Key result
Intravenous imipramine in healthy individuals did not change sinus recovery time, decreased atrial repolarization duration, and increased ventricular repolarization duration.
Why the study?
Does intravenous imipramine alter cardiac electrophysiological parameters in healthy individuals?
Does intravenous imipramine alter cardiac electrophysiological parameters in healthy individuals?
Intravenous imipramine alters cardiac repolarization by decreasing it in the atrium and increasing it in the ventricle, which may explain its observed antiarrhythmic effects on ventricular ectopics.
Requires validation in patients before any clinical use; leaves open differential repolarization effects as antiarrhythmic mechanism.
The tricyclic antidepressant agent imipramine was tested intravenously in 8 healthy individuals with respect to its effect on sinus recovery time, intervals in His bundle electrograms and the duration of the repolarization in the right atrium and ventricle judged from the refractoriness and monophasic action potential duration. Sinus recovery time was unchanged after the drug. The interval between the His bundle deflection and the start of the QRS complex in the standard lead showed no consistent changes but increased to pathological values in two individuals. The duration of the repolarization decreased in the atrium--an effect which could be arrhythmia-provoking or arrhythmia-protecting. The duration increased at the ventricular level. This effect could explain the antiarrhythmic effect on ventricular ectopics observed in other investigations.
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Brorson et al. (1978) studied Healthy (n=8). Imipramine was evaluated on Sinus recovery time, intervals in His bundle electrograms, and duration of repolarization in the right atrium and ventricle. Intravenous imipramine in healthy individuals did not change sinus recovery time, decreased atrial repolarization duration, and increased ventricular repolarization duration.
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