13th International Congress
THE "NEW FRONTIERS"
OF ARRHYTHMIAS 1998

January 24-31, 1998
Marilleva, Trento, Italy

RT-187

Low energy endocavitary cardioversion: safety, effectiveness and tolerability

Claudio Pandozi, Giuseppe Gentilucci, Massimo Santini.
Department of Cardiology, S. Filippo Neri Hospital, Rome, Italy

Introduction

Atrial fibrillation is a common arrhythmia with a high prevalence in the elderly^1,2. The symptoms related to the arrhythmia represent a large spectrum going from palpitation to more serious consequences as left ventricular dysfunction³, thromboembolism⁴ and a higher risk of death^5,6.

Restoration of the sinus rhythm can be traditionally achieved by pharmacological treatment or by external cardioversion. Intraatrial defibrillation, now performed using low energies after the first experience with high energies, is a new technique to obtain cardioversion of atrial fibrillation.

Low energy endocavitary cardioversion may be performed using different techniques. In this paper the most commonly used procedure will be described.

Three intracavitary temporary leads are used in each patient. Two temporary catheters are used for the shock and one tetrapolar lead for ventricular synchronisation. The leads for shock delivering have a large active surface area (ten parallel electrodes or a long coil). The first lead is generally positioned, under fluoroscopic control, in the distal part of the coronary sinus in order to embrace as much as possible the left atrium. The second lead is positioned in the high right atrium or in contact with its lateral wall. This configuration has experimentally shown to be associated with the lowest atrial defibrillation threshold⁷. Beginning from 50-100 volts the voltage is increased progressively by step of 40-50 volts until the restoration of the sinus rhythm is obtained or the maximum programmed voltage or energy is achieved. In this way it is possible to determine the atrial defibrillation threshold.