED CARDIOMYOPATHY) OyindamolaAlabi 701
Introduction • cardiomyopathies as “a heterogeneous group of diseases of the myocardium associated with mechanical &/or electrical dysfunction that usually (but not invariably) exhibit inappropriate ventricular hypertrophy or dilatation and are due to a variety of causes that frequently are genetic.” • Cardiomyopathies either are confined to the heart or are a part of generalized systemic disorders
OVERVIEW. As cardiomyopathy worsens, the heart becomes weaker. It's less able to pump blood through the body and maintain a normal electrical rhythm. This can lead toheart failure or irregular heartbeats called arrhythmias. In turn, heart failure can cause fluid to build up in the lungs, ankles, feet, legs, or abdomen.The weakening of the heart also can cause other complications, such as heart valve problems.
Functional classification • Dilated(congestive, DCM, IDC) • ventricular enlargement and syst dysfunction • Hypertrophic (IHSS, HCM, HOCM) • inappropriate myocardial hypertrophyin the absence of HTN or aortic stenosis • Restrictive (infiltrative) • abnormal filling and diastolic function • also, • Arrthymogenic right ventricular disease(ARVD) • Other type include “unclassified cardiomyopathy”
Specific classification. • Specific heart muscle disease (secondary) • Infective • Metabolic • Systemic disease • Heredofamilial • Sensitivity • Toxic
Cardiomyopathy can be acquired or inherited,most times the cause of cardiomyopathy is unknown. • Cardiomyopathy can affect people of all ages. • Some people who have cardiomyopathy have no signs or symptoms and need no treatment. For other people, the disease develops quickly, symptoms are severe, and serious complications occur.
Signs and symptoms. • These signs and symptoms include:-- Shortness of breath or trouble breathing, especially with physical exertion-- Fatigue (tiredness)-- Swelling in the ankles, feet, legs,abdomen, and veins in the neck
IDC - Definition • a disease of unknown etiology that principally affects the myocardium • LV dilatation and systolic dysfunction • pathology • increased heart size and weight • ventricular dilatation, normal wall thickness • heart dysfunction out of portion to fibrosis
Causes • Genetic influences- • 20-50% are familial • Autosomal dominant –predominant pattern • Mutations in genes encoding dystrophin,δsarcoglycan,troponin T,β MHC etc • Myocarditis • Alcohol and other toxins • Childbirth (peripartumcardiomyopathy)
Morphology • Heart enlarged,heavy,flabby • Mural thrombi common • Dilatation of all chambers,both ventricular hypertrophy • Microscopically-atrophic and hypertrophic myocardial fibres,cardiacmyocytes show degenerative changes • Interstitial and endocardial fibrosis
Clinical features- • Highest incidence in middle age • Symptoms may be gradual in onset • Acute presentation • Misdiagnosed as viral URI in young adults • Arrhythmia • Atrial fibrillation, conduction delays,,sudden death
DCM - Incidence and Prognosis • Prevalence is 36 per 100,000 population • Third most common cause of heart failure • Most frequent cause of heart transplantation • Complete recovery is rare • 50% die within 2yrs and 25% survive longer than 5yrs
History and physical examination. • Symptoms of heart failure • pulmonary congestion (left HF)dyspnea (rest, exertional, nocturnal), orthpnea • systemic congestion (right HF)edema, nausea, abdominal pain, nocturia • low cardiac outputfatigue and weakness • hypotension, tachycardia, tachypnea, JVD
diagnosis-Cardiac Imaging • Chest radiogram • Electrocardiogram • 24-hour ambulatory ECG (Holter) • lightheadedness, palpitation, syncope • Two-dimensional echocardiogram • Radionuclide ventriculography • Cardiac catheterization • age >40, ischemic history, high risk profile, abnormal ECG
Management of DCM • Limit activity based on functional status • salt restriction of a 2-g Na+ (5g NaCl) diet • fluid restriction for significant low Na+ • initiate medical therapy • ACE inhibitors, diuretics • digoxin, carvedilol • hydralazine / nitrate combination
consider adding ß-blocking agents if symptoms persists • anticoagulation for EF <30%, history of thromboemoli, presence of mural thrombi • intravenous dopamine, dobutamine and/or phosphodiesterase inhibitors • cardiac transplantation
HIV associated Dilated Cardiomyopathy
Etiology • HIV cardiac muscle auto-immunity, HIV positive patients are 4x more likely to have cardiac auto-antibodies • In one study 43% of had cardiac specific auto-antibodies
Nutritional Factors • Malabsorption and diarrhea in HIV may lead to micro-nutrient deficiency • Selenium replacement may restore LV function in HIV and reverse DCM in selenium deficient patients • HIV may be associated with vitamin B12, carnitine, growth hormone and thyroid hormone deficiencies all of which may be associated with LV dysfunction
Association with HIV Encephalopathy • HIV Encephalopathy is associated with severe LV dysfunction • HIV virus persists in myocardial and cerebral viral reservoir even after starting HAART • These cells may cause progressive tissue damage by the release of cytotoxic cytokines
Clinical presentation. Physical signs • May present as acute myocarditis if seen early • Fever with flu-like symptoms • Palpitations • Atypical chest pain • Shortness of breath • Physical exam may be normal • Signs of heart failure may be present • Bilateral basal crackles • Bi-pedal edema • Pericardial friction rub
Lab investigations. • New changes from baseline EKG • Usually conduction abnormalities, LBBB, First degree AV block • Chest X-ray • Cardiomegaly mainly LV Dilatation with rounding of the apex • Elevated Cardiac Troponins • Occurs in early stages with myocarditis may be confused with a new Myocardial Infarction • Increase in CK-MB
Diagnosis. • Echocardiography is the mainstay diagnosis • There is Concentric Left Ventricular hypertrophy • There is ventricular dilatation • Left Ventricular Ejection Fraction is reduced with global hypokinesia • Usually no regional wall motion abnormalities
Histopathology • HIV associated Cardiomyopathy is associated with intense staining for TNF α and iNOS (inducible Nitric Oxide Synthase) compared with Idiopathic DCM • Other histological features did not differ significantly from idiopathic DCM • Histopathology shows myocarditis with fibromatous degeneration of the conduction system m
Clinical management • In one Pediatric series patients treated with monthly IV Immunoglobulin infusions were shown to revert back to normal LV wall thickness1 • Therapy for LV systolic dysfunction is otherwise the mainstay of management2
Patients with systolic dysfunction are treated like standard CHF patients • Loop Diuretics • Aldosterone Receptor Blockers • Ace-Inhibitors • B-blockers can be started once patient is euvolemic • Digoxin may be added to improve contractility
AICD (Automatic Implantable Cardiac Defibrillators) • Can be used in patients with severely depressed LV dysfunction • This has not been validated to reduce incidence of sudden cardiac death in the HIV positive population
Hypertrophic cardiomyopathy • Characterised by myocardial hypertrophy,abnormal diastolic filling,intermittent ventricular outflow obstruction • Related to defects in force generation owing to altered sarcomeric function • Leading cause of LVH,unexplained by other clinical/pathologic cause • Caused by mutation of genes encoding sarcomeric proteins
Pathogenesis • Autosomal dominant with variable penetrance • Remaining are sporadic • Mutations are mostly missense • Mutations causing HCM found in genes encoding βMHC,cardiacTnT,αtropomyosin,myosin binding protein C
The major abnormality of the heart in HCM -- excessive thickening of the muscle. Thickening usually begins during early adolescence and stops when growth has finished. uncommon for thickening to progress after this age • left ventricle almost always affected • Hypertrophy is usually greatest in the septum, associated with obstruction to the flow of blood into the aorta
Asymmetric septal hypertrophy with obstruction to the outflow of blood from the heart may occur. The mitral valve touches the septum, blocking the outflow tract. Some blood is leaking back through the mitral valve causing mitral regurgitation
Histologic features • Extensive myocyte hypertrophy • Myofiber disarray • Interstitial and replacement fibrosis
Pathophysiology • Impaired diastolic filling-----reduced stroke volume • Reduced CO and increase in pulm venous pressure---exertionaldyspneoa • Diastolic dysfunction • Impaired diastolic filling, filling pressure • Myocardial ischemia • Mitral regurgitation • Arrhythmias
Clinical features • Asymptomatic • Echocardiographic finding only • Symptomatic • Dyspnea in 90% • Harsh systolic ejection murmur • Angina pectoris in 75% • Fatigue, pre-syncope, syncope, risk of SCD • Palpitation, PND, CHF, dizziness • Atrial fibrillation, thromboembolism
Restrictive cardiomyopathy • Hallmark: abnormal diastolic function • Rigid ventricular wall with impaired ventricular filling ,contractile functions are normal • Much less common then DCM or HCM • Characterised by primary disease in ventricular compliance resulting in impaired ventricular filing during diastole
CAUSES • Primary---idiopathic • Associated with – • Radiation fibrosis • Amyloidosis • Sarcoidosis • Metastatic tumors • Metabolic deposition diseases
Morphology • Ventricles are of normal size • Cavities are not dilated • Myocardium is firm and non compliant • Biatrial dilatation is common • Patchy/diffuse interstitial fibrosis
Clinical manifestations • Symptoms of right and left heart failure • Echo-Doppler • Abnormal mitral inflow pattern -Prominent E wave (rapid diastolic filling) • Almost invariably progresses to congestive heart failure,10% survive for 10 yrs
Amyloidosis • Cardiac enlargement without ventricular dilatation • Ventricular walls are thickened and rubbery • Amyloid deposition is most prominent in interstitial,perivascular and endocardial regions
Arrythmogenic right ventricular cardiomyopathy • Inherited disease of cardiac muscle • RVF,rhytmdisturbances,ventriculartachycardia,fibrillation • Rt ventricular wall is thinned,extensive fatty infiltration and fibrosis • Autosomal dominant inheritence