Catheter ablation of atrioventricular junction using radiofrequency current in 17 patients : comparison of standard and large-tip catheter electrodes

• Published in: Circulation (New York, N.Y.) N.Y.), 1991-05, Vol.83 (5), p.1562-1576
• Main Authors: JACKMAN, W. M, XUNZHANG WANG, PITHA, J. V, DYER, J, LAZZARA, R, FRIDAY, K. J, FITZGERALD, D. M, ROMAN, C, MOULTON, K, MARGOLIS, P. D, BOWMAN, A. J, KARL-HEINZ KUCK, NACCARELLI, G. V
• Format: Article
• Language: English
• Subjects: Atrioventricular Node - surgery; Biological and medical sciences; Cardiac Catheterization - instrumentation; Cardiac dysrhythmias; Cardiac Surgical Procedures - instrumentation; Cardiac Surgical Procedures - methods; Cardiology. Vascular system; Electrodes; Equipment Design; Follow-Up Studies; Heart; Heart - physiopathology; Humans; Medical sciences; Myocardium - pathology; Postoperative Period; Radio Waves
• ISSN: 0009-7322; 1524-4539
• DOI: 10.1161/01.cir.83.5.1562

Two catheter electrode systems were compared for delivering radiofrequency current for ablation of the atrioventricular junction. Seventeen patients with drug-resistant supraventricular tachyarrhythmias were studied. A 6F or 7F catheter with six or eight standard electrodes (1.25 mm wide, 2.5-mm spacing) was used in the first seven patients (group 1). A 7F quadripolar catheter with a large-tip electrode (4 mm long; surface area, 27 mm2) was used in the final 10 patients (group 2). Both ablation catheters were positioned to record a large atrial potential and a small but sharp His bundle potential from the distal bipolar electrode pair. Radiofrequency current was applied between a large skin electrode on the left posterior chest and either 1) each individual electrode on the standard-tip electrode catheter at 40 V (group 1) or 2) the large-tip electrode at 50-60 V (group 2). Radiofrequency current was limited to 40 V in group patients because of the strong potential for an early impedance rise when higher voltage is applied through standard electrodes. Complete atrioventricular block was achieved in six of seven group 1 patients and all 10 group 2 patients. A junctional escape rhythm followed ablation in five or six group 1 patients (mean cycle length, 1,066 +/- 162 msec) and eight of 10 group 2 patients (mean cycle length, 1,281 +/- 231 msec). Atrioventricular block was produced in a mean of 4.7 +/- 4.6 radiofrequency current applications delivered over a period of 42 +/- 45 minutes using the large-tip electrode (group 2) compared with 46 +/- 22 applications using standard electrodes (15.9 +/- 10.2 applications delivered through the standard-tip electrode) over a period of 147 +/- 59 minutes (group 1). For the application producing atrioventricular block, the large-tip electrode used higher voltage (58 +/- 17 versus 38 +/- 5 V, p less than 0.03) and had lower impedance (103 +/- 22 versus 148 +/- 40 omega, p less than 0.01), resulting in greater power (33.0 +/- 13.0 versus 10.2 +/- 0.6 W, p less than 0.003) and shorter time to block (8 +/- 3 versus 22 +/- 3 seconds, p less than 0.001). Current delivery through standard electrodes was limited by an impedance rise occurring 7 +/- 7 seconds after the onset of one or more radiofrequency current applications at 10 +/- 1 W in six of seven patients. Using the large-tip electrode, an impedance rise occurred in five of 10 patients, but at 25 +/- 10 W and after 21 +/- 9 seconds. Atrioventricular block occurred before