Inter-relationship between electrocardiographic left ventricular hypertrophy and QT prolongation as predictors of increased risk of mortality in the general population.
BACKGROUND
Prolonged-QT commonly coexists in the ECG with left ventricular hypertrophy (ECG-LVH). However, it is unclear whether to what extent QT prolongation coexisting with ECG-LVH can explain the prognostic significance of ECG-LVH, and whether prolonged-QT coexisting with ECG-LVH should be considered as an innocent consequence of ECG-LVH.


RESULTS
The study population consisted of 7506 participants (mean age, 59.4±13.3 years; 49% whites; and 47% men) from the US Third National Health and Nutrition Examination Survey. ECG-LVH was defined by Cornell voltage criteria. Prolonged heart-rate-adjusted QT (prolonged-QTa) was defined as QTa≥460 ms in women or 450 ms in men. Cox proportional hazards analysis was used to calculate the hazard ratios with 95% confidence intervals for the risk of all-cause mortality for various combinations of ECG-LVH and prolonged-QTa. ECG-LVH was present in 4.2% (N=312) of the participants, of whom 16.4% had prolonged-QTa. In a multivariable-adjusted model and compared with the group without ECG-LVH or prolonged-QTa, mortality risk was highest in the group with concomitant ECG-LVH and prolonged-QTa (hazard ratio, 1.63; 95% confidence interval, 1.12-2.36), followed by isolated ECG-LVH (1.48; 1.24-1.77), and then isolated prolonged-QTa (1.27; 1.12-1.46). In models with similar adjustment where ECG-LVH and prolonged-QTa were entered as 2 separate variables and subsequently additionally adjusted for each other, the mortality risk was essentially unchanged for both variables.


CONCLUSIONS
Although prolonged-QT commonly coexists with LVH, both are independent markers of poor prognosis. Concomitant presence of prolonged-QT and ECG-LVH carries a higher risk than either predictor alone.
From the Division of Public Health Sciences, Department of Epidemiology and Prevention, Epidemiological Cardiology Research Center (EPICARE) (E.Z.S., Y.L., P.M.R.) and Section on Cardiology, Department of Internal Medicine (E.Z.S.), Wake Forest School of Medicine, Winston Salem, NC; Department of Epidemiology, Emory University, Atlanta, GA (A.J.S.); and Department of Internal Medicine, Wake Forest Baptist Medical Center, Winston Salem, NC (A.B.). esoliman@wakehealth.edu.
Elsayed Z
EZ
Soliman
From the Division of Public Health Sciences, Department of Epidemiology and Prevention, Epidemiological Cardiology Research Center (EPICARE) (E.Z.S., Y.L., P.M.R.) and Section on Cardiology, Department of Internal Medicine (E.Z.S.), Wake Forest School of Medicine, Winston Salem, NC; Department of Epidemiology, Emory University, Atlanta, GA (A.J.S.); and Department of Internal Medicine, Wake Forest Baptist Medical Center, Winston Salem, NC (A.B.).
Amit J
AJ
Shah
From the Division of Public Health Sciences, Department of Epidemiology and Prevention, Epidemiological Cardiology Research Center (EPICARE) (E.Z.S., Y.L., P.M.R.) and Section on Cardiology, Department of Internal Medicine (E.Z.S.), Wake Forest School of Medicine, Winston Salem, NC; Department of Epidemiology, Emory University, Atlanta, GA (A.J.S.); and Department of Internal Medicine, Wake Forest Baptist Medical Center, Winston Salem, NC (A.B.).
Andrew
A
Boerkircher
From the Division of Public Health Sciences, Department of Epidemiology and Prevention, Epidemiological Cardiology Research Center (EPICARE) (E.Z.S., Y.L., P.M.R.) and Section on Cardiology, Department of Internal Medicine (E.Z.S.), Wake Forest School of Medicine, Winston Salem, NC; Department of Epidemiology, Emory University, Atlanta, GA (A.J.S.); and Department of Internal Medicine, Wake Forest Baptist Medical Center, Winston Salem, NC (A.B.).
Yabing
Y
Li
From the Division of Public Health Sciences, Department of Epidemiology and Prevention, Epidemiological Cardiology Research Center (EPICARE) (E.Z.S., Y.L., P.M.R.) and Section on Cardiology, Department of Internal Medicine (E.Z.S.), Wake Forest School of Medicine, Winston Salem, NC; Department of Epidemiology, Emory University, Atlanta, GA (A.J.S.); and Department of Internal Medicine, Wake Forest Baptist Medical Center, Winston Salem, NC (A.B.).
Pentti M
PM
Rautaharju
D017677:Age Distribution; D000368:Aged; D002423:Cause of Death; D015331:Cohort Studies; D015897:Comorbidity; D016001:Confidence Intervals; D016208:Databases, Factual; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000175:diagnosis* / Q000453:epidemiology*; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008133:Long QT Syndrome / Q000175:diagnosis* / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D018570:Risk Assessment; D012720:Severity of Illness Index; D017678:Sex Distribution; D016019:Survival Analysis
electrocardiography; left ventricular hypertrophy; prolonged QT