Epicardial ablation with irrigated electrodes: - effect of bipolar vs. unipolar ablation on lesion formation -.
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BACKGROUND: Ablation of ventricular tachycardia originating from the left ventricular (LV) epicardium is often limited by the radiofrequency power delivery. We compared the effect of bipolar vs. unipolar epicardial ablation on lesion size. METHODS AND RESULTS: Eleven excised pig hearts were superfused with saline (2 L/min). Unipolar ablation (25 or 30 W for 120 s) was performed between the LV epicardial saline-irrigated electrode and an indifferent electrode (n = 33 lesions). Bipolar ablation (25 or 30 W for 120 s) was performed between a 4-mm saline-irrigated-tip (20 ml/min) electrode on the LV epicardium and an opposing 10-mm non-irrigated-tip electrode on the LV endocardium (n = 38 lesions). Wall thickness did not differ between experiments (15.4 +/- 2.4 vs. 15.3 +/- 2.1 mm). Impedance was lower at the beginning and end of unipolar ablation than at the beginning and end of bipolar ablation (163.2 +/- 20.3Omega and 109.9 +/- 16.0Omega vs. 194.6 +/- 23.3Omega and 127.1 +/- 16.4Omega, respectively) (P<0.001). Epicardial lesion width did not differ between unipolar and bipolar ablation (10.1 +/- 2.7 vs. 10.2 +/- 2.4 mm), but lesion depth was greater with bipolar ablation (10.6 +/- 2.7 vs. 7.5 +/- 1.0 mm) (P<0.001). Unipolar ablation produced no transmural lesion, but bipolar ablation produced 15 (46%) (P<0.001). Steam pop occurred in 11 (29%) and 3 (9%) cases, respectively (P = 0.036). CONCLUSIONS: Bipolar ablation of the LV free wall is highly effective at creating an appropriately deep epicardial lesion. (+info)
Steam sauna and mother roasting in Lao PDR: practices and chemical constituents of essential oils of plant species used in postpartum recovery.
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