Influence of short atrioventricular delay on late diastolic transmitral flow and stroke volume.
Atrial transport function and the corresponding transmitral flow and stroke volume depend on the timing of atrial contraction. To study the influence of short atrioventricular delay (AVD) on these hemodynamic parameters, transmitral flow velocity (by pulsed wave Doppler) and aortic flow (by electromagnetic technique) were studied and compared (paired t test) during normal and short AVD at fixed rate DDD pacing (80 bpm) in AV-blocked, open-chest canine preparations (n:16). The short AVD resulted in a shorter acceleration (difference 4.1 +/- 4.9 msec, mean +/- SD, p less than 0.05), a lower peak velocity (difference: 7.1 +/- 3.2 cm/sec, p less than 0.001), a shorter (difference: 26.9 +/- 16.2 msec, p less than 0.001) and more rapid deceleration (difference: 220.7 +/- 291.7 cm/sec2, p less than 0.005) of the late diastolic transmitral flow elicited by atrial systole. Stroke volume decreased (7.8 +/- 5.2%, p less than 0.001) during short AVD as a consequence of a reduced left ventricular filling due to the interruption of the active atrial transport by the onset of the ventricular contraction.
Ronaszeki
A
A
Department of Cardiology, University Hospital Gasthuisberg, Leuven, Belgium.
Denef
B
B
Ector
H
H
Aubert
A E
AE
Van de Werf
F
F
De Geest
H
H
D000818:Animals; D016275:Atrial Function; D001783:Blood Flow Velocity / Q000502:physiology; D002138:Calibration; D003971:Diastole / Q000502:physiology*; D004285:Dogs; D015150:Echocardiography, Doppler / Q000379:methods; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging; D006327:Heart Block / Q000503:physiopathology; D008297:Male; D008943:Mitral Valve / Q000000981:diagnostic imaging / Q000502:physiology*; D009200:Myocardial Contraction / Q000502:physiology*; D013318:Stroke Volume / Q000502:physiology*; D013997:Time Factors; D016277:Ventricular Function, Left / Q000502:physiology