Association of corrected QT interval with long-term mortality in patients with syncope.
BACKGROUND
The electrocardiographic parameters QRS duration, QRS-T angle and QTc can predict mortality in patients with cardiovascular disease. The prgnostic value of these parameters in hospitalized patients with syncope needs investigation.


METHODS
We retrospectively studied 590 consecutive patients hospitalized with syncope. After excluding patients with baseline abnormal rhythm, QT- prolonging medications, and missing data, 459 patients were analyzed. Baseline demographic characteristics, co-morbidities, medication use, San Francisco Syncope Rule (SFSR) and Osservatorio Epidemiologico sulla Sincope nel Lazio (OESIL) score and data on mortality were collected. The categorical variables and continuous variables of the 2 groups of patients with prolonged QTc and normal QTc interval were analyzed by Fischer's exact test and Mann-Whitney Test. A stepwise Cox regression model was used for time to death analysis.


RESULTS
Of 459 patients, prolonged QTc interval was observed in 122 (27%). Mean follow-up was 41 months. Patients with prolonged QTc interval had higher prevalence of cardiovascular disease, OESIL score, high risk SFSR, hypertension, dyslipidemia, coronary artery disease, congestive heart failure, and increased mortality. Stepwise Cox regression analysis showed that significant independent prognostic factors for time to death were prolonged QTc interval (p = 0.005), age (p = 0.001), diabetes mellitus (p = 0.001) and history of malignancy (p = 0.006). QRS duration and QRS-T angle were not independent predictors of mortality.


CONCLUSIONS
A prolonged QTc interval is an independent predictor of long-term mortality in hospitalized patients with syncope.
Department of Medicine, Division of Internal Medicine, Westchester Medical Center/ New York Medical College, Valhalla, New York, USA.
Nivas
N
Balasubramaniyam
Department of Medicine, Cardiology Division, New York Medical College at Westchester Medical Center, Valhalla, New York, USA.
Chandrasekar
C
Palaniswamy
Department of Medicine, Cardiology Division, New York Medical College at Westchester Medical Center, Valhalla, New York, USA.
Wilbert S
WS
Aronow
Department of Medicine, Division of Internal Medicine, Westchester Medical Center/ New York Medical College, Valhalla, New York, USA.
Sahil
S
Khera
Department of Medicine, Division of Internal Medicine, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, USA.
Gokulakrishnan
G
Balasubramanian
Department of Medicine, Division of Internal Medicine, Westchester Medical Center/ New York Medical College, Valhalla, New York, USA.
Prakash
P
Harikrishnan
Department of Medicine, Cardiology Division, New York Medical College at Westchester Medical Center, Valhalla, New York, USA.
Jay V
JV
Doshi
Department of Medicine, Division of Internal Medicine, Westchester Medical Center/ New York Medical College, Valhalla, New York, USA.
Christopher
C
Nabors
Department of Medicine, Division of Internal Medicine, Westchester Medical Center/ New York Medical College, Valhalla, New York, USA.
Stephen J
SJ
Peterson
Department of Medicine, Division of Internal Medicine, Westchester Medical Center/ New York Medical College, Valhalla, New York, USA.
Sachin
S
Sule
QTc interval; mortality; syncope