Bradycardia and atrial fibrillation in patients with stable coronary artery disease treated with ivabradine: an...

Area of Science:

• Cardiology
• Clinical Trials
• Pharmacology

Background:

• The SIGNIFY trial (ISRCTN61576291) investigated the effects of ivabradine in patients with stable coronary artery disease (CAD).
• Emergent bradycardia and atrial fibrillation (AF) are potential side effects of heart rate-lowering medications.

Purpose of the Study:

• To assess the impact of emergent bradycardia and AF on cardiovascular outcomes in 19,083 patients with stable CAD receiving ivabradine or placebo.
• To determine if these emergent arrhythmias influence the efficacy of ivabradine in preventing cardiovascular events.

Main Methods:

• Analysis of data from the SIGNIFY trial, comparing outcomes in patients who developed bradycardia or AF on ivabradine versus placebo.
• Cardiovascular outcomes included cardiovascular death and non-fatal myocardial infarction.

Main Results:

• Bradycardia (heart rate <50 bpm) occurred in 37.4% of ivabradine-treated patients but did not increase the risk of primary composite endpoint (cardiovascular death or non-fatal myocardial infarction).
• Emergent AF occurred at a higher rate with ivabradine (2.2% per year) versus placebo (1.5% per year), but did not lead to a significant difference in cardiovascular outcomes or stroke between treatment groups.
• No significant difference in treatment effect was observed in patients with limiting angina.

Conclusions:

• Emergent bradycardia is common with ivabradine in CAD patients but does not appear to adversely affect cardiovascular outcomes.
• Emergent AF is relatively rare and, despite a higher incidence with ivabradine, does not significantly impact outcomes compared to placebo.