Impact of carvedilol versus metoprolol on ventricular arrhythmia burden and ICD therapies: a systematic review and meta-analysis

Clinical Snapshot

Key Findings

• P Value: Inappropriate ICD shocks: P=0.009; Inappropriate ATP: P=0.01; Recurrent VA and mortality: not significant (exact P-values not reported)

• Effect Size: HR = 0.66 (inappropriate ICD shocks); HR = 0.67 (inappropriate anti-tachycardia pacing); No significant difference in recurrent ventricular tachyarrhythmias or all-cause mortality

• Primary Outcome: Inappropriate ICD shocks: carvedilol associated with significantly lower risk compared to metoprolol

• Nnt Or Sensitivity: NNT not calculable from available data (absolute event rates not reported). Hazard ratios suggest a 33–34% relative risk reduction in inappropriate ICD therapies with carvedilol versus metoprolol

• Confidence Interval: Inappropriate ICD shocks: 95% CI 0.48–0.90; Inappropriate ATP: 95% CI 0.49–0.91

Clinical Application

Both carvedilol and metoprolol succinate are widely available, orally administered, and familiar to cardiologists and general physicians. Switching between agents is feasible in stable outpatients with appropriate monitoring. However, the evidence base is insufficient to mandate a formulary switch without higher-quality confirmatory data. Both carvedilol and metoprolol succinate are listed on the Australian Pharmaceutical Benefits Scheme (PBS) for heart failure and hypertension indications. Carvedilol is PBS-listed for chronic heart failure (HF-rEF). The RACGP and the Cardiac Society of Australia and New Zealand (CSANZ) guidelines for heart failure and ICD management do not currently differentiate between beta-blockers specifically for ICD shock reduction. TGA approval exists for both agents. Australian electrophysiologists should note that inappropriate ICD therapies are a recognised quality-of-life concern, and this meta-analysis provides preliminary signal — but not sufficient evidence — to preferentially recommend carvedilol over metoprolol succinate in ICD patients. Prospective Australian registry data or RCT participation would be valuable. Adult patients with structural heart disease (particularly heart failure with reduced ejection fraction) who have an ICD implanted for primary or secondary prevention of sudden cardiac death and are candidates for beta-blocker therapy

Abstract

BACKGROUND: Ventricular arrhythmias (VA) are major causes of morbidity and mortality in patients with cardiovascular disease. Implantable cardioverter-defibrillators (ICDs) are commonly used to prevent sudden cardiac death. However, patients with ICDs frequently experience recurrent arrhythmias and inappropriate shocks, which impact quality of life. Beta-blockers, specifically carvedilol and metoprolol, are commonly prescribed in this context. This meta-analysis aims to compare the impact of both medications in this patient population. METHODS: Comprehensive literature search was conducted to identify relevant studies comparing carvedilol to metoprolol in patients with VA or ICDs. Study outcomes included all-cause mortality, recurrent VA, and inappropriate ICD shocks. Effect estimates are presented as hazard ratios (HR) with 95% confidence intervals (CI). RESULTS: Five independent study populations, reported across six publications, including 7,777 patients (5,138 on carvedilol, 2,639 on metoprolol) were analyzed. Carvedilol was associated with a significantly lower risk of inappropriate ICD shocks (HR = 0.66, 95% CI: 0.48-0.90, P = 0.009) and inappropriate anti-tachycardia pacing (HR = 0.67, 95% CI: 0.49-0.91, P = 0.01) compared with metoprolol. There were no significant differences between the two beta-blockers in recurrent ventricular tachyarrhythmias or all-cause mortality. CONCLUSION: Carvedilol may provide additional benefit over metoprolol in reducing inappropriate ICD therapies and anti-tachycardia pacing, while no significant differences were found in recurrent ventricular arrhythmias or all-cause mortality. These findings support consideration of carvedilol in patients with ICDs, but further research is warranted to guide optimal beta-blocker selection.

References

1. 1.Ali, A. E., Ahmed, M. H., Ali, K., Ali, M., & Awad, M. K. A. (2026). Impact of carvedilol versus metoprolol on ventricular arrhythmia burden and ICD therapies: a systematic review and meta-analysis. European Journal of Clinical Pharmacology. https://doi.org/10.1016/j.amjmed.2014.05.032