Inadvertently Developed Ventricular Fibrillation during Electrophysiologic Study and Catheter Ablation: Incidence, Cause, and Prognosis

BACKGROUND AND OBJECTIVES: Ventricular fibrillation (VF) can inadvertently occur during electrophysiologic study (EPS) or catheter ablation. We investigated the incidence, cause, and progress of inadvertently developed VF during EPS and catheter ablation. SUBJECTS AND METHODS: We reviewed patients who had developed inadvertent VF during EPS or catheter ablation. Patients who developed VF during programmed ventricular stimulation to induce ventricular tachycardia or VF were excluded. RESULTS: Inadvertent VF developed in 11 patients (46.7+/-9.3 years old) among 2624 patients (0.42%); during catheter ablation for atrial fibrillation (AF) in nine patients, frequent ventricular premature beats (VPBs) in one, and Wolff-Parkinson-White (WPW) syndrome were observed in one. VF was induced after internal cardioversion in six AF patients due to incorrect R-wave synchronization of a direct current shock. Two AF patients showed spontaneous VF induction during isoproterenol infusion while looking for AF triggering foci. The remaining AF patient developed VF after rapid atrial pacing to induce AF, but the catheter was accidentally moved to the right ventricular (RV) apex. A patient with VPB ablation spontaneously developed VF during isoproterenol infusion. The focus of VPB was in the RV outflow tract and successfully ablated. A patient with WPW syndrome developed VF after rapid RV pacing with a cycle length of 240 ms. Single high energy (biphasic 150-200 J) external defibrillation was successful in all patients, except in two, who spontaneously terminated VF. The procedure was uneventfully completed in all patients. At a mean follow-up period of 17.4+/-15.5 months, no patient presented with ventricular arrhythmia. CONCLUSION: Although rare, inadvertent VF can develop during EPS or catheter ablation. Special caution is required to avoid incidental VF during internal cardioversion, especially under isoproterenol infusion.

Severe Stenosis of the Left Main Coronary Artery Detected on Electrophysiologic Study

A cardiac electrophysiologic study (EPS) is a safe procedure with a low complication rate. We report here a case of severe stenosis of the left main coronary artery (LMCA) that was incidentally detected during an EPS; this was successfully managed by stenting the LMCA. The patient was a 75-year-old man with recurrent chest fluttering and no previous angina underwent EPS and he developed acute ischemic chest pain due to induced atrial fibrillation. The coronary angiography showed a critical stenosis in the distal LMCA. The patient underwent percutaneous coronary intervention with a sirolimus-eluting stent in the LMCA. The patient has remained asymptomatic during a 1-year follow-up period. To prevent potentially catastrophic complications, performing a stress myocardial imaging test should be strongly considered before conducting EPS in elderly patients.