Chronic transmural atrial ablation by using bipolar radiofrequency energy on the beating heart

A real-time graph of tissue conductance (measured in Mhos on the Y axis) between the 2 electrodes on the arms of the device and time (measured in seconds on the X axis). This graph was taken from an RAA lesion on the beating heart. It shows the decrease in tissue conductance at 5.5 seconds and a stable minimal level afterward. Energy was delivered for 11 total seconds during this ablation.

An in vivo picture of 2 connecting lesions of the body of the right atrium. These 2 lines of block electrically isolated the appendage from the body of the right atrium.

An ex vivo picture of the superior RPV. The device is able to isolate a cuff of atrial tissue at the RPV-left atrial junction by producing a continuous linear lesion circumferentially around the targeted tissue. There was no gross pulmonary vein stenosis or thrombosis.

An ex vivo picture of a lesion at the junction of the SVC and the body of the right atrium after 30 days. The anterior portion of the right atrium was opened so that the lesion could be better visualized. The lesion was continuous, linear, and discrete.

A lesion on the anterior surface of the RAA stained with Masson Trichrome stain. (Original magnification 10×.) In every instance the RAA tip was viable, and the lesion was transmural. In this ablation the width of the lesion was 1.3 cm, and the depth was 2.5 cm.