Mapping of Atrial Activation Patterns After Inducing Contiguous Radiofrequency Lesions: An Experimental Study

• Published in: Pacing and clinical electrophysiology 2001-02, Vol.24 (2), p.147-156
• Main Authors: CHORRO, FRANCISCO J., MAINAR, LUIS, SANCHIS, JUAN, CÁNOVES, JOAQUÍN, LLAVADOR, ESTEBAN, SUCH, LUIS M., CERDÁ, MIGUEL, LÓPEZ-MERINO, VICENTE, SUCH, LUIS
• Format: Article
• Language: English
• Subjects: Animals; atrial activation; Atrial Function - physiology; cardiac electrophysiology; Catheter Ablation; Electrophysiologic Techniques, Cardiac; experimental models; Heart Atria - physiopathology; Heart Block - physiopathology; Heart Conduction System - physiopathology; linear lesions; mapping; Perfusion; Rabbits; radiofrequency ablation; Tachycardia - physiopathology; Tachycardia, Atrioventricular Nodal Reentry - physiopathology
• ISSN: 0147-8389; 1540-8159
• DOI: 10.1046/j.1460-9592.2001.00147.x

CHORRO, F.J., et al.: Mapping of Atrial Activation Patterns After Inducing Contiguous Radiofrequency Lesions: An Experimental Study. High resolution mapping techniques are used to analyze the changes in atrial activation patterns produced by contiguous RF induced lesions. In 12 Langendorff‐perfused rabbit hearts, left atrial activation maps were obtained before and after RF induction of epicardial lesions following a triple‐phase sequential protocol: (phase 1) three separate lesions positioned vertically in the central zone of the left atrial wall; (phase 2) the addition of two lesions located between the central lesion and the upper and lower lesions; and (phase 3) the placement of four additional lesions between those induced in the previous phases. In six additional experiments a pathological analysis of the individual RF lesions was performed. In phase 1 (lesion diameter = 2.8 ± 0.2 mm, gap between lesions = 3 ± 0.8 mm), the activation process bordered the lesions line in two (2.0‐ms cycles) and four experiments (1.0‐ms cycles). In phase 2, activation bordered the lesions line in eight (2.0‐ms cycles, P < 0.01 vs control) and nine experiments (1.0‐ms cycles, P < 0.001), and in phase 3 this occurred in all experiments except one (both cycles, P < 0.001 vs control). In the experiments with conduction block, the increment of the interval between activation times proximal and distal to the lesions showed a significant correlation to the length of the lesions (r = 0.68, P < 0.05, 100‐ms cycle). In two (17%) experiments, sustained regular tachycardias were induced with reentrant activation patterns around the lesions line. In conclusion, in this acute model, atrial RF lesions with intact tissue gaps of 3 mm between them interrupt conduction occasionally, and conduction block may be frequency dependent. Lesion overlap is required to achieve complete conduction block lines. Tachycardias with reentrant activation patterns around a lesions line may be induced.