Preserved cardiac synchrony and function with single-site left ventricular epicardial pacing during mid-term follow-up in paediatric patients

Right ventricular (RV) pacing may cause dyssynchronous left ventricular (LV) contraction and systolic dysfunction. Left ventricular-based pacing may prevent such deterioration. The aim of this study was to evaluate ventricular synchrony and function with permanent LV pacing (LVP) vs. RV pacing (RVP) in paediatric patients with normal cardiac anatomy. Twenty-five paediatric patients with normal cardiac anatomy and single-site epicardial RV apex pacing (RVP, n = 10, pacing duration: 7.9 +/- 2.9 years) or LV free wall pacing (LVP, n = 15, pacing duration: 4.3 +/- 2.6 years) for complete heart block were enrolled. A total of 15 healthy children served as a control group. Conventional echocardiography, myocardial circumferential (LV), and longitudinal (RV) 2D strain (2Ds) analysis were obtained. Paced QRS duration did not differ between groups (P = 0.915). Interventricular mechanical delay (LVP: 17 +/- 10, RVP: 62 +/- 15 ms; P < 0.0001), septal-to-posterior wall motion delay (LVP: 59 +/- 23, RVP: 294 +/- 84 ms; P < 0.0001), septal-to-lateral wall motion delay (LVP: 40 +/- 19, RVP: 59 +/- 12 ms; P = 0.009), and LV mechanical delay (LVP: 35 +/- 9, RVP: 63 +/- 17 ms; P < 0.0001) were preserved for LVP but not for RVP. Right ventricular mechanical delay was similar among paced groups (P = 0.639). Left ventricular ejection fraction was normal for LVP but not for RVP (LVP: 60 +/- 6%, RVP: 45 +/- 6%; P = 0.012). Left ventricular pacing did not differ from controls for synchrony or function. Conventional and 2Ds echocardiographic measurements indicate preserved LV synchrony and function in paediatric patients with LVP compared with RVP. Permanent LVP has no impact on RV synchrony.