Bundle branch block and other cardiovascular disease risk factors: US–Japan comparison

Bundle branch block and nonspecific intraventricular conduction delay prevalence using Chinese nationwide survey data

Objective

We aimed to determine the prevalence of and the factors associated with intraventricular conduction disturbance in the Chinese population.

Methods

Electrocardiographic data from 42,031 people were retrospectively analysed. The weighted prevalences of left bundle branch block (LBBB), right bundle branch block (RBBB), bifascicular block and nonspecific intraventricular conduction delay (NS-IVCD) were calculated. The independently associated factors were determined using logistic regression analysis.

Results

The weighted prevalence for Chinese people older than 45 years was 0.17% for LBBB, 2.16% for RBBB and 0.44% for NS-IVCD. The weighted prevalence for RBBB combined with left anterior fascicular block was 0.17%, and 0.05% for RBBB combined with left posterior fascicular block. There were significant differences in the weighted prevalences of RBBB and NS-IVCD between men and women. The weighted prevalence of LBBB and RBBB increased markedly with increasing age. Age and diabetes were independent factors associated with LBBB, compared with age and sex for RBBB and sex and coronary artery disease for NS-IVCD.

Conclusions

This study provided reliable data for the weighted prevalence of and factors associated with LBBB, RBBB and NS-IVCD in Chinese adults.

The impact of sex on risk of cardiovascular disease and all-cause mortality in adults with or without diabetes mellitus: A comparison between the U.S. and Japan

AIMS

To test a hypothesis that women with diabetes mellitus (DM) versus those without DM had a significantly higher risk of heart disease (HD), stroke and all-cause mortality than their male counterparts in the U.S. as well as in Japan.

METHODS

We analyzed two nationally representative datasets, one from the U.S. NHANES III cohort (n = 13,169), and the other from the Japan NIPPON DATA90 cohort (n = 7445). Hazard ratios (HRs) of DM for risk of mortality and sex-DM interaction effect on mortality were analyzed prospectively using Cox's proportional hazards regression models.

RESULTS

Patients with DM had significantly higher mortality from HD, stroke and all-cause mortality in the U.S. and in Japan. However, the HRs of DM versus non-DM for HD and all-cause mortality were significantly higher in women compared to men in the U.S. (sex-DM interaction: HR = 1.59, p = 0.01, and 1.24, p = 0.045 for HD and all-cause mortality), but the sex-DM interaction effect was not statistically significant in the Japanese cohort.

DISCUSSION

Patients with DM had a significantly higher risk of mortality than those without DM in the U.S. and Japan. However, women with DM versus those without DM had a higher relative risk of HD and all-cause mortality than their counterparts in men in the U.S, but this sex difference by DM status was not observed in the Japanese cohort. Whether the sex-difference effect of DM on HD and all-cause mortality is due to a difference in metabolic disorders between the two populations warrants consideration and further studies.

Right bundle branch block and cardiovascular morbidity and mortality in healthy patients

The clinical significance of a right bundle branch block (RBBB) in an asymptomatic adult without evidence of cardiovascular disease is controversial. To establish the relationship between the appearance of the RBBB and the increase of cardiovascular morbidity and mortality in healthy patients, we have carried out a literature review of documents available until September 2017 through a systematic search on the Pubmed database, Cochrane library and a manual search of the mentioned literature and related articles. From the 29 articles included in the study sample, eight showed mortality and 16 morbidity outcomes. An increase of risk of death is observed is eight articles and an increase of cardiovascular events is observed in 11 articles. The most recent publications suggest that the appearance of an RBBB in healthy individuals should not be underestimated, thus further studies are needed to analyse the type of follow-up that should be carried out in these patients.

Differences in Cardiovascular Aging in Men and Women

Cardiovascular diseases increase dramatically with age in both men and women. While it is clear that advanced age allows more time for individuals to be exposed to risk factors in general, there is strong evidence that age itself is a major independent risk factor for cardiovascular disease. Indeed, there are distinct age-dependent cellular, structural, and functional changes in both the heart and blood vessels, even in individuals with no clinical evidence of cardiovascular disease. Studies in older humans and in animal models of aging indicate that this age-related remodeling is maladaptive. An emerging view is that the heart and blood vessels accumulate cellular and subcellular deficits with age and these deficits increase susceptibility to disease in older individuals. Aspects of this age-dependent remodeling of the heart and blood vessels differ between the sexes. There is also new evidence that these maladaptive changes are more prominent in older animals and humans with a high degree of frailty. These observations may help explain why men and women are susceptible to different cardiovascular diseases as they age and why frail older adults are most often affected by these diseases.

Detection of inter-patient left and right bundle branch block heartbeats in ECG using ensemble classifiers

BACKGROUND

Left bundle branch block (LBBB) and right bundle branch block (RBBB) not only mask electrocardiogram (ECG) changes that reflect diseases but also indicate important underlying pathology. The timely detection of LBBB and RBBB is critical in the treatment of cardiac diseases. Inter-patient heartbeat classification is based on independent training and testing sets to construct and evaluate a heartbeat classification system. Therefore, a heartbeat classification system with a high performance evaluation possesses a strong predictive capability for unknown data. The aim of this study was to propose a method for inter-patient classification of heartbeats to accurately detect LBBB and RBBB from the normal beat (NORM).

METHODS

This study proposed a heartbeat classification method through a combination of three different types of classifiers: a minimum distance classifier constructed between NORM and LBBB; a weighted linear discriminant classifier between NORM and RBBB based on Bayesian decision making using posterior probabilities; and a linear support vector machine (SVM) between LBBB and RBBB. Each classifier was used with matching features to obtain better classification performance. The final types of the test heartbeats were determined using a majority voting strategy through the combination of class labels from the three classifiers. The optimal parameters for the classifiers were selected using cross-validation on the training set. The effects of different lead configurations on the classification results were assessed, and the performance of these three classifiers was compared for the detection of each pair of heartbeat types.

RESULTS

The study results showed that a two-lead configuration exhibited better classification results compared with a single-lead configuration. The construction of a classifier with good performance between each pair of heartbeat types significantly improved the heartbeat classification performance. The results showed a sensitivity of 91.4% and a positive predictive value of 37.3% for LBBB and a sensitivity of 92.8% and a positive predictive value of 88.8% for RBBB.

CONCLUSIONS

A multi-classifier ensemble method was proposed based on inter-patient data and demonstrated a satisfactory classification performance. This approach has the potential for application in clinical practice to distinguish LBBB and RBBB from NORM of unknown patients.

Impact of metabolic syndrome on the risk of cardiovascular disease mortality in the United States and in Japan

The United States has a higher prevalence of metabolic syndrome (MS) and cardiovascular disease (CVD) mortality than Japan, but it is unknown how much of the difference in MS accounts for the mortality difference. The aim of this study was to examine the impact of MS on the excess CVD mortality in the United States compared with that in Japan. Data from the United States Third National Health and Nutrition Examination Survey (NHANES III; n = 12,561) and the Japanese National Integrated Project for Prospective Observation of Noncommunicable Disease and Its Trends in Aged (NIPPON DATA; n = 7,453) were analyzed. MS was defined as ≥3 of 5 risk factors (obesity, high blood pressure, decreased high-density lipoprotein cholesterol, elevated glycosylated hemoglobin, and elevated triglycerides). The results show that after a median of 13.8 years of follow-up in the United States, 1,683 patients died from CVD (11.75 per 1,000 person-years), and after a median of 15 years of follow-up in Japan, 369 patients died from CVD (3.56 per 1,000 person-years). The age-adjusted prevalence of MS was 26.7% in the United States and 19.3% in Japan. Of 5 MS factors, obesity, high blood pressure, elevated triglycerides, and glycosylated hemoglobin in the United States, and high blood pressure and elevated glycosylated hemoglobin in Japan were significant risk factors for CVD mortality. Estimates of 13.3% and 44% of the excess CVD mortality for the United States could be explained by the higher prevalence of MS and MS plus baseline CVD history than in Japan. In conclusion, the present study is the first to quantitatively demonstrate that MS and MS plus baseline CVD history may significantly contribute to the explanation of excess CVD mortality in the United States compared with Japan.

Global variability in diabetes mellitus and its association with body weight and primary healthcare support in 49 low- and middle-income developing countries

AIMS

In the absence of any previous global comparison, we examined the variability in prevalence of diabetes mellitus across 49 developing countries, and the associations of diabetes with body weight and primary healthcare support using data from the World Health Survey.

METHODS

Diabetes mellitus was defined by individuals' self-report of a physician diagnosis of diabetes. BMI is the weight (kg)/the square of the height (m). Healthcare support was assessed using clinical treatment status and whether patients with diabetes followed prescribed behaviour changes to control diabetes. Associations of diabetes with BMI and diabetes treatment status were analysed cross-sectionally.

RESULTS

A total of 215898 participants were included in the analysis. Age-adjusted prevalence of diabetes ranged from 0.27% (Mali) to 15.54% (Mauritius). Participants who were underweight (BMI <18.5 kg/m(2) ), overweight (BMI 25-29.9 kg/m(2) ) and obese (BMI ≥ 30 kg/m(2) ) were significantly associated with odds of having diabetes as compared with those who were of normal weight (BMI 18.5-24.9 k/m(2) ), with corresponding values of multivariate adjusted odds ratios (95% CI) of 1.15 (1.07-1.24), 1.56 (1.44-1.68) and 2.35 (2.17-2.61), respectively. The overall untreated rate of those with diabetes mellitus was 9.6% in the total sample. Patients with underweight had the highest diabetes untreated rate, followed by those with normal weight, overweight and obesity.

CONCLUSION

There are significant variations in prevalence of diabetes and primary healthcare support for diabetes across low- and middle-income countries. Aggressively preventing abnormal body weight and improving healthcare support may play a pivotal role in ameliorating the unfavourable epidemic of diabetes in developing countries.