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

Beta-blockade is sometimes used in dogs with pulmonic stenosis with the intent of reducing frequency of ventricular arrhythmias during right heart catheterization.

To evaluate if pretreatment with atenolol reduces frequency of ventricular arrhythmias, anesthetist interventions, or shortens procedure time.

Thirty dogs with pulmonic stenosis scheduled for interventional procedures.

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.

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).

No benefit of preoperative atenolol treatment was identified in this small group of dogs.