Catheter Ablation of Refractory Ventricular Fibrillation Storm After Myocardial Infarction

Abstract

Background: Ventricular fibrillation (VF) storm after myocardial infarction (MI) is a life-threatening condition that necessitates multiple defibrillations. Catheter ablation is a potentially effective treatment strategy for VF storm refractory to optimal medical treatment. However, its impact on patient survival has not been verified in a large population. Methods: We conducted a multicenter, retrospective observational study involving consecutive patients who underwent catheter ablation of post-MI refractory VF storm without preceding monomorphic ventricular tachycardia. The target of ablation was the Purkinje-related ventricular extrasystoles triggering VF. The primary outcome was in-hospital and long-term mortalities. Univariate logistic regression and Cox proportional-hazards analysis were used to evaluate clinical characteristics associated with in-hospital and long-term mortalities, respectively. Results: One hundred ten patients were enrolled (age, 65±11years; 92 men; left ventricular ejection fraction, 31±10%). VF storm occurred at the acute phase of MI (4.5±2.5 days after the onset of MI during the index hospitalization for MI) in 43 patients (39%), the subacute phase (>1 week) in 48 (44%), and the remote phase (>6 months) in 19 (17%). The focal triggers were found to originate from the scar border zone in 88 patients (80%). During in-hospital stay after ablation, VF storm subsided in 92 patients (84%). Overall, 30 (27%) in-hospital deaths occurred. The duration from the VF occurrence to the ablation procedure was associated with in-hospital mortality (odds ratio for each 1-day increase, 1.11 [95% CI, 1.03–1.20]; P =0.008). During follow-up after discharge from hospital, only 1 patient developed recurrent VF storm. However, 29 patients (36%) died, with a median survival time of 2.2 years (interquartile range, 1.2–5.5 years). Long-term mortality was associated with left ventricular ejection fraction <30% (hazard ratio, 2.54 [95% CI, 1.21–5.32]; P =0.014), New York Heart Association class ≥III (hazard ratio, 2.68 [95% CI, 1.16–6.19]; P =0.021), a history of atrial fibrillation (hazard ratio, 3.89 [95% CI, 1.42–10.67]; P =0.008), and chronic kidney disease (hazard ratio, 2.74 [95% CI, 1.15–6.49]; P =0.023). Conclusions: In patients with MI presenting with focally triggered VF storm, catheter ablation of culprit triggers is lifesaving and appears to be associated with short- and long-term freedom from recurrent VF storm. Mortality over the long-term follow-up is associated with the severity of underlying cardiovascular disease and comorbidities in this specific patient population.

Ventricular fibrillation after ablation of a benign arrhythmia. Angry Purkinje syndrome?

“…Polymorphic VT caused by short coupled ventricular extrasystoles, in patients with coronary disease without evident myocardial ischemia, usually originates from Purkinje fibers located within areas of recent myocardial injury. 4 We therefore speculate that the RF lesions made along the peripheral conduction system within the interventricular septum, caused injury to some Purkinje fibers, provoking short-coupled ventricular extrasystoles within the relative ventricular refractory period, thus triggering VF. Alternatively, the RF lesions may have led to small areas of myocardial necrosis where Purkinje fibers remained vital.…”

“…Fearing the possibility of an arrhythmic storm of polymorphic VT, 4 we started quinidine therapy. 5,6 Intravenous quinidine gluconate (Quinidine Gluconate Injection, Lilly) at a rate of 15 mg/min led to immediate (within minutes) suppression of all ventricular ectopic activity; the infusion rate was then reduced by 50% every 15 minutes until a final dose 2 mg/min was achieved and maintained for a total dose of 800 mg intravenous quinidine gluconate over 4 hours.…”

The year in cardiology: arrhythmias and pacing

“…55 CA of VF storm after myocardial infarction was reported in a multicentre study of 110 patients. 61 In-hospital mortality (27%) and 2year follow-up mortality (36%) were high and associated with the time taken to perform CA.…”

Idiopathic Ventricular Fibrillation: Diagnosis, Ablation of Triggers, Gaps in Knowledge, and Future Directions

“…In addition to being the most common site of origin for PVC-VF triggers in patients with IVF, Purkinje PVC-VF triggers have been mapped and successfully ablated in patients with channelopathy including long-QT syndrome, 29,30 catecholaminergic PMVT, 31 and early-repolarization syndrome. 32 Purkinje PVC-VF triggers have also been mapped and ablated in patients with structural heart disease including ischemic heart disease, [33][34][35][36][37] hypertrophic cardiomyopathy, 38 left ventricular noncompaction, 39 amyloidosis, 40 dilated cardiomyopathy, 41 myocarditis, 42 and valvular heart disease. 43 The Purkinje system is an endocardial structure in humans and constitutes 1% to 2% of the myocardium mass.…”