Speckle-Tracking Radial Strain Reveals Left Ventricular Dyssynchrony in Patients With Permanent Right Ventricular Pacing

ObjectivesSpeckle-tracking strain analysis was used to assess the effects of permanent right ventricular (RV) pacing on the heterogeneity in timing of regional wall strain and left ventricular (LV) dyssynchrony.BackgroundRecent studies have shown detrimental effects of RV pacing, possibly related to the induction of LV dyssynchrony.MethodsFifty-eight patients treated with His bundle ablation and pacemaker implantation were studied. To assess the effect of RV pacing on time-to-peak radial strain of different LV segments, we applied speckle-tracking analysis to standard LV short-axis images. In addition, New York Heart Association (NYHA) functional class, LV volumes, and systolic function were assessed at baseline and after long-term RV pacing.ResultsAt baseline, similar time-to-peak strain for the 6 segments was observed (mean 371 ± 114 ms). In contrast, after a mean of 3.8 ± 2.0 years of RV pacing, there was a marked heterogeneity in time-to-peak strain of the 6 segments. In 33 patients (57%), LV dyssynchrony, represented by a time difference ≥130 ms between the time-to-peak strain of the (antero)septal and the posterolateral segments, was present. In these patients, a deterioration of LV systolic function and NYHA functional class was observed. In 11 patients, an “upgrade” of the conventional pacemaker to a biventricular pacemaker resulted in partial reversal of the detrimental effects of RV pacing.ConclusionsSpeckle-tracking analysis revealed that permanent RV pacing induced heterogeneity in time-to-peak strain, resulting in LV dyssynchrony in 57% of patients, associated with deterioration of LV systolic function and NYHA functional class. Biventricular pacing may reverse these adverse effects of RV pacing.