Right ventricular pacing acutely impaired left atrial emptying fraction by 44% and increased minimal volume by 42% during VVI pacing in patients with LV dysfunction (P<0.0009).
Observational (n=45)
Does right ventricular pacing acutely impair left atrial function in patients with LV dysfunction compared to intrinsic conduction?
Right ventricular pacing acutely impairs left atrial emptying and increases minimal volume in patients with LV dysfunction, even with preserved AV synchrony, suggesting impaired diastolic recoil as a mechanism for pacing-induced atrial fibrillation.
p-value: p=<0.0009
BACKGROUND: RV pacing (RVP), even with preserved atrioventricular (AV) synchrony, may lead to left atrial (LA) enlargement and atrial fibrillation. However, inciting events are unknown. We hypothesized that RVP acutely impairs LA function by mechanisms affecting atrial contraction and/or ventricular diastole. METHODS: LA function in ICD patients (n = 31, LVEF ≤ 40%) and controls (n = 14, LVEF > 50%) was contrasted between intrinsic conduction versus RVP during asynchronous (ICD, n = 17, control, n = 7), and synchronous (ICD, n = 14, control, n = 14) pacing at long (LAVd, 107 ±16 ms) and short (SAVd, 31 ± 5 ms) AV delays. LA maximal volume (LA (Max) ), minimal volume (LA (Min) ), and emptying fraction LA (EmF) = (LA (Max) -LA (Min) ) /LA (Max) were measured echocardiographically. Six-segment mean mitral annular tissue doppler E' (global E') assessed diastolic recoil during baseline and LAVd. RESULTS: In the ICD group, LA (Min) increased by 42% (P < 0. 0009) during VVI, by 31% (P = 0. 0002) during SAVd, and by 17% (P < 0. 0007) during LAVd. LA (EmF) decreased by 44% (P < 0. 0008), 27% (P < 0. 0001), and by 15% (P = 0. 003) during VVI, SAVd, and LAVd respectively. LA (Max) was unaltered. Global E' was reduced by 12%. In control, LA (Min) increased and LA (EmF) decreased significantly during VVI (82 and 58%) and SAVd (46 and 41%), but not during LAVd. CONCLUSION: In patients with LV dysfunction, RVP acutely impaired LA emptying, and increased minimal volume, most prominently when atrial contraction was impeded (VVI, DDD-SAVd) but also when completed (DDD-LAVd), indicating impaired diastolic recoil as an important mechanism. When LV function was normal, similar changes were present when atrial filling is impeded (VVI, SAVd), but not when completed (LAVd).
Sanagala et al. (Wed,) conducted a observational in Heart Failure (n=45). Right Ventricular Pacing (RVP) vs. Intrinsic conduction was evaluated on Left atrial minimal volume (LA(Min)) and emptying fraction (LA(EmF)) (p=<0.0009). Right ventricular pacing acutely impaired left atrial emptying fraction by 44% and increased minimal volume by 42% during VVI pacing in patients with LV dysfunction (P<0.0009).