Prevention of tachycardia with atenolol pretreatment for carotid endarterectomy under cervical plexus blockade.

A double-blind, randomised, controlled trial of forty patients was carried out to determine if oral atenolol pretreatment would reduce the incidence of tachycardia during carotid endarterectomy performed under cervical plexus block. Twenty patients received a placebo and twenty patients 50 mg of atenolol two hours prior to surgery. The superficial and deep cervical blocks were performed with 1.5% lignocaine containing 1:200,000 adrenaline. The patients were monitored with the V5 lead of the electrocardiogram and intra-arterial blood pressure. These measurements were recorded on a correctly calibrated paper recorder. Tachycardia (heart rate greater than 90 beats per minute for more than three minutes) occurred in thirteen patients in the placebo group and two patients in the atenolol group (P less than 0.01). There was no difference in the occurrence of bradycardia, hypotension or hypertension between the two groups. It is concluded that atenolol pretreatment is an effective method of reducing the incidence of tachycardia during carotid endarterectomy performed under cervical plexus blockade.