Clinically silent electrocardiographic abnormalities and risk of primary cardiac arrest among hypertensive patients

Racial differences in prevalence and impact of electrocardiographic subclinical myocardial injury risk factors

BACKGROUND

We explored whether the reported racial differences in subclinical myocardial injury (SCMI) are due to variations in the prevalence or differential impact of the SCMI risk factors.

METHODS

This analysis included 3074 Whites, 1337 Blacks, and 1441 Mexican Americans from the Third National Health and Nutrition Examination Survey who were free of cardiovascular disease. SCMI was defined from standard electrocardiograms as a cardiac infarction/injury score ≥ 10 points. Multivariable logistic regression analysis was used to assess the association of SCMI with its risk factors stratified by race. Multiplicative interaction between each risk factor and race was also examined.

RESULTS

Overall prevalence of SCMI was 20.3%, with Mexican Americans exhibiting a lower prevalence than Whites and Blacks (16.5%, 20.4%, and 20.7%, respectively). Whites had more prevalence of dyslipidemia and smoking. Mexican Americans had more diabetes, while Blacks had more hypertension, obesity, and left ventricular hypertrophy. Significant risk factors for SCMI were older age, lower income (<20 K), smoking, diabetes, and no regular exercise. The association of SCMI with age was more pronounced in Mexican Americans (p-value for interaction 0.03), whereas the associations of SCMI with smoking, no-regular exercise, and diabetes were stronger in Whites (p-value for interaction 0.04, 0.001, 0.007, respectively).

CONCLUSIONS

Heterogeneity in the racial differences in the prevalence of SCMI risk factors exists, but they do not explain racial differences in SCMI. The stronger associations of smoking, diabetes, and no regular exercise with SCMI partially explain the higher prevalence of SCMI in Whites.

The Heart–Brain Interplay in Multiple Sclerosis from Pathophysiology to Clinical Practice: A Narrative Review

Multiple sclerosis (MS) is a chronic neurological disorder characterized by inflammation in the central nervous system (CNS) that leads to neurodegeneration. The clinical course is highly variable, but its prevalence is rising worldwide, partly thanks to novel disease-modifying therapies. Additionally, the lifespan of people with MS is increasing, and for this reason, it is fundamental to have a multidisciplinary approach to MS. MS may be associated with cardiovascular diseases (CVD), but there is scarce attention on this issue. In particular, CNS is essential in regulating the autonomic system and heart activity. Moreover, cardiovascular risk factors show a higher prevalence in MS patients. On the other hand, conditions like Takotsubo syndrome are rare complications of MS. The parallelism between MS and myocarditis is also interesting. Finally, cardiac toxicity represents a not infrequent adverse reaction to MS drugs. This narrative review aims to provide an overview of cardiovascular complications in MS and their management to prompt further clinical and pre-clinical research on this topic.

Subclinical myocardial injury and cardiovascular mortality: Racial differences in prevalence and risk (from the third National Health and Nutrition Examination survey)

Background

Subclinical myocardial injury (SCMI) determined from the Electrocardiographic Cardiac Infarction/Injury Score (CIIS) is associated with increased risk of cardiovascular disease and mortality. We hypothesized that SCMI prevalence and association with mortality would differ by race, categorized as non‐Hispanic White (White), non‐Hispanic Black (Black), and Mexican American.

Methods

Our analysis included 5,852 participants (age 58.5 ± 13.2 years; 54% women, 52% Whites, 23% Blacks, and 25% Mexican American participants) from the National Health and Nutrition Examination Survey (NHANES III, 1988–94) who were free of cardiovascular disease at the time of enrollment. SCMI was defined as the presence of CIIS ≥ 10 score points on the 12‐lead ECG. Prevalence of SCMI and its association with cardiovascular mortality were examined in each race/ethnic group in models adjusted for sociodemographics and common cardiovascular risk factors.

Results

SCMI prevalence was 23.4% in Whites, 21.8% in Blacks, and 18.0% in Mexican Americans. Compared to Whites, Blacks were as likely to have SCMI (odds ratio [OR] 0.95, 95% confidence interval [CI] 0.80–1.13), while Mexican Americans were less likely (OR 0.74, 95% CI 0.62–0.88). SCMI was not associated with increased risk of cardiovascular mortality in either Whites (hazard ratio [HR] 1.18, 95% CI 0.95–1.48) or Blacks (HR 1.19, 95% CI 0.79–1.80). In contrast, SCMI in Mexican Americans was associated with increased risk of cardiovascular mortality (HR 1.74, 95% CI 1.13–2.67, p < .05).

Conclusion

Mexican Americans had a lower prevalence of SCMI, but increased risk of cardiovascular mortality. Screening for SCMI may identify individuals at increased risk and improve targeted prevention efforts.

Electrocardiographic myocardial injury and stroke mortality in the general population

BACKGROUND

Recent evidence suggests a link between myocardial infarction and stroke risk, but it is unclear whether such risk exists with electrocardiographic myocardial injury in otherwise healthy individuals. Therefore, we explored the association of myocardial injury with stroke mortality in participants free of cardiovascular disease.

METHODS

This analysis included 6017 participants (58.4 ± 13.4 years, 54.1% women, 50.3% white) from the Third National Health and Nutrition Examination Survey. Cardiac infarction/injury score (CIIS), a weighted scoring system composed of several electrocardiographic waveform components related to myocardial injury and ischemia, was used to define myocardial injury. Stroke mortality was ascertained using the National Death Index during follow-up. Multivariable adjusted Cox proportional hazard analysis was used to examine the association between baseline myocardial injury and risk of stroke mortality.

RESULTS

Over a median follow-up of 14 years, 152 stroke deaths occurred. Stroke mortality was more common in those with than those without myocardial injury (3.8% vs. 2.1%, respectively; p = 0.0003). In a model adjusted for potential confounders, the myocardial injury was associated with a 44% increased risk of stroke mortality (HR (95%CI):1.44(1.02-2.03)). In a similar model, each 1 CIIS score point increase was associated with a 2% increase in the risk of stroke mortality (HR (95%CI):1.02 (1.00-1.04), p = 0.01).

CONCLUSIONS

Electrocardiographic myocardial injury in cardiovascular disease-free adults is associated with an increased risk of stroke mortality suggesting a potential link between asymptomatic myocardial injury and risk of cardiac thromboembolism. Whether screening and management of myocardial injury would reduce such risk requires further investigation.

Coronary Artery Disease and Atherosclerotic Risk Factors in a Population-Based Study of Sudden Death

BACKGROUND

Sudden death is a public health problem with major impact on society. Coronary artery disease (CAD) is believed to underlie 60-80% of these deaths. While deaths from CAD have decreased in the recent decades, sudden death rates remain unacceptably high.

OBJECTIVE

We aimed to assess the prevalence of CAD and its risk factors among 18-64-year-old adults in a population-based case registry of sudden deaths and compare them to a living population from the same geographical area.

DESIGN

From 2013 to 2015, all sudden deaths among 18-64-year-old adults in Wake County, NC, were identified (n = 371). A comparison group was formed by randomly selecting individuals from an electronic health record repository of a major healthcare system in the area (N = 4218).

MAIN MEASURES

Prevalence of CAD and its risk factors among cases of sudden death and living population across sex and age groups. Odds of sudden death associated with atherosclerotic risk factors and comorbidities.

KEY RESULTS

CAD was present in 14.8% of sudden death cases. Among sudden death victims, most risk factors and comorbidities were more common in the older age group, except for obesity which was more common in younger cases, and diabetes which was equally prevalent in younger and older cases. Compared to living population, sudden death cases had higher prevalence of atherosclerotic risk factors across all gender and age groups. Sudden death cases had a numerically higher number of risk factors compared to living population, regardless of age group or presence of CAD.

CONCLUSIONS

Coronary artery disease is not common among sudden death cases, but risk factors and comorbidities are prevalent. Our findings support the changing etiology of sudden death. In the absence of clinically diagnosed CAD, use of novel imaging modalities and biomarkers may identify high-risk individuals and lead to prevention of sudden death.

Relations Between Physical Activity, Subclinical Myocardial Injury, and Cardiovascular Mortality in the General Population

We examined the association between poor physical activity (PA) and subclinical myocardial injury (SC-MI), and how concomitant exposure to poor PA and SC-MI modifies their association with cardiovascular disease (CVD) mortality. This analysis included 6,044 participants free of CVD from the NHANES-III survey. Leisure time PA was defined as: ideal (3 to 5.99 METs and ≥5 times/week or any PA with ≥6METs and ≥3times/week), intermediate (any activity other than ideal), or poor (no activity at all). SC-MI was defined as an electrocardiographic cardiac infarction/injury score ≥10 units. CVD mortality was ascertained from the National Death Index. In multivariable logistic regression analysis, poor PA (odds ratio [OR] [95% confidence interval, CI]: 1.30 [1.10 to 1.54]) and intermediate PA (OR [95%CI]: 1.19 [1.02 to 1.38]), compared with ideal PA, were associated with an increased odds of SC-MI. During a median follow-up of 14 years, 589 CVD deaths occurred. In multivariable Cox-proportional hazard analysis, the presence (vs absence) of SC-MI was associated with a 33% increased risk of CVD mortality whereas poor (vs ideal) PA was associated with a 67% increased risk of CVD mortality (HR [95%CI]: 1.33 [1.11 to 1.58] and 1.67 [1.37 to 2.05], respectively). Additionally, the concomitant presence of both poor PA and SC-MI were associated with a higher risk of CVD mortality (HR [95%CI]: 2.25[1.68 to 3.00]) compared with ideal PA and the absence of SC-MI. In conclusion, poor PA is associated with an increased risk of SC-MI and their concomitant presence is associated with a marked increase in CVD mortality, underscoring the potential role of PA in preventing clinical and subclinical CVD outcomes.

Blood pressure-related electrocardiographic findings in healthy young individuals

Purpose: Elevated blood pressure induces electrocardiographic changes and is associated with an increase in cardiovascular disease later in life compared to normal blood pressure levels. The purpose of this study was to evaluate the association between normal to high normal blood pressure values (90-139/50-89 mmHg) and electrocardiographic parameters related to cardiac changes in hypertension in healthy young adults.Methods: Data from 1449 volunteers aged 18-30 years collected at our centre were analyzed. Only subjects considered healthy by a physician after review of collected data with systolic blood pressure values between 90 and 139 mmHg and diastolic blood pressure values between 50 and 89 mmHg were included. Subjects were divided into groups with 10 mmHg systolic blood pressure increment between groups for analysis of electrocardiographic differences. Backward multivariate regression analysis with systolic and diastolic blood pressure as a continuous variable was performed.Results: The mean age was 22.7 ± 3.0 years, 73.7% were male. P-wave area, ventricular activation time, QRS-duration, Sokolow-Lyon voltages, Cornell Product, J-point-T-peak duration corrected for heart rate and maximum T-wave duration were significantly different between systolic blood pressure groups. In the multivariate model with gender, body mass index and cholesterol, ventricular rate (standardized coefficient (SC): +0.182, p < .001), ventricular activation time in lead V6 (SC= +0.065, p = .048), Sokolow-Lyon voltage (SC= +0.135, p < .001), and Cornell product (SC= +0.137, p < .001) were independently associated with systolic blood pressure, while ventricular rate (SC= +0.179, p < .001), P-wave area in lead V1 (SC= +0.079, p = .020), and Cornell product (SC= +0.091, p = .006) were independently associated with diastolic blood pressure.Conclusion: Blood pressure-related electrocardiographic changes were observed incrementally in a healthy young population with blood pressure in the normal range. These changes were an increased ventricular rate, increased atrial surface area, ventricular activation time and increased ventricular hypertrophy indices on a standard 12 lead electrocardiogram.

Risk Stratification for Sudden Cardiac Death After Myocardial Infarction

Sudden cardiac death (SCD) accounts for ∼50% of mortality after myocardial infarction (MI). Most SCDs result from ventricular tachyarrhythmias, and the tachycardias that precipitate cardiac arrest result from multiple mechanisms. As a result, it is highly unlikely that any single test will identify all patients at risk for SCD. Current guidelines for use of implantable cardioverter-defibrillators (ICDs) to prevent SCD are based primarily on measurement of left ventricular ejection fraction (LVEF). Although reduced LVEF is associated with increased total cardiac mortality after MI, the focus of current guidelines on LVEF omits ∼50% of patients who die suddenly. In addition, there is no evidence of a mechanistic link between reduced LVEF and arrhythmias. Thus, LVEF is neither sensitive nor specific as a tool for post-MI risk stratification. Newer tests to screen for predisposition to ventricular arrhythmias and SCD examine abnormalities of ventricular repolarization, autonomic nervous system function, and electrical heterogeneity. These tests, as well as older methods such as programmed stimulation, the signal-averaged electrocardiogram, and spontaneous ventricular ectopy, do not perform well in patients with LVEF ≤30%. Recent observational studies suggest, however, that these tests may have greater utility in patients with LVEF >30%. Because SCD results from multiple mechanisms, it is likely that combinations of risk factors will prove more precise for risk stratification. Prospective trials that evaluate the performance of risk stratification schema to determine ICD use are necessary for cost-effective reduction of the incidence of SCD after MI.

Risk factors for sudden cardiac death to determine high risk patients in specific patient populations that may benefit from a wearable defibrillator

BACKGROUND

There is a high risk for sudden cardiac death (SCD) in certain patient groups that would not meet criteria for implantable cardioverter defibrillator (ICD) therapy. In conditions such as hypertrophic cardiomyopathy (HCM) there are clear risk scores that help define patients who are high risk for SCD and would benefit from ICD therapy. There are however many areas of uncertainty such as certain patients post myocardial infarction (MI). These patients are high risk for SCD but there is no clear tool for risk stratifying such patients.

AIM

To assess risk factors for sudden cardiac death in major cardiac disorders and to help select patients who might benefit from Wearable cardiac defibrillators (WCD).

METHODS

A literature search was performed looking for risk factors for SCD in patients post-MI, patients with left ventricular systolic dysfunction (LVSD), HCM, long QT syndrome (LQTS). There were 41 studies included and risk factors and the relative risks for SCD were compiled in table form.

RESULTS

We extracted data on relative risk for SCD of specific variables such as age, gender, ejection fraction. The greatest risk factors for SCD in post MI patients was the presence of diabetes [Hazard ratio (HR) 1.90-3.80], in patient with LVSD was ventricular tachycardia (Relative risk 3.50), in LQTS was a prolonged QTc (HR 36.53) and in patients with HCM was LVH greater than 20 mm (HR 3.10). A proportion of patients currently not suitable for ICD might benefit from a WCD

CONCLUSION

There is a very high risk of SCD post MI, in patients with LVSD, HCM and LQTS even in those who do not meet criteria for ICD implantation. These patients may be candidates for a WCD. The development of more sensitive risk calculators to predict SCD is necessary in these patients to help guide treatment.

The impact of multiple sclerosis onset symptom on cardiac repolarization

INTRODUCTION

Multiple sclerosis is associated with prolonged cardiac repolarization but the underlying physiology has remained unknown. In this study, we compared cardiac repolarization during the relapsing-remitting multiple sclerosis (RRMS) disease course in patients with motor and sensory onset symptom.

METHODS

Twenty-five RRMS patients with motor and 33 RRMS patients with sensory onset symptom having 12-lead electrocardiogram (ECG) recorded at the time of the first demyelinating event (ECG1) as well as at the later disease course (ECG2) were identified from the patient records. The average time interval between ECG1 and ECG2 was 8.6 ± 5.9 y. Heart rate-corrected QT intervals reflecting cardiac repolarization were calculated by Bazett (QTcBaz), Fridericia (QTcFri), and Karjalainen (QTcKar) formulas.

RESULTS

Heart rate-corrected QT intervals as well as heart rate were similar in patients with motor and sensory onset symptom in ECG1. However, QTcBaz (p = .002), QTcFri (p = .019), and QTcKar (p = .026) were longer and heart rate was higher (p = .035) in patients with motor than sensory onset symptom in ECG2. Correspondingly, QTcBaz (p = .002), QTcFri (p = .033), and QTcKar (p = .043) prolonged and heart rate tended to increase (p = .060) during the disease course only in the patients with motor onset symptom.

CONCLUSIONS

Cardiac repolarization prolonged and heart rate increased during the disease course in RRMS patients with motor but not with sensory onset symptom. This suggests different traits in RRMS according to its initial manifestation and also association of motor onset symptom with more unfavorable cardiovascular prognostic determinants.

Subclinical myocardial injury identified by cardiac infarction/injury score and the risk of mortality in men and women free of cardiovascular disease

Previous studies have explored the ability of the Cardiac Infarction/Injury Score (CIIS) to identify individuals who are high risk for cardiovascular disease (CVD) mortality. However, its prognostic significance among those without CVD in the United States general population has not been established. This analysis included 6,298 participants (mean age 59±13 years, 53% women, 51% nonwhites) from the Third National Health and Nutrition Examination Survey, excluding participants with a history of CVD or electrocardiographic evidence of old myocardial infarction or ischemic ST depression at baseline. Subclinical myocardial injury was defined as CIIS≥10. Mortality data were ascertained using the National Death Index. Cox proportional hazards regression was used to compute hazard ratios (HRs) and 95% confidence intervals (95% CIs) for the association between subclinical myocardial injury and CVD and all-cause mortalities. Subclinical myocardial injury was detected in 1,376 participants (22%). A total of 1,928 deaths occurred during a median follow-up of 14 years of which 765 (40%) were due to CVD. In a multivariate model adjusted for demographics, traditional CVD risk factors, and other medical co-morbidities, subclinical myocardial injury was associated with an increased risk of CVD (HR 1.26, 95% CI 1.02 to 1.56) and all-cause (HR 1.42, 95% CI 1.23 to 1.63) mortalities. In conclusion, subclinical myocardial injury in those without manifestations of CVD is associated with an increased risk of CVD and all-cause mortalities. These findings highlight the important role of CIIS to identify subclinical myocardial injury and its association with mortality among men and women in the United States.

The genetics of sudden cardiac death

Sudden cardiac death (SCD), a sudden pulseless condition due to cardiac arrhythmia, remains a major public health problem despite recent progress in the treatment and prevention of overall coronary heart disease. In this review, we examine the evidence for genetic susceptibility to SCD in order to provide biological insight into the pathogenesis of this devastating disease and to explore the potential for genetics to impact clinical management of SCD risk. Both candidate gene approaches and unbiased genome-wide scans have identified novel biological pathways contributing to SCD risk. Although risk stratification in the general population remains an elusive goal, several studies point to the potential utility of these common genetic variants in high-risk individuals. Finally, we highlight novel methodological approaches to deciphering the molecular mechanisms involved in arrhythmogenesis. Although further epidemiological and clinical applications research is needed, it is increasingly clear that genetic approaches are yielding important insights into SCD that may impact the public health burden imposed by SCD and its associated outcomes.

Sudden cardiac death risk stratification in patients with heart failure

The multiplicity of mechanisms contributing to arrhythmogenesis in patients with heart failure carries obvious implications for risk stratification. If patients having the propensity to develop arrhythmias by these different mechanisms are to be identified, tests must be devised that reveal the substrates or other factors that relate to each mechanism. In the absence of this, efforts to risk stratify patients are likely to be neither cost-effective nor accurate. This article reviews the current knowledge base of risk stratification for sudden death in patients with heart failure, while acknowledging several limitations in the studies examined.

Acute adverse effects of fine particulate air pollution on ventricular repolarization

BACKGROUND

The mechanisms for the relationship between particulate pollution and cardiac disease are not fully understood.

OBJECTIVE

We examined the effects and time course of exposure to fine particulate matter < or = 2.5 microm in aerodynamic diameter (PM(2.5)) on ventricular repolarization of 106 nonsmoking adults who were living in communities in central Pennsylvania.

METHODS

The 24-hr beat-to-beat electrocardiogram (ECG) data were obtained using a high-resolution 12-lead Holter system. After visually identifying and removing artifacts and arrhythmic beats, we summarized normal beat-to-beat QTs from each 30-min segment as heart rate (HR)-corrected QT measures: QT prolongation index (QTI), Bazett's HR-corrected QT (QTcB), and Fridericia's HR-corrected QT (QTcF). A personal PM(2.5) monitor was used to measure individual-level real-time PM(2.5) exposures for 24 hr. We averaged these data and used 30-min time-specific average PM(2.5) exposures.

RESULTS

The mean age of the participants was 56 +/- 8 years, with 41% male and 74% white. The means +/- SDs for QTI, QTcB, and QTcF were 111 +/- 6.6, 438 +/- 23 msec, and 422 +/- 22 msec, respectively; and for PM(2.5), the mean +/- SD was 14 +/- 22 microg/m3. We used distributed lag models under a framework of linear mixed-effects models to assess the autocorrelation-corrected regression coefficients (beta) between 30-min PM(2.5) and the HR-corrected QT measures. Most of the adverse ventricular repolarization effects from PM(2.5) exposure occurred within 3-4 hr. The multivariable adjusted beta (SE, p-value) due to a 10-microg/m3 increase in lag 7 PM(2.5) on QTI, QTcB, and QTcF were 0.08 (0.04, p < 0.05), 0.22 (0.08, p < 0.01), and 0.09 (0.05, p < 0.05), respectively.

CONCLUSIONS

Our results suggest a significant adverse effect of PM(2.5) on ventricular repolarization. The time course of the effect is within 3-4 hr of elevated PM(2.5).

Analysis of genetic and non-genetic factors that affect the QTc interval in a Mongolian population: the GENDISCAN study

The QTc interval is a complex quantitative trait and a strong prognostic indicator of cardiovascular mortality in general, healthy people. The aim of this study was to identify non-genetic factors and quantitative trait loci that govern the QTc interval in an isolated Mongolian population. We used multiple regression analysis to determine the relationship between the QTc interval and non-genetic factors including height, blood pressure, and the plasma lipid level. Whole genome linkage analyses were performed to reveal quantitative trait loci for the QTc interval with 349 microsatellite markers from 1,080 Mongolian subjects. Among many factors previously known for association with the QTc interval, age, sex, heart rate, QRS duration of electrocardiogram and systolic blood pressure were also found to have influence on the QTc interval. A genetic effect for the QTc interval was identified based on familial correlation with a heritability value of 0.31. In a whole genome linkage analysis, we identified the four potential linkage regions 7q31-34, 5q21, 4q28, and 2q36.

Regional differences in the prevalence of left ventricular hypertrophy within Germany

BACKGROUND

There are considerable regional disparities in the prevalence of cardiovascular risk factors within Germany. We undertook this study to investigate differences in the prevalence of left ventricular hypertrophy (LVH) between northeast and southwest Germany.

METHODS

Data from two population-based studies, Kooperative Gesundheitsforschung im Raum Augsburg (KORA) conducted in southwest and Study of Health in Pomerania (SHIP) conducted in northeast Germany, were utilized. The study population comprised 2,516 women and men (835 from KORA and 1,681 from SHIP) aged 45-74 years who had no history of myocardial infarction. Echocardiograms were obtained according to standard protocols. Left ventricular mass (LVM), left ventricular mass indexed for body height, and left ventricular hypertrophy were used as dependent variables in multivariable analyses.

RESULTS

SHIP participants had higher LVM and left ventricular mass index values compared with KORA participants. These differences remained after analyses were adjusted for major confounders including obesity and hypertension. Consequently, there were higher proportions of LVH in SHIP compared with KORA across all 10-year age groups. Multivariable logistic regression revealed that the odds for LVH in participants living in northeast Germany were higher in women and men, respectively, by 1.57 (95% confidence interval: 1.18-2.09) and 1.68 (95% confidence interval: 1.25-2.27) than in participants living in southwest Germany. Potential methodological differences between studies do not seem to account for these findings.

CONCLUSION

There is a higher prevalence of LVH in northeast compared with southwest Germany. Regional disparities in hypertension and overweight only partly explain this difference.

Drug-sensitized zebrafish screen identifies multiple genes, including GINS3, as regulators of myocardial repolarization

BACKGROUND

Cardiac repolarization, the process by which cardiomyocytes return to their resting potential after each beat, is a highly regulated process that is critical for heart rhythm stability. Perturbations of cardiac repolarization increase the risk for life-threatening arrhythmias and sudden cardiac death. Although genetic studies of familial long-QT syndromes have uncovered several key genes in cardiac repolarization, the major heritable contribution to this trait remains unexplained. Identification of additional genes may lead to a better understanding of the underlying biology, aid in identification of patients at risk for sudden death, and potentially enable new treatments for susceptible individuals.

METHODS AND RESULTS

We extended and refined a zebrafish model of cardiac repolarization by using fluorescent reporters of transmembrane potential. We then conducted a drug-sensitized genetic screen in zebrafish, identifying 15 genes, including GINS3, that affect cardiac repolarization. Testing these genes for human relevance in 2 concurrently completed genome-wide association studies revealed that the human GINS3 ortholog is located in the 16q21 locus, which is strongly associated with QT interval.

CONCLUSIONS

This sensitized zebrafish screen identified 15 novel myocardial repolarization genes. Among these genes is GINS3, the human ortholog of which is a major locus in 2 concurrent human genome-wide association studies of QT interval. These results reveal a novel network of genes that regulate cardiac repolarization.

Identification of a common variant at the NOS1AP locus strongly associated to QT-interval duration

QT-interval prolongation is an electrophysiologic phenomenon associated with sudden cardiac death. The QT-interval in the general population is approximately 35% heritable. In genome-wide association studies, a common variant (rs10494366T > G) within the nitric oxide synthase 1 adaptor protein (NOS1AP) gene was identified and consistently associated with QT-interval duration. Yet, the causal variant remains unclear. Therefore, we performed fine mapping of the association of the NOS1AP locus with QT-interval within the Rotterdam Study, a population-based, prospective cohort study of individuals of > or =55 years of age. First, we tested the association of single-nucleotide polymorphisms (SNPs) in or within +/-100 kb of the NOS1AP gene with QT-interval duration, using sex-specific unstandardized residuals after regression on age and RR-interval, in 385 individuals using the combined set of SNPs present in the Affymetrix 500k and Illumina 550k chip arrays. Subsequently, we examined correspondence of the association signals in 4606 individuals using the Illumina 550k array. A C-to-T SNP at chromosome 1 position 160300514 (rs12143842, T-allele frequency = 24%) was associated with a QT-interval duration increase of 4.4 ms per additional T-allele (P = 4.4 x 10(-28)). For comparison, the most strongly associated variant to date, rs10494366T > G, was associated with a 3.5 ms increase (P = 1.6 x 10(-23)) per additional G-allele. None of the inferred haplotypes showed a stronger effect than the individual rs12143842C > T SNP. In conclusion, we found rs12143842 6 kb upstream distance of NOS1AP to be more strongly associated to QT-interval duration than rs10494366T > G. Functional analysis of this marker is warranted.

Genetics of sudden cardiac arrest

Sudden cardiac arrest (SCA) due to ventricular arrhythmias is a major cause of mortality in western populations with up to 450,000 deaths in the United States each year. Although environmental factors clearly contribute to the determinants of SCA, familial aggregation studies and advances in the molecular genetics of inherited arrhythmias suggest that genetic factors confer susceptibility to SCA in the general population. Research in this area typically has focused on association of common genetic variants with intermediate phenotypes that predispose to SCA risk, such as QT interval, but few studies have examined genetic risk factors for SCA. We review the evidence for genetic susceptibility to SCA in the general population and focus on the studies published to date that have explored genetic risk factors.

Association of NOS1AP genetic variants with QT interval duration in families from the Diabetes Heart Study

OBJECTIVES

Prolongation of the electrocardiographic QT interval is a risk factor for sudden cardiac death (SCD). Diabetic individuals are at increased risk for prolonged QT interval and SCD. We sought to replicate the finding that genetic variants in the nitric oxide synthase 1 adaptor protein (NOS1AP) gene are associated with QT interval duration in a type 2 diabetes-enriched sample of European ancestry.

RESEARCH DESIGN AND METHODS

Two single nucleotide polymorphisms (SNPs) in NOS1AP were genotyped in 624 European Americans and 127 African Americans from 400 pedigrees enriched for type 2 diabetes. An additive genetic model was tested for each SNP in ancestry-specific analyses in the total sample and the diabetic subset (European Americans, n = 514; African Americans, n = 115), excluding from the analyses individuals taking QT-altering medications.

RESULTS

In European Americans, rs10494366 minor homozygotes had a 9.3-ms-longer QT interval compared with major homozygotes (P = 5.7 x 10(-5)); rs10918594 minor homozygotes had a 12.5-ms-longer QT interval compared with major homozygotes (P = 1.5 x 10(-6)). Restricting analyses to the diabetic European Americans strengthened the effect despite the reduction in sample size (11.3-ms difference, P = 5.1 x 10(-5); 13.9-ms difference, P = 1.6 x 10(-6), respectively). No association between the NOS1AP SNPs and QT interval duration was observed in the limited number of African Americans.

CONCLUSIONS

Two NOS1AP SNPs are strongly associated with QT interval duration in a predominately diabetic European-American sample. Stronger effects of NOS1AP variants in diabetic individuals suggest that this patient subset may be particularly susceptible to genetic variants that influence myocardial depolarization and repolarization as manifest in the QT interval.

Relationship of electrocardiographic repolarization measures to echocardiographic left ventricular mass in men with hypertension

OBJECTIVE

Arterial hypertension often leads to an increase in left ventricular mass (LVM). Marked left ventricular hypertrophy (LVH) is associated with potentially arrhythmogenic ventricular repolarization abnormalities, which may contribute to the increased risk of sudden cardiac death in this disorder. We studied whether electrocardiographic repolarization changes are already detectable in mild LVM increase associated with hypertension.

METHODS

In 220 men (mean age 51+/-6 years) attending the GENRES hypertension study, we measured QT intervals (QTend and QTpeak), T-wave peak to T-wave end (TPE) intervals, and novel T-wave morphology parameters (principal component analysis ratio, T-wave morphology dispersion, total cosine R-to-T, and T-wave residuum) from a digital standard 12-lead electrocardiogram, and related them to echocardiographically determined LVM.

RESULTS

In this group of moderately hypertensive men, the mean LVM index (LVMI; LVM divided by body surface area) was 99+/-19 g/m2, with only 18% of the subjects showing evidence of echocardiographic LVH (LVMI>116 g/m2). LVMI correlated significantly with QT intervals (r=0.16-0.21, P=0.018-0.002), TPE intervals (r=0.23-0.27, P<0.001), and T-wave morphology parameters (r=0.22-0.39, P<0.001). Except for the QTpeak interval, the relationship between LVMI and electrocardiographic repolarization parameters was independent in multivariate analyses.

CONCLUSION

Altered electrocardiographic ventricular repolarization, indicating reduced repolarization reserve and possibly increased repolarization heterogeneity, is already present in hypertensive men with only mild LVM increase. At a population level, this may carry important risk implications for the large group of hypertensive patients.

Perioperative hypertension: new strategies for management

Perioperative hypertension is a very frequent occurrence and requires the anaesthetist to make clinical decisions regarding antihypertensive therapy, evaluation of risk, cancellation of surgery and treatment of high and low blood pressure. Perioperative management of hypertensive patients must take into account the possible consequences of left ventricular diastolic dysfunction and reduced coronary reserve.

Importance of hepatitis C coinfection in the development of QT prolongation in HIV-infected patients

BACKGROUND

Case reports and unblinded studies suggest that human immunodeficiency virus (HIV) disease is associated with QT prolongation and torsade de pointes ventricular tachycardia. Hepatitis C coinfection is common in patients with HIV disease, and cirrhosis is also associated with QT prolongation. We therefore undertook a systematic analysis of the role of liver injury, nutritional state, and coinfection with hepatitis C in the etiology of QT prolongation in HIV disease.

METHODS

We performed a blinded, controlled retrospective cohort study of 1648 patients over a 3-year period at a university-affiliated municipal hospital. All electrocardiograms were included if patients with HIV disease had measurements of CD4 count and viral load within 3 months and serum electrolytes within 30 days (n = 816). Control subjects were chosen randomly from the general medicine service (n = 832). QT interval was measured in lead II and corrected for heart rate by Bazett's formula (QTc).

RESULTS

QTc was slightly but significantly longer in patients with HIV disease than in controls (443 +/- 37 vs 436 +/- 36 milliseconds, P < .001). Patients with hepatitis C had more pronounced QTc prolongation (452 +/- 41 vs 437 +/- 35 milliseconds, P < .001). CD4 count, HIV viral load, and HIV medications had no effect on QTc. When patients with hepatitis C were excluded from the analysis, there was no statistical difference between patients with HIV disease and controls (438 +/- 34 vs 436 +/- 36 milliseconds, P = .336). Multiple linear regression revealed that both HIV and hepatitis C infection predicted QTc prolongation, as did age, female sex, history of hypertension, use of opiates, low serum K+ and albumin, and high AST. Hepatitis C coinfection nearly doubled the risk of QTc of 470 milliseconds or greater in patients with HIV disease (29.6% vs 15.8%, P < .001).

CONCLUSIONS

Human immunodeficiency virus and hepatitis C infections both independently prolong QTc. Coinfection with hepatitis C greatly increases the likelihood of clinically significant QTc prolongation in patients with HIV disease.

QT interval is a heritable quantitative trait with evidence of linkage to chromosome 3 in a genome-wide linkage analysis: The Framingham Heart Study

OBJECTIVES

To identify genomic regions linked to QT interval duration in an unselected population.

BACKGROUND

QT interval prolongation is associated with increased risk of sudden cardiac death and coronary heart disease and may result from acquired conditions or inherited ion channel defects. The influence of genetic variants on QT interval length in apparently healthy individuals is uncertain.

METHODS

We studied subjects from the Framingham Heart Study in whom 12-lead ECGs were available from regular clinic examinations. QT, QT-peak, and RR intervals were measured using digital calipers. A 10-centiMorgan (cM) density genome-wide scan was performed in a subset of the largest families having at least two members with ECG phenotypes (326 families). Variance components methods (Genehunter) were used.

RESULTS

Evidence was observed for significant heritability of the QT interval (h(2) 0.35; 95% CI, 0.29-0.41), QT-peak interval (h(2) 0.37; 95% CI, 0.29-0.45), and calculated JT interval (h(2) 0.25; 95% CI, 0.19-0.31). In the genome-wide linkage analysis, we found suggestive evidence for linkage of the QT interval 19 to 48 cM from the tip of the short arm of chromosome 3 (maximum two-point LOD score 3.00, maximum multipoint LOD score 2.71). After fine-mapping with seven microsatellite markers, the peak multipoint LOD score rose to 2.84 at 24.4 cM. The region of linkage contains potassium and sodium channel genes, including the SCN5A gene, which has been implicated in one form of the long QT syndrome and in the Brugada syndrome.

CONCLUSIONS

QT and related ECG intervals are heritable traits in a large unselected population. We provide suggestive evidence for a quantitative trait locus on chromosome 3 influencing QT interval duration. Further studies are warranted to identify genes that influence QT interval variation and to determine the role of heritable factors in life-threatening QT prolongation.

Notable effects of angiotensin II receptor blocker, valsartan, on acute cardiotoxic changes after standard chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisolone

BACKGROUND

There are three distinct types of doxorubicin-induced cardiotoxicity (acute, chronic, and late-onset). Although previous studies with animal models suggest that angiotensin II plays a key role in the process of the doxorubicin-induced cardiotoxicity, there has been no such observation in humans. This randomized study investigated whether valsartan, a new class of angiotensin II receptor blocker (ARB), can inhibit acute cardiotoxicity after doxorubicin-based chemotherapy.

METHODS

Forty consecutive patients with untreated non-Hodgkin lymphoma who were scheduled to undergo standard chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP) (mean age, 56 yrs; range, 24-70 yrs) were randomized with minimization methods to receive CHOP with or without 80 mg/day of valsartan. Acute cardiotoxicity was comprehensively evaluated with neurohumoral, echocardiographic, and electrocardiographic markers before and on Days 3, 5, and 7 after the initiation of CHOP.

RESULTS

CHOP induced transient increases in the left ventricular end-diastolic diameter in an echocardiogram, the QTc interval and QTc dispersion in an electrocardiogram, and in the plasma brain and atrial natriuretic peptides. All these changes returned to nearly normal levels within a week after CHOP (P < 0.001). Notably, valsartan significantly prevented all these changes except for the elevation in atrial natriuretic peptide (P < 0.05). No significant change was observed in blood pressure or heart rate between the valsartan and control groups.

CONCLUSIONS

The results indicate that angiotensin II may play an essential role in acute CHOP-induced cardiotoxicity in humans. Future long-term studies are necessary to judge whether ARBs have a potential to prevent the chronic or late-onset types of doxorubicin-induced cardiotoxicity.

Left ventricular hypertrophy is a common echocardiographic abnormality in severe obstructive sleep apnea and reverses with nasal continuous positive airway pressure

STUDY OBJECTIVES

To determine cardiac structural abnormalities by echocardiography in subjects with severe obstructive sleep apnea (OSA), and to determine the long-term effects of nasal continuous positive airway pressure (CPAP) on such abnormalities.

DESIGN

Polysomnography was conducted on oximetry-screened patients who showed a desaturation index > 40/h and > or = 20% cumulative time spent below 90%. From these, 25 patients with severe OSA but without daytime hypoxemia underwent echocardiography prior to, then 1 month and 6 months following initiation of CPAP treatment.

SETTING

Outpatient sleep disorders center.

RESULTS

Of the 25 patients, 13 patients (52%) had hypertension by history or on physical examination. Baseline echocardiograms showed that severe OSA was associated with numerous cardiovascular abnormalities, including left ventricular hypertrophy (LVH) [88%], left atrial enlargement (LAE) [64%], right atrial enlargement (RAE) [48%], and right ventricular hypertrophy (16%). In all patients (intent to treat) as well as those patients compliant with CPAP therapy (84% > 3 h nightly), there was a significant reduction in LVH after 6 months of CPAP therapy as measured by interventricular septal distance (baseline diastolic mean, 13.0 mm; 6-month mean after CPAP, 12.3 mm; p < 0.02). RAE and LAE were unchanged after CPAP therapy.

CONCLUSIONS

LVH was present in high frequency in subjects with severe OSA and regressed after 6 months of nasal CPAP therapy.

Relation of QT interval and QT dispersion to regression of echocardiographic and electrocardiographic left ventricular hypertrophy in hypertensive patients: the Losartan Intervention For Endpoint Reduction (LIFE) study

BACKGROUND

In hypertensive patients, both echocardiographic and electrocardiographic left ventricular hypertrophy (LVH) increase the risk of sudden death, possibly in part because of LVH-induced proarrhythmic repolarization changes. Experimentally, regression of LVH normalizes ventricular electrophysiology.

METHODS

To assess the relation of regression of LVH to changes in electrocardiographic measures of ventricular repolarization, we studied 317 hypertensive (61.2% men, mean age 65 +/- 7 years) participants in the Losartan Intervention For Endpoint Reduction (LIFE) study with electrocardiographic evidence of LVH, at study baseline, and after 1 year of blood pressure-lowering treatment with losartan or atenolol and hydrochlorothiatzide as the first adjunct therapy if needed to reach target blood pressure of 140/90 mm Hg. As indexes of LVH, we used echocardiographically determined LV mass as well as the Sokolow-Lyon and Cornell voltages from the electrocardiogram. QT interval duration and QT dispersion from the 12-lead electrocardiogram were used as ventricular repolarization measures.

RESULTS

By using tertiles of LV mass change and adjusting for the difference in treatment (losartan or atenolol), shortening of the rate-adjusted QT intervals as well as reduction in QT(apex) dispersion were observed in the tertile showing the greatest decrease in LV mass but not in the tertile without substantial changes in LV mass despite a significant reduction in blood pressure. Similar results were obtained with the use of Sokolow-Lyon and Cornell voltage change tertiles.

CONCLUSIONS

In hypertensive patients with electrocardiographic evidence of LVH, regression of echocardiographically determined LV mass and electrocardiographic indexes of LVH may partially reverse the LVH-induced proarrhythmic repolarization changes. This may have a beneficial impact on the increased incidence of sudden death in these patients.

Electrocardiogram is very useful for predicting acute heart failure following myeloablative chemotherapy with hematopoietic stem cell transplantation rescue

A prospective study was conducted in 71 evaluable patients who received myeloablative hematopoietic stem cell transplantation (HSCT) at our facility from 1995 to 2002, to find a sensitive marker for post-transplant heart failure, including echocardiographic systolic and diastolic markers and QTc interval. QTc was found to be an independent and significant risk factor for acute heart failure (AHF) on multivariate logistic regression analysis (OR 1.5, P=0.01, 95% confidence interval (CI) 1.1-2.0), while no significant differences between patients with AHF and those without AHF were found in age, sex, treatment history, type of conditioning regimen, and echocardiographic systolic and diastolic markers. On further analysis, post-transplant risk of AHF appeared to be increased as QTc was prolonged. The post-transplant risk of AHF in the group with longest QTc on multivariate logistic regression analysis was found to be 9.8 times that in the group with shortest QTc (P=0.04, 95% CI 1.0-100). These results suggest that echocardiographic markers are less valuable predictors of post-transplant AHF, but that prolongation of the QTc, an ECG marker, before HSCT is strongly associated with onset of AHF after HSCT.

Thioridazine and sudden unexplained death in psychiatric in-patients

BACKGROUND

Sudden death has been linked to antipsychotic therapy, but the relative risk associated with specific drugs is unknown.

AIMS

To assess the risk of sudden unexplained death associated with antipsychotic drug therapy and its relation to drug dose and individual agents.

METHOD

A case-control study of psychiatric in-patients dying suddenly in five hospitals in the north-east of England and surviving controls matched for age, gender and mental disorder. Logistic regression analysis was used to identify significant risk factors, and odds ratios were calculated.

RESULTS

Sixty-nine case-control clusters were identified. Probable sudden unexplained death was significantly associated with hypertension, ischaemic heart disease and current treatment with thioridazine (adjusted odds ratio=5.3, 95% CI 1.7-16.2, P=0.004). There was no significant association with other individual antipsychotic drugs.

CONCLUSIONS

Thioridazine alone was associated with sudden unexplained death, the likely mechanism being drug-induced arrhythmia.

Relation of QT interval and QT dispersion to echocardiographic left ventricular hypertrophy and geometric pattern in hypertensive patients. The LIFE study. The Losartan Intervention For Endpoint Reduction

OBJECTIVE

In hypertensive patients, left ventricular hypertrophy (LVH) predicts increased mortality, in part due to an increased incidence of sudden death. Repolarization-related arrhythmogenesis may be an important mechanism of sudden death in hypertensive patients with LVH. Increased QT interval and QT dispersion are electrocardiographic (ECG) measures of ventricular repolarization, and also risk markers for ventricular tachyarrhythmias. We assessed the relation of QT intervals and QT dispersion to echocardiographically determined left ventricular (LV) mass and geometry in a large population of hypertensive patients with ECG evidence of LVH.

METHODS

QT intervals and QT dispersion were determined from baseline 12-lead ECGs in 577 (57% male; mean age 65 +/- 7 years) participants in the LIFE study. LV mass index (LVMI) and geometric pattern were determined by echocardiography and QT interval duration and QT dispersion were assessed in relation to gender-specific LVMI quartiles.

RESULTS

In both genders, increasing LVMI was associated with longer rate-adjusted QT intervals. QT dispersion measures showed a weaker association with LVMI quartiles. Both concentric and eccentric LVH were associated with increased QT interval duration and QT dispersion. These relations remained significant after controlling for relevant clinical variables.

CONCLUSIONS

In hypertensive patients with ECG evidence of LVH, increased LVMI and LVH are associated with a prolonged QT interval and increased QT dispersion. These findings suggest that an increased vulnerability to repolarization-related ventricular arrhythmias might in part explain the increased risk of sudden death in hypertensive patients with increased LV mass.

Familial aggregation of QT-interval variability in a general population: results from the NHLBI Family Heart Study

QT-interval prolongation is associated with increased risk of cardiac death. Although information on genetics and molecular mechanisms of the congenital long QT syndrome is mounting, limited data are available on the genetics of QT interval in the general population. Heart rate adjusted QT intervals (Bazett's QTc, and QT index (QTI)) were assessed by electrocardiography in 2399 members aged 25-91 years of 468 randomly selected families participating in the NHLBI Family Heart Study. Familial correlation and segregation analyses were performed to evaluate the genetics of the variability of QT interval in this population. The parent-offspring (0.14+/-0.03) and sibling (0.18+/-0.03) correlations for age and sex-adjusted QTc were moderate, while the spouse correlation was close to zero (0.09+/-0.06). This suggests that there are familial/genetic influences on QT-interval variability. Segregation analysis results suggest that there is a major effect in addition to heritable multifactorial effects (h2=0.34), but the major effect did not follow Mendelian inheritance. Further adjustments of QTc for other major cardiovascular risk factors did not significantly change the results. Similar results were found for QTI. The QT-interval variation in the general population is influenced by moderate heritable multifactorial effects in addition to a major effect. A major gene effect is not directly supported.

Incidence and risk factors associated with cardiac arrhythmias during rehabilitation after coronary artery bypass surgery

OBJECTIVE

To evaluate the clinical relevance of cardiac arrhythmias during rehabilitation after coronary artery bypass graft (CABG) surgery.

DESIGN

Survey of consecutive patients admitted to an inpatient cardiac rehabilitation center.

SETTING

A rehabilitation center acting as a reference for cardiology clinics lacking this facility. The program was performed in the inpatient setting.

PATIENTS

Two hundred sixty patients undergoing elective CABG surgery for angina.

INTERVENTIONS

Four-week cardiac rehabilitation program. A 24-hour electrocardiographic examination was performed during the first 2 days and, subsequently, on a daily basis.

MAIN OUTCOME MEASURES

Incidence and type of cardiac arrhythmias during rehabilitation; identification of factors associated with an increased risk of cardiac arrhythmias.

RESULTS

Cardiac arrhythmias were recorded in 33.5% of the patients and were more frequent in patients with hypertension (47%), diabetes (42.4%), and hyperlipidemia (36.5%), compared with patients free from these diseases (15.5%) (p < .05). Arrhythmias were also recorded in patients older than 70 years (49%), compared with those younger (29.2%) (p < .01), and in patients who discontinued amiodarone (64.3%) compared with those who did not interrupt the drug (16%) (p < .005). Arrhythmias precluded rehabilitation in 5% of the patients and caused death in one patient.

CONCLUSION

Surveillance for the development of cardiac arrhythmias during cardiac rehabilitation after CABG surgery may allow the early detection and treatment of arrhythmias in a substantial number of patients.

QT interval dispersion and autonomic modulation in subjects with anxiety

This study was designed to assess Q-T interval dispersion as a marker of electrical instability in subjects with anxiety. Recent observations have shown that the presence of anxiety symptoms increases the risk of sudden death. The Kawachi anxiety questionnaire identified 29 subjects (male/female ratio 13:16) who scored 0, 22 subjects (male/female ratio 14:8) who scored 1, and 37 subjects (male/female ratio 13:24) who scored 2 or more. In all subjects we measured electrocardiographic interlead QT dispersion and autonomic function through spectral analysis of R-R interval and blood pressure variabilities and left ventricular mass. Compared with subjects who scored 0, those reporting 2 or more symptoms showed increased heart rate-corrected QT dispersion (54.9+/-1.7 ms vs. 34.9+/-3.2 ms, P<.001), sympathetic modulation (normal logarithm low-frequency power/high-frequency power 0.59+/-0.1 vs. 0.12+/-0.04, P<.05), and left ventricular mass (120.7+/-3.5 g/m2 vs. 97.9+/-2.8 g/m2, P<.001). Probably because it augments sympathetic activity, anxiety causes left ventricular mass to increase and, like hypertension, increases heart rate-corrected Q-T interval dispersion. The consequent electrical instability could be the substrate responsible for inducing fatal ventricular arrhythmias.

Prognostic value of a new electrocardiographic method for diagnosis of left ventricular hypertrophy in essential hypertension

OBJECTIVES

We tested the prognostic value of a new electrocardiographic (ECG) method (Perugia score) for diagnosis of left ventricular hypertrophy (LVH) in essential hypertension and compared it with five standard methods (Cornell voltage, Framingham criterion, Romhilt-Estes point score, left ventricular strain, Sokolow-Lyon voltage).

BACKGROUND

Several standard ECG methods for assessment of LVH are used in the clinical setting, but a comparative prognostic assessment is lacking.

METHODS

A total of 1,717 white hypertensive subjects (mean age 52 years; 51% men) were prospectively followed up for up to 10 years (mean 3.3).

RESULTS

At entry, the prevalence of LVH was 17.8% (Perugia score), 9.1% (Cornell), 3.9% (Framingham), 5.2% (Romhilt-Estes), 6.4% (strain) and 13.1% (Sokolow-Lyon). During follow-up there were 159 major cardiovascular morbid events (33 fatal). The event rate was higher in the subjects with than in those without LVH (all p < 0.001) according to all methods except the Sokolow-Lyon method. By multivariate analysis, an independent association between LVH and cardiovascular disease risk was maintained by the Perugia score (hazard ratio [HR] 2.04, 95% confidence interval [CI] 1.5 to 2.8) and the Framingham (HR 1.91, 95% CI 1.1 to 3.2), Romhilt-Estes (HR 2.63, 95% CI 1.7 to 4.1) and strain methods (HR 2.11, 95% CI 1.4 to 3.2). The Perugia score showed the highest population-attributable risk for cardiovascular events, accounting for 15.6% of all cases, whereas the Framingham, Romhilt-Estes and strain methods accounted for 3.0%, 7.4% and 6.8% of all events, respectively. LVH diagnosed by the Perugia score was also associated with an increased risk of cardiovascular mortality (HR 4.21, 95% CI 2.1 to 8.7), with a population-attributable risk of 37.0%.

CONCLUSIONS

The Perugia score carried the highest population-attributable risk for cardiovascular morbidity and mortality compared with classic methods for detection of LVH. Traditional interpretation of standard electrocardiography maintains an important role for cardiovascular risk stratification in essential hypertension.