Cardiovascular research
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Cardiovascular research · May 1983
Electrophysiological effects of thoracic epidural analgesia in the dog heart in situ.
To investigate cardiac electrophysiological effects of thoracic epidural analgesia, a local anaesthetic solution, 0.5% bupivacaine, was administered into the thoracic epidural space in twelve pentobarbital anaesthetised dogs. Intracardiac conduction times were measured by His bundle electrography and refractoriness was determined by programmed electrical stimulation. Monophasic action potentials were recorded from the right ventricle by a suction electrode technique. ⋯ Thoracic epidural analgesia induced AV block of the second degree in most experiments after a second dose of bupivacaine during pacing at higher frequencies. We conclude that thoracic epidural analgesia has significant cardiac electrophysiological effects which may be both antiarrhythmic and arrhythmogenic. Thoracic epidural analgesia should be used with care in patients with atrioventricular conduction disturbances.