Cardiomyopathies - Cardiovascular

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
EtiologyABCD
Alcohol abuse
Beriberi (wet)
Coxsackie B viral myocarditis
ChronicCocaine 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
PathologySystolic dysfunction from ↓ contractility and↓ ejection fraction
Eccentric hypertrophy (sarcomeres added in series)
Stiff myocardium causesdiastolic dysfunction
Preserved left ventricular systolic function
Diastolic dysfunctionfrom↓ compliance of left ventricle
Septal hypertrophy
Majority of cases areobstructive(hypertrophic obstructive cardiomyopathy)
Concentric hypertrophy (sarcomeres added in parallel)
Clinical presentation
Congestive heart failure
S3 sound
Systolic murmur
Progressive heart failure
Sudden cardiac death
S4 sound (and others can present with S3)
+ Kussmaul sign
Syncope with activity
Sudden cardiac death (especially in young athletes)
S4 sound
Systolic 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 radiographyballooning of heart
Echocardiogramdilated ventricles and↓ ejection fraction
Electrocardiogrambundle branch block
Chest radiographycardiomegaly and pulmonary congestion
Echocardiogramthickening of all structures
diastolic dysfunction
Endomyocardial biopsythe most accurate test for etiology
Electrocardiogrammay have low voltages
Echocardiographynormal ejection fraction
hypertrophy
mitral regurgitation
decreased end systolic volume and end diastolic volume
Electrocardiogramleft ventricular hypertrophy
Histologytangled and disoriented myofibrils
TreatmentAngiotensin-converting enzyme inhibitors
β-blockers
Spironolactone
Automatic implantable cardioverter/defibrillator
Biventricular pacemaker
Treat underlying condition
Diuretics
Heart transplant
Avoid athletic activities
β-blockers
Non-dihydropyridine calcium channel blockers
Implantable cardioverter/defibrillator

Action	Numeric Key	Letter Key	Function Key
Show Bullets		S	Enter (frontside only)
20%	1	N
40%	2	H
60%	3	F	Enter (backside only)
80%	4	E
100%	5	M
Toss	0	T

Cardiomyopathies
	Dilated	Restrictive/Infiltrative	Hypertrophic
Etiology	ABCD Alcohol abuse Beriberi (wet) Coxsackie B viral myocarditis ChronicCocaine 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 fraction Eccentric hypertrophy (sarcomeres added in series)	Stiff myocardium causesdiastolic dysfunction Preserved left ventricular systolic function	Diastolic dysfunctionfrom↓ compliance of left ventricle Septal hypertrophy Majority of cases areobstructive(hypertrophic obstructive cardiomyopathy) Concentric hypertrophy (sarcomeres added in parallel)
Clinical presentation	Congestive heart failure S3 sound Systolic murmur	Progressive heart failure Sudden cardiac death S4 sound (and others can present with S3) + Kussmaul sign	Syncope with activity Sudden cardiac death (especially in young athletes) S4 sound Systolic 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 Electrocardiogram bundle branch block	Chest radiography cardiomegaly and pulmonary congestion Echocardiogram thickening of all structures diastolic dysfunction Endomyocardial biopsy the most accurate test for etiology Electrocardiogram may have low voltages	Echocardiography normal ejection fraction hypertrophy mitral regurgitation decreased end systolic volume and end diastolic volume Electrocardiogram left ventricular hypertrophy Histology tangled and disoriented myofibrils
Treatment	Angiotensin-converting enzyme inhibitors β-blockers Spironolactone Automatic implantable cardioverter/defibrillator Biventricular pacemaker	Treat underlying condition Diuretics Heart transplant	Avoid athletic activities β-blockers Non-dihydropyridine calcium channel blockers Implantable cardioverter/defibrillator