Single-center experience with quinidine for patients with electrical storm due to ventricular arrhythmias associated with short-coupled premature ventricular contractions

Abstract Background Quinidine has been associated with excellent outcomes in patients with ventricular arrhythmias (VA) associated with short-coupled premature ventricular contractions (SCPVC) 1. Purpose To assess the efficacy and safety of quinidine in patients in electrical storm (ES) due to VA associated with SCPVC. Methods This is a single-center retrospective study including consecutive patients with ES due to VA associated with SCPVC (<450 ms). We excluded patients with channelopathies and patient with signs or symptoms of acute ischaemia prior ES onset. Patient characteristics and clinical data were collected. Efficacy endpoint was graded in optimal response (abolishment of VA after quinidine initiation), suboptimal response (reduction in VA) or no response. Safety was assessed with the Incidence of adverse events after quinidine start. Results Between January of 2020 and July of 2024, we identified 10 patient (90% males; 68.3 ± 9.3 years) with VA due to SCPVC in ES treated with quinidine sulfate (80%) or hydroquinidine (20%). Most of ES (70%) were initiated in the sub-acute phase of a preceding ischemic event. ES started after a median of 6 (1-9) days of hospitalization and 9 (6-11.5) days after ischemic symptoms onset. Most of patients (90%) presented a cQT interval below 500 ms (467 ± 42 ms) and 9 (90%) patients were in cardiogenic shock when ES was established. VA were sustained polymorphic ventricular tachycardia (50%), sustained monomorphic ventricular tachycardia (10%) and a combination of both in 40% of cases. In all the cases quinidine was started after the failure of other antiarrhythmic drugs (amiodarone, 100%; lidocaine 80%; procainamide 20%) and in 50% of cases temporary cardiac pacing had been initiated. Patients presented a poor clinical situation at the time of quinidine administration. Six patient (60%) experienced an optimal response (60%) after quinidine start and 2 (20%) presented a suboptimal response. Three (30%) patients (2 without response and 1 with suboptimal response) underwent electrophysiological study and ablation of Purkinje-related PVC. After a median hospitalization of 20 (15 - 32) days, 5 patients (50%) died, mainly due to ischemic and haemorragic complications. Three patients with optimal response (60%) were successfully discharged. Two (20%) patients experienced a quinidine-related adverse event: 1 diarrhea and 1 toxic liver injury. Patient characteristics and evolution are detailed in Table 1. Conclusion Quinidine could be considered an effective therapy for patients in drug-refractory ES due to VA associated with SCPVC.Table 1