Researchers in Germany have found that high-dose laser ablation is more beneficial than low-dose treatment in acute and chronic success of patients with drug refractory atrial fibrillation (AF). Stefano Bordignon (Cardioangiologisches Centrum Bethanien, Frankfurt, Germany) and colleagues reported acute pulmonary vein isolation (PVI) rate of 89% after an initial visually guided ablation circle and reported a long-term clinical success rate of 83% off antiarrhythmic drugs after a single procedure.
Data are published in the November 2012 online issue of EP Europace – The European Journal of Pacing, Arrhythmias and Cardiac Electrophysiology of the European Heart Rhythm Association of the European Society of Cardiology.
Bordignon et al set out to evaluate the effects of low-dose and high-dose ablation on acute and chronic success in patients with atrial fibrillation. “While the concept of visually guided pulmonary vein isolation has been established little is known on energy titration using laser ablation,” the authors wrote.
The study involved 60 symptomatic, drug refractory AF patients between the ages of 18–70 who had never before had PVI attempted to control their AF symptoms. Patients were prospectively assigned to two groups, high-dose and low-dose, for PVI with the HeartLight endoscopic ablation system (Cardiofocus). In the high-dose group ablation energy was titrated at >8.5 to 12W and in the low-dose group it was titrated at 5.5 < 8.5W. The number of laser applications and total energy deployed was collected for each individual pulmonary vein.
Investigator Boris Schmidt, Cardioangiologisches Centrum Bethanien, Frankfurt, Germany, said, “Laser ablation with the HeartLight system has demonstrated proof of concept in many feasibility studies over the last few years and has become routine in my practice. In this clinical experience, we aimed to understand the optimal energy needed to achieve chronically transmural lesions and provide guidance on different energy dosing strategies. We are most pleased to find that high-dose ablation demonstrates such significant clinical benefits. In particular, most patients in the high-dose group were found to be free of AF symptoms almost 11 months after the single ablation procedure.”
The findings demonstrate that acute pulmonary vein isolation was achieved after a single visually guided circular lesion set in 89% and 69% of patients in the high and low-dose groups, respectively. During a mean follow-up of 311 days, the AF recurrence rate was only 17% in the high-dose group while 40% in the low-dose group. In addition, it was found that high-dose ablation significantly reduced procedure times, by reducing the number of ablation lesions needed and lowering the need for gap mapping (128+17 vs. 154+38 min; P = 0.001).
Stephen Sagon, president and CEO of CardioFocus, said: “This publication reveals the benefits of high-dose laser ablation and continues to validate the HeartLight technology. It also represents the creative fine tuning of our unique and innovative ablation technique by key thought leaders in the field. We hope this clinical experience will provide a guide to current and new HeartLight adopters to inform dosing strategies and optimise results for patients.”