Left ventricular hypertrophy detection from simple clinical measures combined with electrocardiographic criteria in a group of African ancestry

Predictors of diastolic dysfunction in ethnic groups: observations from the Hypertensive Cohort of The Ethnic-Echocardiographic Heart of England Screening Study (E-ECHOES)

The study aimed to establish a relationship of ethnicity to diastolic dysfunction in subjects of African-Caribbean and South Asian origins and the impact of diastolic dysfunction and ethnicity on all-cause and cardiovascular mortality.

Hypertensive subjects with ejection fraction ≥55% and no history of ischemic heart disease/valve pathology (n=1546, 830 South Asians and 716 African-Caribbeans) were identified from the Ethnic - Echocardiographic Heart of England Screening Study (E-ECHOES). Diastolic function and cardiac remodelling were measured by echocardiography.

African-Caribbean ethnicity was associated with lower prevalence of having diastolic dysfunction (odds ratio 0.67, 95% confidence interval 0.51-0.87, p=0.003) and increased left ventricular filling pressure (odds ratio 0.48, 95% confidence interval 0.34-0.69, p<0.001) as well as lower left atrial index (p<0.001). This was the case despite the fact that African-Caribbean ethnicity was independently associated with higher left ventricular mass index (p<0.001). Ninety-two deaths (6%) occurred during 68±21 months follow up. On Cox regression analysis, South Asian ethnicity (p=0.024) was predictive of all-cause death before adjustment for parameters of diastolic dysfunction, but it was no longer predictive of death after accounting for these variables.

South Asian ethnicity is independently associated with worse parameters of diastolic function in hypertension, despite African-Caribbeans having more prominent hypertrophy.

Electrocardiographic Criteria for the Diagnosis of Left Ventricular Hypertrophy

BACKGROUND

Current electrocardiographic (ECG) criteria for the diagnosis of left ventricular hypertrophy (LVH) have low sensitivity.

OBJECTIVES

The goal of this study was to test a new method to improve the diagnostic performance of the electrocardiogram.

METHODS

The study was divided into 2 groups, a test and a validation cohort. In the test cohort, 94 patients were analyzed, including 47 with the diagnosis of hypertensive crisis and 47 with normal blood pressure at admission. Echocardiography was used to estimate the left ventricular mass index. Area under the curve (AUC) analysis was used for comparison of single and combined leads. The McNemar test was used to assess agreement among the ECG criteria against the left ventricular mass index. The proposed ECG criteria involved measuring the amplitude of the deepest S wave (S_D) in any single lead and adding it to the S wave amplitude of lead V₄ (SV₄). Currently accepted LVH ECG criteria such as Cornell voltage and Sokolow-Lyon were used for comparison. The validation cohort consisted of 122 consecutive patients referred for an echocardiogram regardless of the admitting diagnosis.

RESULTS

The S_D was the most accurate single lead measurement for the diagnosis of LVH (AUC: 0.80; p < 0.001). When both cohorts were analyzed, the S_D + SV₄ criteria outperformed Cornell voltage with a significantly higher sensitivity (62% [95% confidence interval [CI]: 50% to 72%] vs. 35% [95% CI: 24% to 46%]). The specificities of all the criteria were ≥90%, with no significant difference among them.

CONCLUSIONS

The proposed criteria for the ECG diagnosis of LVH improved the sensitivity and overall accuracy of the test.

Novel Approach to the Detection of Left Ventricular Hypertrophy Using Body Mass Index-Corrected Electrocardiographic Voltage Criteria in a Group of African Ancestry

BACKGROUND

Electrocardiographic (ECG) QRS voltages used to generate criteria for left ventricular hypertrophy (LVH) detection are considerably attenuated by obesity. This effect renders the utility of ECG criteria to detect LVH in obese individuals of African ancestry to be of limited value.

HYPOTHESIS

A novel approach to correcting QRS voltages for the attenuating effect of body mass index (BMI) will improve the ability of ECG criteria to detect LVH in a group of African descent.

METHODS

Left ventricular mass was determined from echocardiography in 661 randomly selected participants (43.0% obese) of black African ancestry in South Africa.

RESULTS

As compared with Cornell and Sokolow-Lyon voltage criteria, BMI best correlated with RaVL , Gubner-Ungerleider, and Lewis QRS complex voltages, but these relations were noted only in those with BMI <29 kg/m(2) . Correcting RaVL and Lewis voltages by the difference in the slope of BMI-voltage relations in those with BMI <29 kg/m(2) vs those with BMI ≥29 kg/m(2) showed the greatest performance for LVH detection (uncorrected RaVL : 0.695 ± 0.025, corrected RaVL : 0.733 ± 0.022; P < 0.0001), and also increased the sensitivity (uncorrected RaVL : 30.6%, corrected RaVL : 42.4%; P < 0.0005) with no significant change in specificity (uncorrected RaVL : 86.3%, corrected RaVL : 83.0%; P = 0.28).

CONCLUSIONS

We offer a novel approach to correcting ECG voltages for the attenuating effects of obesity in individuals of African ancestry, and this improves the performance and sensitivity for LVH detection.