Clinical characteristics, therapy and long-term outcome of short-coupled idiopathic ventricular fibrillation. A systematic review of published case reports with new extended long-term follow-up

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background Short-coupled idiopathic ventricular fibrillation (SC-IVF) is a rare, potentially lethal arrhythmia, initiated by SC-PVCs. Only small series have been published. Purpose To assess the clinical characteristics, therapies and long-term outcomes of patients (pts) with SC-IVF. Methods Data from all published case reports on SC-IVF/Polymorphic VT were collected. Inclusion criteria were normal cardiac work-up including during follow-up (FU), and documented SC-PVC-VF available for our analysis and ruling out early repolarization syndromes and CPVT at VF onset. Updated information was provided by 82% of authors contacted, with 22 additional ECG tracings provided. Results A total of 100 pts’ cases were identified, including 82 who met inclusion criteria. Mean FU increased from 2.75+3.6 years in the original publications to 10.5+7.9 years (p<0.0001). There were 42 (51%) males, aged 39.6+13.5 years at the time of SC-IVF diagnosis. Pts presented with syncope (40%), aborted cardiac arrest (ACA) (16%), ACA + arrhythmic storm (13%), arrhythmic storm (10%), ICD shocks (8%) or palpitations (1%). Prior history included syncope in 32 (39%) pts. Mean coupling interval of the SC-PVC was 293.6+50.7ms. Presumed sites of PVC origin were the RV, LV and RVOT in 54%, 21% and 5% of pts, respectively. A total of 69 (84%) pts had an ICD implanted before or after SC-IVF documentation. During long-term treatment with quinidine (n=11) or verapamil (n=32), SC-IVF did not recur in 82% and 50% of pts, respectively (p=0.08). Ablation was performed in 43 (92%) of the 47 pts in whom it was attempted. Ablation sites were the Purkinje RV (43%) or LV (23%), and the non-Purkinje RV (19%) or LV (2%). Acute and late success rates after a first ablation were 83% and 61.7%, respectively. A second ablation in 7 pts yielded a 74.5% total success rate. No difference was found in the success rate of quinidine compared with ablation procedures (p=0.6). During FU, 4 pts died including 2 from sudden cardiac death; both pts were treated with verapamil and refused ICD implantation or replacement. Conclusion SC-IVF mainly presents following syncope. Quinidine and ablation procedures have comparable long-term high efficacy in arrhythmia control. The commonest sites of successful ablation are the RV and LV Purkinje fibers.