Quantitative indices of dispersion of refractoriness for identification of propensity to re-entrant ventricular tachycardia in a canine model of myocardial infarction.
OBJECTIVE
To identify propensity to re-entry in a canine model of 7 day old myocardial infarction, the sensitivity and specificity of five indices of dispersion of refractoriness (ERP) were investigated.


METHODS
With an epicardial patch electrode containing 47 electrodes, ERP was measured by S1-S2 method at each site overlying the infarct. ERP range, maximum adjacent dispersion, difference between mean ERPS of the infarct and normal zones, standard deviation (sigma) of the mean ERP, and sigma/mean ERP X 100 were calculated.


METHODS
42 dogs were divided into three groups; 20 dogs with epicardial functional block on induction of sustained ventricular tachycardia or fibrillation, 10 dogs with inducible ventricular tachycardia or fibrillation but without epicardial functional block, and 12 control dogs without ventricular tachycardia, fibrillation or block.


RESULTS
All five indices were significantly greater in the 20 dogs with ventricular tachycardia or fibrillation than in control dogs. A receiver operating characteristic curve analysis of the five indices showed that sigma was the most sensitive and specific index for discriminating these 20 dogs. The sensitivity and specificity of a sigma value greater than 14 ms (the mean value plus two SD of the control dogs) were 70% and 100%, respectively.
Ogawa
S
S
Department of Medicine, Keio University, School of Medicine, Tokyo, Japan.
Furuno
I
I
Satoh
Y
Y
Yoh
S
S
Saeki
K
K
Sadanaga
T
T
Katoh
H
H
Nakamura
Y
Y
D000818:Animals; D004195:Disease Models, Animal; D004285:Dogs; D004594:Electrophysiology; D006352:Heart Ventricles; D009203:Myocardial Infarction / Q000150:complications*; D010496:Pericardium / Q000503:physiopathology*; D012032:Refractory Period, Electrophysiological; D013610:Tachycardia / Q000209:etiology* / Q000503:physiopathology; D013997:Time Factors