991-74 Circumferential Temperature Monitoring versus Single Point Monitoring During Microwave Ablation

Secause microwave (MW) energy may achieve high temperatures (TEMP), TEMP monitoring may be important to prevent excessive endocardial damage. Since MW delivery is radial, we examined the value of TEMP monitoring using 3 circumferentially placed thermocouples (THERMO) rather than a single TEMP monitoring. During 15 energy deliveries of 20–40 Watts for 30sec at separate left ventricular sites in 5 dogs, there was a significant difference in maximum TEMP recorded among the 3 THERMO: 93.6±25.32 vs. 68.73±18.28 degrees C (p<0.001). Mean TEMP curves are shown:Thus, a single THERMO recording may underestimate the maximum TEMP. We conclude that because of the radial nature of the MW delivery accurate TEMP monitoring requires multiple THERMO rather than a single THERMO as used in RF ablation