Ivabradine reduces myocardial stunning in patients with exercise-inducible ischaemia

Ivabradine is an effective treatment for angina in patients with stable coronary artery disease (CAD) and for heart failure. Experiments in a canine model have shown that ivabradine reduces both acute left ventricular (LV) dysfunction and post-ischaemic stunning. Aim of this study was to investigate the effect of ivabradine on LV dysfunction and stunning in patients with CAD and exercise-inducible ischaemia. Fifteen patients with ejection fraction >40 % and heart rate >70 bpm were enrolled. After pharmacologic washout, echocardiography was performed at rest, at peak treadmill exercise and during recovery until return to baseline. After 2 weeks of ivabradine (7.5 mg bid) stress echocardiography was repeated at the same workload achieved during washout. Peak global and segmental (ischaemic vs. remote normal segments) LV longitudinal strain (LS) was assessed by 2D speckle tracking analysis. At washout, LS was significantly impaired in ischaemic compared to remote segments at peak stress and for several minutes during recovery. After ivabradine a smaller, albeit still significant, impairment of LS in ischaemic segments was observed at peak whilst no difference with remote segments was present during recovery. Furthermore, the average global LS value improved significantly after treatment. In conclusion, ivabradine reduces both acute LV dysfunction and stunning in patients with CAD and exercise-inducible ischaemia. We hypothesise that this mechanism might contribute to reduce chronic LV dysfunction in patients with CAD. In this setting the drug might limit the development of hibernating myocardium which is believed to result from repeated episodes of ischaemia and stunning.