Quinidine vs. ICD in patients with short-coupled idiopathic ventricular fibrillation: a call for a multicenter randomized trial

This commentary refers to ‘Short-coupled ventricular fibrillation represents a distinct phenotype among latent causes of unexplained cardiac arrest: a report from the CASPER registry’, by C. Steinberg et al., doi:10.1093/eurheartj/ehab275 and the discussion piece ‘Quinidine vs. ICD therapy in short-coupled ventricular fibrillation—is a randomized trial the next logical step?’, by C. Steinberg et al., doi:10.1093/eurheartj/ehab614. Dr Steinberg and co-workers should be complimented for their characterization of a group of 24 patients with short-coupled ventricular fibrillation (VF) among a cohort of 364 consecutive patients who survived an unexplained cardiac arrest.1 In 1997, our group reported similar findings in a group of 9 patients with ‘idiopathic VF’.2 During follow-up, Steinberg et al.1 gave quinidine (average daily dose of 667 ± 400 mg) to 12 of 24 individuals who exhibited recurrent VF (the salt of quinidine that was used was not indicated). These patients were typically those who had multiple appropriate implanted cardioverter defibrillator (ICD) shocks or those who had experienced electrical storm. Over a median follow-up duration of 65.5 months (19.5, 138) on quinidine, VF recurrence with appropriate ICD therapy occurred in 2/12 (16.6%) patients. The authors noted that the 2 patients with recurrent VF on quinidine received extremely low quinidine doses (<300 mg) and rightly suggested that higher doses might have been effective. In our >40-year experience in managing idiopathic VF using electrophysiologic-guided quinidine therapy, doses of up to 2250 mg quinidine bisulphate were used and necessary to achieve VF non-inducibility.3 Viskin et al.4 used initial daily doses ranging from 1200 to 2000 mg of quinidine sulphate or 600–1200 mg of hydroquinidine for successfully treating short-coupled polymorphic ventricular tachycardia (PVT) in patients with coronary heart disease and low left ventricular function. Based on the reproducible extraordinary efficacy demonstrated with quinidine in patients with no obvious heart disease and short-coupled PVT/VF, resulting in arrhythmia-free periods of >40 years in some patients,5 as well as the expected high rate of ICD-related complications during long-term in this relatively young patient population (mean 40–45 years old), I believe that time is come to initiate a multicenter randomized clinical trial comparing quinidine and ICD for managing this rare type of life-threatening arrhythmia. Meanwhile, I believe that the patients should be aware about the option to treat their arrhythmia using adequate doses of quinidine without the need for implanting an ICD. Conflict of interest: none declared.