EVALUATION OF A SIMPLIFIED ELECTRODE FOR INTRACAVITARY ATRIAL DEFIBRILLATION

Abstract

The habitual methods of low energy intracardiac atrial fibrillation (AF) reversion apply electrical discharges between right atrium and coronary sinus or kit pulmonary artery. The need of fluoroscopy and trained staff are conditions which make the procedure complicated. The authors have developed flow energy atrial defibrillating catheter with a single uncoiling looping electrode in the right atrium (RA) the other electrode being a plate applied externally to the thoracic wall. The insertion is done in a straightforward manner through a venous catheter of the Intracath® type. OBJECTIVES: To evaluate the defibrillating ability concerning energy required, of the present catheter (B) against a conventional right atrium-left pulmonary artery one (A). MATERIALS AND METHOD: Five mongrel dogs were anesthetized, intubated and submitted to mechanical ventilation. The right jugular vein was dissected and a plain catheter with stimulating electrode was placed in the RA where high frequency stimulation with unipolar pulses of 600 ppm frequency, 0.5 ms duration, and amplitude sufficient for atrial capture were delivered until AF was produced and sustained without stimuli. After 5 min. of spontaneous AF the uncoiling looping electrode in catheter B was placed in the RA and a 5 J synchronized discharge was delivered against an external plate electrode of 120 cm2area. One reversion to sinus rhythm was obtained the procedure was repeated with discharges of 4, 3, 2, 1, and 0.5 1. The same sequence was followed using catheter A. RESULTS: With AF induced according to the described experimental model catheters A and R were equally efficient in reversing AF to normal rhythm with low energy shocks. CONCLUSION: The present experiment has shown that the currently developed uncoiling looping electrode with an external metallic plate is as efficient in reverting AF as the well-known RA-Left Pulmonary electrode, being of much simpler construction, and positioned without fluoroscopy or specialized staff.