Objective To investigate the influence of various physical factors on the size of the resultant lesion during ultrasound catheter ablation. Methods An ultrasound catheter ablation system was constructed and a thermodynamic model in isolated perfused and superfused canine right or left free wall was established. Different levels of electrical power and acoustic time were adopted and the size of the resulting lesions was measured to observe the dose-response relationship. Lesions resulted by using different levels of power and duration of radiofrequency energy delivery were also observed for comparison. Results There was a linear relationship between the increasing electrical power and the depth of lesion. There were also positive relationships between the lesion area and the sonication time. Electrical power was a better predictor of the lesion depth

while energy is a better physical variable to describe the lesion area. Transducer-tissue contact pressure has no significant effect on the lesion size. The lesion depth of ultrasound ablation was much greater than that of the radiofrequency ablation. Conclusion In comparison with radiofrequency

ultrasound should be able to create the deeper lesions that should be beneficial for the treatment of ventricular tachycardia after myocardial infarction.