Spontaneous angina is an ideal condition in which to study left ventricular (LV) dysfunction induced by acute myocardial ischemia. In 6 patients with Prinzmetal's angina, LV diastolic function during 16 episodes of spontaneous angina was studied by simultaneous recordings of electrocardiographic (ECG), echocardiographic and hemodynamic parameters. In particular, pulsed Doppler echocardiography measured peak velocity of early (E) and late (A) transmitral flow and E A ratio, as indexes of relative early versus late LV filling. During the ischemic attacks, the time sequence of pulsed Doppler echocardiographic and ECG changes showed 3 distinct phases: (1) waxing phase: transmitral flow changes with minimal ECG modifications ( E A = 0.85 ± 0.1); (2) "steady" phase: maximal ECG changes ( E A = 0.9 ± 0.1); and (3) "waning" phase: regression of the ECG changes ( E A = 1.26 ± 0.15). In each phase, E A ratio showed a significant difference from the baseline value ( E A = 1.17 ± 0.2) as a result of changes in E, suggesting that myocardial ischemia affects mainly the early phase of diastole. In the waxing phase, LV diastolic dysfunction preceded systolic abnormalities, as documented by a significant reduction of E A ratio in the absence of alterations in LV ejection fraction, as well as in systemic arterial and pulmonary wedge pressures. Finally, all the recorded parameters were consistent with LV "contractile rebound" occurring in the waning phase and affecting both diastole and systole.
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine