Cardiomyopathies

Snapshot

A 16-year-old boy presents to his pediatrician for syncope. In the past few months, he had syncopal episodes when he played football, soccer, and sprinting. His family history includes sudden cardiac death in several relatives. An echocardiogram shows marked hypertrophy and abnormal systolic anterior leaflet motion of the mitral valve. (Hypertrophic cardiomyopathy)

Introduction

Clinical definition

cardiomyopathies intrinsically affect the myocardium, leading to systolic or diastolic dysfunction
these do not include changes in the myocardium secondary to hypertension, coronary artery disease, or valvular disorders

types of cardiomyopathies

dilated cardiomyopathy (most common)
- restrictive/infiltrative cardiomyopathy
- hypertrophic cardiomyopathy (obstructive vs non-obstructive)

Cardiomyopathies
	Dilated	Restrictive/Infiltrative	Hypertrophic
Etiology	ABCD Alcohol abuse Beriberi (wet) Coxsackie B viral myocarditis Chronic Cocaine use Chagas disease Doxorubicin toxicity Hemochromatosis Sarcoidosis Titin mutation Peripartum cardiomyopathy	Radiation therapy Loffler endocarditis (with endomyocardial fibrosis and eosinophilic infiltrate) Endocardial fibroelastosis (in children) Amyloidosis Sarcoidosis Scleroderma Troponin mutation Hemochromatosis	Familial (most common) autosomal dominant mutations in sarcomere proteins (β-myosin heavy chain = myosin binding protein C > tropomyosin = troponin I/C – in order of frequency of mutations) Idiopathic
Pathology	Systolic dysfunction from ↓ contractility and ↓ ejection fractionEccentric hypertrophy (sarcomeres added in series)	Stiff myocardium causes diastolic dysfunctionPreserved left ventricular systolic function	Diastolic dysfunction from ↓ compliance of left ventricle Septal hypertrophyMajority of cases are obstructive (hypertrophic obstructive cardiomyopathy)Concentric hypertrophy (sarcomeres added in parallel)
Clinical presentation	Congestive heart failureS3 soundSystolic murmur	Progressive heart failureSudden cardiac deathS4 sound (and others can present with S3)+ Kussmaul sign	Syncope with activitySudden cardiac death (especially in young athletes) S4 soundSystolic murmur without radiation ↑ with decrease in preload or afterload, e.g., Valsalva, standing up, diuretics, nitroglycerin ↓ with increase in preload or afterload, e.g., hand grip and squatting
Diagnostic studies	Chest radiography ballooning of heart Echocardiogram dilated ventricles and ↓ ejection fraction Electrocardiogrambundle branch block	Chest radiographycardiomegaly and pulmonary congestion Echocardiogram thickening of all structuresdiastolic dysfunctionEndomyocardial biopsythe most accurate test for etiologyElectrocardiogrammay have low voltages	Echocardiography normal ejection fractionhypertrophymitral regurgitationdecreased end systolic volume and end diastolic volumeElectrocardiogramleft ventricular hypertrophyHistology tangled and disoriented myofibrils
Treatment	Angiotensin-converting enzyme inhibitorsβ-blockersSpironolactoneAutomatic implantable cardioverter/defibrillatorBiventricular pacemaker	Treat underlying conditionDiureticsHeart transplant	Avoid athletic activitiesβ-blockersNon-dihydropyridine calcium channel blockersImplantable cardioverter/d

We at USMLEStrike® precisely adopt the unique strategies in our educational process to ensure that every student here enjoys learning the syllable knowledge along with acquiring wisdom for life.

Useful Links

Information

Socials

Copyright © 2024 USMLEStrike®. All rights reserved.

© Designed and Developed By Cloudstar Digital