QT-interval prolongation in right precordial leads: an additional electrocardiographic hallmark of Brugada syndrome.
OBJECTIVE
The aim of this study was to evaluate whether the occurrence of the Brugada Syndrome typical electrocardiogram (ECG) pattern (i.e., right bundle branch block, coved-type ST-segment elevation, and T-wave inversion in the right precordial leads) is characterized by a concomitant lengthening of QT intervals in the right precordial leads.


BACKGROUND
It has been suggested that the typical ECG pattern of Brugada syndrome is due to a decreased net inward current during phase 1 of the action potential, which also leads to its prolongation in the right epicardium.


METHODS
Thirty-two subjects (19 males) age 37 +/- 15 years with a suspicious baseline ECG, or who were relatives of Brugada syndrome patients, underwent 12-lead ECG before and after the administration of flecainide.


RESULTS
The flecainide test was negative in 14 and positive in 18 subjects. After flecainide administration, the positive ECGs were characterized by a greater QT interval corrected for heart rate (QTc) prolongation in the right precordial leads than that in the negative ECGs (78.2 +/- 35.5 ms vs. 22.0 +/- 28.4 ms in V(1) and 107.1 +/- 43.8 ms vs. 26.7 +/- 30.1 ms in V(2); p < 0.01), whereas there was no difference in the QTc prolongation in the left precordial leads (55.2 +/- 25.3 ms vs. 35.1 +/- 28.1 ms in V(5) and 53.1 +/- 32.8 ms vs. 27.3 +/- 22.4 ms in V(6); p = NS).


CONCLUSIONS
In accordance with the electrophysiological background, the typical ECG pattern of Brugada syndrome is also characterized by a considerable prolongation of the QT interval in right precordial leads.
Pitzalis
Maria Vittoria
MV
Institute of Cardiology, University of Bari, Bari, Italy. mariavittoria.pitzalis@cardio.uniba.it
Anaclerio
Matteo
M
Iacoviello
Massimo
M
Forleo
Cinzia
C
Guida
Pietro
P
Troccoli
Rossella
R
Massari
Francesco
F
Mastropasqua
Filippo
F
Sorrentino
Sandro
S
Manghisi
Andrea
A
Rizzon
Paolo
P
D000328:Adult; D000889:Anti-Arrhythmia Agents; D002037:Bundle-Branch Block / Q000175:diagnosis* / Q000235:genetics / Q000503:physiopathology; D004562:Electrocardiography; D005260:Female; D005424:Flecainide; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018807:Polymorphism, Single-Stranded Conformational; D012372:ROC Curve; D012680:Sensitivity and Specificity
D000889:Anti-Arrhythmia Agents; D005424:Flecainide