23 Hypertrophic cardiomyopathy
Salient features
History
Examination
• Carotid pulse is bifid (Fig. 23.1)
• ‘a’ wave in the JVP (see Case 15)
• Double apical impulse (left ventricular heave with a prominent presystolic pulse caused by atrial contraction)
• Pansystolic murmur at the apex caused by mitral regurgitation
• Ejection systolic murmur along the left sternal border (across the outflow tract obstruction); accentuated by standing and Valsalva manoeuvre and softer on squatting (squatting increases LV cavity size and reduces outflow tract obstruction). Remember the Valsalva manoeuvre decreases the duration of murmur of aortic stenosis and increases the murmur of hypertrophic cardiomyopathy
Advanced-level questions
How would you investigate this patient?
• Echocardiogram is useful for assessing LV structure and function, gradients (Fig. 23.2), valvular regurgitation, and atrial dimensions. Doppler echocardiography shows characteristic high-velocity late peaking or dagger-shaped spectral waveform (Fig. 23.2A). Characteristic findings include systolic anterior motion of mitral valve (SAM), asymmetric hypertrophy (ASH) and mitral regurgitation.
• ECG may be normal (in about 5% of patients) or show abnormalities including left ventricular hypertrophy, atrial fibrillation, left axis deviation, right bundle branch block and myocardial disarray (e.g. ST–T wave changes, intraventricular conduction defects, abnormal Q waves); bizarre or abnormal findings in young patients should raise suspicion of hypertrophic cardiomyopathy, (especially if family members also affected) (Fig. 23.3).
• Chest radiograph may be normal or show evidence of left or right atrial or left ventricular enlargement.
