31: Overdrive Pacing: A Lifeline in Refractory Electrical Storm for Patients on VA ECMO

Introduction: Electrical storm (ES) is a life-threatening condition characterized by recurrent episodes of ventricular arrhythmias, often due to myocardial ischemia. Treatments range from antiarrhythmic medications and cardioversion to stellate ganglion block and radiofrequency ablation. Temporary overdrive pacing, where the heart is paced faster than its intrinsic rhythm, has been proposed as a bridge therapy for refractory ES when other treatments fail. Methods: Retrospective case series.We are reporting two patients admitted to the ICU with cardiogenic shock secondary to decompensated heart failure and acute coronary syndrome (ACS), supported by VA ECMO following cardiac interventions. The first patient underwent transcatheter aortic valve implantation (TAVI), and the second received percutaneous coronary intervention (PCI). Despite undergoing cardiac intervention and LV unloading strategies with VA ECMO, both patients experienced refractory electrical storm unresponsive to medical therapy and direct-current cardioversion. Overdrive pacing was initiated due to refractory arrhythmias, with the pacing rate set above the intrinsic ventricular rhythm. Both patients responded to temporary override pacing and remained on VA ECMO as a bridge to recovery, eventually weaning off ECMO without requiring a permanent ICD. Results: Both patients experienced resolution of their arrhythmias following the initiation of overdrive pacing. This intervention effectively terminated refractory ES and can be considered before proceeding to stellate ganglion block or ablation therapy. Conclusion: Temporary overdrive pacing is an effective and safe treatment for resistant electrical storm when conventional methods have been exhausted, although long-term outcome data is lacking. Future prospective studies with larger patient cohorts are needed to validate the findings.