BACKGROUND: In off-pump stand-alone atrial fibrillation (AF) treatment, posterior wall isolation (PWI) of the left atrium is most commonly performed with bipolar bidirectional radiofrequency clamps and bipolar unidirectional radiofrequency pens. Clamps are utilized to isolate each set of pulmonary veins, while pens are used to create interconnecting “roof” and “floor” lines to complete the left atrial “box”, aka PWI. Due to the unidirectional application of the pens, the in-contact cardiac tissue may be inadequately stabilized and its linear lesions are prone to gaps or “leaks,” leading to failure of PWI. To improve our PWI rates, we developed a unique application of the bipolar bidirectional clamp to create the interconnecting “roof” and “floor” lines without the use of pens. We hypothesize that this novel All Bipolar Clamp (ABC) technique improves PWI when compared to the classic combination of Clamp And Pen (CAP) ablations.
METHODS: We performed a retrospective (2017 to 2023) comparison of patients with stand-alone AF treated with off-pump CAP PWI or ABC PWI. Patients with prior catheter ablation were excluded to ensure comparison of ablation techniques in unablated native cardiac myocardium. Electrophysiologic voltage mapping was conducted 6-weeks after the initial off-pump surgery to determine durable PWI. Patient characteristics were gathered from our institutional AF database. Data are presented as mean + SD, p<0.05 defines significance.
RESULTS: One-hundred fourteen qualifying patients were analyzed (CAP n=83 vs ABC n=31). Patient demographics were not significantly different between groups. Averages: Age 68 + 7.6 years, BMI 31 + 5.9 kg/m2, CHA2DS2-VASc 2.7 + 1.4, Time in AF prior to surgical ablation 4.2 + 4.7 years, Ejection Fraction % 51 + 11, and Left atrial diameter 4.5 + 0.71 cm. Surgical duration was significantly reduced in the ABC cohort (CAP 98.9 + 20.9 vs ABC 70.6 + 16.8 minutes; p<0.0001). PWI was significantly improved with an ABC technique (CAP 50.6% vs ABC 87.1%, OR 6.6 95% CI 2.1-18.5, p=0.0004). No significant difference in complications was observed.
CONCLUSIONS: In the treatment of stand-alone AF we observed that a novel ABC PWI technique provides improved durable left atrial PWI with an overall shorter surgical duration time when compared to our prior CAP PWI strategy. Long-term clinical rhythm outcomes are needed to validate the clinical superiority of this apparent electrophysiologic advantage.
