Assessment of delayed ventricular activation after myocardial infarction

Abstract

Experimental and clinical studies have shown that after myocardial infarction (MI), increases the risk to develop cardiac arrhythmias. We have evaluated the ventricular activation during healing (MI7) and healed (MI60) stages after MI. We carried out a comparative study between the QRS spectral variance (QRSSV) index and late potentials (LPs) obtained by the Signal-averaged (SaECG) technique. The electrocardiograms of 48 healthy subjects (CTRL); 84 patients in MI7 and 41 in MI60 without VT/VF; and also 7 patients in MI7 and 6 in MI60 with VT/VF, were analysed utilizing the Frank leads. The QRSSV has increased (p < 0.05) in patients without VT/VF for all leads during MI7 and MI60 with respect to CTRL, and just in a few leads in patients with VT/VF. Conversely, we have only found significant proportion of LPs in MI7 with respect to CTRL in patients with VT/VF and none without VT/VF. This investigation might help to comprehend the influence of time in patients with and without VT/VF. We conclude that SaECG could be restricted to locate stable and delayed depolarization, while the QRSSV index could detect both stable and unstable activation disorders in whole depolarization.