Cardiomyopathies Dr. Munaf Inamdar (MD Med.) Associate Professor, BHRC, Pune .
Definition “A primary disorder of the heart muscle that causes abnormal myocardial performance and is not the result of disease or dysfunction of other cardiac structures … myocardial infarction, systemic hypertension, valvular stenosis or regurgitation”
WHO Classification Unknown cause (primary) Dilated Hypertrophic Restrictive Specific heart muscle disease (secondary) due to a known cause: Infective Metabolic Systemic disease Herediofamilial Sensitivity Toxic(alcohol)
Functional Classification Dilated (congestive, DCM, IDC) ventricular enlargement and syst dysfunction Hypertrophic (IHSS, HCM, HOCM) inappropriate myocardial hypertrophy in the absence of HTN or aortic stenosis Restrictive (infiltrative) abnormal filling and diastolic function
We are going to cover…. 1. dilated cardiomyopathy (DCM) 2. hypertrophic cardiomyopathy (HCM) 3. restrictive cardiomyopathy (RCM) And in addition… 4. arrhythmogenic right ventricular dysplasia (ARVD) 5. obliterative cardiomyopathy (OCM)
Diagramatic representation of different cardiomyopathies
Dilated cardiomyopathy
Idiopathic Dilated Cardiomyopathy 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
Most common cause of clinical syndrome of Heart Failure
Incidence and Prognosis 3-10 cases per 100,000 20,000 new cases per year in the U.S.A. death from progressive pump failure 1-year 25% 2-year 35-40% 5-year 40-80% stabilization observed in 20-50% of patient complete recovery is rare
Symptoms. Symptoms of heart failure Due to pulmonary congestion (left HF) dyspnea (rest, exertional , nocturnal), orthpnea Due to systemic congestion (right HF) edema, nausea, abdominal pain, nocturia Due to low cardiac output fatigue and weakness
Clinical Signs. Pulsus alternans Pulsus tardus Systolic blood pressure normal or less than normal. Raised JVP Prominent a and v waves tricuspid regurgitation b/l basal crepts Pedal edema Hepatomegaly Gallop rhythm Systolic murmurs— Mitral,tricuspid reg.
Findings on ECG Sinus tachycardia in presence of heart failure. Atrial and ventricular tachyarryhthmias Poor r wave progression Anterior q waves Intaventricular conduction defects –mostly LBBB Left atrial abnormality Hypertensive changes by voltage criteria not evident ST –T changes are seen.
Chest X Ray
Findings on 2D Echo. Dilated chambers Left atrium is usualy enlarged Left ventricle is enlarged.normal 3.8—5.0cm Mitral and tricuspid regurgitation on doppler flow. LV or Global hypokinesia with an LVEF of <45% Stress testing -- tachyarryhthmias Dobutamine stress echo helpful in assessing the clinical prognosis.
Treatment— ACE, B blockers in symptomatic, Diuretics- vol. overload, Spironolactone –advanced, Digoxin is drug of choice, Treatment of arrhythmias. Biventricular pacing—plus ICDs—IVCDS, Anticoagulation, Amiodarone ,
Hypertrophic Cardiomyopathy
Anatomical subtypes of HCM
HCM: Incidence Most common cause of sudden death in young athletes. Prevalence approx. 100 per 1 lakh population Characterized by in appropriate and elaborate LV hypertrophy with misalignment of the myocardial fibres . Hypertrophy may be generalized or confined largely to interventricular septum.
Pathophysiology Heart failure may develop because stiff non-compliant ventricles impede systolic filling. Septal hypertrophy may cause dynamic LV outflow obstruction. Mitral regurgitation occur due to abnormal systolic anterior mitral valve leaflet.
Clinical Features Symptoms…. S A D S yncope on effort/pre-syncope A ngina on effort D yspnea on effort Sudden death (SCD) (less frequent )…palpitations, PND, dizziness Signs Jerky pulse Palpable LV heave Double impulse at apex mid-systolic murmur –sign of LV outflow obstruction Pansystolic murmur
Risk factors for SCD Young age (<30 years) “Malignant” family history of sudden death Gene mutations prone to SCD (ex. Arg403Gln) Aborted sudden cardiac death Sustained VT or SVT Recurrent syncope in the young Nonsustained VT ( Holter Monitoring) Brady arrhythmias (occult conduction disease)
Treatment B-blocker and rate-limiting calcium antagonists ( eg . verapamil ) No pharmacological treatment is known to improve prognosis Arrhythmia is common and responds well to amiodarone . Outflow tract obstruction can be improved by partial surgical resection ( myectomy ) or iatrogenic infarction of basal septum ( septal ablation) Implantable cardiac defibrillation (ICD) for patient with risk of sudden death.
Surgical intervention may better the prognosis
Restrictive Cardiomyopathy
Background Rare condition Ventricular filling is impaired because ventricles are stiff. Lead to high atrial pressure with atrial hypertrophy, dilatation and later atrial fibrillation. Amyloidosis is the most common cause. Other form: Idiopathic perimyocyte fibrosis Familial restrictive cardiomyopathy
Clinical Features Symptoms of right and left heart failure Jugular Venous Pulse prominent x and y descents Echo-Doppler abnormal mitral inflow pattern prominent E wave (rapid diastolic filling) reduced deceleration time ( LA pressure)
Differential diagnosis Hallmark: abnormal diastolic function due to a rigid ventricular wall with impaired ventricular filling. Bear some functional resemblance to constrictive pericarditis . Importance lies in its differentiation from operable constrictive pericarditis
Restrictive v/s Constrictive History provide can important clues Constrictive pericarditis history of TB, trauma, pericarditis , collagen vascular disorders Restrictive cardiomyopathy amyloidosis , hemochromatosis Mixed mediastinal radiation, cardiac surgery
Diagnosis and Treatment. Diagnosis is difficult Require complex Doppler echocardiography CT and MRI and endomyocardial biopsy may be done. No satisfactory medical therapy Drug therapy must be used with caution diuretics for extremely high filling pressures vasodilators may decrease filling pressure ? Calcium channel blockers to improve diastolic compliance digitalis and other inotropic agents are not indicated Transplantation is the best treatment
Arrhythmogenic Right Ventricular Dysplasia In this condition, patches of the right ventricular myocardium are replaced with fibrous and fatty tissue. Inherited as autosomal dominant trait Prevalence in India is 10 per 1 lakh population. Dominant clinical problems are ventricular arrhythmia Sudden death Right sided cardiac failure ECG shows inverted T waves in the right precordial leads. MRI useful diagnostic tool and used to screen 1 st degree relatives from having the same pathology.
Obliterative Cardiomyopathy It is also rare in India. Involves the endocardium of one or both ventricles and is characterized by thrombosis and elaborate fibrosis with gradual obliteration of the ventricular cavities. Mitral and tricuspid valves are regurgitant . Heart failure and pulmonary and systemic embolism are prominent. Anticoagulation and antiplatelet therapy is advisable and diuretics may help symptoms of HF. Surgery valve replacement with decortication of endocardium may be helpful in certain cases.
A Quick Look
References: Harrison 18 th Edtn . Braunwald heart disease 8th Edtn . Hurst Heart 12 th Edtn . Jr. of the American Heart Association. British Medical Jr. Google.com for images.