Heart rate in heart transplant: should ivabradine take control?

Background Heart transplantation (HT) is the treatment of choice for patients with refractory heart failure without contraindications. However, long-term survival remains a challenge. Due to the loss of autonomic modulation, the denervated heart exhibits sinus tachycardia and an elevated resting heart rate (HR), a condition associated with reduced survival in clinical studies. Beta-blockers, due to their mechanism of action, may have a limited effect in this setting. Ivabradine, a selective If channel inhibitor, could be a suitable alternative for HT patients. Purpose This study aimed to evaluate the impact of ivabradine compared to beta-blockers on HR reduction in HT patients after six months of follow-up. Methods A retrospective study was conducted on HT patients treated with either ivabradine or beta-blockers at a cardiology referral center. The absolute and relative changes in HR at six months were analyzed using linear regression models adjusted for sex, age, left ventricular ejection fraction (LVEF), and baseline HR. Residual normality and homoscedasticity were verified using the Shapiro-Wilk and Breusch-Pagan tests. Results A total of 112 patients were included: 73 received beta-blockers (80.8% women, median age: 56.0 years [interquartile range, IQR: 51–63]) and 39 received ivabradine (53.8% women; median age: 48.1 years [IQR: 31–61]). HR reduction was more significant at six months with ivabradine than with beta-blockers (-20.5 ± 12.9 bpm vs. -2.12 ± 13.1 bpm; p < 0.001). In the adjusted linear regression model, ivabradine was significantly associated with a greater absolute HR reduction compared to beta-blockers (β = -12.23 bpm; 95% CI: -17.03 to -7.43; p < 0.001). Similarly, the percentage change in HR was more pronounced with ivabradine (-18.9 ± 10.6%) than with beta-blockers (-1.05 ± 15.2%), with a significant effect in the adjusted model (β = -11.90%; 95% CI: -17.23 to -6.58; p < 0.001). Age, LVEF, and sex showed no significant association with HR reduction. Conclusion(s) In HT patients, ivabradine use was associated with a significantly greater HR reduction at six months compared to beta-blockers. These findings suggest that, in the denervated heart, ivabradine could be an effective alternative for medium-term HR control.Ivabradine vs.