Dynamic Intracavitary Left Ventricular Obstruction

Abstract

To characterize the differences between hypertrophic obstructive cardiomyopathy, left ventricular cavity obliteration and midventricuiar obstruction, a systematic analysis of the flow profiles was performed utilizing pulsed, continuous and color flow Doppler imaging in 31 patients (13 with hypertrophic obstructive cardiomyopathy, 9 with left ventricular cavity obliteration and 9 with midventricuiar obstruction). All three groups showed similar high velocity jets that initially gradually, then rapidly increased in systole (‘ski-slope’ systolic flow profiles). The calculated mean gradient was higher in the hypertrophic obstructive group than in the left ventricular cavity obliteration and midventricuiar obstruction groups. All patients in the midventricuiar obstruction group had increased early diastolic velocity at midventricuiar level (36.4 ± 32.2 cm/s), whereas the normal progressive decrease in velocity through the ventricle was observed in the other groups. A distinct outflow-directed isovolumic signal was observed in 7 of the 9 patients with apical dyskinesia in the midventricuiar obstruction group. In addition, an apically-directed isovolumic signal was present in 10 of 13 patients with hypertrophic obstructive cardiomyopathy in 6 of 9 patients with left ventricular cavity obliteration and in 2 of 9 with midventricuiar obstruction. Thus, two-dimensional echocardiography coupled with Doppler evaluation allows characterization of dynamic intracavitary obstruction syndromes.