CORONARY FLOW DYNAMICS AND RESERVE ASSESSED BY TRANSESOPHAGEAL ECHOCARDIOGRAPHY IN OBSTRUCTIVE HYPERTROPHIC - CARDIOMYOPATHY

Myocardial ischemia is frequently associated with left ventricular out flow obstruction. To assess coronary flow impairment in obstructive hy pertrophic cardiomyopathy (HC), 10 patients with echo-Doppler-detected obstructive HC and normal coronary arteries underwent transesophageal echo-Doppler examination of both coronary flow velocity (CFV) at rest , recorded in the proximal left anterior descending coronary artery, a nd coronary now reserve (CFR) evaluated by means of dipyridamole infus ion response. Ten normal patients were similarly studied and served as a control group. Two relevant alterations in coronary flow dynamics w ere detected in patients with HC: (1) a significantly increased diasto lic/systolic CFV ratio, and (2) a significantly reduced dipyridamole/b aseline CFV ratio. Compared with normal subjects, the CRI pattern show ed a significantly greater diastolic and a significantly lower systoli c component at rest (in some patients it was reversed). Diastolic/syst olic CRI ratio was significantly higher in pa tients with HC at baseli ne (3.1 +/- 1 vs 1.6 +/- 0.5; p < 0.01) and increased further after di pyridamole infusion (4.9 +/- 2 vs 2.2 +/- 0.7; p < 0.01). In addition, CFR was impaired in patients with HC (1.8 +/- 0.3 vs 3.1 +/- 0.5; p < 0.01). Furthermore, a significant correlation between CFR and intrave ntricular pressure gradient was found. Thus, transesophageal echo-Dopp ler examination is a useful tool for evaluating CFV dynamics and CFR a s demonstrated in patients with obstructive HC.