Ranolazine as an adjunct to standard therapy for angina in myocardial bridging: a randomized clinical trial

Myocardial bridging (MB) is a common anatomical variation in which myocardial fibers traverse over an epicardial coronary artery, potentially leading to angina or angina- equivalent symptoms. Ranolazine, known for its efficacy in chronic stable angina, might offer benefits in symptomatic MB, where traditional treatments often fall short. This prospective, parallel-group, double-blind, randomized add-on clinical trial was conducted at Al-Zahra Cardiovascular Teaching Hospital, Shiraz, Iran, from 2023 to 2024. We included patients with MB and angina symptoms who had normal epicardial coronary arteries. Participants were randomized into two groups: one receiving standard therapy (β-blockers) and the other receiving standard therapy plus ranolazine (500 mg twice daily). Outcomes were assessed using the Canadian Cardiovascular Society (CCS) classification of angina, echocardiographic left ventricular ejection fraction (LVEF), and electrocardiogram (ECG) parameters. Trial registry number: IRCT20230801059005N2 (08/11/2023). Among 52 participants, ranolazine addition significantly improved angina severity, with more patients transitioning to CCS grade I (p = 0.001 after adjusting for confounders). While univariate analysis showed no differences in ECG parameters, multivariate analysis revealed a modest but statistically significant QTc prolongation in the ranolazine group (OR = 1.055, 95%CI:1.012-1.100, p = 0.012). PR and QRS intervals remained unaffected. Post-treatment LVEF was comparable between the two groups. Ranolazine, as an adjunct to β-blockers, significantly improved angina symptoms in patients with myocardial bridging and was associated with a mild but significant QTc prolongation, without causing substantial changes in LVEF or other ECG parameters. These findings suggest that ranolazine could be a beneficial addition to the management of angina in MB patients.