B-po04-047 ventricular dyssynchrony assessed with speckle-tracking echocardiography is lower in leadless pacemakers compared to transvenous pacemakers

Frequent right ventricular pacing (>40%) with transvenous pacemakers (TVP) is associated with the development of pacing induced cardiomyopathy (PICM) in 10-15% of patients. Recent studies have suggested a significantly lower incidence of PICM in patients with leadless pacemakers (LP). The underlying mechanism for the decreased incidence of PICM in patients with LP is not known. To assess ventricular dyssynchrony, as measured by global longitudinal strain (GLS), in contemporaneous cohorts of pacemaker dependent patients with LP and TVP. The study included pacemaker dependent patients with left ventricular ejection fraction ≥50% at time of device implant. Right (RV) and left ventricular (LV) global longitudinal strain, assessed by speckle-tracking echocardiography, was obtained prior to and after pacemaker implantation in each group. This study included 103 patients (LP: 38; TVP: 65). After a median duration of 254 days (interquartile range: 470), 2 patients in the LP and 15 in the TVP groups developed PICM. Incidence of PICM was significantly higher in TVP group, p=0.02. At baseline, RV and LV GLS were similar in both LP and TVP groups [(RV: LP = -17.9 ± 4.5, TVP = -17.3 ± 4.5, p=0.55) (LV: LP = -16.2 ± 2.3, TVP = -15.8 ± 2.9, p=0.52)]. However, post-device implantation, both RV and LV GLS were significantly impaired in the TVP group [(RV: LP = -17.5 ± 4.6, TVP = -14.1 ± 3.7, p < 0.0001) (LV: LP = -15.4 ± 2.4, TVP = -12.4 ± 3.6, p < 0.0001)]. Pre- and post-device RV and LV GLS did not differ significantly within the LP group, p=0.72 and p=0.17, but were significantly less negative in the TVP group, both with p < 0.0001. In pacemaker dependent patients, the incidence of PICM is lower with LP compared to TVP. Despite a similar baseline GLS, patients with TVP had significantly less negative GLS when compared to LP. Ventricular dyssynchrony, as assessed by GLS, could be responsible for the higher incidence of PICM in TVP patients.