Surgical ablation for atrial fibrillation: The efficacy of a novel bipolar pen device in the cardioplegically arrested and beating heart

Abstract

Objective The introduction of ablation technology has simplified surgical intervention for atrial fibrillation. However, most ablation devices cannot create focal transmural lesions on the beating heart and have difficulty ablating specific regions of the atria, such as the atrioventricular isthmus, coronary sinus, and ganglionated plexus. The purpose of this study was to examine the efficacy of a pen-type bipolar radiofrequency ablation device on both arrested and beating hearts. Methods Endocardial and epicardial atrial tissues in the free wall, left atrial roof, atrioventricular annuli, and coronary sinus were ablated for varying time intervals (2.5–15 seconds) in porcine cardioplegically arrested (n = 6) and beating (n = 9) hearts. The hearts were stained with 1%2,3,5-triphenyl-tetrazolium chloride solution and sectioned to determine lesion depth and width. In 5 animals epicardial fat pads containing ganglionated plexus were stimulated and ablated. Results Lesion depth increased with ablation time similarly in both arrested and beating hearts. Transmurality was fully achieved in the thin atrial tissue (<4 mm) at 10 seconds in the beating and arrested hearts. The device had a maximal penetration depth of 6.1 mm. Epicardial ablation of the coronary sinus showed complete penetration through the left posterior atrium only in the arrested heart. Seven of 17 fat pads demonstrated a vagal response. All vagal responses were eliminated after ablation. Conclusion The bipolar pen effectively ablated atrial tissue in both arrested and beating hearts. This device might allow the surgeon to ablate tissue in regions not accessible to other devices during atrial fibrillation surgery.

Histopathology of Bipolar Radiofrequency Ablation in the Human Atrium

“…In prior studies, ovine and porcine hearts were used to evaluate ablative lesions with bipolar RF energy; transmurality of lesions was achieved with atrial wall thicknesses as much as 5 mm [7,[9][10][11][12][13]. Of note, these hearts did not have hypertrophy of the atrial wall or atherosclerosis of the coronary arteries.…”

Treatment of Wolff-Parkinson-White Syndrome With a Thoracoscopic Surgical Procedure

“…In this case, a bipolar radiofrequency pen device was applied to ablate the accessory pathway. This device has been shown to create sufficient lesion depth on the beating heart with a stamping technique [6]. Irreversible disappearance of the delta wave suggested that the pen device achieved complete ablation of the accessory pathway.…”

Exploration of Theoretical Ganglionated Plexi Ablation Technique in Atrial Fibrillation Surgery

“…The ablation duration was set at 15 s in accordance with the acceptable ablation depth and width determined in a previous experimental study [7]. Ablation was repeated as many as three times until the vagal response was completely eliminated.…”