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Cardiomyopathies & Valvular Disease

Name: Cardiomyopathies & Valvular Disease
Creator: Veli Bakalov, MD

Three failing muscles, six murmurs, and the maneuvers that separate them

Cardiovascular·Myocardial, Valvular & Pericardial Disease·4 min read·9 high-yield points·Reviewed by Veli Bakalov, MD @HemeOncBuddy

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Dilated cardiomyopathy = systolic failure with eccentric hypertrophy, S3, and MR/TR: alcohol, wet beriberi, Coxsackie B, Chagas, cocaine, doxorubicin (dexrazoxane protects), peripartum.
Hypertrophic cardiomyopathy = autosomal dominant sarcomere mutations (MYH7 β-myosin heavy chain, MYBPC3): asymmetric septal hypertrophy, myofiber disarray, sudden VF death in young athletes.
HOCM: systolic anterior motion of the mitral valve obstructs outflow; treat with β-blockers and avoid dehydration and preload reducers.
Restrictive cardiomyopathy: amyloid (low-voltage ECG, speckled sparkling myocardium), sarcoid, hemochromatosis, endomyocardial fibrosis, post-radiation fibrosis.
Aortic stenosis: crescendo-decrescendo murmur at the right upper sternal border to the carotids, pulsus parvus et tardus, syncope–angina–dyspnea; senile calcification or bicuspid valve.
Aortic regurgitation: early diastolic decrescendo murmur with wide pulse pressure (water-hammer, head bobbing, Quincke pulses).
Mitral stenosis is almost always rheumatic: opening snap, mid-diastolic rumble, left atrial enlargement with AF; shorter S2–OS interval = more severe.
MR: holosystolic apical murmur to the axilla; MVP: mid-systolic click and late murmur from myxomatous degeneration, the most common valve lesion.
Hand grip (↑ afterload) increases MR, AR, VSD and softens AS and HOCM; Valsalva/standing (↓ preload) make HOCM louder and AS softer and move the MVP click earlier.

Cardiomyopathies: the systolic–diastolic split

Organizing principle. Dilated cardiomyopathy is a systolic problem: a weak, dilated pump with a low EF. Hypertrophic and restrictive cardiomyopathies are diastolic problems: a stiff ventricle that cannot fill. This split organizes the whole topic.

The three cardiomyopathies

Feature	Dilated	Hypertrophic	Restrictive
Core problem	Systolic dysfunction, low EF	Diastolic dysfunction ± outflow obstruction	Diastolic dysfunction from stiff, infiltrated walls
Morphology	Dilated chambers, eccentric hypertrophy	Asymmetric septal hypertrophy, myofiber disarray	Normal or small ventricles, enlarged atria
Exam clues	S3, mitral and tricuspid regurgitation	S4, systolic murmur if obstructive	Low-voltage ECG in amyloid
Classic causes	Alcohol, wet beriberi, Coxsackie B, Chagas, cocaine, doxorubicin, peripartum	Autosomal dominant sarcomere mutations	Amyloid, sarcoid, hemochromatosis, endomyocardial fibrosis, radiation

Dilated cardiomyopathy

The balloon heart. The most common cardiomyopathy. The chambers dilate through eccentric hypertrophy (sarcomeres added in series), EF falls, and the stretched mitral and tricuspid annuli leak, producing regurgitant murmurs along with an S3.

Causes. Many cases are idiopathic or familial (for example, titin mutations). Acquired causes to know:

Alcohol and wet beriberi (thiamine deficiency)
Coxsackie B myocarditis and Chagas disease (Trypanosoma cruzi)
Cocaine
Doxorubicin: dose-dependent free-radical injury, reduced by the iron chelator dexrazoxane
Peripartum cardiomyopathy: last month of pregnancy to 5 months postpartum
Duchenne and Becker muscular dystrophy (dystrophin)

Hypertrophic and restrictive cardiomyopathy

HCM genetics. Autosomal dominant mutations in sarcomere genes, most often β-myosin heavy chain (MYH7) and myosin-binding protein C (MYBPC3); HCM is also associated with Friedreich ataxia.

Sarcomere mutationMYH7 or MYBPC3, autosomal dominant.
Asymmetric septal hypertrophyMyofiber disarray on histology.
Diastolic dysfunction and obstructionStiff ventricle (S4); in HOCM, the septum and systolic anterior motion (SAM) of the mitral valve block LV outflow.
Sudden cardiac deathVentricular fibrillation, classically in a young athlete.

Obstruction is dynamic. Anything that shrinks the LV cavity — dehydration, low preload, vasodilation — pulls the mitral leaflet into the outflow tract and worsens the systolic murmur, which often comes with mitral regurgitation.

Treat HOCM with β-blockers (or verapamil) to slow the heart, lengthen filling, and reduce contractility. Avoid dehydration and preload-reducing drugs such as diuretics and vasodilators.

Restrictive cardiomyopathy. Stiff or infiltrated walls impair filling while ventricular size stays normal or small. Causes: amyloidosis (low-voltage ECG despite a thick wall, with a speckled, sparkling myocardium on echo), sarcoidosis, hemochromatosis, endomyocardial fibrosis, Löffler (eosinophilic) endocarditis, and post-radiation fibrosis.

Valvular lesions and their murmurs

Timing. Systolic murmurs: aortic and pulmonic stenosis, mitral and tricuspid regurgitation, VSD, and MVP. Diastolic murmurs: aortic and pulmonic regurgitation, mitral and tricuspid stenosis. Inspiration increases venous return to the right heart and accentuates right-sided murmurs; expiration accentuates left-sided ones.

Left-sided valve lesions

Lesion	Murmur	Site and radiation	Key findings	Causes
Aortic stenosis	Crescendo-decrescendo systolic ejection	Right upper sternal border → carotids	Pulsus parvus et tardus; syncope, angina, dyspnea	Senile calcification, bicuspid valve (younger), rheumatic
Aortic regurgitation	Early diastolic decrescendo, blowing	Left sternal border, leaning forward	Wide pulse pressure: Corrigan, de Musset, Quincke signs	Root dilation (Marfan, syphilis), bicuspid valve, endocarditis
Mitral stenosis	Opening snap, then mid-diastolic rumble	Apex	Left atrial enlargement: AF, dysphagia, hoarseness (Ortner)	Almost always rheumatic
Mitral regurgitation	Holosystolic (pansystolic)	Apex → axilla	Louder with hand grip and squatting	MVP, ischemic papillary muscle, LV dilation, rheumatic, endocarditis
Mitral valve prolapse	Mid-systolic click, late systolic murmur	Apex	Most common valvular lesion	Myxomatous degeneration (Marfan, Ehlers-Danlos)

Aortic stenosis. The syncope–angina–dyspnea triad marks severe disease, and the pressure-loaded LV develops concentric hypertrophy. Weak, delayed carotid upstrokes reflect the fixed outflow limit.

Aortic regurgitation. A large stroke volume leaks back in diastole, widening the pulse pressure: Corrigan water-hammer pulse, de Musset head bobbing, and Quincke nail-bed pulsations. A regurgitant jet striking the anterior mitral leaflet can add an apical diastolic rumble (Austin Flint murmur).

Mitral stenosis. A shorter S2-to-opening-snap interval means higher left atrial pressure and more severe disease. The enlarged left atrium triggers atrial fibrillation and can compress the esophagus (dysphagia) or recurrent laryngeal nerve (hoarseness, Ortner syndrome).

Dynamic auscultation: maneuvers

Maneuvers and murmur intensity

Maneuver	Main effect	Louder	Softer or later
Squatting, leg raise	↑ Preload (squatting also ↑ afterload)	AS, MR, AR, VSD	HOCM; MVP click later
Hand grip	↑ Afterload	MR, AR, VSD	AS, HOCM; MVP click later
Valsalva, standing	↓ Preload	HOCM; MVP (earlier click, longer murmur)	Most others, including AS
Inspiration	↑ Right-heart venous return	Right-sided murmurs	Left-sided murmurs

HOCM vs aortic stenosis. Both produce systolic ejection murmurs, but they respond oppositely to Valsalva. Less preload leaves less blood to stent open the outflow tract, so the HOCM murmur gets louder, whereas the AS murmur softens because less blood crosses the fixed valve.

MVP follows ventricular size: a smaller LV (Valsalva, standing) lets the leaflets prolapse sooner, moving the click earlier and lengthening the murmur; a larger LV (squatting, hand grip) delays it.