Abstract 15834: Stimulation Within the Scar is Superior to Right Ventricular Stimulation for the Induction of Clinical Arrhythmias in Patients with Post-Infarction Ventricular Tachycardia
Introduction. Programmed ventricular stimulation from the right ventricle (RV) is the most commonly adopted induction protocol in patients with post-infarction ventricular tachycardia (VT). Lack of VT inducibility or induction of non-clinical VT(s) constitute major limitations of such protocol. Through pacing within or close to critical zones of the reentry circuit(s), programmed stimulation within the infarct scar might provide incremental benefit. In this prospective study, we compared RV stimulation with stimulation within the scar for clinical VT induction in patients with post-infarction VT.
Methods. We included 156 consecutive patients referred to our Institutions for catheter ablation of post-infarction VT. Programmed ventricular stimulation (600-, 500-, and 400-ms drive cycle with up to 3 extrastimuli) was carried out sequentially from the RV apex, outflow tract, and within the infarct scar, as defined through high-density three-dimensional electroanatomic mapping system (CARTOTM, Biosense Webster). The end-point was induction of clinical VT(s), defined as matching the clinical cycle length and morphology of the clinical VT(s) on the 12-lead ECG and on the ICD interrogation when available.
Results. A total of 141 (90%) patients achieved clinical VT(s) induction, with 15 (10%) patients being inducible only for non-clinical VT(s). RV stimulation induced clinical VT(s) in 44/141 (31%) cases, while stimulation within the scar achieved the endpoint in 97/141 (69%) cases (risk ratio [RR] = 2.20, 95% confidence interval [CI] 1.68 to 2.89, P < 0.001). The rate of only non-clinical VT(s) induction was also significantly lower with scar stimulation compared to RV stimulation (35% vs. 10%, RR = 0.27, 95% CI 0.16 to 0.46, P < 0.001). A total of 13 (8%) patients were inducible only from the scar.
Conclusions. In patients undergoing catheter ablation of post-infarction VT, programmed ventricular stimulation within the scar doubles the chances of inducing clinical VT(s) and strikingly reduces the risk of only non-clinical VT(s) induction compared to standard right ventricular stimulation.
- © 2012 by American Heart Association, Inc.