Electrical remodeling in left ventricular hypertrophy—is there a unifying hypothesis for the variety of electrocardiographic criteria for the diagnosis of left ventricular hypertrophy?

LBBB and heart failure-Relationships among QRS amplitude, duration, height, LV mass, and sex

BACKGROUND

Height, left ventricular (LV) size, and sex were proposed as additional criteria for patient selection for cardiac resynchronization therapy (CRT) but their connections with the QRS complex in left bundle branch block (LBBB) are little investigated. We evaluated these.

METHODS

Among patients with "true" LBBB, QRS duration (QRSd) and amplitude, and LV hypertrophy indices, were correlated with patient's height and LV mass, and compared between sexes.

RESULTS

In this study cohort (n = 220; 60 ± 12 years; left ventricular ejection fraction [LVEF] 21 ± 7%; mostly New York Heart Association II-III, QRSd 165 ± 19 ms; 57% female; 70% responders [LVEF increased ≥5%]), LV mass was increased in all patients. QRS amplitude did not correlate with LV mass or height in any individual lead or with Sokolow-Lyon or Cornell-Lyon indices. QRSd did not correlate with height. In contrast, QRSd correlated strongly with LV mass (r = .51). CRT response rate was greater in women versus men (84% vs. 58%, p < .001) despite shorter QRSd [7% shorter (p < .0001)]. QRSd normalized for height resulted in a 2.7% and for LV mass 24% greater index in women.

CONCLUSION

True LBBB criteria do not exclude HF patients with increased LV mass. QRS amplitudes do not correlate with height or LV mass. Height does not affect QRSd. However, QRSd correlates with LV size. QRSd normalized for LV mass results in 24% greater value in women in the direction of sex-specific responses. LV mass may be a significant nonelectrical modifier of QRSd for CRT.

Normal limits of the electrocardiogram in Angolans

INTRODUCTION

Studies on the normal electrocardiogram limits in African populations are limited, especially in sub-Saharan Africa. There is no literature describing normal ECG limits in Angolans.

OBJECTIVES

The aim of this study is to establish the normal ECG limits for adult Angolans, without established heart disease, stratified by gender and age.

METHODS

A cross-sectional study was performed, involving 2179 participants from a population in northern Angola, without established heart disease, aged between 15 and 74 years. A 12‑lead ECG and a rhythm strip were recorded for all participants and analysed and processed by the University of Glasgow software and encoded by the Minnesota Code. The normal range of the electrocardiographic parameters were established as the 2nd and 98th percentiles of the measurement distribution per age group and gender. Mann-Whitney and Kruskal-Wallis tests were used for two independent groups and Bonferroni adjustments were used for multiple testing. GAMLSS models were used to obtain the continuous age-dependent percentile curves.

RESULTS

The normal range of the ECG differed between men and women: heart rate 49 to 100 bpm vs. 55 to 108 bpm, P wave duration 81 to 130 ms vs. 84 to 130 ms, PR interval 119 to 210 ms vs. 120 to 202 ms, QRS duration 74 to 110 ms vs. 70 to 104 ms, QT interval 324 to 441 ms vs. 314 and 438 ms, P-wave axis - 29 to 85⁰ vs. -18 to 81⁰, QRS-wave axis - 13 to 85⁰ vs. -18⁰ and 82⁰, T-wave axis 0 to 72⁰ vs. -8 to 73⁰, Sokolow-Lyon index 2.13 to 6.21 mV vs. 1.60 to 4.87 mV, Cornell index 0.17 to 6.24 mV vs. 0.14 mV to 4.35 mV.

CONCLUSIONS

The values described for the electrocardiographic measurements above can act as a reference framework for Angolan adults without established heart disease. Our study suggests that the normal range of most ECG parameters vary according to age and sex and the ECG diagnostic criteria must therefore be specific for these demographic measures.

Electrocardiographic predictors of atrial fibrillation in nonhypertensive and hypertensive individuals

OBJECTIVE

The aim of this study was to compare the predictive value of ECG abnormalities for atrial fibrillation in nonhypertensive versus hypertensive individuals.

METHODS

We recorded ECG and measured conventional cardiovascular risk factors in a nationwide population-based sample of 5813 Finns. We divided the participants into nonhypertensive (n = 3148) and hypertensive (n = 2665) individuals and followed the participants for incident atrial fibrillation events. We evaluated the predictive ability of 12 ECG abnormalities for atrial fibrillation using multivariable-adjusted Fine-Gray models.

RESULTS

During a follow-up of 11.9 ± 2.9 years, 111 nonhypertensive and 301 hypertensive participants developed atrial fibrillation. Negative T wave in lateral leads predicted atrial fibrillation in both nonhypertensive [hazard ratio (HR), 4.59; 95% confidence interval (95% CI) 1.84-11.44] and hypertensive participants (HR, 1.81; 95% CI 1.16-2.84). In nonhypertensive participants, 1-SD increments in corrected QT interval (HR, 1.42; 95% CI, 1.18-1.71) and T-wave amplitude in lead augmented vector R (aVR) (HR, 1.40; 95% CI, 1.10-1.80) were related to atrial fibrillation. In hypertensive participants, prolonged PR interval (HR, 1.59; 95% CI 1.05-2.41), prolonged P-wave duration (HR, 1.43; 95% CI 1.07-1.91), left ventricular hypertrophy by Sokolow-Lyon criteria (HR, 1.55; 95% CI, 1.12-2.14) and poor R-wave progression (HR, 1.59; 95% CI, 1.02-2.48) predicted atrial fibrillation. Corrected QT interval and T-wave amplitude in lead aVR were stronger predictors of atrial fibrillation in nonhypertensive than in hypertensive participants. ECG abnormalities improved risk prediction only marginally (delta area under receiver-operating-characteristic curve = 0.000-0.005).

CONCLUSION

Several ECG abnormalities associate with incident atrial fibrillation in hypertensive and nonhypertensive individuals but provide only marginal incremental predictive value. Corrected QT interval and T-wave amplitude in lead aVR may relate stronger to incident atrial fibrillation in nonhypertensive than in hypertensive individuals.

The 4th Report of the Working Group on ECG diagnosis of Left Ventricular Hypertrophy

The 4th Report provides a brief review of publications focused on the electrocardiographic diagnosis of left ventricular hypertrophy published during the period of 2010 to 2016 by the members of the Working Group on ECG diagnosis of Left Ventricular Hypertrophy. The Working Group recommended that ECG research and clinical attention be redirected from the estimation of LVM to the identification of electrical remodeling, to better understanding the sequence of events connecting electrical remodeling to outcomes. The need for a re-definition of terms and for a new paradigm is also stressed.

The association of uncoupling protein 2 (UCP2) exon 8 insertion/deletion polymorphism and ECG derived QRS duration: A cross-sectional study in an Australian rural population

BACKGROUND

Associations between inherited mitochondrial disease and cardiac conduction have been previously described. However, there are no available studies exploring the mitochondrial uncoupling protein 2 gene (UCP2) insertion/deletion (I/D) polymorphisms interaction on cardiac electrical conduction. Our aim was to determine if ECG-derived QRS duration is associated with UCP2 DD genotype in a cross-sectional Australian aging rural population.

METHODS

A retrospective study design utilizing a rural health diabetic screening clinic data-base containing observational data from September 2011 to September 2014. Inclusion criteria included were having ECG parameters such as QRS duration measures and a DNA sample within the same subject. Genomic DNA was extracted and subjects were genotyped for the 45-bp I/D polymorphism in the 3'-untranslated region of UCP2.

RESULTS

281 individuals were available for analysis. On the basis of QRS duration >140ms we found an increased percentage of our population with DD homozygotes, compared to ID heterozygotes and II homozygotes (p=0.047). For other ECG parameters; mean PQ duration, QTc across UCP2 genotypes was not significant (p=NS). QTc using a cut-off >440ms in contingency table analysis revealed no significant differences across UCP2 I/D genotypes. Mean QT dispersion (QTd) was paradoxically less in the UCP2 DD genotype compared to UCP2 II subgroup (p=0.034).

DISCUSSION

We have demonstrated an association between increasing ECG-derived QRS duration >140ms and the UCP2 DD polymorphism. The lack of association with ECG derived QTd and UCP2 DD may suggest that gene-related QRS duration prolongation is independent of cardiac hypertrophy.

Electrocardiogram Derived QRS Duration >120 ms is Associated With Elevated Plasma Homocysteine Levels in a Rural Australian Cross-Sectional Population

Homocysteine levels in the low to moderate range for cardiovascular risk have been previously associated with left ventricular cardiac hypertrophy (LVH). Electrocardiogram (ECG) derived QRS duration has also been used as an epidemiological screening marker for cardiac hypertrophy risk. QRS duration cut offs have not been previously modeled to assess homocysteine levels in community populations. Our aims are to determine if QRS duration is associated with an elevated homocysteine level in a cross-sectional Australian aging rural population.A retrospective study design utilizing a rural health diabetic screening clinic database containing observational data from the period January 9, 2002 till September 25, 2012. One hundred seventy-eight individuals (>21 years of age) from the database were included in the study. Inclusion criteria included being nondiabetic and having both a QRS duration measure and a matching homocysteine level within the same subject. All participants were from the Albury-Wodonga area, with a mean age of >64 years for both sexes.Mean population homocysteine plasma levels were 10.4 μmol/L (SD = 3.6). The mean QRS duration was 101.8 ms (SD = 17.4). Groups were stratified on the basis of QRS duration (≤120 ms [n = 157] and >120 ms [n = 21]). QRS duration subgroup (≤120 ms vs >120 ms) mean differences across homocysteine levels were 10.1 μmol/L (SD = 3.3) and 12.2 μmol/L (SD = 4.7), respectively (P = 0.016). Other ECG parameters (PQ interval, QTc interval, and QT dispersion) measurements were not significantly associated with differences in plasma homocysteine (P = not significant).We conclude that in community populations homocysteine may be moderately elevated when QRS durations are >120 ms. Small additional increases in homocysteine levels may suggest a risk factor for ECG diagnosis of LVH.

Levels of cornell voltage and cornell product for predicting cardiovascular and stroke mortality and morbidity in the general Japanese population

BACKGROUND

ECG-diagnosed left ventricular hypertrophy (LVH), the Cornell voltage (CV: ≥2.8mV in males and ≥2.0mV in females) or Cornell product (CP: ≥244.0mV×ms), were selected in Western countries for their ability to diagnose anatomical LVH.

METHODS AND RESULTS

 We aimed to elucidate the CV and CP values that were associated with a significantly increased risk of cardiovascular or stroke mortality and morbidity in a Japanese general population (n=10,172). In the receiver-operating curves analysis of CV and CP for predicting the risks, the area under the curve in females was greater than in males. In a quintile-based multivariate analysis that was performed separately for females and males, the mortality and morbidity risks of CV were significantly increased at the highest quintile of CV (>1.71mV) in females. In males, the mortality risk was significantly increased at the highest quintile of CV (>2.04mV). Additionally, in the parallel analysis of CP that included both males and females, the morbidity risk was significantly elevated in subjects with CP belonging to the 4th (158.7-193.4mV×ms; hazard ratio=1.387) or 5th quintiles (≥193.5mV×ms; hazard ratio=1.507), compared with those with CP values within the lowest quintile (<101.9mV×ms).

CONCLUSIONS

Cardiovascular and stroke risks may be elevated at lower levels of CV and CP in Japanese subjects, especially females.