MYOCARDIAL DISEASES
By
Nusrum Iqbal MD
Myocardial diseases of Heart
Three categories
•an acute or chronic inflammatory pathology (myocarditis)
•specific diseases of the heart muscle
•idiopathic myocardial disease (cardiomyopathy)
ACUTE MYOCARDITIS
•Acute inflammatory and potentially reversible condition
•inflammation may be due the infection or toxins
•viral myocarditis is the most common reason
Causative factors
Viruses
•Coxsakie, influenza,rubella, polio, adenovirus, echovirus and rarely HIV
Protozoa
•Trypanosoma cruzi, toxoplasma gondii
Radiation, chemical and drugs,
•lead, chloroquine
Bacterial infections
•Diphtheria, rickettsia, chlamydia, coxiella
Autoimmunity
Clinical Features
•Acute illness
•fever
•cardiac failure
•history of previous respiratory or febrile illness
•soft heart sounds
•prominent 3rd heart sound
•tachycardia
•Pericardial friction rub
INVESTIGATIONS
CHEST X-RAY
•some cardiac enlargement
ECG
•ST and T wave abnormality
•arrhythmias
•heart blocks
Cardiac enzymes
•elevated
Endomyocardial biopsy
•acute inflammation
Viral antibody titer
•increased
Treatment
•Bed rest
•Eradication of acute infection
•Management of heart failure
•Management of arrhythmia
Specific diseases of heart muscles
Infections
•viral, e.g. coxsakie A and B, influenza, HIV
•bacterial, e.g. diphtheria
•protozoa, e.g. trapanosomiasis
Endocrine and Metabolic disorders
•diabetes, hyper or hypothyroidism, acromegaly, carcinoid syndrome, inherited storage
diseases
Connective tissue diseases
•systemic sclerosis, systemic lupus erythematosus, polyarteritis nodosa
Endomyocardial fibrosis and eosinophilic heart disease
Infiltrative disorders
•hemachromatosis,hemosiderosis, sarcoidosis, amyloidosis
Toxins
•drugs, alcohol, irradiation
Neuromuscular disorders
•dystrophia myotonica, Friedreich ataxia
Etiology
Ischemic heart disease
Toxins
•alcohol, antiretroviral drugs (ddI, ddC, AZT)
•cocaine, mercury
Metabolic disorders
•Nutritional, e.g. thiamine, selenium
•Endocrinologic, e.g. hypothyroidism, acromegaly, thyrotoxicosis, pheochromocytoma
•Electrolyte disturbances, e.g. hypocalcemia, hypophosphatemia
•Hemochromatosis
Inflammatory/Infectious/Infiltrative
•sarcoidosis, peripartum, infections
Miscellaneous
•tachycardia induced
•idiopathic
CARDIOMYOPATHY
Three type
Dilated cardiomyopathy
Restrictive cardiomyopathy
Hypertrophic cardiomyopathy
Dilated Cardiomyopathy
•Cardiac enlargement is the hallmark
•Dilatation of all four cardiac chambers and diminished systolic function
•Thickness of the ventricular wall is mildly increased
•Histopathologically, there is an evidence of varrying degrees of myocyte degeneration,
eccentric hypertrophy, and atrophy of the myofibrils
Clinical Features
•Symptoms depends on relative degree of heart failure, incidence of arrhythmias and
emboli
•Physical signs- cardiomegaly, tachycardia, jugular venous pressure elevation, 3rd or 4th
heart sounds, basal crackles, functional mitral or tricuspid murmur
Investigations
CHEST X-RAY
•generalized cardiac enlargement
ECG
•diffuse nonspecific ST segment and T wave changes
•sinus tachycardia
•conduction abnormality
•atrial fibrillation, ventricle premature contractions or ventricular tachycardia
ECHOCARDIOGRAM
•Dilatation of the left and/or right ventricle
•poor global contraction function
MANAGEMENT
•Treatment of the heart failure
•Treatment of the arrhythmias
•Anticoagulation for documented atrial fibrillation or embolization
•Prolonged bed rest, avoidance of alcohol and nutritional supplements
•Metoprolol
•Cardiac transplantation
RESTRICTIVE CARDIOMYOPATHY
•Ventricular filling is restricted because the ventricles are stiff (like constrictive
pericarditis)
•Donot present with hypertrophy or dilatation
•Leads to high atrial pressures with atrial atrial hypertrophy, dilatation and later atrial
fibrillation
Etiology
Amyloidosis
Sarcoidosis
Loeffler’s endocarditis
endomyocardial fibrosis
Clinical Features
•Dyspnea
•Fatigue
•Embolic symptoms
•Hepatic enlargement
•Ascites
•Dependent edema
•High jugular venous pressure with diastolic collapse (Friedreich’s sign)
•Elevation of venous pressure with inspiration (kussmaul’s sign)
•3rd or 4th heart sound (cardiac enlargement)
Investigations
CHEST X-RAY
•cardiac enlargement
ECG
•low voltage and ST segment and T wave abnormality
ECHOCARDIOGRAM
•symmetrical myocardial thickening, normal ejection fraction and impaired diastolic
function
CARDIAC CATHETERIZATION AND HEMODYANAMICS
•distinction from the contrictive pericarditis
ENDOMYOCARDIAL BIOPSY
TREATMENT
•Symptomatic
•management of cardiac failure
•management of embolization
•melphalan plus prednisone (amyloidosis)
•Transplantation
•excision of endocardial fibrosis
HYPERTROPHIC CARDIOMYOPATHY
•Familial condition (50% cases)
•Inappropriate and elaborate ventricle hypertrophy with malalignment of the myocardial
fibers
•May be generalized or confined to the interventricular septum (asymmetric septal
hypertrophy) or the apex(far east)
•Obstruction of the left ventricular outflow by the hypertrophy (HOCM Hypertrophic
obstructive cardiomyopathy)
Etiology
Famailial
•autosomal dominant
•mutation in the genescoding for sarcometric proteins
•several mutations of Beta-myosin (ch 14)
•High incidence of sudden death
Associated with
•Noonan’s syndrome
•Friedrich’s ataxia
•glycogen storage disease
•mitochondrial myopathies
CLINICAL FEATURES
Symptoms
•Chest pain
•Dyspnea
•Syncope
•Pre-syncope (typically with exertion)
•Cardiac arrhythmias (Ventricular tachycardia)e
•Sudden death
•Family history of sudden death
•Recurrent syncope
•non -sustained Ventricular tachycardia
Continued
physical findings
Double apical pulsation (forceful atrial contraction producing a fourth heart sound)
Jerky carotid pulse
Ejection systolic murmur
•increase with valsalva or standing
•decrease with squatting
Pansystolic murmur due to mitral regurgitation
Fouth heart sound
INVESTIGATIONS
CHEST X-RAY
•unremarkable
ECG
•LVH , ST segment or T wave abnormality
ECHOCARDIOGRAM
•left ventricular hypertrophy
•Septal hypertrophy greater than posterior wall
•systolic anterior motion of the mitral valve
•vigorously contrating ventricle
Pedigree analysis
Genetic analysis provides confirmation
Exercise test and ECG ambulatory recording
Management
•Amiodarone treatment (antiarrhythmic)
•Implantable defibrillator
•B-blockers and verapamil (chest pain/dyspnea)
•Dual chamber pacing with significant outflow obstruction
•Resection of the septal myocardial septum
Vasodilator and Diuretics should be avoided