Spatial Dispersion of Activation and Repolarization Times Associated with Different Cardiac Pacing Modes

Various modes of ventricular pacing are currently applied to patients with an indication for permanent pacemaker implantation. The so-called physiological pacing modes, like His bundle pacing (HBP) and left bundle branch pacing (LBBP), stimulate the cardiac conduction system to induce efficient physiological activation. Other techniques, such as left ventricular septal pacing (LVSP) and right ventricular septal and apical pacing (RVSP and RVAP), stimulate the ventricular septum or right ventricular apex. 695 ultra-high-frequency electrocardiograms (UHF-ECG)from 176 patients with narrow QRS and pacemaker indication were analyzed to characterize their activation (AT) and repolarization (RT) time. AT and RT were grouped into three regions (R1: leads V1-V2; R2: V3-V4; R3: V5-V6). Overall, selective HBP (sHBP), non-selective LBBP (nsLBBP) and LVSP recordings had the closest AT and RT values to spontaneous rhythm recordings. For AT, the mean R1-R2 and R3-R2 differences with respect to spontaneous rhythm were, in absolute value, below 3, 16 and 10 ms for sHBP, nsLBBP and LVSP, respectively. For RT, the corresponding mean differences were below 11, 34 and 24 ms for sHBP, nsLBBP and LVSP. In conclusion, HBP, LBBP and LVSP render the closest ventricular AT and RT to the spontaneous rhythm in patients with physiological conduction (narrow QRS).