Abstract 15166: The Effect of Ivabradine on Silent Ambulatory Myocardial Ischemia
Introduction: Heart rate (HR) reduction is a powerful method used to reduce myocardial oxygen demand thus reducing the frequency and duration of angina in chronic ischemic heart disease (CIHD). Ivabradine selectively inhibits the Na+/K+ current (I/f current) in pacemaker cells of the sinoatrial node, this will reduce the slope of diastolic depolarization resulting in slower HR without causing other side effect on myocardial contractility or AV conduction. Treating silent myocardial ischemia has a prognostic effect and may improve long term mortality of (CIHD). The effect of Ivabradine on angina frequency was already studied but its effect on silent ambulatory myocardial ischemia (SAMI) has not been reported yet. In this study we report the effect of ivabradine on (SAMI)
Methods: We enrolled 50 patients with proven stable coronary artery disease (CAD) and at least one episode of ST-segment depression on ambulatory ECG monitoring. All of them were receiving optimal therapy for CIHD. 25 patients were randomized to receive Ivabradine 7.5mg bid and the other 25 patients received placebo. Ambulatory monitoring was repeated after 4 to 6 months of therapy. The two groups were comparable with respect to baseline characteristics, number of episodes of ST-segment depression, and baseline serum cholesterol levels. Holters were read by a blinded cardiologist.
Results: The Ivabradine group had lower mean HR at study end and experienced a significant reduction in the number of episodes of ST-segment depression compared with the placebo group. ST-segment depression was completely resolved in 9 of 25 patients (36%) in the Ivabradine group versus 3 of 25 (12%) in the placebo group. The Ivabradine group exhibited a highly significant reduction in (SAMI) (P<.001). By logistic regression, treatment with Ivabradine was an independent predictor of (SAMI) resolution.
Conclusions: Further lowering of HR with Ivabradine can result in reduction or resolution of (SAMI) recorded as episodes of ST-segment depression in ambulatory monitoring of the ECG. A larger study is required to confirm this theory and to see the effect of SAMI reduction on long term mortality of CIHD.
Author Disclosures: W. Kadro: None. M. Turkmani: None. H. Rahim: None. A. Al Karmi: None. F. Al Ahdab: None.
- © 2014 by American Heart Association, Inc.