Prediction of drug-related morphological changes of the T wave.
OBJECTIVE
To describe the characteristics of patients presenting with morphological T wave changes that lead to measurement difficulties, and to identify possible predictors of such changes at baseline and early after start of treatment.


METHODS
ECGs from 145 patients receiving a combined potassium and sodium channel blocking agent for conversion of atrial fibrillation (AF), underwent semiautomatic analysis in a digitalized high-precision analysis program. In 15 patients, one or more ECGs were identified as difficult to interpret due to morphological T wave changes. They were compared with the 130 patients without such changes.


RESULTS
A history of cardiac failure (p=0.027), a smaller left atrial area (p=0.010) and a longer QT(tang) minus QT(top) interval (p<0.001) at baseline was significantly more frequent as compared to the controls. Identified patients also had somewhat longer baseline QT interval duration (median QT(cB) 432 vs. 408 ms, N.S.) and a larger proportion of them were females (47% vs. 27%, N.S.). After start of infusion the QT(cB) became significantly longer in identified patients than in controls (p=0.012).


CONCLUSIONS
Independent predictors of subsequent morphological changes were found at baseline and shortly after start of treatment, and may be of use to identify individuals with a reduced repolarization reserve.
Tjäderborn
Micaela
M
AstraZeneca R&D, Mölndal, Sweden.
Aunes-Jansson
Maria
M
Samuelsson
Emma
E
Frison
Lars
L
Johansson
Susanne
S
Berggren
Anders
A
Edvardsson
Nils
N
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage / Q000009:adverse effects*; D001145:Arrhythmias, Cardiac / Q000139:chemically induced* / Q000503:physiopathology; D001281:Atrial Fibrillation / Q000188:drug therapy* / Q000503:physiopathology; D004311:Double-Blind Method; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000187:drug effects* / Q000503:physiopathology; D006801:Humans; D007263:Infusions, Parenteral; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009930:Organic Chemicals / Q000008:administration & dosage / Q000009:adverse effects*; D026902:Potassium Channel Blockers / Q000008:administration & dosage / Q000009:adverse effects*; D011237:Predictive Value of Tests; D018570:Risk Assessment; D012307:Risk Factors; D026941:Sodium Channel Blockers / Q000008:administration & dosage / Q000009:adverse effects*; D013548:Sweden; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
C514242:AZD 7009; D000889:Anti-Arrhythmia Agents; D009930:Organic Chemicals; D026902:Potassium Channel Blockers; D026941:Sodium Channel Blockers