Effects of Ivabradine on Residual Myocardial Ischemia after PCI Evaluated by Stress Echocardiography

Hyperpolarization-activated cyclic nucleotide-gated channel inhibitor in myocardial infarction: Potential benefits beyond heart rate modulation

Myocardial infarction (MI) and its associated complications including ventricular arrhythmias and heart failure are responsible for a significant incidence of morbidity and mortality worldwide. The ensuing cardiomyocyte loss results in neurohormone-driven cardiac remodeling, which leads to chronic heart failure in MI survivors. Ivabradine is a heart rate modulation agent currently used in treatment of chronic heart failure with reduced ejection fraction. The canonical target of ivabradine is the hyperpolarization-activated cyclic nucleotide-gated channels (HCN) in cardiac pacemaker cells. However, in post-MI hearts, HCN can also be expressed ectopically in non-pacemaker cardiomyocytes. There is an accumulation of intriguing evidence to suggest that ivabradine also possesses cardioprotective effects that are independent of heart rate reduction. This review aims to summarize and discuss the reported cardioprotective mechanisms of ivabradine beyond heart rate modulation in myocardial infarction through various molecular mechanisms including the prevention of reactive oxygen species-induced mitochondrial damage, improvement of autophagy system, modulation of intracellular calcium cycling, modification of ventricular electrophysiology, and regulation of matrix metalloproteinases.

The Role of Ranolazine for the Treatment of Residual Angina beyond the Percutaneous Coronary Revascularization

INTRODUCTION

Despite a successful percutaneous coronary intervention (PCI), several studies reported that the recurrence of angina after revascularization, even complete, is a particularly frequent occurrence in the first year after PCI.

METHODS

The aim was to evaluate the efficacy of treatment with ranolazine in addition to conventional anti-ischemic therapy in patients who underwent coronary angiography for persistent/recurrent angina after PCI and residual ischemia only due to small branches not suitable for further revascularization. Forty-nine consecutive patients were included in our registry, adding the ranolazine (375 mg b.i.d) to optimal medical therapy (OMT). The Exercise ECG Test (EET) was performed in all patients before to start the therapy (baseline BL) and at 30 days (T1) after enrollment.

RESULTS

The average duration of the exercise was increased after the therapy with ranolazine comparing to baseline (RG 9'1'' ± 2' versus BL 8'10'' ± 2', p = 0.01). Seven (14.3%) patients after receiving ranolazine had not crossed the threshold of six minutes (75 watts) compared to 20 (40.8%) of BL (p = 0.0003). Stress angina appeared more frequently at BL than at 30 days (T1 4.1% versus BL 16.3%, p = 0.04) as well as exercise-induced arrhythmias (BL 30.6% versus T1 14.3%, p = 0.05).

CONCLUSIONS

The addition of ranolazine to standard anti-ischemic therapy showed a significant improvement in EET results after one month of therapy, including reduced exercise angina, increased exercise tolerance, and reduced exercise arrhythmias.

Ivabradine and endothelium: an update

Ivabradine is a pure heart-rate lowering drug that is nowadays used, accordingly to the last ESC Guidelines, to reduce mortality and heart failure (HF) hospitalization in patients with HF with reduced ejection fraction and in symptomatic patiens with inappropriate sinus tachycardia. Moreover, interesting effect of ivabradine on endothelial and myocardial function and on oxidative stress and inflamation pathways are progressively emerging. The aim of this paper is to highlight newer evidences about ivabradine effect (and consequently possible future application of the drug) in pathological settings different from guidelines-based clinical practice.