Calculating Cornell voltage from nonstandard chest electrode recording site in the Reasons for Geographic And Racial Differences in Stroke study☆
Received 31 August 2009 published online 10 December 2009.
Abstract
Background
To minimize participants' burden and the need for disrobing, a 7-lead electrocardiogram (ECG) recording using a single mid-sternal chest lead was recorded at the initial stages of The REasons for Geographic And Racial Differences in Stroke (REGARDS) study. Electrocardiogram-detected left ventricular hypertrophy (ECG-LVH) by Cornell voltage (RaVL + S-wave amplitude in V3 [SV3]) cannot be assessed from this method because of the absence of V3. We examined the possibility that the S-wave amplitude in the mid-sternal lead (SV) could be used as a surrogate for SV3.
Methods
The REGARDS study is a US national study where 7-lead ECGs were performed in 8,330 (29%) participants and standard 12-lead EGCs were performed in 20 811 (71%). Cornell voltage was calculated as the sum of aVL amplitude + SV (in the 7-lead group) or SV3 (in the 12-lead group). Logistic regression analysis was used to examine and compare the magnitude of the association between the LVH risk factors with ECG-LVH in both groups, and Cox proportional hazards analysis was used to examine and compare the hazard ratios of overall mortality and cardiovascular mortality associated with ECG-LVH in both groups.
Results
Regardless of the Cornell voltage calculation method, ECG-LVH was significantly associated with LVH risk factors; and with the exception of sex, there was no evidence of a difference in the magnitude of the association. ECG-LVH from both approaches were significantly and similarly associated with both all-cause and cardiovascular mortality.
Conclusion
ECG-LVH by Cornell voltage calculated from a 7-lead ECG (using SV in the formula) has demographic and clinical associations that are similar to that calculated from a standard 12-lead ECG (using SV3). In epidemiologic studies recording 7-lead ECG, SV could be used as an alternative to SV3 in the Cornell voltage formula.
aDepartment of Epidemiology and Prevention, Wake Forest University School of Medicine, Winston-Salem NC, USA
bDepartment of Biostatistics, School of Public Health, University of Alabama at Birmingham, Birmingham, AL, USA
cDepartment of Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, AL, USA
Corresponding author. Epidemiological Cardiology Research Center (EPICARE), Department of Epidemiology and Prevention, Wake Forest University School of Medicine, 2000 West First St., Piedmont Plaza 2, Suite 505, Winston Salem, NC 27104, USA.
☆ This research is supported by the NIH (National Institute of Neurological Disorders and Stroke, U01 NS041588 G.H.).
ABSTRACT