Inducibility of clinical ventricular tachycardia by pre-ablation noninvasive programmed stimulation predicts favorable outcomes after catheter ablation

Introduction Noninvasive ventricular programmed stimulation (NIPS) using an implantable cardioverter-defibrillator (ICD) enables bedside assessment of ventricular tachycardia (VT) inducibility. Its role in risk stratification and outcome prediction before catheter ablation for VT has not been well established. Purpose To evaluate the clinical utility of pre-procedural NIPS in predicting outcomes after catheter ablation for VT in ICD recipients. Methods Between 2014 and 2024, 95 consecutive patients underwent catheter ablation for VT at our institution. Among them, 40 patients underwent bedside NIPS using their ICD prior to ablation. Thirty-one patients with complete clinical data were retrospectively analyzed. Based on inducibility during NIPS, patients were classified into three groups:Group 1 (G1): inducible clinical VT onlyGroup 2 (G2): inducible clinical and non-clinical VTGroup 3 (G3): inducible non-clinical VT only Clinical and non-clinical VTs were distinguished using 12-lead electrocardiograms and intracardiac electrograms. The primary endpoint was freedom from ICD therapies (including anti-tachycardia pacing and shocks) after ablation. Freedom from electrical storm was also assessed. Outcomes were compared among groups. Results The mean age was 67 years, 90.3% were male, and 25.8% had ischemic heart disease. Clinical VT was inducible in 74.2% (23/31). Fourteen patients were classified as G1, nine as G2, and eight as G3. Among patients with inducible clinical VT (G1+G2), concordant VT was reproduced during the ablation procedure in 91.3% (21/23), and clinical VT inducibility was successfully eliminated after ablation in 78% (18/23). During a median follow-up of 20 months, Kaplan–Meier analysis demonstrated significantly higher freedom from ICD therapies (including anti-tachycardia pacing and shocks) in patients with inducible clinical VT compared with those without inducible clinical VT (P = 0.04, Fig. A). Similarly, freedom from electrical storm was significantly greater in patients with inducible clinical VT (P = 0.003, Fig. B). Overall, inducibility of clinical VT prior to ablation was significantly associated with improved post-ablation VT control. Conclusion Inducibility of clinical VT during pre-procedural NIPS is highly concordant with intra-procedural VT and is associated with improved post-ablation arrhythmia control. Pre-ablation NIPS may serve as a useful tool for risk stratification and therapeutic decision-making in ICD recipients undergoing catheter ablation for VT.