DYNAMIC DETERMINANTS OF LEFT-VENTRICULAR EARLY DIASTOLIC FILLING IN OLD MYOCARDIAL-INFARCTION

The determinants of left ventricular early diastolic filling were assessed in 15 patients with old myocardial infarction. The left atrial pressure (LAP) and left ventricular pressure (LVP) were simultaneously measured by a Millar's multisensor micromanometer with the pulsed Doppler mitral inflow velocity at baseline and during angiotensin infusion (20 ng/kg/min). Cardiac output was measured by a thermodilution method. LV peak systolic pressure and end-diastolic pressure were significantly (p<0.001) increased during angiotensin infusion from 137+/-19 to 170+/-21 mmHg and from 13.3+/-5.9 to 20.4+/-6.2 mmHg, respectively. Cardiac index was significantly decreased during angiotensin infusion. Heart rate, diastolic time, and peak positive dP/dt were unchanged. Although the LA-LV peak pressure gradient[(LAP-LVP) max] was unchanged (from 2.8+/-1.0 to 3.0+/-1.4 mmHg), the pressure gradient interval (the interval between the first and second points of transmitral pressure crossover) was significantly (p<0.001) decreased from 154+/-38 to 117+/-26 msec during angiotensin infusion. Peak early diastolic mitral inflow velocity (peak E) and the time-velocity integral of E wave (Ei) were significantly decreased during angiotensin infusion from 51+/-10 to 45+/-11 cm/sec (p<0.002) and from 7.47+/-1.96 to 5.70+/-1.66 cm (p<0.001), respectively. Peak E had a significant linear correlation with[(LAP-LVP) max](r=0.660, p<0.0001), while Ei had a significant linear correlation with pressure gradient interval (r=0.751, p<0.0001). Thus, LV early diastolic filling is determined not only by the LA-LV peak pressure gradient, but also by the pressure gradient interval in the diseased human LV.