Impact of dexmedetomidine on electrophysiological properties and arrhythmia inducibility in adult patients referred for reentrant supraventricular tachycardia ablation.

Background: Drugs used for sedation/analgesia may affect the basic cardiac electrophysiologic properties or even supraventricular tachycardia (SVT) inducibility. Dexmedetomidine (DEX) is a selective alpha-2 adrenergic agonist with sedative and analgesic properties. A comprehensive evaluation on use of DEX for reentrant SVT ablation in adults is lacking. The present study aims to systematically assess the impact of DEX on cardiac electrophysiology and SVT inducibility.

Methods: Hemodynamic, electrocardiographic, and electrophysiological parameters and SVT inducibility were assessed before and after DEX infusion in patients scheduled for ablation of reentrant SVT.

Results: The population of this prospective observational study included 55 patients (mean age of 58.7 ± 14 years, 29 males [52.7%]). A decrease in systolic and diastolic blood pressure and in heart rate was observed after DEX infusion (p = 0.001 for all). DEX increased corrected sinus node refractory time, atrial effective refractory period, AH interval, AV Wenckebach cycle length, and AV node effective refractory period without affecting the His-Purkinje conduction or ventricular myocardium refractoriness. No AV blocks or sinus arrests occurred during DEX infusion. Globally, there was no difference in SVT inducibility in basal condition or after DEX infusion (46/55 [83.6%] vs. 43/55 [78.1%] patients; p = 0.55), without a difference in isoprenaline use (p = 1.0). In 4 (7.3%) cases, the SVT was inducible only after DEX infusion. In 34.5% of cases, DEX infusion unmasked the presence of an obstructive sleeping respiratory pattern, represented mainly by snoring.

Conclusions: DEX depresses sinus node function and prolongs atrioventricular refractoriness without significantly affecting the rate of SVT inducibility in patients scheduled for reentrant SVT ablation.