Related Experiment Videos
Effect of verapamil on QT interval dynamicity
L Fauchier1, D Babuty, P Poret
1Service de Cardiologie B et Laboratoire d'électrophysiologie Cardiaque, Centre Hospitalier Universitaire Trousseau, Tours, France. lfau@med.univ-tours.fr
The American Journal of Cardiology
|March 18, 1999
Summary
Verapamil treatment shortened the QT interval in patients with paroxysmal atrioventricular nodal reentrant tachycardia, particularly at lower heart rates. This QT interval dynamicity may contribute to verapamil
Area of Science:
- Cardiology
- Pharmacology
Background:
- Paroxysmal atrioventricular nodal reentrant tachycardia (AVNRT) is a common supraventricular tachycardia.
- Verapamil is a calcium channel blocker frequently used to manage AVNRT.
- The effect of verapamil on cardiac repolarization, specifically the QT interval, requires further elucidation.
Purpose of the Study:
- To evaluate the effect of oral verapamil on QT interval dynamicity in patients with AVNRT.
- To investigate the relationship between verapamil's effect on QT interval and its protective role against torsades de pointes.
Main Methods:
- Utilized a computerized Holter system to measure QT/RR slopes.
- Assessed QT interval dynamicity in 19 patients with normal structural hearts before and 2 months after verapamil treatment.
- Analyzed heart rate variability and its impact on QT interval changes.
Main Results:
- Verapamil significantly shortened the QT interval, especially at lower heart rates.
- The most pronounced QT shortening effect was observed during the diurnal period.
- QT interval dynamicity was altered by verapamil treatment.
Conclusions:
- Oral verapamil alters QT interval dynamicity in patients with AVNRT.
- The observed QT shortening effect of verapamil, particularly at low heart rates, may contribute to its antiarrhythmic properties.
- These findings provide insights into the electrophysiological mechanisms underlying verapamil's efficacy in preventing torsades de pointes.