Global T-wave inversion: limited QT dispersion despite QTc prolongation--a correlate of benignity in patients with strikingly abnormal electrocardiograms.
BACKGROUND
The global T-inversion (GTI) electrocardiogram (ECG) is strikingly abnormal with major QTc prolongation, but with a surprisingly good prognosis by Kaplan-Meier curve. This contrasts with most significant QTc prolongations.


OBJECTIVE
This study was undertaken to ascertain QT interval dispersion (QTd) in global T wave inversion, a clinically benign long QTc ECG.


METHODS
Longest and shortest QT intervals in all 12 leads in 35 consecutive patients with GTI were determined by two mutually blinded observers. QTd was determined by subtraction (maximum-minimum) and QTc was calculated using the Bazett formula.


RESULTS
There was a 2:1 female preponderance QTc was prolonged and equal for men (0.471) and women (0.469). Observer variability of under 2% permitted averaging of QT measurements. Composite mean QTd was 55 ms. The literature revealed a range of QTd in normal subjects of 39 to 59 ms (mostly 49 to 59 ms). Patient series with abnormal QTd were well above this level.


CONCLUSIONS
Despite a strikingly abnormal ECG with marked QTc prolongation, QT dispersion was limited in global T inversion, consistent with its previously demonstrated benignity.
Desai
S A
SA
Cardiology Division, St. Vincent Hospital, Worcester, MA 01604, USA.
Mehrok
S
S
Spodick
D H
DH
D001145:Arrhythmias, Cardiac / Q000503:physiopathology*; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male