Abstract 8715: Multidirectional Left Ventricular Performance Using Three-Dimensional Speckle-Tracking Strain in Patients with Chronic Right Ventricular Pacing and Preserved Ejection Function
Background: Right ventricular (RV) pacing has a detrimental effect on global left ventricular (LV) function even in some patients with preserved ejection fraction (EF), but its mechanism remains unclear. Our objective was to evaluate early subtle changes by chronic RV pacing in patients with preserved EF using novel three-dimensional (3-D) speckle-tracking strain.
Methods: We studied 112 subjects; 52 patients with chronic RV pacing and preserved EF (all ≥ 50%), an EF-matched 20 normal controls, and 30 heart failure (HF) patients with chronic RV pacing and reduced EF (all≤35%). Radial, circumferential and longitudinal dyssynchrony and function were quantified as standard deviation of time-to-peak strain and global peak strain using 3-D speckle-tracking strain from all 16 LV segments (Aplio Artida, Toshiba Corp.).
Results: The degree of radial and circumferential dyssynchrony and function in patients with chronic RV pacing and preserved EF and controls were similar (radial dyssynchrony: 28±20ms vs. 26±19ms, circumferential dyssynchrony: 31±14ms vs. 29±14ms, and global radial strain: 37±20% vs. 39±12%, global circumferential strain: 27±14% vs. 30±11%, respectively). Patients with chronic RV pacing and preserved EF, however, had greater longitudinal dyssynchrony with 42±22ms vs. 27±13ms, and lower global longitudinal strain with 21±13% vs. 30±19% compared to controls (both p<0.05). Furthermore, longitudinal strain in septum was significantly lower than that in posterior-lateral wall (19±9% vs. 27±10%, p<0.05), and longitudinal dyssynchrony at apex was significantly larger compared to mid and basal level (51±14ms vs. 40±9ms and 38±8ms, p<0.05) in patients with chronic RV pacing and preserved EF. In contrast, HF patients with chronic RV pacing and reduced EF had greater radial, circumferential and longitudinal dyssynchrony, and lower global radial, circumferential and longitudinal strain compared to controls (all p<0.001).
Conclusion: Longitudinal dyssynchrony was observed in patients with chronic RV pacing and preserved EF with impaired longitudinal function. 3-D speckle-tracking strain was useful at evaluating early subtle changes by chronic RV pacing, and may play a clinical role at predicting future global LV dysfunction.
- © 2011 by American Heart Association, Inc.