Role of Antiarrhythmic Drugs: Frequent Implantable Cardioverter-Defibrillator Shocks, Risk of Proarrhythmia, and New Drug Therapy

Does Sotalol Still Have a Role in the Management of Arrhythmias?

Despite proven effectiveness in treating tachyarrhythmias, sotalol is proarrhythmic and can cause torsades de pointes. Given the emergence of studies that show no benefit from rhythm control strategies in managing atrial fibrillation, as well as the introduction of nonpharmacological approaches to treating arrhythmias, we felt it necessary to ascertain if there was any role for sotalol given its side effects. Review of the literature regarding sotalol use in the prevention and treatment of supraventricular and ventricular tachyarrhythmias seems to show that more effective and safer agents and nonpharmacological alternatives are currently available. However, sotalol still seems to be useful in preventing supraventricular tachyarrhythmias postcardiac surgery and in reverting hemodynamically stable sustained ventricular tachycardias in the setting of coronary artery disease. Its role in the prevention of tachyarrhythmias in the setting of arrhythmogenic right ventricular cardiomyopathy requires further investigation.

Optimal Strategies to Reduce Inappropriate Implantable Cardioverter-defibrillator Shocks

Since the widespread implementation of implantable cardioverter-defibrillators (ICDs), their effectiveness in various situations has become well-established. However, despite many advances in both the technology and its utilization, inappropriate therapy remains a risk. Here, we review ICD shocks, their effect on outcomes, and current methods to reduce inappropriate therapy, finding overall that inappropriate ICD shocks are common and associated with adverse outcomes. However, strategies do exist to minimize inappropriate shock rates including device selection and programming, medication, catheter ablation, and remote monitoring. Overall, ICDs are useful in reducing the risk of sudden cardiac death, but many patients with an ICD will receive an inappropriate shock. Understanding strategies to prevent inappropriate shocks is crucial to improving the care of patients with ICDs.

Results of a curtailed randomized controlled trial, evaluating the efficacy and safety of azimilide in patients with implantable cardioverter-defibrillators: The SHIELD-2 trial

BACKGROUND

Frequent hospital attendances in patients with implantable cardioverter-defibrillators (ICDs) result in significant morbidity and health care costs. Current drugs to reduce ICD shocks and hospital visits have limited efficacy and considerable toxicity. We evaluated the efficacy and safety of azimilide, a novel oral class III antiarrhythmic, for use in ICD patients.

METHODS

A total of 240 patients were enrolled in a prospective, randomized, double-blind, placebo-controlled trial to evaluate the effect of oral azimilide 75 mg daily in ICD patients with previously documented ventricular tachycardia or ventricular fibrillation, and a left ventricular ejection fraction ≤40%. The primary outcome metric was the adjudicated time-to-first unplanned cardiovascular (CV) hospitalization, or CV emergency department (ED) visit, or CV death. The trial was prematurely discontinued due to withdrawal of study sponsorship.

RESULTS

Azimilide demonstrated numerical but statistically nonsignificant reductions in the primary composite outcome (odds ratio [OR] 0.79, 95% CI 0.44-1.44), unplanned CV hospitalizations (OR 0.75, 95% CI 0.41-1.38), ED visits (OR 0.68, 95% CI 0.35-1.31), and all-cause shocks (OR 0.58, 95% CI 0.32-1.05). The incidence of adverse events was lower in the azimilide group. Neutropenia was not observed (absolute neutrophil count <1000 μ/L), and there was one possible torsade de pointes case that led to a successful ICD discharge.

CONCLUSION

The SHIELD-2 trial was statistically underpowered due to early trial termination and did not meet its primary objective. Despite this limitation, azimilide showed promise as a safe and effective drug in reducing all-cause shocks, unplanned hospitalizations, and ED visits in ICD patients.

6-Month Outcomes in Patients With Implantable Cardioverter-Defibrillators Undergoing Renal Sympathetic Denervation for the Treatment of Refractory Ventricular Arrhythmias

OBJECTIVES

This study aimed to assess 6-month outcomes in patients with implantable cardioverter-defibrillators (ICDs) undergoing renal sympathetic denervation (RSD) for refractory ventricular arrhythmias (VAs).

BACKGROUND

ICDs are generally indicated for patients at high risk of malignant VAs. Sympathetic hyperactivity plays a critical role in the development, maintenance, and aggravation of VAs.

METHODS

A total of 10 patients with refractory VA underwent RSD. Underlying conditions were Chagas disease (n = 6), nonischemic dilated cardiomyopathy (n = 2), and ischemic cardiomyopathy (n = 2). Information on the number of ventricular tachycardia (VT)/ventricular fibrillation (VF) episodes and device therapies (antitachycardia pacing/shocks) in the previous 6 months as well as 1 and 6 months post-treatment was obtained from ICD interrogation.

RESULTS

The median number of VT/VF episodes/antitachycardia pacing/shocks 6 months before RSD was 28.5 (range 1 to 106)/20.5 (range 0 to 52)/8 (range 0 to 88), respectively, and was reduced to 1 (range 0 to 17)/0 (range 0 to 7)/0 (range 0 to 3) at 1 month and 0 (range 0 to 9)/0 (range 0 to 7)/0 (range 0 to 3) at 6 months afterward, respectively. There were no major procedure-related complications. Two patients experienced sustained VT within the first week; in both cases, no further episodes occurred during follow-up. Two patients were nonresponders: 1 with persistent idioventricular rhythm and 1 with multiple renal arteries and incomplete ablation. Three patients died during follow-up. None of the deaths was attributed to VA.

CONCLUSIONS

In patients with ICDs and refractory VAs, RSD was associated with reduced arrhythmic burden with no procedure-related complications. Randomized controlled trials investigating RSD for treatment of refractory VAs in patients with increased sympathetic activity are needed.