Atenolol premedication in patients undergoing closed mitral commissurotomy

Perioperative tachycardia is common in patients undergoing surgery. In patients with mitral valve stenosis, the tachycardia can precipitate congestive heart failure and pulmonary oedema. Efficacy of atenolol premedication (0.5 mg/kg) for haemodynamic stability was assessed in 37 patients undergoing closed mitral commissurotomy (Group I) and compared with 43 patients who did not receive it (Group II). Patients with mild aortic regurgitation, atrial fibrillation, mild to moderate pulmonary artery hypertension or severe pulmonary artery hypertension without right ventricular failure were all included in the study. All patients were premedicated with tablet diazepam 0.1 mg/Kg, on the previous night and on the day of surgery and intramuscular morphine 0.1 mg/kg and glycopyrrolate 0.2 mg 45 min before surgery. In addition, in group I, atenolol 0.5 mg / kg was administered at night and 2 hours prior to surgery. Anaesthesia was induced with thiopental, morphine, oxygen and isoflurane. Tracheal intubation was facilitated by pancuronium bromide 0.12 mg/kg. Maintenance was with morphine, isoflurane and nitrous oxide in oxygen. The study was confined to the periods of maximal anaesthetic and surgical haemodynamic stress like laryngoscopy, intubation, surgical incision and commissurotomy. For all periods of haemodynamic stress, heart rate was significantly lower in group I, (p<0.05) than Group II. Blood pressure variations were comparable in both the groups. A statistically significant (p<0.001) decrease in systolic, diastolic, and mean arterial pressures, were observed in patients of both groups before and during valvotomy. One patient in atenolol group experienced bradycardia of <45 beats per minute. This was not associated with hypotension and it was easily treated with atropine. This study documents that, selective ss - blockade with atenolol in patients undergoing closed mitral commissurotomy, ensure a predictable control of heart rate in the perioperative period.