ALTERATION OF LEFT-VENTRICULAR DIASTOLIC FUNCTION DURING CORONARY ANGIOPLASTY-INDUCED ISCHEMIA - A COLOR M-MODE DOPPLER STUDY

Objectives. The aim of this study was to assess the effects of ischemi a on diastolic function by analyzing flow propagation velocity with co lor M-mode Doppler echocardiography. Background. Color M mode Doppler echocardiography has been proposed as a method of assessing left ventr icular filling. Methods. Color M-mode Doppler echocardiography and mea surement of hemodynamic data were performed simultaneously at baseline and during angioplasty induced ischemia. Tau was compared with flow p ropagation velocity. Late diastolic indexes, left ventricular pressure and flow cessation time were also investigated.Results. During ischem ia, left ventricular relaxation rate (tau) increased, whereas flow pro pagation velocity decreased, from (mean +/- SD) 46.8 +/- 10 ms to 72.6 +/- 18.3 ms and from 59.8 +/- I5.8 cm/s to 30 +/- 8 cm/s, respectivel y (all p < 0.0001). The maximal slowing of flow propagation velocity w as observed 20 to 30 s after the beginning of the inflation, coexistin g with a notch on the ascending limb of the negative rate of rise of t he left ventricular pressure (dP/dt) curve. Flow propagation velocity was correlated with tau both at baseline (r = 0.53, p < 0.05) and duri ng inflation (r = 0.53, p < 0.03). Left ventricular end-diastolic pres sure increased during ischemia from 13.5 +/- 8 mm Hg at baseline to 27 .5 +/- 7 mm Hg, while a premature cessation of the entering how occurr ed -13.8 +/- 23 ms before the next Q wave onset, compared with 4.5 +/- 19.6 ms after the Q wave onset at baseline (all p < 0.0001). Conclusi ons. The analysis of how propagation velocity showed that early fillin g is highly dependent on left ventricular relaxation rate, particularl y through the phenomenon of asynchrony. During ischemia, the premature cessation of late filling is associated with increased diastolic pres sures. (C) 1997 by the American College of Cardiology.