Diagnosis and Treatment of Cardiomyopathies

Predominant pathophysiology

Systolic and diastolic dysfunction with ventricular dilation

Diastolic dysfunction ± dynamic LVOT obstruction; often hyperdynamic systolic function

Diastolic dysfunction with relatively preserved systolic function

Non-ischemic LV scarring ± LV systolic dysfunction without ventricular dilation

Clinical findings

LV ± RV failure, atrial and ventricular arrhythmias, sudden death

Functional mitral/tricuspid regurgitation

S3 and/or S4

Exertional dyspnea, angina, syncope, sudden death

Dynamic systolic murmur (in obstructive HCM) ± mitral regurgitation murmur, S4

Bifid carotid pulse with a brisk upstroke and rapid downstroke

Exertional dyspnea, fatigue, peripheral edema, arrhythmias

LV ± RV failure

Functional mitral/tricuspid regurgitation, atrial enlargement

Often asymptomatic, may develop shortness of breath, palpitations or syncope, S3 and/or S4

ECG

Nonspecific ST- and T-wave abnormalities

Conduction abnormalities, including BBB/IVCD

Poor R-wave progression and Q waves (precordial/lateral leads

Q Conduction abnormalities: BBB/IVCD, poor R-wave progression, Q waves (precordial/lateral leads)

Atrial fibrillation common

LV hypertrophy and repolarization abnormalities

Deep septal Q waves

LV hypertrophy or low QRS voltage (especially in infiltrative cardiomyopathies), conduction abnormalities, atrial arrhythmias

AV block

Low QRS amplitude

BBB

Echocardiography

Dilated hypokinetic ventricles ± mural thrombus

Systolic dysfunction and, frequently, functional mitral/tricuspid regurgitation

LV hypertrophy, typically normal or hyperdynamic LV systolic function, ± systolic anterior motion of the mitral valve ± LVOT obstruction ± mitral regurgitation

Normal or reduced ventricular cavity size, increased wall thickness (in infiltrative disease), biatrial enlargement

LV diastolic dysfunction with restrictive filling pattern

Normal LV cavity size

LV systolic dysfunction (± regional wall motion abnormalities) OR normal LV systolic function with non-ischemic LV scarring

Radiography

Enlarged cardiac silhouette

± Pulmonary venous congestion

No or mild cardiomegaly

No or mild cardiomegaly; possible atrial enlargement

± Pulmonary venous congestion

Cardiac silhouette normal in size

± Pulmonary venous congestion

Hemodynamics

Normal or high EDP

Normal or low CO

High EDP ± LVOT gradient ± mitral regurgitation

Normal or low CO

High EDP, "dip and plateau" sign

Normal or low CO

Normal or high EDP

Normal or low CO

Prognosis

Variable; improved with guideline-directed therapy; mortality remains significant in advanced disease

Generally favorable; < 0.5% annual risk of sudden death (higher in high-risk patients)†

Often poor depending on etiology; high morbidity and mortality

Not well defined

Treatment

GDMT: ARNi (ACE inhibitors orangiotensin II receptor blockers if ARNi not feasible), SGLT2 inhibitor, beta-blockers, mineralocorticoid receptor antagonists ; diuretics for congestion; ICD/CRT-D in selected patients

For obstructive HCM: Beta-blockers or non-dihydropyridine calcium channel blockers, cardiac myosin inhibitors, disopyramide, septal reduction therapy

ICD in high-risk patients

Diuretics for symptom relief

Treatment of underlying cause if known

GDMT

Diuretics for congestion relief

ICD/CRT-D in selected patients