Interrelationship between electrocardiographic left ventricular hypertrophy, QT prolongation, and ischaemic stroke: the REasons for Geographic and Racial Differences in Stroke Study

Predicting stroke in Asian patients with atrial fibrillation using machine learning: A report from the KERALA-AF registry, with external validation in the APHRS-AF registry

Atrial fibrillation (AF) is a significant risk factor for stroke. Based on the higher stroke associated with AF in the South Asian population, we constructed a one-year stroke prediction model using machine learning (ML) methods in KERALA-AF South Asian cohort. External validation was performed in the prospective APHRS-AF registry. We studied 2101 patients and 83 were to patients with stroke in KERALA-AF registry. The random forest showed the best predictive performance in the internal validation with receiver operator characteristic curve (AUC) and G-mean of 0.821 and 0.427, respectively. In the external validation, the light gradient boosting machine showed the best predictive performance with AUC and G-mean of 0.670 and 0.083, respectively. We report the first demonstration of ML's applicability in an Indian prospective cohort, although the more modest prediction on external validation in a separate multinational Asian registry suggests the need for ethnic-specific ML models.

Prevalence of Increased QTc Dispersion Among Hypertensive Patients and Its Correlation to Clinical Risk Factors: A Hospital-Based Case-Control Study

Background In Ghana and other sub-Saharan African countries, hypertension (HTN) prevalence is rapidly increasing. Hypertensive left ventricular hypertrophy (LVH) is associated with excess fibrous tissue deposition throughout the myocardium. This could lead to ventricular arrhythmias and sudden cardiac death. Increased corrected QT dispersion (QTcd) can cause ventricular repolarization and be used to identify patients at risk of ventricular tachyarrhythmia. The measurement of increased QTcd among hypertensive patients is a simple screening tool to stratify patients at cardiovascular risk. Methods A case-control hospital-based study was conducted on 200 consecutive hypertensive patients. Age- and sex-matched control groups of 200 normotensive individuals who gave informed consent were also recruited. The baseline clinical and demographic characteristics of participants were acquired using structured questionnaires. A physical examination and a resting 12-lead ECG were performed. Increased QTcd and LVH were determined. Results The mean age of hypertensive patients was 50.99±6.73 and 48.19±7.17 for the controls (p-value 0.63). The study population was predominantly female (1:2.4 male:female ratio). Higher mean values for QTcd and LVH (Sokolow-Lyon) were observed among hypertensive patients compared to controls. The prevalence of increased QTcd was 45.0% among hypertensive patients compared to 16.5% in controls (χ2 =38.14, p-value <0.0000001, odds ratio = 4.14). Conclusion Increased QTcd is prevalent among hypertensive Ghanaians. Its measurement can be an effective non-invasive screening tool to risk-stratify hypertensive patients.

Transient cardiac electrophysiological changes in a rat model of subarachnoid haemorrhage: a brain-heart interaction

AIMS

Subarachnoid haemorrhage (SAH) is one of the causes of sudden cardiac death (SCD). However, the time course of ventricular arrhythmias and potential mechanisms responsible for this effect after SAH remain unknown.

OBJECTIVE

This study aims to investigate the effect of SAH on ventricular electrophysiological changes and its potential mechanisms in long-term phase.

METHODS AND RESULTS

We examined the ventricular electrophysiological remodelling and potential mechanisms in a Sprague Dawley rat model of SAH at six time points (baseline, and Days 1, 3, 7, 14 and 28) and explored the potential mechanisms. We measured the ventricular effective refractory period (ERP), ventricular fibrillation threshold (VFT) and left stellate ganglion (LSG) activity at different time points before and after SAH. We also detected neuropeptide Y (NPY) levels in plasma and myocardial tissues by enzyme-linked immunosorbent assay, and quantified NPY 1 receptor (NPY1R) protein and mRNA expression levels by western blotting and quantitative real-time reverse transcription-polymerase chain reaction, respectively. Subarachnoid haemorrhage gradually prolonged QTc intervals, shortened ventricular ERP and reduced VFT during the acute phase, peaking at Day 3. However, no significant changes were observed from Days 14 to 28 compared to Day 0. Subarachnoid haemorrhage gradually increased LSG activity, increased NPY concentrations and up-regulated NPY1R expression in the acute phase of SAH, peaking at Day 3. However, no significant variations were found from Days 14 to 28 compared to Day 0.

CONCLUSION

Subarachnoid haemorrhage increases the transient susceptibility of VAs in the acute phase, and the underlying mechanisms for this response included increased sympathetic activity and up-regulated NPY1R expression.

Prolongation of the heart rate-corrected QT interval is associated with cardiovascular diseases: Systematic review and meta-analysis

BACKGROUND

Conflicting findings have described the association between prolonged heart rate-corrected QT interval (QTc) and cardiovascular disease.

AIMS

To identify articles investigating the association between QTc and cardiovascular disease morbidity and mortality, and to summarize the available evidence for the general and type 2 diabetes populations.

METHODS

A systematic search was performed in PubMed and Embase in May 2022 to identify studies that investigated the association between QTc prolongation and cardiovascular disease in both the general and type 2 diabetes populations. Screening, full-text assessment, data extraction and risk of bias assessment were performed independently by two reviewers. Effect estimates were pooled across studies using random-effect models.

RESULTS

Of the 59 studies included, 36 qualified for meta-analysis. Meta-analysis of the general population studies showed a significant association for: overall cardiovascular disease (fatal and non-fatal) (hazard ratio [HR] 1.68, 95% confidence interval [CI] 1.33-2.12; I²=69%); coronary heart disease (fatal and non-fatal) in women (HR 1.27, 95% CI 1.08-1.50; I²=38%; coronary heart disease (fatal and non-fatal) in men (HR 2.07, 95% CI 1.26-3.39; I²=78%); stroke (HR 1.59, 95% CI 1.29-1.96; I²=45%); sudden cardiac death (HR 1.60, 95% CI 1.14-2.25; I²=68%); and atrial fibrillation (HR 1.55, 95% CI 1.31-1.83; I²=0.0%). No significant association was found for cardiovascular disease in the type 2 diabetes population.

CONCLUSION

QTc prolongation was associated with risk of cardiovascular disease in the general population, but not in the type 2 diabetes population.

Corrected QT Interval Is Associated With Stroke but Not Coronary Heart Disease: Insights From a General Chinese Population

Background: Prolonged heart rate-corrected QT (QTc) interval has been associated with incident cardiovascular diseases (CVD) in general Western populations. However, this association is unclear in Asian population. We aim to estimate the association between QTc interval and incident CVD in a general Chinese population.

Methods: We analyzed 8,867 participants age ≥35 years and free of CVD at baseline in the Northeast China Rural Cardiovascular Health Study. A resting 12-lead electrocardiogram was performed on all participants, and QTc interval computed using the Framingham formula. Cox proportional hazards models were used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) for associations between QTc interval and incident stroke, coronary heart disease, and combined CVD events.

Results: Over a median follow-up of 4.66 years, a total of 439 CVD events occurred (298 stroke cases and 152 CHD cases). After full adjustment, prolonged QTc defined by a sex-specific cutoff was associated with increased risk of developing stroke (HR: 1.82, 95% CI 1.20–2.75, P = 0.004) and combined CVD (HR: 1.52, 95% CI 1.05–2.19, P = 0.026). Spline analyses demonstrated no clear thresholds; when modeled as a linear relationship, each 10 ms increase of QTc interval was associated with an HR of 1.12 (95% CI 1.06–1.19, P < 0.001) for stroke and an HR of 1.10 (95% CI 1.05–1.15, P < 0.001) for combined CVD. Baseline QTc interval was not associated with incident CHD with either modeling strategy.

Conclusions: Baseline QTc interval is associated with incident stroke and CVD in adults without prior CVD from a general Chinese population.

QT Interval Dispersion as a Predictor of Clinical Outcome in Acute Ischemic Stroke

Background and Purpose: QT dispersion (QTd) abnormalities are widely documented in stroke patients. This study aims to investigate the association between QTd and clinical outcomes in IS patients.

Methods: IS patients registered in the Blood Pressure and Clinical Outcome in transient ischemic attack (TIA) or IS (BOSS) registry between 2012 and 2014 within 24 h of onset were analyzed. In this prospective observational study, we identified 1,522 IS cases with adequate electrocardiographic evaluations to assess QTd after the index stroke. Patients were classified into four groups based on the quartile of QTd, with the lowest group as the reference. The primary stroke outcome was defined as a modified Rankin Scale score ≥3 at 1-year. Multiple logistic regressions were utilized to investigate the association between QTd and outcome events.

Results: The mean QTd across all cases was 57 ms (40–83). Functional dependency or death was documented in 214 (14.98%) cases at 1 year. After adjusting for confounders, the prevalence of death and major disability (mRS ≥ 3) showed significant differences according to the quartile of QTd, with the risk of death and major disability (mRS ≥ 3) at 1 year being significantly higher for patients in Q4 than for those in Q1 (adjusted OR = 1.626, 95% CI:1.033–2.560). However, there were no significant correlation between QTd and the event outcomes at 1 year.

Conclusions: QTd was associated with poor functional outcomes at 1 year. QTd is a useful surrogate marker for adverse functional prognosis, which might help to stratify risk in patients with acute IS.

Impact of Multiple Social Determinants of Health on Incident Stroke

BACKGROUND AND PURPOSE

Social determinants of health (SDOH) have been previously associated with incident stroke. Although SDOH often cluster within individuals, few studies have examined associations between incident stroke and multiple SDOH within the same individual. The objective was to determine the individual and cumulative effects of SDOH on incident stroke.

METHODS

This study included 27 813 participants from the REGARDS (Reasons for Geographic and Racial Differences in Stroke) Study, a national, representative, prospective cohort of black and white adults aged ≥45 years. SDOH was the primary exposure. The main outcome was expert adjudicated incident stroke. Cox proportional hazards models examined associations between incident stroke and SDOH, individually and as a count of SDOH, adjusting for potential confounders.

RESULTS

The mean age was 64.7 years (SD 9.4) at baseline; 55.4% were women and 40.4% were blacks. Over a median follow-up of 9.5 years (IQR, 6.0-11.5), we observed 1470 incident stroke events. Of 10 candidate SDOH, 7 were associated with stroke (P<0.10): race, education, income, zip code poverty, health insurance, social isolation, and residence in one of the 10 lowest ranked states for public health infrastructure. A significant age interaction resulted in stratification at 75 years. In fully adjusted models, among individuals <75 years, risk of stroke rose as the number of SDOH increased (hazard ratio for one SDOH, 1.26 [95% CI, 1.02-1.55]; 2 SDOH hazard ratio, 1.38 [95% CI, 1.12-1.71]; and ≥3 SDOH hazard ratio, 1.51 [95% CI, 1.21-1.89]) compared with those without any SDOH. Among those ≥75 years, none of the observed effects reached statistical significance.

CONCLUSIONS

Incremental increases in the number of SDOH were independently associated with higher incident stroke risk in adults aged <75 years, with no statistically significant effects observed in individuals ≥75 years. Targeting individuals with multiple SDOH may help reduce risk of stroke among vulnerable populations.

Cardiovascular Changes Associated with Hypertensive Heart Disease and Aging

Cardiovascular diseases are the leading cause of mortality and morbidity worldwide and account for more than 17.9 million deaths (World Health Organization report). Hypertension and aging are two major risk factors for the development of cardiac structural and functional abnormalities. Hypertension, or elevated blood pressure, if left untreated can result in myocardial hypertrophy leading to heart failure (HF). Left ventricular hypertrophy consequent to pressure overload is recognized as the most important predictor of congestive HF and sudden death. The pathological changes occurring during hypertensive heart disease are very complex and involve many cellular and molecular alterations. In contrast, the cardiac changes that occur with aging are a slow but life-long process and involve all of the structural components in the heart and vasculature. However, these structural changes in the cardiovascular system lead to alterations in overall cardiac physiology and function. The pace at which these pathophysiological changes occur varies between individuals owing to many genetic and environmental risk factors. This review highlights the molecular mechanisms of cardiac structural and functional alterations associated with hypertension and aging.

Interferon gamma-induced protein 10 (IP-10) and cardiovascular disease in African Americans

Biomarkers of chronic inflammation (such as C-reactive protein) have long been associated with cardiovascular disease and mortality; however, biomarkers involved in antiviral cytokine induction and adaptive immune system activation remain largely unexamined. We hypothesized the cytokine interferon gamma inducible protein 10 (IP-10) would be associated with clinical and subclinical cardiovascular disease and all-cause mortality in African Americans. We assessed these associations in the Jackson Heart Study (JHS) cohort and the REasons for Geographic and Racial Differences in Stroke (REGARDS) study. There was a modest association of IP-10 with higher odds of left ventricular hypertrophy (OR = 1.20 (95% confidence interval (CI) 1.03, 1.41) per standard deviation (SD) higher natural log-transformed IP-10 in JHS). We did not observe associations with ankle brachial index, intima-media thickness, or arterial calcification. Each SD higher increment of ln-transformed IP-10 concentration was associated with incident heart failure (hazard ratio (HR) 1.26; 95% CI 1.11, 1.42, p = 4x10-4) in JHS, and with overall mortality in both JHS (HR 1.12 per SD, 95% CI 1.03, 1.21, p = 7.5x10-3) and REGARDS (HR 1.31 per SD, 95% CI 1.10, 1.55, p = 2.0 x 10-3), adjusting for cardiovascular risk factors and C-reactive protein. However, we found no association between IP-10 and stroke or coronary heart disease. These results suggest a role of IP-10 in heart failure and mortality risk independent of C-reactive protein. Further research is needed to investigate how the body's response to chronic viral infection may mediate heart failure and overall mortality risk in African Americans.

Does the Association of Diabetes With Stroke Risk Differ by Age, Race, and Sex? Results From the REasons for Geographic and Racial Differences in Stroke (REGARDS) Study

OBJECTIVE

Given temporal changes in diabetes prevalence and stroke incidence, this study investigated age, race, and sex differences in the diabetes-stroke association in a contemporary prospective cohort, the REasons for Geographic and Racial Differences in Stroke (REGARDS) Study.

RESEARCH DESIGN AND METHODS

We included 23,002 non-Hispanic black and white U.S. adults aged ≥45 years without prevalent stroke at baseline (2003-2007). Diabetes was defined as fasting glucose ≥126 mg/dL, random glucose ≥200 mg/dL, or use of glucose-lowering medication. Incident stroke events were expert adjudicated and available through September 2017.

RESULTS

The prevalence of diabetes was 19.1% at baseline. During follow-up, 1,018 stroke events occurred. Among adults aged <65 years, comparing those with diabetes to those without diabetes, the risk of stroke was increased for white women (hazard ratio [HR] 3.72 [95% CI 2.10-6.57]), black women (HR 1.88 [95% CI 1.22-2.90]), and white men (HR 2.01 [95% CI 1.27-3.27]) but not black men (HR 1.27 [95% CI 0.77-2.10]) after multivariable adjustment. Among those aged ≥65 years, diabetes increased the risk of stroke for white women and black men, but not black women (HR 1.05 [95% CI 0.74-1.48]) or white men (HR 0.86 [95% CI 0.62-1.21]).

CONCLUSIONS

In this contemporary cohort, the diabetes-stroke association varied by age, race, and sex together, with a more pronounced effect observed among adults aged <65 years. With the recent increase in the burden of diabetes complications at younger ages in the U.S., additional efforts are needed earlier in life for stroke prevention among adults with diabetes.

Value of electrocardiographic left ventricular hypertrophy as a predictor of poor blood pressure control: Evidence from the China stroke primary prevention trial

Recent studies have shown that hypertension is poorly controlled in many populations worldwide. Electrocardiographic left ventricular hypertrophy is a common manifestation of preclinical cardiovascular disease that strongly predicts cardiovascular disease morbidity and mortality. However, little information is available regarding the role of left ventricular hypertrophy in blood pressure (BP) control. We aimed to assess the relationship between electrocardiographic left ventricular hypertrophy and BP control in the China Stroke Primary Prevention Trial. The study population included 17,312 hypertensive patients who were selected from a group of 20,702 adults who had participated in the China Stroke Primary Prevention Trial and had undergone electrocardiography at baseline visit. Multivariate analysis identified left ventricular hypertrophy as a predictor of unsatisfactory BP control. The results revealed that 8.1% of hypertensive adults exhibit left ventricular hypertrophy and that the disease is more prevalent in males (12.8%) than in females. Multivariate regression analysis showed that the electrocardiographic left ventricular hypertrophy group had a significantly higher rate of unsatisfactory BP control [odds ratio (OR) 1.42, 95% confidence interval (95% CI) 1.26-1.61, P < .001) than the nonleft ventricular hypertrophy group.Notable differences in BP control were also observed among males (OR 1.37, 95% CI 1.17-1.60, P < .001) and females (OR 1.45, 95% CI 1.18-1.77, P < .001) and especially among patients with comorbid diabetes (OR 2.32, 95% CI 1.31-4.12, P = .004). In conclusion, the results of this study indicate that electrocardiographic left ventricular hypertrophy appears to be an independent predictive factor for poor BP control, especially in females and patients with comorbid diabetes.

Racial Differences in the Association Between Nonexercise Estimated Cardiorespiratory Fitness and Incident Stroke

OBJECTIVE

To examine the association between estimated cardiorespiratory fitness (eCRF) and incident stroke by black and white race.

PARTICIPANTS AND METHODS

A total of 24,162 participants from the REasons for Geographic And Racial Differences in Stroke study (13,232 [54.8%] women; 9543 [39.5%] blacks; mean age, 64.6±9.3 years) without stroke at enrollment between January 15, 2003, and October 30, 2007, were followed for incident stroke through March 31, 2016. Baseline eCRF in maximal metabolic equivalents was determined using nonexercise sex-specific algorithms and further grouped into age- and sex-specific tertiles.

RESULTS

Over a mean of 8.3±3.2 years of follow-up, 945 (3.9%) incident strokes occurred (377 in blacks and 568 in whites). The association between eCRF and stroke risk differed significantly by race (PInteraction<.001). In whites, after adjustment for stroke risk factors and physical functioning score, the hazard ratio of stroke was 0.82 (95% CI, 0.67-1.00) times lower in the middle tertile of eCRF than in the lowest tertile and was 0.54 (95% CI, 0.43-0.69) times lower in the highest tertile of eCRF. The protective effect of higher levels of eCRF on stroke incidence was more pronounced in those 60 years or older among whites. No association between eCRF and stroke risk was observed in blacks.

CONCLUSION

Estimated cardiorespiratory fitness measured using nonexercise equations is a useful predictor of stroke in whites. The lack of an overall association between eCRF and stroke risk in blacks suggests that the assessment of eCRF in blacks may not be helpful in primary stroke prevention.