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Non‐dipolar content of the T‐wave as a measure of repolarization inhomogeneity in ST‐elevation myocardial infarction
Author(s) -
Kesek Milos,
Bjorklund Erik,
Jernberg Tomas,
Lindahl Bertil,
Xue Joel,
Englund Anders
Publication year - 2006
Publication title -
clinical physiology and functional imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.608
H-Index - 67
eISSN - 1475-097X
pISSN - 1475-0961
DOI - 10.1111/j.1475-097x.2006.00701.x
Subject(s) - medicine , repolarization , cardiology , myocardial infarction , dipole , electrophysiology , physics , quantum mechanics
Summary The non‐dipolar content of the T‐wave, i.e. the component of the signal, which cannot be explained by a dipolar model, has been suggested as a measure of the local repolarization inhomogeneity. Our purpose was to study the non‐dipolar content of the T‐wave during the initial course of ST‐elevation myocardial infarction (STEMI), when local repolarization inhomogeneity presumably is markedly increased. Twelve‐lead ECG was semicontinuously collected in 211 patients with STEMI, treated with a thrombolytic agent. The T‐wave was processed by principal component analysis. The absolute and relative T‐wave residues were used as measures of the non‐dipolar content. The median values for each hour and for the entire monitoring time were computed. Changes in the parameters were closer studied in two windows, 0–10 respectively, 11–24 h after start of ECG‐monitoring. The median of the absolute T‐wave residue during the entire monitoring period was 25 000 units in the STEMI‐group and 13 500 units in the comparison group. The median for hour 1 was 36 500 units and 28 800 units for hour 2. The decrease was greater in patients with ≥50% resolution of the ST‐elevation at 60 min. The moment of change, identified by cumulative sum‐method, showed no correlation to the time for 50% ST‐resolution. We conclude, that patients with thrombolysed STEMI have an increased non‐dipolar content of the T‐wave. Resolution of the ST‐elevation is associated with a decrease. The increased non‐dipolar content reflects a property of the repolarization phase, which is related to but separated from the ST‐elevation.