Early mitral deceleration and left atrial stiffness

Abstract

Left ventricular (LV) filling deceleration time (DT) is determined by the sum of atrial and ventricular stiffnesses ( KLA+ KLV). If KLA, however, is close to zero, then DT would reflect KLVonly. The purpose of this study was to quantify KLAduring DT. In 15 patients, KLVwas assessed, immediately after cardiopulmonary bypass, from E wave DT as derived from mitral tracings obtained by transesophageal echocardiography and computed according to a validated formula. In each patient, a left atrial (LA) volume curve was also obtained combining mitral and pulmonary vein (PV) cumulative flow plus LA volume measured at end diastole. Time-adjusted LA pressure was measured simultaneously with Doppler data in all patients. KLAwas then calculated during the ascending limb of the V loop and during DT. LA volume decreased by 7.3 ± 6.5 ml/m2during the first of mitral DT, whereas LV volume increased 9.4 ± 8.4 ml/m2(both P < 0.001). There was a small amount of blood coming from the PV during the same time interval, with the cumulative flow averaging 3.2 ± 2.4 ml/m2( P < 0.001). Mean LA pressure was 10.0 ± 5.1 mmHg, and it did not change during DT [from 7.8 ± 4.3 to 8.0 ± 4.3 mmHg, not significant (NS)], making KLA, which averaged 0.46 ± 0.39 mmHg/ml during the V loop, close to zero during DT [ KLA(DT): from −0.002 ± 0.08 to −0.001 ± 0.031 mmHg/ml, NS]. KLV, as assessed noninvasively from DT, averaged 0.25 ± 0.32 mmHg/ml. In conclusion, notwithstanding the significant decrement in LA volume, KLAdoes not change and can be considered not different from zero during DT. Thus KLAdoes not affect the estimation of KLVfrom Doppler parameters.