Prevention of Atrial Tachycardia After a Right Atriotomy

Patient selection Consecutive patients operated in the Department of Cardiothoracic Surgery, Aarhus University Hospital at Skejby were included. Inclusion criteria were: 1. Clinical indication for corrective operation for congenital heart disease with the use of a right lateral atriotomy, 2. Age >18 years, 3. Ability to give an informed consent. The only exclusion criterion was acute operation.

Written informed consent was obtained from all the patients prior to the inclusion in the study. The ethical committee for Aarhus County approved the study September 18, 2003.

Operation and postoperative care The operation was performed in the usual fashion. Additionally, a single linear endocardial 1-minute cryolesion connecting the right lateral atriotomy with the tricuspid annulus anteriorly and with crista terminalis posteriorly was performed before the right atriotomy has been sutured (Figure 1). SurgiFrost® cryosurgical probe (Endocare Inc., Irvine, California) was used. Two pairs of epicardial electrodes were placed on the atrium between the incision and the tricuspid annulus 1.5 cm cranially, and caudally from the cryolesion at the end of the repair. They were brought out together to the thorax on the patient's right side. Subsequently, the thorax was closed in the usual way.

Patients were monitored continuously using bedside monitors or telemetry for the first 16-24 hours after the operation. A 12-lead electrocardiogram (ECG) was obtained at any clinical suspicion of arrhythmia. Atrial tachycardia was defined as a sustained regular monomorphic atrial rhythm at a constant rate >100/min originating outside the sinus node.

Measurement of conduction time On the second postoperative day, the conduction time was measured with the help of pacing the electrode pair on the one side of the cryolesion between the incision and the tricuspid annulus and sensing the unipolar signals on the other side (Figure 2). Signals were recorded at 100 mm/s using a commercially available ECG machine.