INTRAVENTRICULAR EARLY DIASTOLIC FILLING DURING ACUTE MYOCARDIAL-ISCHEMIA - ASSESSMENT BY MULTIGATED COLOR M-MODE DOPPLER-ECHOCARDIOGRAPHY

Background. Color M-mode Doppler echocardiography has been suggested a s a new noninvasive technique for assessing left ventricular diastolic function. The present study investigated intraventricular filling pat tern by color M-mode Doppler in patients during percutaneous translumi nal coronary angioplasty (PICA). In a dog model of myocardial ischemia , the color M-mode flow pattern was related to indices of global and r egional myocardial function. Methods and Results. From color M-mode im ages, the time difference (TD) between occurrence of peak velocity in the apical region and at the mitral tip was determined in 20 patients and eight anesthetized dogs during coronary occlusions. During PTCA, t he timing of peak velocity was progressively delayed from mitral valve to apex. Consistent with this, the dog model showed delayed apical fi lling during coronary occlusion; TD increased from 18+/-4 to 71+/-9 mi lliseconds (P<.01). In the ischemic region, systolic shortening (sonom icrometry) decreased from 20+/-3% to -5+/-2% (P<.01). The one-third fi lling fraction decreased from 59+/-5% to 31+/-6% (P<.01) and correlate d with TD (r=.85, P<.01). The time constant of isovolumic relaxation ( tau) increased slightly and correlated with TD (r=.81, P<.01). Pacing tachycardia, caval constriction, and volume loading were performed to mimic the ischemia-induced changes in heart rate, stroke volume, and i ntracavitary filling pressure, respectively. There were no significant changes in TD or tau during these interventions. Conclusions. Color M -mode Doppler echocardiography showed a marked delay of apical peak fi lling velocity during PTCA. The experimental data suggest that this re flects retarded filling of the ischemic ventricle. Thus, color M-mode Doppler may provide a useful method for assessing diastolic dysfunctio n.