Repolarization changes in a double-blind crossover study of dofetilide versus sotalol in the treatment of ventricular tachycardia

Role of dofetilide in patients with ventricular arrhythmias

BACKGROUND OR PURPOSE

To assess effectiveness of dofetilide in reducing the burden of ventricular arrhythmias (VAs).

BACKGROUND

Prior small sample studies show that dofetilide has benefit in reducing VA. However, large sample investigations with long-term follow-up are lacking.

METHODS

Two hundred seventeen consecutive patients admitted between January 2015 and December 2021 for dofetilide initiation for control of VA were assessed. Dofetilide was successfully started in 176 patients (81%) and had to be discontinued in the remaining 41 patients (19%). Dofetilide was initiated for control of ventricular tachycardia (VT) in 136 patients (77%), whereas 40 (23%) patients were initiated on dofetilide for reducing the burden of premature ventricular complexes (PVCs).

RESULTS

The mean follow-up was 24 ± 7 months. In total, among the 136 VT patients, 33 (24%) died, 11 (8%) received a left ventricular assist device (LVAD), and 3 (2%) received a heart transplant during follow-up. Dofetilide was discontinued in 117 (86%) patients due to lack of sustained effectiveness during follow-up. Dofetilide use was associated with similar odds of the composite outcome of all-cause mortality/LVAD/heart transplant (OR: 0.97, 0.55-4.23) in patients with ischemic cardiomyopathy (ICM) compared to those with non-ischemic cardiomyopathy (NICM). Dofetilide did not reduce PVC burden during follow-up in the 40 patients with PVCs (mean baseline PVC burden: 15%, at 1-year follow-up: 14%).

CONCLUSIONS

Dofetilide use was less effective in reducing VA burden in our cohort of patients. Randomized controlled studies are needed to confirm our findings.

Role of drug therapy for sustained ventricular tachyarrhythmias

Antiarrhythmic drug therapy, broadly defined, is the mainstay of treatment and prevention of ventricular tachycardia (VT)/ventricular fibrillation (VF), which can lead to sudden death. This article evaluates the evidence for and appropriate use of class I antiarrhythmic drugs, class III antiarrhythmic drugs, beta-blockers, nondihydropyridine calcium-channel blockers, statins, angiotensin enzyme inhibitors, angiotensin receptor blockers, aldosterone blockers, and digoxin for antiarrhythmic benefits in patients who have a propensity for VT/VF and therefore are at risk of sudden death.

Atrial fibrillation recurrence after internal cardioversion: prognostic importance of electrophysiological parameters

OBJECTIVE

To evaluate the clinical and electrophysiological determinants of arrhythmia recurrence in patients undergoing internal atrial cardioversion for chronic atrial fibrillation (AF).

SETTING

Tertiary cardiac referral centre.

METHODS

101 consecutive patients with failed external cardioversion or AF > or = 1 year underwent internal atrial cardioversion; once stable sinus rhythm (SR) was obtained, electrophysiological study was performed in 73 patients (72%) who gave informed consent. Patients were then followed on antiarrhythmic treatment.

RESULTS

101 consecutive patients underwent internal atrial cardioversion in the period 1996-1999 with 100% conversion to SR; prophylactic antiarrhythmic treatment was flecainide (52%), amiodarone (37%), and sotalol (11%). Average follow up at first AF recurrence was 18.4 (14.4) months (range 0.1-49.8 months); persistence of SR was observed in 72/101 (72%) patients. By logistic regression, AF duration (odds ratio (OR) 1.07, 95% confidence interval (CI) 1.01 to 1.13) and a lower sinus rate at discharge on antiarrhythmic drugs (OR 0.92, 95% CI 0.85 to 0.99) were independent predictors of AF recurrence, whereas age, New York Heart Association functional class, left atrial dimensions, and left ventricular ejection fraction were not predictive of arrhythmia recurrence. When electrophysiological parameters were added to the statistical model in 73 patients, a shorter atrial effective refractoriness (OR 1.04, 95% CI 1 to 1.08) and an abnormal relation of atrial effective refractoriness to cycle length (OR 31, 95% CI 3.7 to 266) were also independent predictors of AF recurrence at follow up, beyond AF duration and heart rate at discharge.

CONCLUSIONS

Patients with failed external cardioversion or long lasting AF may benefit from internal atrial cardioversion and antiarrhythmic treatment to keep SR at long term; electrophysiological study may identify patients at the highest risk of arrhythmia recurrence. Although preservation of SR seems unlikely for AF duration > 3 years, a consistent minority of this subgroup (38%) may benefit from this approach.