Primary Myocardial Disease Dr. Raid Jastania

Case

The Medical Examiner's office calls to inform you that they are investigating the sudden death of one of your patients. The patient in question was a 23-year-old man recently evaluated in your office after an episode of syncope that occurred shortly after a funeral for a 21-year-old cousin who had also died suddenly. Your patient's episode of syncope was associated with transient mild dyspnea on exertion and palpitations. There was no associated chest pain. The patient denied prior medical illness.

He had never been told he had a heart murmur, and there was nothing in his history to suggest prior acute rheumatic fever. Physical exam revealed a forceful systolic heave. The chest radiograph showed cardiomegaly with slight atrial enlargement. An EKG confirmed the presence of left ventricular hypertrophy (LVH). Serum markers of cardiac injury (enzymes, troponin) were negative for myocardial infarction

The patient had been referred to a cardiologist for an echocardiogram to rule out hypertrophic cardiomyopathy, valvular heart disease, or coarctation of the aorta. The medical examiner relates that the patient collapsed suddenly at work while unloading a truck. Extended attempts to revive him were unsuccessful, and he was pronounced dead at the hospital a few hours later.

Primary Myocardial Disease Myocarditis Cardiomyopathy –Dilated cardiomyopathy –Hypertrophic cardiomyopathy –Restrictive cardiomyopathy

Myocarditis

Infections: –Viruses: Coxsackievirus, adeno virus, CMV –Bacteria: meningcoccus –Fungi –Protozoa: Chagas disease (Trypanosoma cruzi) –Chlamydia Immune disease: –Post viral –Post Strptococcal –SLE –Drugs –Rejection Unknown: –Sarcoidosis –Giant cell myocarditis

Myocarditis Morphology: –Viral myocarditis: edema, inflammatory cells, lymphocytes, plasma cells, macrophages, myocardial necrosis, fibrosis –Ventricular dilatation –Bacterial myocarditis: acute inflammation

Myocarditis Clinical Presentation: –Asymptomatic –Congestive heart failure –Heart dysfunction Dyspnea, fatigue, chest pain –Arrhythmia

Cardiomyopathy

Primary abnormality of the myocardium Frequently of unknown cause 3 types –Dilated cardiomyopathy –Hypertrophic cardiomyopathy –Restrictive cardiomyopathy

Dilated Cardiomyopathy Progressive cardiac hypertrophy, dilation and contractile (systolic) dysfunction Associated with Coxackievirus Associated with alcohol Others: toxins: cobalt, chemotherapy Genetic: 20-30% –Mutation in genes of cytoskeleton proteins –Dystrophin gene

Dilated Cardiomyopathy Clinical: –Most common form of cardiomyopathy –Poor contraction of LV –CHF –Age 20 and 60 –Familial cases Enlarged heart, >900g, dilated, hypertrophied

Hypertrophic Cardiomyopathy Asymmetric septal hypertrophy Idiopathic hypertrophic sub-aortic stenosis Myocardial hypertrophy with abnormal diastolic filling and ventricular outflow obstruction 50% inherited as autosomal dominant Mutation in heavy chain beta-myosin

Hypertrophic Cardiomyopathy Morphology: –Hypertrophy in LV and septum –>800g Clinical: –Diastolic dysfunction –Dyspnea on exertion –Systolic murmur –Risk of ischemia –Common cause of sudden death in young athletes

Restrictive Cardiomyopathy Primary decrease in the ventricular compliance, impaired ventricular filling Caused by infiltrative process of the myocardium: –Endomyocardial fibrosis –Amyloidosis –Hemochromatosis

Restrictive Cardiomyopathy Morphology: –Endocardial thickening and fibrosis –Deposition of amyloid in amyloidosis, –Deposition of iron in hemochromatosis Clinical: –Diastolic dysfunction –Fatigue, dyspnea, chest pain

Amyloidosis