Effects of deep sedation on cardiac electrophysiology in patients undergoing radiofrequency ablation of supraventricular tachycardia: impact of propofol and ketamine

Propofol is commonly used as an anaesthetic during catheter ablation. Bradycardia and termination of supraventricular tachycardia (SVT) under propofol are reported. Ketamine is used for cardiac catheterization procedures and increases heart rate and blood pressure. Our study aimed to determine the effects of propopfol and ketamine on atrial electrophysiology.

Thirty-one patients undergoing electrophysiological study prior to SVT ablation were enrolled. Patients received a combination of propofol/midazolam (n = 10), ketamine/midazolam (n = 9), or midazolam alone (n = 12). Electrophysiological study was performed before and after administration of the anaesthetic agents. Blood pressure, corrected sinus node recovery time, Wenckebach cycle length, and atrial conduction time were measured. We found a significant increase in heart rate, systolic, and diastolic blood pressure and a significant shortening of atrial conduction time after administration of ketamine compared with propofol and the control. Results for ketamine, propofol and the control, respectively: mean (SD) change in heart rate was 12.4 (8.3), −1.4 (8), and 1 (7.5) b.p.m. (P = 0.002); mean (SD) change in systolic blood pressure was 19.2 (8.1), −22 (9), and 0.1 (5.7) mmHg (P < 0.001); mean (SD) change in diastolic blood pressure was 6.6 (9.7), −7.8 (2.9), and 2.3 (4.5) mmHg (P = 0.001); and mean (SD) change in atrial conduction time was −13.7 (16.4), 4.5 (11.1), and −0.3 (3.8) ms (P = 0.008). No significant affection of sinus node or antrioventricular node function was seen.

Our results show stimulatory effects of ketamine on heart rate, atrial conduction, and blood pressure. Ketamine, therefore, may be beneficial in patients with pre-existing hypotension and bradycardia.