Distorted T-vector loop and increased heart rate are associated with ventricular fibrillation in a porcine ischemia-reperfusion model.
BACKGROUND
The ventricular repolarization (VR) response to short-lasting coronary occlusion has been characterized by 3-dimensional vectorcardiography during angioplasty in humans; the T-vector loop becomes distorted (increased T(avplan)) and more circular (decreased T(eigenvalue)), but these changes have not been related to ventricular arrhythmias.


OBJECTIVE
The VR response was therefore explored in a porcine ischemia-reperfusion model and compared in pigs with (n = 16) vs without (n = 17) ventricular fibrillation (VF).


METHODS
Different aspects of VR were evaluated at baseline, at maximum ischemia, before reperfusion and at the subsequent ST maximum, after 1 hour of reperfusion, and before VF. Three aspects of the VR response were assessed: the ST-segment, the T-vector angles, and the T-vector loop morphology.


RESULTS
All parameters changed significantly from baseline during ischemia and/or reperfusion. The early changes were similar to those previously observed in humans during angioplasty. The VF episodes were preceded by a significantly exaggerated T-loop distortion (increased T(avplan)) and increased heart rate.


CONCLUSIONS
Aggravated T-loop distortion might, in this porcine ischemia-reperfusion model, reflect aspects of VR relevant to arrhythmogenesis.
Odenstedt
Jacob
J
Department of Molecular and Clinical Medicine/Cardiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Rubulis
Aigars
A
Grip
Lars
L
Bergfeldt
Lennart
L
D000818:Animals; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006339:Heart Rate; D006801:Humans; D015428:Myocardial Reperfusion Injury / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology*; D013552:Swine; D014693:Ventricular Fibrillation / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology*