DIFFERENCES IN THE EFFECT OF ACUTE-ISCHEMIA ON LATE POTENTIALS IN SUSCEPTIBLE AND RESISTANT DOGS FOR SUDDEN CARDIAC DEATH

The low predictive value of the signal averaged ECG (SAECG) at rest ma y be due to the absence of any physiological perturbation. This study assessed changes of late potentials (LP) in the SAECG due to acute isc hemia in five susceptible (S) and five resistant (R) dogs for sudden c ardiac death. SAECGs were measured at rest prior to and during the las t 3 min of 4 min transient occlusion of the left circumflex artery (CA O). At rest no significant differences were seen in the QRS duration ( QRSD), the low amplitude signal duration (LAS40) and the root mean squ are voltage (RMS20) between S and R dogs. However, acute ischemia caus ed significant increases in QRSD and LAS40, but only in the S dogs. Th ese results indicate differences in the ischemic modulation of the arr hythmogenic substrate in S and R group. Analysis of LP during acute is chemia may provide an important increase in the positive predictive va lue of the SAECG.