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

Abstract

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][3][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][6][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.