Fine structural alterations in radiofrequency energy-induced lesions in dog hearts: possible basis for reduced arrhythmic complications.
OBJECTIVE
To define fine structural changes in canine myocardium due to radiofrequency energy; to compare these changes with those due to direct current shock; and to determine if differences found can explain the reduction in arrhythmic complications observed following the use of radiofrequency energy.


METHODS
Ten mongrel dogs were used for radiofrequency energy and seven for direct current shock experiments.


METHODS
Twenty-five Joules of direct current and 150 to 300 J of radiofrequency energy were delivered via catheters to the myocardium of anesthetized dogs. The endomyocardium was excised and processed for electron microscopy.


RESULTS
The endomyocardial damage produced by radiofrequency energy and direct current shock was similar at the light microscopic levels. Ultrastructurally, the myocyte changes were similar but the supporting vasculature was better preserved in the direct current-damaged myocardium.


CONCLUSIONS
The lack of vascular preservation in radiofrequency energy-induced damage compared to direct current shock myocardial damage may provide a morphological background for the reduced arrhythmic complications noted.
Idikio
H A
HA
Department of Pathology, Faculty of Medicine, University of Alberta, Edmonton.
Humen
D P
DP
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000209:etiology / Q000473:pathology*; D004285:Dogs; D004597:Electroshock; D008854:Microscopy, Electron; D009206:Myocardium / Q000648:ultrastructure*; D011846:Radio Waves / Q000009:adverse effects