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Determinants of Lesion Dimensions during Transcatheter Microwave Ablation
Author(s) -
TSE HUNGFAT,
LIAO SONGYAN,
SIU CHUNGWAH,
YUAN LIU,
NICHOLLS JOHN,
LEUNG GEORGE,
ORMSBY TED,
FELD GREGORY K.,
LAU CHUPAK
Publication year - 2009
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/j.1540-8159.2008.02203.x
Subject(s) - medicine , ablation , lesion , microwave ablation , microwave , catheter ablation , radiology , cardiology , surgery , telecommunications , computer science
Background: Transcatheter microwave ablation is a novel technique for treating cardiac arrhythmias.Methods: We investigated the effects of catheter temperature, application duration, and antenna length on lesion dimensions during catheter‐based microwave ablation. In a swine thigh muscle preparation, microwave was delivered at targeted temperatures of 60°C (n = 18), 70°C (n = 27), 80°C (n = 43), or 90°C (n = 18) for 120 seconds with 10‐mm antenna; and at targeted temperatures of 80°C for 120 seconds (n = 22), 150 seconds (n = 18), 180 seconds (n = 18), 210 seconds (n = 18), and 240 seconds (n = 17) with 20‐mm antenna using 10 F catheter (MedWaves, San Diego, CA, USA) during parallel orientation. Conventional radiofrequency ablation (RF) using a 4‐mm tip electrode was performed as control.Results: With 120‐second energy applications, lesion length and depth were significantly larger with targeted temperatures of 80°C and 90°C than 60°C (P< 0.05). Furthermore, lesion depth and width, but not length, were significantly increased by prolonging energy application duration from 120 to 240 seconds at targeted temperature of 80°C (P< 0.05). Compared to RF, microwave lesions were significantly longer but had comparable depth and width. A 20‐mm microwave antenna produced longer lesions than either a 10‐mm antenna or RF ablation catheter. Multivariate analysis demonstrated that targeted temperature ≥80°C, application duration ≥150 seconds, and use of 20‐mm antenna were independent predictors for lesion depth and width (P< 0.05). Surface dessication was observed in 4/18 (22%) lesions at 90°C, as compared with 1/136 (0.7%) at 80°C targeted tip temperature (P < 0.05).Conclusions: This study demonstrated that lesions size with transcatheter microwave ablation can be controlled by adjusting targeted temperature, energy application duration, and antenna length. A targeted temperature of 80°C for more than 150 seconds should provide optimal lesion dimensions and lower risk of surface dessication or charring.