Very High Power Short Duration Ablation: It Takes Two to Make a Thing Go Right?

High power short duration (HPSD) radiofrequency (RF) ablation, utilizing 45-50W for durations of 5-15 seconds per lesion, is increasingly accepted as a safe and effective technique to efficiently achieve pulmonary vein isolation to prevent atrial fibrillation (AF).1 The next contender in the progression of hotter and faster RF technology is very high power short duration (vHPSD) RF ablation - 90W power for a duration of 4 seconds per lesion - using the QDOT-Micro ablation catheter (Biosense Webster, CA, USA). The catheter is designed to mitigate risks of vHPSD RF ablation by monitoring temperature at the catheter-tissue interface using six thermocouples embedded in the electrode's tip which allows for power modulation to maintain a target temperature during RF delivery.2 Relative to HPSD ablation utilizing 45-50W, vHPSD ablation with 90W may further maximize shallow, resistive heating, while the shorter duration may additionally minimize deep, conductive heating.2-4 The frequency and risk factors for the feared complications related to ablation, like steam pop, cardiac perforation, or esophageal injury, are not well understood for vHPSD.5 Early clinical studies of vHPSD ablation reported first pass PVI in approximately 50% of cases, while first pass PVI was achieved in greater frequency with both conventional and HPSD RF ablation using recently described approaches such as the "CLOSE Protocol".5-7 First pass isolation has been shown to be a powerful predictor of procedural efficacy,3,8,9 thus a greater understanding of the underlying biophysics of lesions created with vHPSD RF ablation may inform optimization of timing and spacing to further improve outcomes for this new technology. This article is protected by copyright. All rights reserved.