Abstract
Background: Treatment of hypertensive patients with beta-blockers reduces heart rate (HR) and increases central blood pressure, implying that the decrease in HR could explain reported increases in cardiovascular risk with beta-blocker. This analysis from a randomized, double-blind study explores whether HR reduction with the I f inhibitor ivabradine had an impact on central blood pressure and coronary perfusion. Methods and results: We included 12 normotensive patients with stable CAD, HR ≥70 bpm (sinus rhythm), and stable background beta-blocker therapy. Patients received ivabradine 7.5 mg bid or matched placebo for two 3-week periods with a crossover design and evaluation by aplanation tonometry. Treatment with ivabradine was associated with a significant reduction in resting HR after 3 weeks versus no change with placebo (-15.8±7.7 versus +0.3±5.8 bpm, p=0.0010). There was no relevant between-group difference in change in central aortic SBP (-4.0±9.6 versus +2.4±12.0 mm Hg, p=0.13) or augmentation index (-0.8±10.0% versus +0.3±7.6%, p=0.87). Treatment with ivabradine was associated with prolongation of diastolic perfusion time by 41% from baseline to 3 weeks (+215.6±105.3 versus -3.0±55.8 ms with placebo, p=0.0005) (Figure) and with a pronounced increase in an index of myocardial viability (Buckberg index, +39.3±27.6% versus -2.5±13.5% with placebo, p=0.0015). There were no safety issues during the study. Conclusion: Heart rate reduction with ivabradine does not modify central aortic blood pressure and is associated with a marked prolongation of diastolic perfusion time and an improvement in myocardial perfusion.
Published Version
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