Thermography in Experimental Cardiac Surgery

Atrial fibrillation (AF) is the most common arrhythmia requiring pharmacological or surgical treatment. Limitations of medical treatment have prompted development of non-pharmacological therapies. The goals of this study were to evaluate methods of cooling agent application to terminate atrial fibrillation, and to evaluate the feasibility of thermography as a diagnostic tool during the procedure. Experiments were performed using mongrel canine subjects. The animals were anaesthetized and the chest was opened. On the right atrium, a flexible tube with the cooling agent was applied circularly. Two electrodes were used for pacing and EG registration; one in an isolated area and the second in the intact atrium. Thermography was used to monitor progress during the procedure. Infrared technology revealed that comparing intra-arterial conductivity from the intact to the isolated areas showed blockage after 21.3 min. when cooling liquid ( t, °C ( - 18°C )) was used, and after 5.3 min. when CO2 gas were used. The quicker response of the cooling was unidirectional blockage, with further cooling causing bidirectional blockage.