Lesion characteristics of long application time ablation using unipolar half-normal saline irrigation and bipolar normal saline irrigation

Figures

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  Fig. 1. Schematic representation of experimental preparation of radiofrequency (RF) ablation Panel A is an illustration of unipolar RF ablation using normal saline irrigation (UNIP-NS) and unipolar RF ablation using half-normal saline irrigation (UNIP-HNS). An ablation catheter was placed in contact to the endocardial surface through a pressure control system, and a ground electrode was positioned in a small space facing the epicardial myocardium. Tyrode's solution circulation in the small space was minimized by a plastic board inserted into the inner plastic container. Panel B is an illustration of bipolar RF ablation using normal saline irrigation (BIP-NS). Ablation catheters were placed in contact to the endocardial and epicardial surface. Endocardial ablation catheter (left) was connected to the catheter connector of the generator and epicardial catheter (right) was connected to the cutaneous electrode connector of the same generator. See detailed description in the text.

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  Fig. 2. Methodology of the lesion measurement and gross macroscopic examination of the sectioned transmural lesions Figure-2A illustrates the methodology of the measurement of three lesion patterns. Panel A is the lesion created either by UNIP-NS or UNIP-HNS. Panels B and C are the non-transmural and transmural lesions induced by BIP-NS, respectively. Measured parameters in these lesions are described in the illustrations; (a)–(f). In Figure-2B, panels A and B are lesions created by UNIP-NS and UNIP-HNS, respectively. Panels C and D are non-transmural and transmural lesions induced by BIP-NS ablations. Measured values are shown in each lesion. See detailed description in the text.

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  Fig. 3. Schematic representation of lesion depth created in the three ablations methods Panel A shows estimated lesion depth in all 80 RF applications (including non-transmural and transmural lesions in BIP-NS). Endocardial lesion depth in the transmural lesions was estimated as 50 % of the myocardial thickness. Estimated endocardial lesion depth was not different between UNIP-HNS and BIP-NS, but both were deeper than that in UNIP-NS. Transmural lesion length and % transmural lesion length in the entire myocardial thickness (endocardial plus epicardial lesions) were greatest in BIP-NS. Panel B showed endocardial lesion depth in 45 RF applications (12 in UNIP-NS, 17 in UNIP-HNS, and 16 in BIP-NS) with non-transmural lesions in the thick myocardium (more than 17.9 mm). Similar results as shown in panel A were observed in the 45 RF applications. In transmural lesions of BIP-NS (n = 13), myocardial thickness at the ablation sites was used as the transmural lesion depth. In non-transmural lesions, endocardial lesion depth plus epicardial lesion depth was calculated first, and this number was used as the transmural lesion depth in each lesion. Therefore, upper panels show mean ± standard…