Differences in the effect of acute ischemia on late potentials in susceptible and resistant dogs for sudden cardiac death

Abstract

The low predictive value of the signal averaged ECG (SAECG) at rest may be due to the absence of any physiological perturbation. This study assessed changes of late potentials (LP) in the SAECG due to acute ischemia in five susceptible (S) and five resistant (R) dogs for sudden cardiac death. SAECGs were measured at rest prior to and during the last 3 min of 4 min transient occlusion of the left circumflex artery (CAO). At rest no significant differences were seen in the QRS duration (QRSD), the low amplitude signal duration (LAS40) and the root mean square voltage (RMS20) between S and R dogs. However, acute ischemia caused significant increases in QRSD and LAS40, but only in the S dogs. These results indicate differences in the ischemic modulation of the arrhythmogenic substrate in S and R group. Analysis of LP during acute ischemia may provide an important increase in the positive predictive value of the SAECG.