A modified technique for canine sinoatrial node autoperfusion.
An experimental model for dog sinoatrial node autoperfusion is proposed. A by-pass was performed between right internal mammary artery and right atrial dorsal artery. A blood flow of 2.5 +/- 0.15 ml/min was calculated from blood forward velocity measurements. The injection of either isoproterenol or verapamil into the by-pass was followed by rapid heart rate modifications. These heart rate changes occurred without detectable modifications on the electrical behavior of the remaining myocardium, as assessed by electrocardiogram and endocavitary electrogram recordings. This model leaves right coronary circulation intact. The intrathoracic by-pass reduces heat-losses and lessens the probability of blood clotting. The model is suitable for chronic studies.