- Hypertrophic cardiomyopathy
- Hypertrophy of the interventricular septum narrows the LV outflow tract
- High-velocity systolic flow draws the anterior leaflet of the mitral valve into the tract (via the Bernoulli effect) .(MCQ)
- causes a dynamic left ventricular outflow tract obstruction.
- ∼50% idiopathic
- ∼50% familial (autosomal dominant, with variable penetrance).(MCQ)
- Conditions that increase the LV end diastolic volume decrease the obstruction .(A frequently asked MCQ in MD Entrance )
- increased blood volume
- negative inotropic drugs
- increased peripheral resistance
- Outflow obstruction can result in left atrial dilatation, atrial fibrillation, CHF, right heart failure, etc.
- Signs and symptoms
- Occurs at rest and during exercise
- Frequently unresponsive to nitroglycerin
- May respond to recumbent position (pathognomonic but rare)
- Most often occurs following exercise
- Arrhythmias: Atrial fibrillation, ventricular tachycardia
- Signs of CHF
- Sudden death is usually due to an arrhythmia..(MCQ)
- Systolic ejection murmur.(MCQ)
- heard best along the left sternal border
- decreases with increased LV blood volume (squatting)
- increases with
- increased blood velocities (exercise)
- decreased LV end-diastolic volume (Valsalva)
- Paradoxical splitting of S2
- ECG: .(MCQ)
- LVH, PVCs, atrial fibrillation
- inferiorlateral Q waves
- nonspecific ST segment and T wave abnormalities
- Septal hypertrophy, LVH, small LV
- Patient should refrain from vigorous exercise.
- Beta blockers–first line agents.(MCQ)
- reduce heart rate
- increasing LV filling time
- calcium channel blockers considered second-line agents.
- The roles of antiarrhythmics, septal myomectomy, pacemaker, and defibrillator are all controversial.
- Avoid anything that decreases preload(nitrates, diuretics, volume depletion) as this will worsen obstruction by allowing left ventricular collapse..(MCQ)
- Clinical Vignette in MD Entrance :.(MCQ)
- A18-year-old athlete from Bihar becomes severely dyspneic and collapses while running laps. His father had died suddenly at an early age.
- Diagnosis :Hypertrophic cardiomyopathy.
- Very few murmurs decrease with squatting (HCM does)..(MCQ)
- Systolic ejection murmur.(MCQ)
Hypertrophic cardiomyopathy: Pathophysiology and diagnosis
What is a cardiomyopathy?
Cardiomyopathies are instrinsic diseases of the heart. Here we see a defect in the cardiac muscle fibers. Cardiomypathies are rare heart diseases and these are more commonly used for differential diagnosis (eg inflammatory, valvular, vascular, congenital etc)
There are many types of cardiomyopathies but the common ones include dilated, hypertrophic and restrictive.
Hypertrophic Cardiomyopathy Overview – Mayo Clinic
Dr. Steve Ommen, a cardiologist at Mayo Clinic, discusses Hypertrophic Cardiomyopathy.
Euan Ashley, director of the hypertrophic cardiomyopathy program at Stanford University, discusses hypertrophic cardiomyopathy, an excessive thickening of the heart muscle without an obvious cause and often an inherited condition. Learn about the causes of the disorder, and the existing and emerging treatments for this cryptic disorder.
Hypertrophic Cardiomyopathy (HCM) – Ask The Doctor Series
Dr. Naidu answers your questions about Hypertrophic Cardiomyopathy (HCM)
Steven J. Lester, M.D., cardiologist at Mayo Clinic in Arizona, discusses the symptoms, diagnosis and treatment of hypertrophic cardiomyopathy.
Hypertrophic Cardiomyopathy Explained