[A prominent retrograde flow in coronary artery in patients with hypertrophic cardiomyopathy].

Pathophysiology and clinical significance of a systolic backward flow in the epicardial coronary artery have not been elucidated. Using a 20 MHz Doppler catheter, we assessed coronary flow velocity waveforms in the left anterior descending coronary artery in 19 patients with hypertrophic cardiomyopathy (HCM) and 11 patients without apparent cardiac abnormalities as control subjects. Systolic flow fraction was smaller in HCM than in controls. Only 4 patients with HCM showed a prominent retrograde flow persisting during almost the entire systole. All the 4 had marked cavity obliteration and two of them had systolic intraventricular pressure gradients of 80 and 110 mmHg respectively. Exercise thallium-201 ECT revealed that myocardial hypoperfusion was more frequent in those 4 patients. Through these observations, it is concluded that a high intramyocardial systolic pressure combined with a relatively low coronary perfusing pressure may result in a large systolic retrograde flow in the left epicardial coronary artery, and that it may be related to myocardial ischemia in patients with HCM.