Authors: (including presenting author): :
Yap PM¹, Ng PP¹, Chow CK¹, Lee CY¹, Poon WL¹, Cheng YW², Wong CY²
Affiliation: :
¹Department of Diagnostic and Interventional Radiology, Queen Elizabeth Hospital
²Department of Cardiology, Queen Elizabeth Hospital
Keyword 1: :
Coronary CT angiography
Keyword 3: :
Premedication
Keyword 4: :
Heart rate reduction
Keyword 5: :
Pre-scan waiting time
Keyword 6: :
Image quality
Introduction: :
Coronary CT angiography (CTCA) is a rapidly growing imaging examination, straining radiology capacity and patient flow. Target heart rate (HR≤65 bpm) is essential for image quality, typically requiring premedication. The standard oral ivabradine protocol involves in-department waiting for HR reduction, exacerbating overcrowding.
Objectives: :
This study evaluates a home-initiated 3-day oral ivabradine protocol versus a single high-dose same-day protocol. The primary outcomes are in-department pre-scan waiting time and post-scan monitoring time; secondary outcomes include final scan HR, blood pressure changes, safety profile, and CTCA image quality.
Methodology: :
Consecutive CTCA outpatients, who met none of the exclusion criteria, with baseline HR ≥70 bpm were managed with one of two predefined strategies: • 3-day home-initiated protocol (n=39): ivabradine 5 mg twice daily for 3 days before CTCA • Single-dose same-day protocol (n=66): ivabradine 15 mg upon arrival to department Exclusion criteria included atrial fibrillation, contraindications to ivabradine, and incomplete data. Data collected were compared using T-test and Mann-Whitney U test.
Result & Outcome: :
Median pre-scan waiting time was 39 min (IQR 31.5–53) in the 3-day group vs 126 min (IQR 115–144) in the single-dose group (p< 0.001), reflecting an 87-minute reduction and 69% decrease in pre-scan time. Final HRs during scan were similar in both arms at 58 bpm (IQR 53–63.5) vs 61 bpm (56–68.75; p=0.096), with comparable image quality. Both protocols demonstrated haemodynamic stability, with post-scan systolic blood pressure of 121.6 ± 16.6 mmHg (3-day) vs 134.4 ± 17.6 mmHg (single-dose; p< 0.001). Post-scan monitoring time was identical (42 min in both; p=0.915). No serious adverse events, symptomatic bradycardia, or visual phenomena occurred in either group. This first-in-Hong Kong home-initiated ivabradine protocol achieves equivalent HR control, image quality, and safety as same-day high-dose regimens, while substantially reducing in-department waiting time. By shifting HR-lowering therapy to home, it minimises radiology department occupancy and enhances CT capacity in high-volume public hospitals.
