TIMING OF RECIPIENT ATRIAL CONTRACTION - A MAJOR DETERMINANT OF TRANSMITRAL DIASTOLIC FLOW IN ORTHOTOPIC CARDIAC TRANSPLANTATION

The effect of recipient left atrial contraction on diastolic transmitr al flow was studied in eight asymptomatic heart transplant patients (s even men and one woman, mean age 51.8 +/- 9.7 years) with normal left ventricular systolic function. The transmitral flow velocity profile w as evaluated in 326 beats (mean 40.8 +/- 12 beats, range 20 to 58 beat s/patient). Recipient left atrial contraction was classified as early diastolic, late diastolic, and systolic. Results showed: (1) early dia stolic transmitral flow velocity integral (in centimeters) was lower ( p < 0.05) following late diastolic recipient left atrial contractions (7.5 +/- 2.1) compared with early diastolic (10.1 +/- 2.7) or systolic (8.5 +/- 1.5) recipient left atrial contractions; (2) late diastolic transmitral flow velocity integral was higher following late diastolic (4.7 +/- 1.8) compared with systolic (4.1 +/- 1.9) recipient left atr ial contractions and was virtually abolished (0.45 +/- 14) following e arly diastolic recipient left atrial contractions; and (3) total diast olic transmitral flow velocity integral was significantly higher (p < 0.05) following late diastolic and systolic (12.2 +/- 2.8 and 12.0 +/- 2.5) compared with early diastolic left atrial contractions (10.5 +/- 2.8). Thus recipient left atrial contraction is a significant determi nant of the transmitral diastolic flow pattern in heart transplant pat ients. Variations in the timing of recipient left atrial contraction m ay lead to fluctuations of diastolic flow and may compromise cardiac o utput.