ABLATION OF MANIFEST LEFT FREE-WALL ACCESSORY PATHWAYS WITH POLARITY REVERSAL MAPPING - VENTRICULAR APPROACH

Polarity reversal mapping for localization of the left free wall acces sory pathway(AP) at the atrial insertion site has been shown to be eff ective for successful ablation, but this technique requires atrial sep tal puncture. We evaluated the safety, efficacy, and reproducibility o f two-dimensional polarity reversal mapping at the ventricular inserti on site of the accessory pathway without atrial septal puncture in sym ptomatic patients with manifested left free wall AP. Polarity reversal mapping under the mitral annulus by transaortic approach was performe d in 10 consecutive patients with conventional ablation catheter(6 Fre nch, 4 mm tip, 2 mm interelectrode distance), during sinus rhythm or a trial pacing. A low set high, bandpass filter(0.05-400Hz) was used Rad iofrequency(RF) ablation was performed at the site of ventricular elec trogram polarity reversal during sinus rhythm. Polarity reversal was i dentified in all patients at the ventricular side of the mitral annulu s. Ablation was successful in all patients without complications. The procedure time was 86.0 +/- 21.1 min, the fluoroscopic exposure time w as 16 +/- 12 min, the number of RF applications was 8 +/- 6, the power level 21 +/- 7 watts, and the time to initial AP block was 3.0 +/- 0. 9 sec. Polarity reversal mapping is a safe and efficient technique at the ventricular insertion site. This technique might be complementary to the currently-utilized activation mapping technique.