Comparing the efficacy of metoprolol and ivabradine for heart rate control for coronary computed tomography angiography during monitored anaesthesia care

INTERVENTION: Intervention1: Ivabradine: 5mg per oral, stat dose 1 hour before the planned scan time. No repeated dose. For heart rate optimisation Control Intervention1: Metoprolol: 25 mg oral stat dose 1 hour before planned scan. No reaped dose.For heart rate optimisation CONDITION: PRIMARY OUTCOME: Heart rate optimisationTimepoint: 0, 15 mins, 30 mins, 60 mins and 75 mins SECONDARY OUTCOME: Blood pressure and adverse effects if anyTimepoint: 0, 15mins, 30mins, 60mins and 75 mins INCLUSION CRITERIA: ASA physical status 1 and 2, Baseline heart rate more than 75 bpm, People who are consenting.