Antiarrhythmic and haemodynamic effects of tiapamil, a new calcium antagonist, during coronary artery occlusion and reperfusion in dogs

The antiarrhythmic and haemodynamic effects of tiapamil, a new calcium antagonist, were studied in 28 anaesthetised open chest dogs. Tiapamil (2 mg X kg-1 intravenously over 5 min) was infused 15 min before a 20 min ligature of the left anterior descending coronary artery in 11 dogs. In 17 dogs physiological solution was given instead of tiapamil. In this control group, ventricular fibrillation developed during coronary occlusion in 14 (82%) dogs and after coronary reperfusion in seven of 9 (77%) dogs, which reached this stage. In contrast, in the dogs pretreated with tiapamil, ventricular fibrillation did not develop during coronary occlusion in any of the 11 dogs and did develop after coronary reperfusion in only one (9%). In addition, tiapamil appreciably decreased heart rate and blood pressure and increased cardiac output and stroke volume. These antiarrhythmic and haemodynamic effects of tiapamil suggest that this drug would be useful in the management of patients with coronary artery disease.