Long-QT syndrome after age 40.
BACKGROUND
Previous studies that assessed the risk of life-threatening cardiac events in patients with congenital long-QT syndrome (LQTS) have focused mainly on the first 4 decades of life, whereas the clinical course of this inherited cardiac disorder in the older population has not been studied.


RESULTS
The risk of aborted cardiac arrest or death from age 41 though 75 years was assessed in 2759 subjects from the International LQTS Registry, categorized into electrocardiographically affected (corrected QT interval [QTc] > or = 470 ms), borderline (QTc 440 to 469 ms), and unaffected (QTc < 440 ms) subgroups. The affected versus unaffected adjusted hazard ratio for aborted cardiac arrest or death was 2.65 (P<0.001) in the age range of 41 to 60 years and 1.23 (P=0.31) in the age range of 61 to 75 years. The clinical course of study subjects displayed gender differences: Affected LQTS women experienced a significantly higher cumulative event rate (26%) than borderline (16%) and unaffected (12%) women (P=0.001), whereas event rates were similar among the 3 respective subgroups of men (29%, 26%, and 27%; P=0.16). Recent syncope (< 2 years in the past) was the predominant risk factor in affected subjects (hazard ratio 9.92, P<0.001), and the LQT3 genotype was identified as the most powerful predictor of outcome in a subset of 871 study subjects who were genetically tested for a known LQTS mutation (hazard ratio 4.76, P=0.02).


CONCLUSIONS
LQTS subjects maintain a high risk for life-threatening cardiac events after age 40 years. The phenotypic expression of affected subjects is influenced by age-specific factors related to gender, clinical history, and the LQTS genotype.
Goldenberg
Ilan
I
Cardiology Division of the Department of Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA. Ilan.Goldenberg@heart.rochester.edu
Moss
Arthur J
AJ
Bradley
James
J
Polonsky
Slava
S
Peterson
Derick R
DR
McNitt
Scott
S
Zareba
Wojciech
W
Andrews
Mark L
ML
Robinson
Jennifer L
JL
Ackerman
Michael J
MJ
Benhorin
Jesaia
J
Kaufman
Elizabeth S
ES
Locati
Emanuela H
EH
Napolitano
Carlo
C
Priori
Silvia G
SG
Qi
Ming
M
Schwartz
Peter J
PJ
Towbin
Jeffrey A
JA
Vincent
G Michael
GM
Zhang
Li
L
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000328:Adult; D017677:Age Distribution; D000368:Aged; D016757:Death, Sudden, Cardiac / Q000453:epidemiology*; D004562:Electrocardiography; D005260:Female; D005838:Genotype; D006801:Humans; D053208:Kaplan-Meier Estimate; D008133:Long QT Syndrome / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000235:genetics / Q000401:mortality*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010138:Pacemaker, Artificial; D010641:Phenotype; D012042:Registries; D012307:Risk Factors; D014463:Ultrasonography
D000319:Adrenergic beta-Antagonists