Background: Catheter ablation (CA) has an estimated success rate of 50-90% after first procedure for atrial tachycardia/fibrillation (AT/AF), supraventricular tachycardia (SVT), premature ventricular complexes (PVC) and ventricular tachycardia (VT). We studied if combination of induction agents including isoproterenol (ISO), Caffeine, Calcium Chloride (CC), Atropine and Phenylephrine (PE) is better than ISO alone to uncover additional arrhythmic triggers or substrates, where supplemental CA may potentially improve long term procedural success.
Methods: This is an observational study including 132 consecutive patients [AT/AF (N=27), SVT (N=25), PVC (N=42), VT (N=38)] undergoing CA for symptomatic atrial and ventricular arrhythmias. We compared combination chemical induction protocol (COMBO) which included ISO (range 5-20mcg/min) + Caffeine (50-250 mg) +CC (1gm) ± PE (range 5 -10 mcg/kg) ±intravenous atropine (0.25 mg, one time) with ISO-only (5-20 mcg/min) infusion to assess for arrhythmia re-inducibility after performing standard CA.
Results: There was no significant difference in baseline or procedural characteristics between both groups. COMBO group had significantly higher induction of stable clinical arrhythmia triggers and substrates in patients undergoing CA for AT/AF (53.3% vs. 8.3%, p=0.01), SVT (33% vs 0%, p=0.04), PVC (28.5% vs 0%, p=0.02) and VT (33.3% vs. 4.3%, p=0.02) when compared with ISO group which were additionally ablated. At 1-year follow up, COMBO group had significantly higher freedom from arrhythmias in AT/AF (20% vs. 41.6%, p=0.05), SVT (0% vs. 23%, p=0.04), PVC (4.7% vs. 43%, p=0.009) and VT ablation (26% vs. 61%, p=0.05) groups.
Conclusion: COMBO induction protocol during CA may uncover additional triggers and arrhythmia substrates in patients with supraventricular and ventricular arrhythmias. COMBO directed supplemental CA may improve freedom from clinical arrhythmias on long term follow up.