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High vs. Standard Power RF Ablation for Pulmonary Vein Isolation
Quick Takes
- A strategy of high power, short duration compared to standard power, standard duration RF ablation results in shorter time to achieve PVI, greater medium-term freedom from atrial arrhythmias, though with a trend towards increased asymptomatic cerebral emboli (ACE) among patients undergoing AF ablation.
- Of note, this study was powered for the primary outcome of PVI time and may have been underpowered to detect differences in secondary outcomes including ACE.
- Clinicians need to consider increased ACE when selecting AF ablation strategies using RF energy.
Study Questions:
What is the safety and efficacy of treatment with high power, short duration (HPSD) versus standard power, standard duration (SPSD) radiofrequency (RF) ablation in patients undergoing pulmonary vein isolation (PVI)?
Methods:
The SHORT-AF trial investigators randomized patients with paroxysmal or persistent (<1 year) atrial fibrillation (AF) to HPSD (50 W) or SPSD (25-30 W) RF ablation to achieve PVI. Outcomes assessed included time to achieve PVI (primary), left atrial (LA) dwell time, total procedure time, first pass isolation, PV reconnection with adenosine, procedure complications including asymptomatic cerebral emboli (ACE), and freedom from atrial arrhythmias. The primary efficacy outcome was time to achieve PVI, defined as the duration from the first to final lesions applied to the PVs to achieve entrance/exit block and complete wide area circumferential ablation. Kaplan-Meier survival analysis and a log-rank test was conducted to compare atrial arrhythmia recurrence rates over the duration of follow-up. Hazard ratios (HRs) were calculated using a Cox-proportional hazards regression analysis.
Results:
Sixty patients (median age 66 years, 75% male) with paroxysmal (57%) or persistent (43%) AF were randomized to HPSD (n = 29) or SPSD (n = 31). Median time to achieve PVI was shorter with HPSD versus SPSD (87 vs. 126 minutes; p = 0.003), as was LA dwell time (157 vs. 180 minutes; p = 0.04). There were no differences in first pass isolation (79% vs. 76%, p = 0.65) nor PV reconnection with adenosine (12% vs. 20%, p = 0.26) between groups. At 12 months, recurrent atrial arrhythmias occurred less in the HPSD compared with the SPSD group (3/29 [10%] vs. 11/31 [35%]; HR, 0.26; p = 0.027). There was a trend towards more ACE with HPSD RF ablation (40% HP vs. 17%; p = 0.053).
Conclusions:
The authors report that HPSD compared with SPSD RF ablation results in shorter time to achieve PVI, greater freedom from AF at 12 months, and a trend towards increased ACE.
Perspective:
This study reports that among patients undergoing de novo AF ablation, a strategy of HPSD compared with SPSD RF ablation results in shorter time to achieve PVI, greater medium-term freedom from atrial arrhythmias, though with a trend towards increased ACE. Of note, this study was powered for the primary outcome of PVI time and may have been underpowered to detect differences in secondary outcomes including ACE. Clinicians should consider these findings when selecting AF ablation strategies using RF energy. Finally, given the high rates of ACE observed, future studies assessing different ablation modalities for AF should consider post-ablation brain imaging and clinical assessment for neurological events.
Clinical Topics: Arrhythmias and Clinical EP, Prevention, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias
Keywords: Ablation Techniques, Adenosine, Arrhythmias, Cardiac, Atrial Fibrillation, Embolism, Pulmonary Veins, Radiofrequency Ablation, Recurrence, Secondary Prevention
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