Catheter-directed laser coagulation of atrial myocardium in dogs.
The feasibility of transcatheter laser coagulation of atrial myocardium was tested in a canine model by using a combined electrode-laser catheter. In 17 anaesthetized beagles a total of 264 lesions, 12-19 per dog, and 3-5 in each area were produced in: (1) the lateral walls, (2) the posterior right atrial walls, (3) the inter-atrial septum, and (4) the atrial appendage. The power source was a continuous wave Nd:YAG laser. Irradiance was 1 kW.cm-2, at a wave length of 1064 nm, the irradiated spot diameter was 2.0-2.5 mm, and the pulse duration 5-60 s. Local intra-cardiac atrial potentials recorded from the targeted areas during laser irradiation dwindled after onset of the laser pulse, and their amplitude was reduced persistently by pulses of 15 s or longer. Histopathologically, the acute lesions showed intramural haemorrhage and coagulation necrosis, but there was no tissue vaporization or crater formation. Chronic lesions showed clear-cut oval-shaped areas of transmural fibrosis. Diameters of lesions, dependent on the amount of laser energy applied, measured from 4.6 +/- 0.5 mm (450 J) to 7.8 +/- 1.4 mm (1800 J). Follow-up lasted 6-25 months (average 10.5). All the animals survived the procedure without complications. Transcatheter laser coagulation of atrial myocardium is safe and can be performed in a controllable manner by using the catheter system presented.
Weber
H P
HP
1. Medical Department, Harlaching Hospital, Munich, Germany.
Heinze
A
A
Enders
S
S
Ruprecht
L
L
Unsöld
E
E
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D016275:Atrial Function; D017115:Catheter Ablation / Q000295:instrumentation / Q000379:methods*; D004285:Dogs; D004562:Electrocardiography; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006325:Heart Atria / Q000473:pathology / Q000601:surgery*; D017075:Laser Coagulation / Q000295:instrumentation / Q000379:methods*; D008297:Male; D016343:Monitoring, Intraoperative; D013997:Time Factors