Long QT syndrome in patients over 40 years of age: increased risk for LQTS-related cardiac events in patients with coronary disease.
BACKGROUND
Previous studies of long QT syndrome (LQTS) have focused primarily on the clinical course of affected patients up to 40 years of age to avoid the confounding influence of acquired heart disease on LQTS-related cardiac events in this genetic disorder.


METHODS
Patients were identified as having coronary disease if they had a history of hospitalization for myocardial infarction, coronary angioplasty, coronary artery bypass graft surgery, or were treated with medication for angina. LQTS-related cardiac events included the first occurrence of syncope, aborted cardiac arrest, or sudden cardiac death without evidence suggestive of an acute coronary event. Cox proportional hazards regression modeling was used to analyze the independent contribution of coronary disease to LQTS-related cardiac events.


RESULTS
Time-dependent coronary disease was associated with an increased risk of LQTS-related cardiac events (hazard ratio 2.24, 95% confidence interval 1.23-4.07, P = 0.008) after adjustment for syncopal history before age 40, QTc, and gender. Factors such as diabetes and hypertension that increase the risk for coronary disease were not associated with an increased risk for LQTS-related cardiac events.


CONCLUSIONS
This is the first study to demonstrate that coronary disease augments the risk for LQTS-related cardiac events in LQTS. The findings highlight the need for more focused preventive therapy in LQTS patients above the age of 40.
Sze
Edward
E
Cardiology Division, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642-8653, USA.
Moss
Arthur J
AJ
Goldenberg
Ilan
I
McNitt
Scott
S
Jons
Christian
C
Zareba
Wojciech
W
Qi
Ming
M
Robinson
Jennifer L
JL
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016757:Death, Sudden, Cardiac / Q000209:etiology*; D005260:Female; D006323:Heart Arrest / Q000209:etiology*; D006801:Humans; D008133:Long QT Syndrome / Q000150:complications* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D013575:Syncope / Q000209:etiology*
D000319:Adrenergic beta-Antagonists