Modulation of spatial variance of ventricular repolarization after myocardial infarction

Abstract

Myocardial infarction (MI) alters spatial features of thesurface electrocardiogram. Spatial variance of the T-wave (SVT )describes the interlead dispersion about a mean T-wave morphology. SVTwas linked to arrhythmiavulnerability and sudden cardiac death. In this work, we studied theevolution of SVT over the healing (MI7, up to 7 days after MI) and healed(MI60, from 60 days on post-MI) stages following MI. A control group(n=49) was compared to paired MI7 and MI60 groups (n=39). Fiverepresentative sets of frontal and precordial leads were analyzed: I-IIIII,V1-V2-V3, V4-V5-V6, aVF -V2-V5 and II-aVF -V5. SVT index signicantlyincreased at MI7 (p<0.05) in four out of ve sets and returned towardscontrol values at MI60 (p=NS) on patients without ventricular tachycardiaand/orventricular brillation (VT/VF). The preferential combination of ECG leadsresulted aVF -V2-V5, since it showed the strongest modulation over postMI time. In order totest whether such a modulation was maintained on the presence of VT=VF),recordings from VT=VF patients were also analyzed. SVT modulation waslost in the VT=VF group, signicantly increasing from controls at MI60(p<0.05) for all tested sets of leads. In conclusion, SVT modulation overMI7 and MI60 would signal a good recovery from MI, whereas lack of thismodulation could herald a VT=VF event.