Management of electrical storm of unstable ventricular tachycardia in post myocardial infarction patients: A single centre experience

Abstract

Objective: This is a case series of consecutive patients with past myocardial infarction presenting with Electrical Storm (ES) of unstable ventricular tachycardia (VT) treated by a protocol directed algorithm. Methods: Management protocol involved treatment of reversible causes, ventilatory & hemodynamic support, administration of antiarrhythmic drugs (AAD) & maximally tolerated doses of beta-blockers, stellate ganglionectomy and Radiofrequency ablation (RFA) guided by Electro Anatomic Mapping (EAM). Patients were followed up periodically with review of device data logs. Results: There were 12 patients (mean age = 61.38 ± 6.48 years & mean LVEF = 31.92 ± 4.23%). Presentation was recurrent ICD shocks (n = 5) or VT (n = 7). All were mechanically ventilated. Reversible causes were identified in 4 patients and appropriately addressed. Totally 8 patients underwent endocardial substrate modification by EAM & RFA. Endocardial LV Voltage mapping demonstrated a mean scar area of 70.04 ± 17.63 sq.cm (27.04 ± 6.20% of mapped area). The electrograms targeted for ablation included late potentials, fractionated electrograms, double potentials and channels within the scar. Two patients had stellate ganglionectomy in addition. Ten patients (83.3%) survived to discharge, all of whom are alive at a follow up of 30.12 ± 19 months free of ES. VT free survival at end of follow up was 80%. No patient had hospitalization related to VT. Single episode of VT recurrence was seen in 2 patients at 7 months and 1 year of follow up respectively. Conclusion: In post myocardial infarction patients presenting with ES and unstable VT, a protocol driven approach involving substrate modification targeting abnormal electrograms improves outcomes. Keywords: Catheter ablation, Electro anatomic mapping, Electrical storm, Substrate modification, Ventricular tachycardia