Assessment of length-dependent regulation of myocardial function in coronary surgery patients using transmitral flow velocity patterns

Background: In a subset of coronary surgery patients, a transient increase in cardiac load by leg elevation resulted in a decrease in maximal rate of pressure development (dP/dt(max)) and a major Increase in end-diastolic pre ssure (EDP). This impairment of left ventricular (LV) function appeared to be related to a deficient length-dependent regulation of myocardial functio n. The present study Investigated whether analysis of transmitral flow patt erns with transesophageal echocardiography constituted a noninvasive method to identify these patients. Methods: High-fidelity LV pressure tracings and transmitral flow signals we re obtained in 50 coronary surgery patients during an increase in cardiac l oad by leg elevation. Using Linear regression analysis, changes in transmit ral E-wave velocity and deceleration time (DT) were related to changes in d P/dt(max) and EDP. Results: Changes in dP/dt(max) with leg elevation were closely related to c orresponding changes in E-wave velocity (r = 0.81; P < 0.001) and to change s in DT (r = 0.78; P < 0.001), Similarly, changes in EDP were related to ch anges in E-wave velocity (r = 0.83; P < 0.001) and to changes in DT (r = 0. 84; P < 0.001), The decrease in dP/dt(max) and the major increase in EDP in some patients was associated with an increase in E-wave velocity and a dec rease in DT, indicating development of a restrictive LV filling pattern. Conclusions: Impairment of LV function with leg elevation was associated wi th the development of a restrictive transmitral filling pattern. Analysis o f transmitral flow patterns by means of transesophageal echocardiography th erefore allowed noninvasive identification of a subset of coronary surgery patients with impaired length-dependent regulation of LV function.