Evaluation of Asynchronous Left Ventricular Relaxation by Doppler Echocardiography During Ventricular Pacing with AV Synchrony (VDD): Comparison with Atrial Pacing (AAI)

Abstract

The effect of right ventricular pacing on left ventricular relaxation was studied in 13 patients (age 62 +/- 3 years), with the atrial sensing ventricular pacing mode (VDD). A control group of similar age (64 +/- 4 years) consisted of 11 patients with atrial pacing (AAI). The timing of events was determined in both groups at similar R-R intervals (921 +/- 77 ms vs 967 +/- 37 ms). The loading conditions as estimated by peak systolic wall stress (afterload) and end-diastolic left ventricular dimensions (preload) were approximately the same in both groups. The ratio of late to early filling velocities were similar in both groups. Dominant changes were: increased preejection period (142 +/- 13 ms vs 95 +/- 15 ms); and higher velocities of isovolumic relaxation flow (60 +/- 34 cm/s vs 25 +/- 4 cm/s) in patients with ventricular pacing. The isovolumic relaxation time was longer in patients with VDD pacing (127 +/- 14 ms vs 108 +/- 12 ms). Anterior systolic interventricular septal motion (paradoxal motion) was recorded in nine patients with VDD pacing and in none of the patients with AAI pacing. Isovolumic relaxation flow was detected during atrial pacing in five (45%) patients and in 13 (100%) patients during atrial sensing ventricular pacing, indicating asynchronous left ventricular relaxation. This data shows that VDD pacing compared to atrial pacing resulted in an altered activation pattern of the left ventricle, associated with delayed onset, asynchronous contraction with interventricular septal motion abnormalities and prolonged asynchronous left ventricular relaxation with abnormal motion manifested by the presence of isovolumic relaxation flow.

Improved cardiac function and quality of life following upgrade to dual chamber pacing after long-term ventricular stimulation

“…Further, there was a selection of a subgroup of patients with VVIR pacemakers who had tolerated long-term ventricular stimulation without developing chronic atrial fibrillation. It is possible that the patients in the present study, who had been paced in VVI pacing for an extended period of time, may be more dependent upon atrioventricular synchrony than others due to remodelling of the ventricles [24,25] .…”

Long-Term Effects of Atrial Synchronous Ventricular Pacing on Systolic and Diastolic Ventricular Function in Patients with Normal Left Ventricular Ejection Fraction

“…Looking at conventional Doppler parameters, some data suggest that VP, compared to atrial pacing alone, prolongs IVRT [22, 23]. Our finding of longer IVRT and deceleration time in patients with VP together with decreased E/A ratio and TDI-Ea measures suggest that VP results in more impaired relaxation.…”

“…Despite the presence of atrial systole, RV stimulation in dual-chamber devices may still adversely affect the overall LV systolic performance due to the profoundly modified interventricular septal motion [22, 23]. In this regard, there are discrepant results on whether VP reduces [24] or does not affect LV EF [25].…”

Immediate impairment of left ventricular mechanical performance and force–frequency relation by rate-responsive dual-chamber, but not atrial pacing: Implications from intraventricular isovolumic relaxation flow

“…First, the nonphysiological electrical excitation of the myocardium resulted in asynchronous contraction of the left ventricle. The peak velocity of the mitral annulus systolic wave (Sm), proven to reflect the peak rate of the left ventricular pressure rise during contraction (peak dP / dt) [15], decreased after right ventricular apical pacing [8]. Secondly, several parameters concerning diastolic function were impaired by DDD pacing.…”

“…The intraventricular flow driven by the pressure gradient generated from the physiologic nonuniformity can be used to investigate the disruption of ''optimal tuning'' of cardiac muscle-pump performance in various pathologic conditions [5,6]. Using the continuous wave Doppler echocardiography, previous studies have shown the intraventricular flow during isovolumic relaxation produced by right ventricular pacing [7,8]. The color M-mode echocardiography, having the advantage of temporal and spatial resolution, can describe the influence on isovolumic relaxation flow by disrupted nonuniformity more instructively than the conventional Doppler method [6,9].…”