Background: Inappropriate Sinus Tachycardia (IST) is a common arrhythmic complication of Coronary Artery Bypass Graft (CABG) surgery which left untreated, increases incidence of post-operative stroke. Primary objective was to compare the effectiveness of beta blocker- metoprolol; a specific If blocker- ivabradine and its combination in patients who develop IST as a complication following CABG.
Methodology: An open-labelled, investigator initiated, clinical study was conducted on 150 patients who developed IST (HR > 100 beats/min) following elective CABG surgery. The patients were randomized into to three treatment groups. Group I received Ivabradine 5 mg; Group II-Metoprolol 25 mg; Group III- Ivabradine 5 mg + Metoprolol 25 mg. Treatment was given orally, twice a day for 7 days in all the three groups post operatively. Primary endpoints were comparative effectiveness in heart rate and blood pressure reduction following treatment.
Results: IST was diagnosed by a 12-lead electrocardiogram considering P-wave morphological features and with 32% increase from baseline HR in all the three groups. Compared to IST arrthymic rate, significant(p<0.05) reduction in heart rate was noted in all groups following respective treatment. Reduction in heart rate was significantly greater in combination group followed by ivabradine which was significantly greater than metoprolol treated group. None of the treatments clinically changed the systolic, diastolic and mean blood pressure till discharge. No surgery/treatment related complications were observed in any groups.
Conclusion:Ivabradine stands as a pharmacological strategy for rhythm and heart rate control for IST in post-operative CABG patients without any other side effects.
Keywords: Arrthymias, If blocker, Beta blocker,Coronary artery bypass graft
