Hypertrophic reprogramming of the left ventricle: translation to the ECG

Seamens' Sign: a novel electrocardiogram prediction tool for left ventricular hypertrophy

Introduction

Patients with left ventricular hypertrophy (LVH) diagnosed by electrocardiogram (ECG) have increased mortality and higher risk for life-threatening cardiovascular disease. ECGs offer an opportunity to identify patients with increased risk for potential risk-modifying therapy. We developed a novel, quick, easy to use ECG screening criterion (Seamens' Sign) for LVH. This new criterion was defined as the presence of QRS complexes touching or overlapping in two contiguous precordial leads.

Methods

This study was a retrospective chart review of 2,184 patient records of patients who had an ECG performed in the emergency department and a transthoracic echocardiogram performed within 90 days. The primary outcome was whether Seamens' Sign was noninferior in confirming LVH compared to other common diagnostic criteria. Test characteristics were calculated for each of the LVH criteria. Inter-rater agreement was assessed on a random sample using Cohen's Kappa.

Results

Median age was 63, 52% of patients were male and there was a 35% prevalence of LVH by transthoracic echocardiogram (TTE). Nine percent were positive for LVH on ECG based on Seamens' Sign. Seamens' Sign had a specificity of 0.92. Tests assessing noninferiority indicated Seamens' Sign was non-inferior to all criteria (p < 0.001) except for Cornell criterion for women (p = 0.98). Seamens' Sign had 90% (0.81-1.00) inter-rater agreement, the highest of all criteria in this study.

Conclusion

When compared to both the Sokolow-Lyon criteria and the Cornell criterion for men, Seamens' Sign is noninferior in ruling in LVH on ECG. Additionally, Seamens' Sign has higher inter-rater agreement compared to both Sokolow-Lyon criteria as well as the Cornell criteria for men and women, perhaps related to its ease of use.

Prognostic impact of electrocardiographic left ventricular hypertrophy following transcatheter aortic valve replacement

BACKGROUND

Left ventricular hypertrophy (LVH) develops with both structural and electrical remodeling in response to elevated afterload due to aortic stenosis (AS). This study evaluated the prognostic value of electrocardiographic LVH (ECG LVH) after transcatheter aortic valve replacement (TAVR).

METHODS

A retrospective study including 157 consecutive patients who underwent TAVR was conducted. ECG LVH was defined as Sokolow-Lyon voltage (S in V₁ + R in V_5/6) before TAVR was ≥3.5mV. We investigated the association between ECG LVH and the 1-year composite outcome comprising all-cause death and rehospitalization related to heart failure. ECG and echocardiographic measurements at 1, 6, and 12 months after TAVR were assessed.

RESULTS

The baseline characteristics were comparable between the ECG LVH (n = 74) and non-ECG LVH groups (n = 83). The ECG LVH was associated with a significantly greater reduction of Sokolow-Lyon voltage and LV mass index than the non-ECG LVH after TAVR. The absence of ECG LVH was an independent predictor of the 1-year composite outcome [adjusted hazard ratio (HR), 2.27; 95% confidence interval (CI), 1.01 - 5.60; p = 0.04]. Furthermore, a reduction of Sokolow-Lyon voltage from baseline to 1-month follow-up, but not a reduction of LV mass index, was associated with a lower cumulative composite outcome from 1 month to 1 year (adjusted HR, 0.36; 95% CI, 0.15 - 0.86; p = 0.02).

CONCLUSIONS

ECG LVH was associated with a low incidence of adverse clinical outcomes and greater reverse LV remodeling after TAVR. Preprocedural and serial LVH assessment by ECG might be useful in AS patients undergoing TAVR.

Central aortic systolic blood pressure can predict prolonged QTc duration better than brachial artery systolic blood pressure in rural community residents

OBJECTIVES

Previous studies have suggested that prolonged electrocardiogram QTc duration was independent risk factor for both increased cardiovascular and all-cause mortality, but there was no dating about the relationship between central aortic systolic blood pressure (CASP) and QTc duration. The aim of this study was to analyze the relationship between CASP and QTc duration, and assess whether CASP can predict prolonged QTc duration more than BSBP.

METHODS

A total of 500 patients were enrolled in this study, central and brachial aortic blood pressure and electrocardiogram QTc duration were measured. Pearson correlation was assessed for determining the associations of QTc duration with clinical conditions. Multivariate logistic regression analyses were performed to determine the independent predictor of prolonged QTc duration. Receiver operating characteristic (ROC) curve was used to evaluate the utility of blood pressure for prolonged QTc duration.

RESULTS

We found QTc durations were significantly positive with CASP (r = 0.308, p < 0.001), BSBP (r = 0.227, p < 0.001), and age (r = 0.154, p = 0.010), but negatively related to heart rate (r = -440, p < 0.001). A multiple logistic regression analysis demonstrated that the CASP was an independent determinant of prolonged QTc (OR = 1.648; 95%CI: 1.032, 2.101; p < 0.001). CASP had a better predictive value for prolonged QTc duration than (AUC: 0.771 vs. 0.646, p < 0.001) BSBP.

CONCLUSION

Our results suggested that the non-invasive CASP is independently correlated with QTc duration, and CASP can predict prolonged QTc duration more than BSBP.

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.

Kinetic mRNA Profiling in a Rat Model of Left-Ventricular Hypertrophy Reveals Early Expression of Chemokines and Their Receptors

Left-ventricular hypertrophy (LVH), a risk factor for heart failure and death, is characterized by cardiomyocyte hypertrophy, interstitial cell proliferation, and leukocyte infiltration. Chemokines interacting with G protein-coupled chemokine receptors may play a role in LVH development by promoting recruitment of activated leukocytes or modulating left-ventricular remodeling. Using a pressure overload-induced kinetic model of LVH in rats, we examined during 14 days the expression over time of chemokine and chemokine receptor mRNAs in left ventricles from aortic-banded vs sham-operated animals. Two phases were clearly distinguished: an inflammatory phase (D3-D5) with overexpression of inflammatory genes such as il-1ß, tnfa, nlrp3, and the rela subunit of nf-kb, and a hypertrophic phase (D7-D14) where anp overexpression was accompanied by a heart weight/body weight ratio that increased by more than 20% at D14. No cardiac dysfunction was detectable by echocardiography at the latter time point. Of the 36 chemokines and 20 chemokine receptors analyzed by a Taqman Low Density Array panel, we identified at D3 (the early inflammatory phase) overexpression of mRNAs for the monocyte chemotactic proteins CCL2 (12-fold increase), CCL7 (7-fold increase), and CCL12 (3-fold increase), for the macrophage inflammatory proteins CCL3 (4-fold increase), CCL4 (2-fold increase), and CCL9 (2-fold increase), for their receptors CCR2 (4-fold increase), CCR1 (3-fold increase), and CCR5 (3-fold increase), and for CXCL1 (8-fold increase) and CXCL16 (2-fold increase). During the hypertrophic phase mRNA expression of chemokines and receptors returned to the baseline levels observed at D0. Hence, this first exhaustive study of chemokine and chemokine receptor mRNA expression kinetics reports early expression of monocyte/macrophage-related chemokines and their receptors during the development of LVH in rats, followed by regulation of inflammation as LVH progresses.

Next Generation Sequencing and Linkage Analysis for the Molecular Diagnosis of a Novel Overlapping Syndrome Characterized by Hypertrophic Cardiomyopathy and Typical Electrical Instability of Brugada Syndrome

BACKGROUND

Familial hypertrophic cardiomyopathy (HCM) is an autosomal dominant inherited disorder; mutations in at least 20 genes have been associated. Brugada syndrome (BrS) is an autosomal dominant inherited disorder caused by mutations mainly in theSCN5Agene. A new clinical entity that consists of HCM, typical electrical instability of BrS and sudden death (SD), is described.

METHODS AND RESULTS

The family was constituted by 7 members, 4 of who presented clinical features of HCM and electrical instability of BrS. The clinical presentation of proband was ventricular fibrillation. All members were clinically evaluated by physical examination, 12-lead electrocardiography, 2-dimensional echocardiography, stress test, electrocardiogram Holter, flecainide test, and electrophysiological study. An integrated linkage analysis and next generation sequencing (NGS) approach was used to identify the causative mutation. Linkage with the α-tropomyosin (TPM1) gene on chromosome 15q22 was identified. The NGS study identified a missense mutation within theTPM1gene (c.574G>A; p.E192K), exactly located in a binding domain with polycystin-2 protein. No other pathogenic mutations were identified.

CONCLUSIONS

This is the first report of an association between HCM and BrS, and the first to use a combined approach of linkage and NGS to identify a causative mutation in SD. The present study expands the clinical spectrum of disorders associated with theTPM1gene and may be useful to report novel mechanisms of electrical instability in HCM and BrS.

Electrocardiogram derived QRS duration associations with elevated central aortic systolic pressure (CASP) in a rural Australian population

Background

Prolonged electrocardiogram QRS durations are often present in hypertensive patients. Small increases in QRS duration serve as independent risk factors for both increased cardiovascular and all-cause mortality. Aortic stiffness is associated with increases in central aortic systolic blood pressure (CASP). However CASP and ECG QRS duration interactions have not been established in rural community populations. Our aims are to determine if QRS duration > 100 msec is associated with an elevated CASP measure in an Australian rural population.

Methods

A retrospective cross sectional population was obtained from the CSU Diabetes Screening Research Initiative data base where 68 participants had both central aortic pressure recorded and ECG derived QRS duration. Central aortic pressure was determined by directly recording radial arterial tonometry and brachial cuff pressure (HealthStats, Singapore). Resting 12-lead electrocardiograms were obtained from each subject using a Welch Allyn PC-Based ECG system.

Results

The population had a mean CASP of 137.8 mmHg, higher than previously reported in other population studies. In 8/68 subjects with a prolonged cardiac QRS duration >120 msec, CASP ranged from 129 mmHg – 182 mmHg. When subgroup analysis was stratified on the basis QRS duration <100 msec and ≥100 msec significant differences (p = 0.036) were observed for mean CASP, 130.6 mmHg ± 15.6 (SD) versus 140.6 mmHg ± 16.8 (SD), respectively.

Conclusions

Our results suggest that an arbitrary CASP reading greater than a value 140 mmHg raises suspicion of a prolonged QRS duration. QRS durations ≥100 msec in an aging rural population are associated with higher CASP measures. Our results also suggest in aging Australian rural populations CASP is likely to be elevated, possibly due to age related aortic stiffening.

TRPM4 in cardiac electrical activity

TRPM4 forms a non-selective cation channel activated by internal Ca(2+). Its functional expression was demonstrated in cardiomyocytes of several mammalian species including humans, but the channel is also present in many other tissues. The recent characterization of the TRPM4 inhibitor 9-phenanthrol, and the availability of transgenic mice have helped to clarify the role of TRPM4 in cardiac electrical activity, including diastolic depolarization from the sino-atrial node cells in mouse, rat, and rabbit, as well as action potential duration in mouse cardiomyocytes. In rat and mouse, pharmacological inhibition of TRPM4 prevents cardiac ischaemia-reperfusion injuries and decreases the occurrence of arrhythmias. Several studies have identified TRPM4 mutations in patients with inherited cardiac diseases including conduction blocks and Brugada syndrome. This review identifies TRPM4 as a significant actor in cardiac electrophysiology.

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.

Correlation between global longitudinal strain and QRS voltage on electrocardiogram in patients with left ventricular hypertrophy

PURPOSE

Left ventricular hypertrophy (LVH) is as an independent risk factor. Discrepancies were reported between LV mass (LVM) estimated by echocardiography and electrocardiography (ECG) findings. We hypothesized that QRS voltage criteria may reflect not only anatomical changes (LVM) but also changes in LV function and we tested the relationship between QRS voltage and echocardiographic parameters of LV function in patients (pts) with different types of LVH.

METHODS

We prospectively enrolled pts with LVH and preserved ejection fraction (LVEF >50%): 20 pts with isolated arterial hypertension, HTN, 20 pts with severe aortic stenosis, AS (indexed aortic valve area <0.6 cm(2)/m(2)), and 20 pts with symmetric hypertrophic cardiomyopathy, HCM. Standard 12-lead ECG (including Sokolow and Cornell voltage indices) and a comprehensive two-dimensional (2D) echocardiography were performed in all. Left ventricular mass was calculated according to Devereux formula. Global longitudinal strain (GLS) was assessed by speckle tracking echocardiography.

RESULTS

A significant correlation was found between both ECG indices and LVM assessed by echocardiography. Moreover, significant correlations were found between Sokolow-Lyon voltage and LVEF (r = 0.26; P = 0.03), GLS (r = 0.59; P < 0.001) and E/e' average (r = 0.43; P < 0.001). Cornell voltage index correlated significantly only with GLS. In multivariable analysis GLS emerged as the only independent correlate of both Sokolow-Lyon (ß = 0.6, P < 0.001) and Cornell voltage indices (ß = 0.45, P < 0.001).

CONCLUSION

These findings suggest that in pts with LVH, ECG should no longer be used only as a surrogate method for LVM estimation (structural changes only), but rather as an investigation complementary to imaging, incorporating information on overall LV remodeling (changes in structure and function).