HPSD ablation: Power Settings
The impact of power output during RF ablation on efficacy and safety has been studied in human subjects. There is significant variability in the power settings (ranging from 40 W to 90 W), types of ablation catheters and irrigation flow used in these studies as summarized in Tables 1 and 2. Table 1 lists studies comparing high power to low power ablation strategies.29-39 Table 2 lists studies which only included high power ablation strategies.23, 40-42Conventional irrigated CF-sensing catheters have been safely used to deliver high power (60-70 W) for 5-7 seconds in the left atrium.29, 43 Reddy et al23 studied the concept of very high power short duration (vHPSD) ablation for PV isolation in a multicenter study. The novel CF catheter (QDot Micro catheter, Biosense Webster, Inc., Irvine, CA) used to deliver 90 W/ 4 s lesions allows for real-time temperature monitoring using microelectrodes and 6 thermocouples. The vHPSD algorithm rapidly modulates power based on the hottest surface thermocouple (cutoff at 65° to 70°C) thereby reducing excessive tissue heating leading to steam pops.