[QT interval dispersion analysis in acute myocardial infarction patients: coronary reperfusion effect].
OBJECTIVE
To study the effect of early reperfusion of infarct-related artery on QT(DeltaQT) dispersion interval, as well as how valuable it is as a marker for coronary reperfusion and ventricular arrhythmias.


METHODS
One hundred and six patients with reperfusion (WR) and 48 without reperfusion (WtR) who have received thrombolytic therapy in the acute phase of infarction were studied. ECG carried out on admission as well as on day 4 of patients course were analyzed. DeltaQT - defined as the difference between maximum and minimum QT interval - was measured by 12-lead ECG.


RESULTS
The reperfusion group showed significant DeltaQT reduction - from 89.66+/-20.47ms down to 70.95+/-21.65ms (p<0.001). On the other hand, the group without reperfusion showed DeltaQT significant increase - from 81.27+/-20.52ms up to 91.85+/-24.66ms (p<0.001). Logistic regression analysis showed that reduction magnitude between pre- and post-thrombolysis DeltaQT was the independent factor to most effectively identify coronary reperfusion (OR 1.045, p<0.0001; CI 95%). No significant difference was found in dispersion measures when patients with ventricular arrhythmias were compared with those with no arrhythmias in the course of the first 48 hours.


CONCLUSIONS
The study shows that DeltaQT is significantly reduced in patients with acute myocardial infarction submitted to successful thrombolysis, and is increased in infarcted patients with closed artery. DeltaQT reduction between the pre- and post-thrombolysis condition was a predictor for coronary reperfusion of those patients, and did not show correlation to ventricular arrhythmias.
Lopes
Neuza Helena Moreira
NH
Instituto do Corção, Hospital das Clinicas, FMUSP, São Paulo, SP, Brazil. mass@incor.usp.br
Grupi
César
C
Dina
Cleberson H
CH
de Gois
Aécio F T
AF
Hajjar
Ludhmila A
LA
Ayub
Beatriz
B
Rochitte
Carlos Eduardo
CE
Ramires
José Antonio Franchini
JA
Hueb
Whady A
WA
Kalil
Roberto
R
D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D004562:Electrocardiography; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008133:Long QT Syndrome / Q000175:diagnosis* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy / Q000503:physiopathology*; D015425:Myocardial Reperfusion; D015912:Thrombolytic Therapy
D000889:Anti-Arrhythmia Agents