Effect of preoperative administration of atenolol to dogs with pulmonic stenosis undergoing interventional procedures

Abstract

Background: Beta-blockade is sometimes used in dogs with pulmonic stenosis with the intent of reducing frequency of ventricular arrhythmias during right heart catheterization. Objectives: To evaluate if pretreatment with atenolol reduces frequency of ventricular arrhythmias, anesthetist interventions, or shortens procedure time. Animals: Thirty dogs with pulmonic stenosis scheduled for interventional procedures. Methods: Single center, prospective, randomized, open-label study. Dogs were randomized to treatment with atenolol or no treatment preoperatively for a minimum of 10 days. Variables recorded included heart rate, arrhythmias and complexity, total procedure time and administration of antiarrhythmic treatment, vasopressors, positive chronotropes, or fluid boluses. Results: Fifteen dogs were enrolled in each group. Dogs receiving atenolol had lower mean heart rates during the procedure (atenolol 100 ± 11 bpm vs untreated 115 ± 19 bpm, P =.01). There were no significant differences between the atenolol and untreated groups in the frequency of ventricular ectopic complexes (535 [6-5296] vs 553 [79-2863], P =.9), ventricular couplets (46 [0-481] vs 29 [3-121], P =.59), ventricular triplets (20 [0-265] vs 16 [1-82], P =.67), ventricular tachycardia (8 [0-224] vs 8 [1-118], P =.99), proportion exhibiting R-on-T phenomenon (11/15 vs 14/15, P =.33), proportion receiving intraoperative lidocaine (1/15 vs 3/15, P =.6), vasopressors/positive chronotropes (11/15 vs 5/15, P =.06), or fluid boluses (12/15 vs 7/15, P =.13). The procedure time was similar (atenolol 41 [23-68] min vs untreated 35 [18-98] min, P =.91). Conclusions and Clinical Importance: No benefit of preoperative atenolol treatment was identified in this small group of dogs.