90 vs 50-Watt Radiofrequency Applications for Pulmonary Vein Isolation: Experimental and Clinical Findings

Abstract

BACKGROUND: Fifty-watt radiofrequency applications have proven to be safe and efficient for pulmonary vein isolation (PVI). However, as PV reconnection still occurs and ablation catheter instability significantly contributes to suboptimal lesion formation, a new ablation catheter capable of delivering 90 W for 4 seconds only has been developed with the aim of improving PVI outcomes. In this setting, we sought to determine whether 90 W applications create transmural lesions without collateral damage experimentally and whether they can safely improve PVI procedures clinically compared with 50 W settings. METHODS: Experimentally, individual lesions were created in vivo in the right atrium of 6 swine with 90 W-4 seconds applications using the SmartTouch-SF catheter in a power-controlled mode (3 animals) or the QDOT-MICRO catheter in a temperature-controlled mode (3 animals). Clinically, PVI was performed in a homogenous population of 150 consecutive paroxysmal atrial fibrillation patients using CARTO and the QDOT-MICRO catheter in a temperature-controlled mode (75 patients 50 W-ablation index-guided and 75 patients 90 W-4 seconds). RESULTS: Mostly, (94.9%) experimental lesions were transmural in the thin-walled right atrium of swine. However, collateral damage was observed with both catheters in 17.9% of lesions. Clinically, 90 W procedures had a lower first-pass PVI rate (49% versus 81%, P <10 −4 ) and a higher acute PV reconnection rate (21% versus 5%, P =0.004) than 50 W procedures, whereas total procedural duration (62 versus 66 minutes, P =0.09), 1-year sinus rhythm maintenance (88% versus 90%, P =0.6) and safety (1 tamponade per group) were similar in both groups. CONCLUSIONS: Experimentally, using the QDOT-MICRO catheter, 90 W-4 seconds lesions are mostly transmural in the thin-walled right atrium of swine (median depth 1.87 mm) with a moderate lesion diameter of 6.62 mm but retain the potential for collateral damage. Clinically, 90 W-4 seconds applications are associated with a lower first-pass PVI rate and a higher acute PV reconnection rate than 50 W applications but similar safety outcomes and effectiveness at 1 year.

Very High-Power Short-Duration (HPSD) Ablation for Pulmonary Vein Isolation: Short and Long-Term Outcome Data

“…Within our relatively small sample population, we also realized a statistically non-significant tendency towards time-saving within the other measured procedural times (left atrial dwell time, total procedure time and fluoroscopy time). These later findings are similar but not totally in line with the results of Bortone et al, showing that within their cohort, 90 W 4 s PVI ablation led to similar procedural times due to a lower first pass PVI-rate and higher acute PV reconnection rate [ 10 ]. The minor differences between the results of those two studies might be caused by the relatively small study population size but might partly be explained by the fact that the 90 W 4 s protocol is much more prone to suboptimal lesion formation in cases of an unstable ablation catheter position during RF-energy application.…”

Characterization of high‐power and very‐high‐power short‐duration radiofrequency lesions performed with a new‐generation catheter and a temperature‐control ablation mode

“…For HPSD lesions, the temperature‐controlled QMODE algorithm is used, which modulates irrigation rate (first) and power (afterward, if irrigation rate increase is not enough) based on temperature, allowing for the creation of lesions of up to 50 W. The information is also integrated into the electromagnetic location technology of CARTO3® mapping system (Biosense Webster Inc). Although not developed or validated for QDot‐Micro catheter, AI can be calculated for applications performed with the QMODE algorithm (but not whit QMODE+), and some groups have tested its clinical performance, with good results 11–13 . We employed the same AI objectives that have been proposed for left atrial posterior (400) or anterior (550) wall ablation when using QDot‐Micro for conventional to high‐power lesions (up to 50 W).…”

“…Although not developed or validated for QDot-Micro catheter, AI can be calculated for applications performed with the QMODE algorithm (but not whit QMODE+), and some groups have tested its clinical performance, with good results. [11][12][13] We employed the same AI objectives that have been proposed for left atrial posterior (400) or anterior (550) wall ablation when using QDot-Micro for conventional to high-power lesions (up to 50 W).…”

In vivo tissue temperatures during 90 W/4 sec‐very high power‐short‐duration (vHPSD) ablation versus ablation index‐guided 50 W‐HPSD ablation: A porcine study

“…Therefore, 90 W/4 s‐vHPSD ablation has been reported to be suitable for thin‐walled structures such as the human atrium, with the walls of the PV in humans being very thin, measuring 0.82–1.24 mm on computed tomography 18–20 and 1.7–2.8 mm on autopsy 21 . Nonetheless, a recent study of Bortone et al showed a significantly lower rate of a first‐pass PVI with 90 W/4 s‐vHPSD ablation than 50 W HSPD ablation (37/75 [49.3%] vs. 61/75 [81.3%], p < .001) 22 . The failure sites of the first‐pass PVI were mostly the PV carina regions, which are known as thickened veno‐atrial junction sites 18–20 .…”

“…16,17 We did not incorporate catheter orientation into our in vivo assessment, but most target sites were not perpendicular to the catheter tip, explaining, at least in part, why shallow and relatively wide lesions p < .001). 22 The failure sites of the first-pass PVI were mostly the PV carina regions, which are known as thickened veno-atrial junction sites. [18][19][20] Therefore, shallower lesions with the 90 W/4 s-vHPSD ablation implicated that this ablation setting might not be sufficient for thick atrial walls.…”