B) Other Complications
The concern of HPSD ablation using standard ablation catheters is the potential for tissue and electrode overheating leading to char formation and steam pops. In studies using 50 W and titrating power to echogenic microbubble formation, the rate of pericardial effusion was as high as 20%.34 The researchers speculated that shortening the ablation duration while using high power could have reduced the rate of complications. Real time tissue temperature monitoring may help circumvent this issue. A study using a novel temperature-sensing, diamond-tip open-irrigated catheter showed significantly reduced procedure and RF ablation times.51 However, this catheter is not contact-force sensing, with power limited to 50 W and average duration of 18.8 ± 1.9 seconds per lesion, thus is unable to deliver very high power lesions.51 Interestingly, Kottmaier et al 29 compared a power-controlled ablation protocol with 70 W/ 7 s at the anterior left atrium (LA) and 70 W/ 5 s at the posterior LA to a conventional protocol with 30-40 W/ 20-40 s using a standard non-CF sensing irrigated ablation catheter (FlexAbility SE catheter; Abbott, Minneapolis, MN, USA). There were no complications noted in any of the 197 patients studied, although esophageal temperature monitoring was not used. vHPSD ablation in a temperature-controlled mode (90 W/4 s) using the QDot Micro catheter (Biosense Webster, Inc., Irvine, CA) has been shown to be safe with no incident deaths, stroke, atrioesophageal fistula or PV stenosis.23 The vHPSD ablation strategy enables modulation of power based on temperature leading to reduced risk of char formation due to less tissue overheating.19, 23