14th International Congress
THE "NEW FRONTIERS"
OF ARRHYTHMIAS 2000

Jan. 29 - Feb. 5, 2000
Marilleva, Trento, Italy

RT-168

Technical issues to reduce atrial defibrillation threshold in low energy internal atrial cardioversion

Giuseppe Boriani, Mauro Biffi, Francesco Pergolini, Claudia Camanini, Ivan Corazza, Pietro Bartolini*, Vincenzo Barbaro*, Romano Zannoli, Angelo Branzi.
Institute of Cardiology, University of Bologna, *Istituto Superiore di Sanita, Rome, Italy

Abstract

Aim of the study was to compare different technical features adopted during low energy internal atrial cardioversion (CV), with regard to energy requirements for CV and shock induced discomfort.

Fifty seven patients with chronic persistent atrial fibrillation (AF) lasting more than 1 month were prospectively enrolled in 3 different trials. The aim was to evaluated the impact on atrial defibrillation threshold (ADFT) of 3 different technical aspects: 1) Shock delivery between catheters in right atrium (RA) and coronary sinus (CS) vs. RA and left pulmonary artery in a comparative parallel study involving 26 patients. 2) Shock delivery of asymmetrical (6.5/2.5-ms) vs symmetrical shocks (3.0/3.0-ms) in a RA-CS configuration in a randomized cross over study involving 19 patients. 3) Shock delivery in a RA-CS configuration with a longer RA coil electrode (8 cm vs 5.5 cm length) in a randomized cross over study involving 12 patients. CV was performed in conscious state with delivery of biphasic shocks, according to a step up protocol.

The results showed that by adopting these technical solutions it is possible to lower ADFT, with a reduction in leading edge voltage of effective shocks of 13-14% and a correspondent reduction in delivered energy of effective shocks of 10.5-25%. The reduction in ADFT had a favorable impact on shock-induced discomfort.

In conclusion different technical issues (catheters location, coil length of defibrillating catheters and defibrillating shock waveforms) may have a positive impact on ADFT and this may imply also a reduction in shock induced discomfort. Although further improvements are required, the possibility to adopt these technical solutions and to couple them is of great interest in clinical practice, both for transvenous internal CV of chronic persistent AF and for implantable atrial defibrillators.

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