[SAM sound studied by pulsed Doppler echocardiography].

Abstract

The occurrence of a systolic sound in hypertrophic obstructive cardiomyopathy (HOCM) has been well known for more than 20 years. This was phonoechocardiographically regarded as the sound coincident with the abrupt halt of the systolic anterior movement (SAM) of the mitral valve echo, and it has been termed the SAM sound. A 58-year-old man with HOCM was admitted with right hemiplegia. He was found to have a SAM sound which waxed and waned in intensity, and at times moved earlier into systole. He was studied by cardiac catheterization, M-mode and two-dimensional Doppler echocardiography (pulsed, continuous wave and color flow Doppler methods). Asymmetric septal hypertrophy (interventricular septal thickness = 25 mm, left ventricular posterior wall thickness = 14 mm), as well as SAM and midsystolic aortic valve closure were demonstrated. The presence and intensity of the sound was not related to rhythm (normal sinus rhythm vs atrial flutter), heart rate, respiration, position, or inhalation of amyl nitrite. Two-dimensional Doppler echocardiography revealed the following: 1. In the left ventricular outflow tract just below the aortic valve, a systolic turbulent flow was always present. 2. In the left ventricular chamber near the apex, a systolic laminar flow was interrupted in those cycles where the SAM sound was present. Otherwise, in cycles lacking the SAM sound, laminar flow in this locality continued throughout systole (even shorter duration than normal). 3. In the left ventricular inflow tract, diastolic flow was unaffected by the presence of the sound. 4. No mitral regurgitation was observed using color flow Doppler echocardiography. In summary, a SAM sound appeared to be associated with sudden deceleration of blood flow from the apex to the mid left ventricle.