title: Doppler echocardiographic assessment of the effect of varying atrioventricular delay and pacemaker mode on left ventricular filling.
abstract: Pulsed Doppler echocardiography was used to study the timing and dynamics of left ventricular filling in 14 patients with permanent dual-chamber programmable pacemakers. Pacemakers were programmed to atrial sensed (VDD) mode and atrial-ventricular sequential paced mode at low (DVI-L) and high (DVI-H) heart rates, and pulsed Doppler recordings of transmitral flow were analyzed at atrioventricular delays of 50 to 300 msec in each mode. There was a significant decrease in the one-third filling fraction in both VDD and DVI-L modes and a significant increase in DVI-H modes with increasing atrioventricular delay. The ratio of early filling area to atrial filling area was significantly lower at longer atrioventricular delays in both VDD and DVI-L modes. The time from pacemaker spike to mitral valve closure was highly significantly correlated with atrioventricular delay in VDD, DVI-L, and DVI-H modes (r = -0.92, p = 0.0001; r = -0.90, p = 0.0001; and r = -0.85, p = 0.0001, respectively) as was the diastolic filling time to a lesser extent (r = -0.73, p = 0.0001; r = -0.69, p = 0.0001; r = -0.61, p = 0.0001, respectively). Events reflecting atrial systole occurred at a later time in the cardiac cycle in the atrial paced vs the atrial sensed mode. Thus changes in atrioventricular delay and pacemaker mode in this group of patients are a strong determinant of the timing and dynamics of left ventricular filling.
authors.affiliation: Department of Internal Medicine, St. Louis University Medical Center, MO.
authors.forename: A C
authors.initials: AC
authors.lastname: Pearson
authors.forename: D L
authors.initials: DL
authors.lastname: Janosik
authors.forename: R R
authors.initials: RR
authors.lastname: Redd
authors.forename: T A
authors.initials: TA
authors.lastname: Buckingham
authors.forename: R I
authors.initials: RI
authors.lastname: Blum
authors.forename: A J
authors.initials: AJ
authors.lastname: Labovitz
mesh_terms: D000368:Aged; D001283:Atrioventricular Node / Q000503:physiopathology*; D001783:Blood Flow Velocity; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D003326:Coronary Circulation; D004452:Echocardiography / Q000379:methods*; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006329:Heart Conduction System / Q000503:physiopathology*; D006339:Heart Rate; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000503:physiopathology; D009200:Myocardial Contraction; D013997:Time Factors