Right ventricular basal septal pacing revealed prolonged left ventricular trans-septal activation time in patients with septal scar compared to those without (55.3±33.0 vs 25.7±8.8 ms; P=0.003).
Observational (n=40)
Absolute Event Rate: 55.3% vs 25.7%
p-value: p=0.003
BACKGROUND: Identification of intramural basal-septal ventricular tachycardia (VT) substrate is challenging in nonischemic cardiomyopathy. We sought to (1) characterize normal/abnormal trans-septal right ventricular (RV) to left ventricular activation; (2) assess the effect of opposite RV pacing on left ventricular septal bipolar electrograms (EGMs); and (3) establish criteria for the identification of intramural septal VT substrate. METHODS AND RESULTS: Endocardial activation mapping and local EGM assessment of the left interventricular septum was performed during RV basal septal pacing in 40 patients undergoing VT ablation with no evidence of septal scar (group 1, n=14) and with septal scar (group 2, n=26) defined by low septal unipolar voltage (40 ms (sensitivity 60%, specificity 100%; P95 ms during pacing (sensitivity 22%, specificity 91%; P40 ms) and fractionated, late, split, and wide (>95 ms) bipolar EGMs during RV basal pacing identify intramural VT substrate. In select cases, the basal septum appears compartmentalized as the stimulated wavefront is rerouted to the scar border.
Betensky et al. (Wed,) conducted a observational in Nonischemic cardiomyopathy with ventricular tachycardia (n=40). Right ventricular basal septal pacing vs. No septal scar was evaluated on Left ventricular trans-septal activation time (p=0.003). Right ventricular basal septal pacing revealed prolonged left ventricular trans-septal activation time in patients with septal scar compared to those without (55.3±33.0 vs 25.7±8.8 ms; P=0.003).