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Ethnic differences in the identification of left ventricular hypertrophy in the hypertensive patient
J N Chapman1, J Mayet, C L Chang
1Peart-Rose Clinic and Department of Clinical Pharmacology, Imperial College School of Medicine, London, England. n.chapman@ic.ac.uk
Insights
Electrocardiography (ECG) criteria for left ventricular hypertrophy (LVH) show similar accuracy in Black and White hypertensives. While ECG is generally insensitive for LVH detection, adjusted criteria reveal no significant ethnic differences in test performance.
Area of Science:
- Cardiology
- Medical Diagnostics
- Hypertension Research
Background:
- Left ventricular hypertrophy (LVH) is more common in Black than White individuals with hypertension.
- Existing electrocardiography (ECG) criteria for LVH may exhibit differing specificity and utility across racial groups.
- Echocardiography provides a more direct measure of left ventricular mass index (LVMI).
Purpose of the Study:
- To investigate whether current ECG criteria for LVH are less specific and useful in Black hypertensives compared to White hypertensives.
- To evaluate ethnic differences in ECG voltage criteria for LVH detection, considering left ventricular mass index (LVMI).
Main Methods:
- Retrospective cross-sectional study of 408 hypertensive patients (271 White, 137 Black).
- Measurements included blood pressure, Sokolow-Lyon and Cornell ECG voltage criteria, and echocardiographic LVMI.
- Analysis focused on sensitivity, specificity, and receiver operating characteristic (ROC) curves for ECG criteria across ethnic groups.
Main Results:
- Black subjects exhibited higher ECG voltages than White subjects, independent of LVMI.
- Current ECG criteria were more sensitive in Black individuals (Sokolow-Lyon: 44.9% vs. 22.5%; Cornell: 30.4% vs. 15.7%).
- Specificity was lower in Black individuals using Sokolow-Lyon criteria (73.5% vs. 86.8%), but not significantly different for Cornell criteria (83.8% vs. 91.8%).
- Adjusted ECG criteria and ROC analyses revealed no significant overall differences in test accuracy between ethnic groups.
- ECG detection of LVH was found to be generally insensitive in both populations.
Conclusions:
- Apparent ethnic differences in ECG criteria specificity for LVH are attributable to unrelated ethnic variations in ECG voltages.
- When accounting for these voltage differences, ECG criteria demonstrate comparable accuracy in detecting LVH in Black and White hypertensives.
- Despite limitations in sensitivity, current ECG voltage criteria remain valuable for identifying LVH in Black hypertensives, similar to their utility in White hypertensives.
Abstract:
Left ventricular hypertrophy (LVH) is more prevalent in black than white hypertensives, but this difference is greater when identified by electrocardiography (ECG) than by echocardiography. We evaluated the proposal that current ECG criteria for LVH are less specific, and therefore, less useful, in blacks than whites. In a retrospective cross-sectional study, 408 subjects (271 white, 137 black) referred to a hypertension clinic for assessment of hypertension underwent measurement of blood pressure, ECG voltages (Sokolow-Lyon and Cornell sex-specific), and echocardiographic left ventricular mass index (LVMI). Black subjects had greater ECG voltages than whites, even when closely matched for LVMI. In black subjects, current ECG criteria were twice as sensitive as in whites (Sokolow-Lyon: 44.9% v 22.5%, P = .003. Cornell: 30.4% v 15.7%, P = .03). They were less specific in blacks using the Sokolow-Lyon criteria (73.5% v 86.8%, P = .02) but this failed to reach significance using the Cornell criteria (83.8% v 91.8%, P = .07). When voltage criteria were adjusted to give matched sensitivities and specificities, respectively, differences in specificity and sensitivity were no longer apparent. Receiver operating characteristic curve analyses confirmed no significant differences in overall performance of either ECG criteria between blacks and whites. In conclusion, ECG detection of LVH is insensitive in both ethnic groups. Sensitivity is higher in blacks due to higher LVMI in those with LVH. Apparent differences in specificity are due to ethnic differences in ECG voltages that are unrelated to differences in LVMI. When these differences are taken into account, there are no overall differences in test accuracy. However, given the prognostic importance of the detection of LVH, currently accepted ECG voltage criteria for the detection of LVH remain of equal or greater value in black hypertensives compared with whites.