High energy transcatheter cardioversion of chronic atrial fibrillation

Abstract

A new technique of internal transcatheter cardioversion of chronic atrial fibrillation using high energy shocks (200 to 300 joules) was performed in 10 patients. In all patients, external cardioversion (300 to 400 joules) and pharmacologic therapy failed to restore sinus rhythm. Atrial fibrillation was poorly tolerated despite digitalis therapy alone (five patients) or in combination with amiodarone (five patients). High energy transcatheter cardioversion was performed by pulling back the atrioventricular (AV) junction catheter just inferior to the site of His bundle recording and delivering the shock between a proximal electrode (catheter) and backplate (anode). High energy internal cardioversion restored sinus rhythm in 9 of the 10 patients. However, atrial fibrillation recurred within 3 min in two of them; in the remaining patient, the procedure failed to terminate atrial fibrillation. The only complication observed was transient (3 to 315 s) heart block immediately after shock delivery and this was treated by temporary pacing. Seven patients had sinus rhythm on discharge from the hospital, but in three, recurrent atrial fibrillation appeared at 8 days and 2 and 4 months, respectively. A second attempt of transcatheter cardioversion was performed in two patients and was successful in one patient. With a follow-up ranging from 2 to 11 months, five patients continued to have sinus rhythm. These preliminary results suggest that high energy internal cardioversion may be an alternative to AV junction ablation in selected patients with poorly tolerated chronic atrial fibrillation in whom external cardioversion was unsuccessful.

Atrial fibrillation: current knowledge and recommendations for management*1

“…A technique of high energy (200 J or 300 J) electrical direct current internal cardioversion was shown to be particularly useful in patients who failed both external and pharmacological conversion [95,96] . The technique uses the proximal electrode of a quadripolar catheter as a cathode and a backplate as anode.…”

“…With treatment, recurrence rates are lower but still high (17-89%), predominantly occurring during the first month after cardioversion (Table 5) [93][94][95][96]109,110] . The efficacy of different antiarrhythmic agents is comparable, with the possible exception of amiodarone.…”

A randomized comparison of external and internal cardioversion of chronic atrial fibrillation.

“…If conventional electrical cardioversion is ineffective, internal cardioversion should be attempted. The The following criteria were used to select the subjects for this prospective study: 1) In patients randomly assigned to undergo internal carcatheter with 1-cm interelectrode spacing was inserted into a femoral vein and positioned in the right atrium such that the tip of the catheter was resting on the tricuspid annulus and the most proximal electrode was in the cavity of the right atrium.' A second electrode catheter positioned in the right ventricle was used for ventricular pacing in the event of atrioventricular block after internal cardioversion.…”

Prospective Randomized Trial of Transthoracic Versus Low-Energy Internal Cardioversion in Persistent Atrial Fibrillation Long Term Follow-up

“…7) Transvenous ICV has been performed in various manners since first described. In the earlier reports, [24][25][26] high-energy (200-300 joules) monophasic truncated shocks were applied between a quadripolar intra-atrial catheter and a back plate. With the introduction of biphasic shocks and special intracardiac elec-trode catheters, ICV can now be performed by using low energies in the order of 5-15 joules under only light sedation.…”