Obesity markedly attenuates the validity and performance of all electrocardiographic criteria for left ventricular hypertrophy detection in a group of black African ancestry

Relating QRS voltages to left ventricular mass and body composition in elite endurance athletes

PURPOSE

Electrocardiogram (ECG) QRS voltages correlate poorly with left ventricular mass (LVM). Body composition explains some of the QRS voltage variability. The relation between QRS voltages, LVM and body composition in endurance athletes is unknown.

METHODS

Elite endurance athletes from the Pro@Heart trial were evaluated with 12-lead ECG for Cornell and Sokolow-Lyon voltage and product. Cardiac magnetic resonance imaging assessed LVM. Dual energy x-ray absorptiometry assessed fat mass (FM) and lean mass of the trunk and whole body (LBM). The determinants of QRS voltages and LVM were identified by multivariable linear regression. Models combining ECG, demographics, DEXA and exercise capacity to predict LVM were developed.

RESULTS

In 122 athletes (19 years, 71.3% male) LVM was a determinant of the Sokolow-Lyon voltage and product (β = 0.334 and 0.477, p < 0.001) but not of the Cornell criteria. FM of the trunk (β = - 0.186 and - 0.180, p < 0.05) negatively influenced the Cornell voltage and product but not the Sokolow-Lyon criteria. DEXA marginally improved the prediction of LVM by ECG (r = 0.773 vs 0.510, p < 0.001; RMSE = 18.9 ± 13.8 vs 25.5 ± 18.7 g, p > 0.05) with LBM as the strongest predictor (β = 0.664, p < 0.001). DEXA did not improve the prediction of LVM by ECG and demographics combined and LVM was best predicted by including VO₂max (r = 0.845, RMSE = 15.9 ± 11.6 g).

CONCLUSION

LVM correlates poorly with QRS voltages with adipose tissue as a minor determinant in elite endurance athletes. LBM is the strongest single predictor of LVM but only marginally improves LVM prediction beyond ECG variables. In endurance athletes, LVM is best predicted by combining ECG, demographics and VO₂max.

The risk of hypertension and cardiovascular disease in women with uterine fibroids

Women with fibroids have a notably high hypertension risk. However, adjusted data regarding other cardiovascular disease (CVD) risk factors are scarce. In this cross-sectional study, CVD risk factors, hemodynamic parameters, and asymptomatic organ damage were analyzed between women with uterine fibroids and controls in a multi-ethnic population. In total, 104 women with self-reported fibroids and 624 controls were included. Women with fibroids had significantly higher odds to have hypertension (OR 3.4; 95% CI 2.2-5.2), diabetes (1.7; 1.0-2.9), and hypercholesterolemia (1.8; 1.1-3.2). After adjustment for confounders, only the odds ratio for hypertension was significant (1.8; 1.1-3.1). Asymptomatic organ damage occurred significantly more often in women with fibroids (66.7%; 95% CI 55.8%-77.6% vs 42.9%; 38.0-47.8 in controls), especially in the younger age group (respectively 48.5%; 31.1%-65.9% vs 22.1%; 17.0-27.2). In this study, women with fibroids had a remarkably high hypertension risk compared to controls, with more asymptomatic organ damage, in particular young women.

Implications of World Health Organization classification for body mass index on the correlations between common electrocardiographic indexes for left ventricular hypertrophy and left ventricular mass

BACKGROUND

Some electrocardiographic indexes such as Cornell index, Cornell product index, or Sokolow-Lyon index remain to be used in the clinical setting. We assessed the effects of body mass index (BMI) on the correlations between these ECG indexes and left ventricular mass (LVM).

METHODS

One hundred ninety-six outpatients who underwent both ECG and echocardiography on the same day were included in this study. In accordance with the World Health Organization (WHO) classification of BMI, the patients were classified into the four groups: underweight (<18.5 kg/m², n = 30), normal weight (18.5-24.9 kg/m², n = 83), overweight (25-29.9 kg/m², n = 43), and obese (≥30 kg/m², n = 40).

RESULTS

With increasing WHO classification of BMI, Cornell index (RaVL+SV3), Cornell product index [(RaVL+SV3)RQRS duration], and LVM increased. On the other hand, Sokolow-Lyon index (SV1+RV5) decreased. Cornell index correlated with LVM in normal weight group (r = 0.27, p = 0.015), but did not in the other groups. Cornell product index also correlated with LVM in normal weight group (r = 0.30, p = 0.006), but did not in the other groups. Sokolow-Lyon index correlated with LVM well in normal weight group (r = 0.32, p = 0.004) and better in underweight group (r = 0.61, p = 0.0004). However, no correlations were found in overweight and obese groups.

CONCLUSIONS

Our results suggest that BMI influences the correlations between these ECG indexes and LVM, and should be taken into consideration when assessing LVH.

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.

Does QRS Voltage Correction by Body Mass Index Improve the Accuracy of Electrocardiography in Detecting Left Ventricular Hypertrophy and Predicting Cardiovascular Events in a General Population?

The authors assessed the value of body mass index (BMI) correction of two electrocardiographic criteria in improving detection of left ventricular hypertrophy (LVH) and prediction of cardiovascular and all-cause mortality in the Italian study Pressioni Arteriose Monitorate E Loro Associazioni (PAMELA) population. At entry, 1549 patients underwent diagnostic tests, 24-hour ambulatory blood pressure (BP) monitoring, standard electrocardiography, and echocardiography. The BMI-corrected Cornell voltage and Sokolow-Lyon voltage criteria provided better results for detection of echocardiographic LVH as compared with unadjusted electrocardiographic parameters. Cornell voltage index, but not Sokolow-Lyon index, was associated with an increased risk of cardiovascular events (and all-cause mortality). The adjusted risk of cardiovascular events related to one-standard deviation increment of BMI-corrected Cornell voltage was similar to that conferred by the uncorrected criterion in the total population, but outperformed in obese participants. These findings show that correction for BMI may improve the diagnostic accuracy of Cornell voltage index in detecting LVH and prediction of cardiovascular mortality in obese individuals.

P wave area for quantitative electrocardiographic assessment of left atrial remodeling

BACKGROUND

Left atrial (LA) dilation provides a substrate for mitral regurgitation (MR) and atrial arrhythmias. ECG can screen for LA dilation but standard approaches do not assess LA geometry as a continuum, as does non-invasive imaging. This study tested ECG-quantified P wave area as an index of LA geometry.

METHODS AND RESULTS

342 patients with CAD underwent ECG and CMR within 7 (0.1±1.4) days. LA area on CMR correlated best with P wave area in ECG lead V1 (r = 0.42, p<0.001), with lesser correlations for P wave amplitude and duration. P wave area increased stepwise in relation to CMR-evidenced MR severity (p<0.001), with similar results for MR on echocardiography (performed in 86% of patients). Pulmonary arterial (PA) pressure on echo was increased by 50% among patients in the highest (45±14 mmHg) vs. the lowest (31±9 mmHg) P wave area quartile of the population. In multivariate regression, CMR and echo-specific models demonstrated P wave area to be independently associated with LA size after controlling for MR, as well as echo-evidenced PA pressure. Clinical follow-up (mean 2.4±1.9 years) demonstrated ECG and CMR to yield similar results for stratification of arrhythmic risk, with a 2.6-fold increase in risk for atrial fibrillation/flutter among patients in the top P wave area quartile of the population (CI 1.1-5.9, p = 0.02), and a 3.2-fold increase among patients in the top LA area quartile (CI 1.4-7.0, p = 0.005).

CONCLUSIONS

ECG-quantified P wave area provides an index of LA remodeling that parallels CMR-evidenced LA chamber geometry, and provides similar predictive value for stratification of atrial arrhythmic risk.