Association of major and minor ECG abnormalities with coronary heart disease events

Selection of number of clusters and warping penalty in clustering functional electrocardiogram

Clustering functional data aims to identify unique functional patterns in the entire domain, but this can be challenging due to phase variability that distorts the observed patterns. Curve registration can be used to remove this variability, but determining the appropriate level of warping flexibility can be complicated. Curve registration also requires a target to which a functional object is aligned, typically the cross-sectional mean of functional objects within the same cluster. However, this mean is unknown prior to clustering. Furthermore, there is a trade-off between flexible warping and the number of resulting clusters. Removing more phase variability through curve registration can lead to fewer remaining variations in the functional data, resulting in a smaller number of clusters. Thus, the optimal number of clusters and warping flexibility cannot be uniquely identified. We propose to use external information to solve the identification issue. We define a cross validated Kullback-Leibler information criterion to select the number of clusters and the warping penalty. The criterion is derived from the predictive classification likelihood considering the joint distribution of both the functional data and external variable and penalizes the uncertainty in the cluster membership. We evaluate our method through simulation and apply it to electrocardiographic data collected in the Chronic Renal Insufficiency Cohort study. We identify two distinct clusters of electrocardiogram (ECG) profiles, with the second cluster exhibiting ST segment depression, an indication of cardiac ischemia, compared to the normal ECG profiles in the first cluster.

Routine Electrocardiogram Screening and Cardiovascular Disease Events in Adults

Importance

The resting electrocardiogram (ECG) is commonly performed for cardiovascular disease (CVD) screening purposes in Japan. However, evidence is limited regarding the prognostic significance of ECG in clinical practice settings.

Objective

To investigate the association between ECG abnormalities and CVD outcomes in a working-age population.

Design, Setting, and Participants

This nationwide cohort study included individuals aged 35 to 65 years from the Japan Health Insurance Association database, which covers approximately 40% (30 million) of the working-age population in Japan. Data from April 1, 2015, to March 31, 2022, were included, and analysis was conducted from October 1, 2022, to April 11, 2024.

Exposures

Baseline ECG status (normal, 1 minor abnormality, ≥2 minor abnormalities, or major abnormality).

Main Outcomes and Measures

The primary outcome was a composite of overall death and CVD hospital admission due to myocardial infarction, stroke, or heart failure. The secondary outcome was developing a new major ECG abnormality over the years of screening.

Results

Of 3 698 429 individuals enrolled in the nationwide annual health check program (mean [SD] age, 47.1 [8.5] years; 66.6% male), 623 073 (16.8%) had 1 minor ECG abnormality, 144 535 (3.9%) had 2 or more minor ECG abnormalities, and 56 921 (1.5%) had a major ECG abnormality. During a median follow-up of 5.5 (IQR, 3.4-5.7) years, baseline ECG abnormality was independently associated with an increased incidence of the composite end points of overall death and CVD admission compared with normal ECG (incidence rates per 10 000 person-years: 92.7 [95% CI, 92.2-93.2] for normal ECG, 128.5 [95% CI, 127.2-129.9] for 1 minor ECG abnormality, 159.7 [95% CI, 156.6-162.9] for ≥2 minor ECG abnormalities, and 266.3 [95% CI, 259.9-272.3] for a major ECG abnormality; adjusted hazard ratios: 1.19 [95% CI, 1.18-1.20] for 1 minor ECG abnormality, 1.37 [95% CI, 1.34-1.39] for ≥2 minor ECG abnormalities, and 1.96 [95% CI, 1.92-2.02] for a major ECG abnormality). Furthermore, the presence and number of minor ECG abnormalities were associated with an increased incidence of developing new major ECG abnormalities (incidence rates per 10 000 person-years: 85.1 [95% CI, 84.5-85.5] for normal ECG, 217.2 [95% CI, 215.5-219.0] for 1 minor ECG abnormality, and 306.4 [95% CI, 302.1-310.7] for ≥2 minor ECG abnormalities; and adjusted hazard ratios: 2.52 [95% CI, 2.49-2.55] for 1 minor ECG abnormality and 3.61 [95% CI, 3.55-3.67] for ≥2 minor ECG abnormalities). Associations were noted regardless of baseline CVD risk.

Conclusions and Relevance

The findings of this study suggest that the potential role of routine ECG screening for early prevention of CVD events, along with the optimal follow-up strategy, should be examined in future studies.

Association of major and minor ECG abnormalities with traditional cardiovascular risk factors in the general population: a large scale study

Cardiovascular disease (CVD) can be determined and quantified using the electrocardiogram (ECG) analysis. Identification of the risk factors associated with ECG abnormalities may advise prevention approaches to decrease CVD burden. In this study we aimed to investigate the association between CVD risk factors and minor and major ECG abnormalities in a general Iranian adult population. This study was conducted in 2010 and covered a population of 9035 males and females aged 35 to 65 years recruiting from the phase I of Mashhad Stroke and Heart Atherosclerotic Disorder (MASHAD) cohort study. The participants were drawn by a stratified cluster random sampling technique. The Bivariate and multinomial logistic regression analysis were conducted considering gender stratification to explore the association of ECG abnormalities with traditional cardiovascular risk factors. There was a significant association between minor and major ECG abnormalities and hypertension (HTN), type 2 diabetes (T2DM), smoking, and physical activity (p < 0.005). There was a significant trend, in both genders, for increasing major abnormalities as the number of CVD risk factors increased. But, only in women, the minor abnormalities increase in frequency as the number of CVD risk factors increased. The results of multinomial logistic regression showed that men with HTN [ARRR = 1.25, 95% CI 0.99, 1.57] and T2DM [ARRR = 1.31, 95% CI 0.99, 1.74] had the highest likelihood to have major abnormalities, although these are not statistically significant. For women, those with HTN had the highest likelihood to have major [ARRR = 1.36, 95% CI 1.13, 1.63] and minor [ARRR = 1.35, 95% CI 1.15, 1.58] abnormalities. Also, women aged > 60 years were more likely to have major [ARRR = 2.01, 95% CI 1.49, 2.74] and minor [ARRR = 1.59, 95% CI 1.20, 2.10] abnormalities compared to women aged < 45 years. Age and HTN were significantly associated with major and minor ECG abnormalities in women, and, on the other hand, HTN and T2DM were associated with major abnormalities in men. Taken together, these findings suggest that healthcare providers should advise preventive approaches to the asymptomatic adults with both major and minor electrocardiographic abnormalities that may predict cardiovascular risk.

The effect of anabolic androgenic steroids on heart rate recovery index and electrocardiographic parameters in male bodybuilders

BACKGROUND

The control of the cardiovascular system depends on the autonomic nerve system. Chronic anabolic andorogenic steroids (AAS) use causes sympathovagal imbalance and increases sympathetic nerve activity.

OBJECTIVE

The reduction in heart rate from the peak exercise rate following the end of the exercise stress test is known as the heart rate recovery index (HRRI). Several methods have been utilized to assess myocardial repolarization, such as QT interval (QT), corrected QT interval (QTc), and T-wave peak-to-end interval (Tp-e interval). Based on a growing number of data a higher Tp-e/QT ratio is linked to malignant ventricular arrhythmias, and an increased Tp-e interval may correlate with the transmural dispersion of repolarization. Our hypothesis is that the use of chronic AAS was decrease HRRI during maximal exercise and increased risk of cardiac arrhythmias and sudden cardiac death.

METHODS

This study included 44 male bodybuilders, with an average age of 29.7 ± 8.14 years, divided into AAS abuse [AAS users (n = 21) and AAS nonuser (n = 23)].

RESULTS

The first (p = 0.001) and second minute (p = 0.001) HRRI of the subjects with AAS users were significantly lower than those of the control group. Additionally, HRRI after the third (p = 0.004) and fifth minutes (p = 0.007) of the recovery period were significantly lower in AAS group compared with the control group. Who used AAS had significantly higher QT, QTc, Tp-e, Tp-e/QT, and Tp-e/QTc values than non-users (all p = 0.001).

CONCLUSIONS

Chronic AAS use has been shown to cause sympathetic dominance, which may be a pro arrhythmic state.

Presence and utility of electrocardiographic abnormalities in long-term childhood cancer survivors

BACKGROUND

We assessed the prevalence and diagnostic value of ECG abnormalities for cardiomyopathy surveillance in childhood cancer survivors.

METHODS

In this cross-sectional study, 1381 survivors (≥5 years) from the Dutch Childhood Cancer Survivor Study part 2 and 272 siblings underwent a long-term follow-up ECG and echocardiography. We compared ECG abnormality prevalences using the Minnesota Code between survivors and siblings, and within biplane left ventricular ejection fraction (LVEF) categories. Among 880 survivors who received anthracycline, mitoxantrone or heart radiotherapy, logistic regression models using least absolute shrinkage and selection operator identified ECG abnormalities associated with three abnormal LVEF categories (<52% in male/<54% in female, <50% and <45%). We assessed the overall contribution of these ECG abnormalities to clinical regression models predicting abnormal LVEF, assuming an absence of systolic dysfunction with a <1% threshold probability.

RESULTS

16% of survivors (52% female, mean age 34.7 years) and 14% of siblings had major ECG abnormalities. ECG abnormalities increased with decreasing LVEF. Integrating selected ECG data into the baseline model significantly improved prediction of sex-specific abnormal LVEF (c-statistic 0.66 vs 0.71), LVEF <50% (0.66 vs 0.76) and LVEF <45% (0.80 vs 0.86). While no survivor met the preset probability threshold in the first two models, the third model used five ECG variables to predict LVEF <45% and was applicable for ruling out (sensitivity 93%, specificity 56%, negative predictive value 99.6%). Calibration and internal validation tests performed well.

CONCLUSION

A clinical prediction model with ECG data (left bundle branch block, left atrial enlargement, left heart axis, Cornell's criteria for left ventricular hypertrophy and heart rate) may aid in ruling out LVEF <45%.

Prevalence and prognostic value of electrocardiographic abnormalities in hypokalemia: A multicenter cohort study

BACKGROUND

Hypokalemia is common in hospitalized patients and associated with ECG abnormalities. The prevalence and prognostic value of ECG abnormalities in hypokalemic patients are, however, not well established.

METHODS

The study was a multicentered cohort study, including all ault patients with an ECG and potassium level <4.4 mmol/L recorded at arrival to four emergency departments in Denmark and Sweden. Using computerized measurements from ECGs, we investigated the relationship between potassium levels and heart rate, QRS duration, corrected QT (QTc) interval, ST-segment depressions, T-wave flattening, and T-wave inversion using cubic splines. Within strata of potassium levels, we further estimated the hazard ratio (HR) for 7-day mortality, admission to the intensive care unit (ICU), and diagnosis of ventricular arrhythmia or cardiac arrest, comparing patients with and without specific ECG abnormalities matched 1:2 on propensity scores.

RESULTS

Among 79,599 included patients, decreasing potassium levels were associated with a concentration-dependent increase in all investigated ECG variables. ECG abnormalities were present in 40% of hypokalemic patients ([K+ ] <3.5 mmol/L), with T-wave flattening, ST-segment depression, and QTc prolongation occurring in 27%, 16%, and 14%. In patients with mild hypokalemia ([K+ ] 3.0-3.4 mmol/L), a heart rate >100 bpm, ST-depressions, and T-wave inversion were associated with increased HRs for 7-day mortality and ICU admission, whereas only a heart rate >100 bpm predicted both mortality and ICU admission among patients with [K+ ] <3.0 mmol/L. HR estimates were, however, similar to those in eukalemic patients. The low number of events with ventricular arrhythmia limited evaluation for this outcome.

CONCLUSIONS

ECG abnormalities were common in hypokalemic patients, but they are poor prognostic markers for short-term adverse events under the current standard of care.

Associations of ECG Signs of Ischemic and Non-Specific Signs of Metabolic Changes in the Myocardium With Unfavorable Cardiovascular Prognosis in a 7-Year Prospective Follow-Up of Young People Under 45 Years

AIM

To study ischemic and/or nonspecific ECG signs of metabolic changes in the myocardium and to determine their relationship with unfavorable cardiovascular prognosis in a 7-year prospective observation of young people under 45 years of age.

MATERIAL AND METHODS

A cross-sectional population survey of a random sample aged 25-44 years (n=1363) was conducted in Novosibirsk. The survey program used the standardized epidemiological Rose questionnaire. Biochemical tests were used to measure blood concentrations of total cholesterol (C), triglycerides (TG), low- and high-density lipoprotein cholesterol (LDL-C, HDL-C), and fasting blood plasma glucose. Systolic and diastolic BP (SBP, DBP), the presence of arterial hypertension (AH), body mass index (BMI), waist circumference (WC), and smoking status were assessed. ECG was recorded at rest in 12 standard leads followed by interpretation according to the Minnesota Code. The presence of ischemic and/or nonspecific ECG signs of metabolic changes in the myocardium was determined. Subjects with ECG signs of ischemic changes in the myocardium were selected for long-term follow-up and additional examination by cardiologists. Then the whole cohort was monitored for 7 years, and cardiovascular events were recorded, including using data from the WHO Myocardial Infarction Registry in Novosibirsk. For statistical analysis of the results, cardiovascular events were combined into a composite endpoint.

RESULTS

During 7 years, 40 people (27 men and 13 women) had an unfavorable cardiovascular prognosis. Multivariate regression analysis showed that a 7-year unfavorable cardiovascular prognosis in people younger than 45 years was associated with signs of ischemic myocardial alterations identified on the background ECG (OR 5.319, 95% CI: 1.543-18.342, p=0.008) and nonspecific ECG signs of metabolic changes in the myocardium (OR 2.978, 95% CI: 1.216-7.216, p=0.017) regardless of age, gender, the presence of arterial hypertension (AH) and type 2 diabetes mellitus (DM2).

CONCLUSION

In young people under 45 years of age, not only ECG signs of ischemic changes in the myocardium, but also nonspecific ECG signs of metabolic changes in the myocardium are associated with an unfavorable cardiovascular prognosis, directly and independently on age and gender, in a long-term, 7-year period.

Association Between ECG Abnormalities and Mortality in a Low-Risk Population

BACKGROUND

The ECG is a simple, noninvasive screening method for cardiovascular disease and arrhythmia. The impact of ECG abnormality on mortality is not certain in low-risk populations. To address this, we evaluated the association between ECG abnormality and mortality.

METHODS AND RESULTS

We retrospectively assessed baseline ECG and all-cause mortality and cardiovascular mortality in 660 383 patients presenting for medical check-ups. Baseline ECG abnormalities were classified according to the Minnesota Code. Among the total 660 383 participants, 23 609 (3.6%) had major and 110 038 (16.7%) had minor ECG abnormalities. All-cause mortality occurred in 7751 patients (1.1%) and cardiovascular mortality in 1180 (0.18%) over a median follow-up period of 8.8 years. Major ECG abnormalities were associated with all-cause mortality (hazard ratio [HR], 1.11 [95%, 1.03-1.2]) and cardiovascular mortality (HR, 1.92 [95% CI, 1.63-2.27]) compared with no ECG abnormalities. All-cause mortality was associated with right atrial enlargement (HR, 2.11 [95% CI, 1.1-4.07]), left atrial enlargement (HR, 1.76 [95% CI, 1.1-2.84]), sinus tachycardia (HR, 1.52 [95% CI, 1.15-2.01]), complete atrioventricular block (HR, 2.1 [95% CI, 1.05-4.2]), atrial fibrillation (HR, 1.52 [95% CI, 1.26-1.84]), and left ventricular hypertrophy (HR, 1.15 [95% CI, 1.02-1.3]). Cardiovascular mortality was associated with left atrial enlargement (HR, 4.52 [95% CI, 2.15-9.5]), atrial fibrillation (HR, 3.22 [95% CI, 2.33-4.46]), left ventricular hypertrophy (HR, 1.72 [95% CI, 1.35-2.19]), major Q-wave abnormality (HR, 1.6 [95% CI, 1.08-2.39]), and major ST-T abnormality (HR, 1.76 [95% CI, 1.01-3.04]).

CONCLUSIONS

ECG abnormalities, including left atrial enlargement, left ventricular hypertrophy, atrial fibrillation, and major Q-wave and ST-T abnormalities, were associated with cardiovascular mortality in a low-risk population.

The Association Between Urbanization and Electrocardiogram Abnormalities in China: a Nationwide Longitudinal Study

The health effects of urbanization are controversial. The association between urbanization and reversible subclinical risks of cardiovascular diseases (e.g., electrocardiogram (ECG) abnormalities) has rarely been studied. This study aimed to assess the association between urbanization and ECG abnormalities in China based on the China National Stroke Screening Survey (CNSSS). We used changes in the satellite-measured impervious surfaces rate and nighttime light data to assess the level of urbanization. Every interquartile increment in the impervious surfaces rate or nighttime light was related to a decreased risk of ECG abnormalities, with odds ratios of 0.894 (95% CI, 0.869-0.920) or 0.809 (95% CI, 0.772-0.847), respectively. And we observed a U-shaped nonlinear exposure-response relationship curve between the impervious surfaces rate and ECG abnormalities. In conclusion, the current average level of urbanization among the studied Chinese adults remains a beneficial factor for reducing cardiovascular risks.

Association of insulin resistance and glycemic measures with major abnormal electrocardiogram in older Chinese: Cross-sectional analysis based on the Guangzhou Biobank Cohort study

AIMS

To examine whether insulin resistance (IR) and glycemic measures were associated with major abnormal electrocardiogram (MA-ECG) and its specific abnormalities in the general population.

METHODS

Twelve-lead ECG measurements were performed on 21,720 participants without cardiovascular disease (5,918 men) from the Guangzhou Biobank Cohort Study. The participants were aged 50 years or above (mean age 61.6, standard deviation 7.1 years). Logistic regression was used to assess the associations of IR and glycemic measures with MA-ECG and specific abnormalities.

RESULTS

Ln-fasting insulin was significantly associated with MA-ECG and ST-T abnormalities (adjusted odds ratio = 1.52, 95 % confidence interval = 1.15-2.02 and 1.83, 1.37-2.45, respectively, for per standard deviation), which were stronger than those of TyG index with MA-ECG (1.08, 1.04-1.13) and ST-T abnormalities (1.16, 1.11-1.22). Ln-fasting insulin had association with Q wave abnormalities (3.19, 1.52-6.67). The association of TyG index with prolonged QTc varied by sex and obesity (P for interaction ≤ 0.01). Participants with diabetes had stronger associations of ln-fasting plasma glucose with ECG abnormalities than those without.

CONCLUSIONS

IR and glycemic measures were associated with MA-ECG, ischemia and prolonged QTc in older Chinese, especially in women, those with obesity, and those with diabetes. These findings underscore the importance of regular evaluations for these groups.

The correlation between T-wave abnormalities and adverse cardiovascular events and echocardiographic changes in hypertensive patients

BACKGROUND

Major adverse cardiovascular events (MACE) are common in patients with hypertension and are associated with higher mortality.

METHODS

This study aimed to observe the incidence of MACE in hypertensive patients and the correlation between the electrocardiogram (ECG) T-wave abnormalities and echocardiographic changes. This retrospective cohort study analyzed the incidence of adverse cardiovascular events and changes in echocardiographic features in 430 hypertensive patients admitted to Zhongnan Hospital of Wuhan University from January 2016 to January 2022. Patients were grouped according to a diagnosis of electrocardiographic T-wave abnormalities.

RESULTS

Compared with the normal T-wave group, the incidence of adverse cardiovascular events was significantly higher in hypertensive patients with abnormal T-wave (141 [54.9%] vs 120 [69.4%], x^2 = 9.113, P = .003). However, Kaplan-Meier survival curve showed that no survival advantage was observed in the normal T-wave group at all in the hypertensive patients (P = .83). Echocardiographic values associated with cardiac structural markers, including ascending aorta diameter (AAO), left atrial diameter (LA), and interventricular septal thickness (IVS), were significantly higher in the group with abnormal T-wave than those in the group with normal T-wave at baseline and follow-up (P <.05 for all). In addition, in an exploratory Cox regression analysis model stratified by clinical characteristics of hypertensive patients, the forest plot indicated that the variables, including the age (>65 years), hypertension history (>5 years), premature atrial beats, and severe valvular regurgitation were significantly associated with adverse cardiovascular events (P <.05).

CONCLUSION

Hypertensive patients with abnormal T-wave show a higher incidence of adverse cardiovascular events. The values of cardiac structural markers were significantly higher in the group with abnormal T-wave.

Electrocardiography score based on the Minnesota code classification system predicts cardiovascular mortality in an asymptomatic low-risk population

BACKGROUND

The use of a single abnormal finding on electrocardiography (ECG) is not recommended for stratifying the risk of cardiovascular (CV) events in low-risk general populations because of its low discriminative power. However, the value of a scoring system containing multiple abnormal ECG findings for predicting CV death has not been sufficiently evaluated.

METHODS

In a prospective community-based cohort study, 8417 participants without atherosclerotic CV diseases (ASCVDs) and any related symptoms were followed for 18 years. The standard 12-lead ECGs were recorded at baseline and the ECG findings were categorized using the Minnesota code classification. CV deaths were defined as death from myocardial infarction (MI), chronic ischemic heart disease, heart failure, fatal arrhythmia, cerebrovascular event, pulmonary thromboembolism, peripheral vascular disease and sudden cardiac arrest and identified using the Korean National Statistical Office (KOSTAT) database.

RESULTS

In a multivariate Cox proportional hazard (CPH) model, major and minor ST-T wave abnormalities, atrial fibrillation (AF), Q waves in the anterior leads, the lack of Q waves in the posterior leads, high amplitudes of the left and right precordial leads, left axis deviation and sinus tachycardia were associated with higher risks of CV deaths. The ECG score consisted of these findings showed modest predictive values represented by C-statistics that ranged from 0.632 to 760 during the follow-up and performed better in the early follow-up period. The ECG score independently predicted CV death after adjustment for relevant covariates in a multivariate model, and improved the predictive performance of the 10-year ASCVD risk estimator and a model of conventional risk factors including age, diabetes and current smoking. The combined ECG score (Harrell's C-index: 0.852, 95% confidence interval [CI], 0.828-0.876) composed of the ECG score and the conventional risk factors outperformed the 10-year ASCVD risk estimator (Harrell's C-index: 0.806; 95% CI, 0.780-0.833) and the model of the conventional risk factors (Harrell's C-index: 0.841, 95% CI, 0.817-0.865) and exhibited an excellent goodness of fit between the predicted and observed probabilities of CV death.

CONCLUSIONS

The ECG score could be useful to predict CV death independently and may add value to the conventional CV risk estimators regarding the risk stratification of CV death in asymptomatic low-risk general populations.

Sex differences in the association between minor nonspecific ST-segment and T-wave abnormalities and coronary artery calcification

BACKGROUND AND AIMS

Although minor nonspecific ST-segment and T-wave abnormalities (NSSTTA) have been associated with adverse cardiovascular outcomes, their relationship with subclinical atherosclerosis remains controversial. Therefore, the associations between electrocardiographic (ECG) abnormalities, including NSSTTA, and coronary artery calcification (CAC) were investigated in this study.

METHODS

This cross-sectional study included 136,461 Korean participants with no known cardiovascular disease or cancer, who underwent a health checkup including ECG and computed tomography to measure the coronary artery calcium score (CACS) by Agatston method between 2010 and 2018. ECG abnormalities were defined in accordance with the Minnesota Code using an automated ECG analysis program. A multinomial logistic regression model was used to calculate prevalence ratios (PRs) with 95% confidence intervals (CI) for each CACS category.

RESULTS

In men, both NSSTTA and major ECG abnormalities were associated with all levels of CACS. The multivariable-adjusted PRs (95% CI) for CACS >400 comparing NSSTTA and major ECG abnormalities to the reference (neither NSSTTA nor major ECG abnormalities) were 1.88 (1.29-2.74) and 1.50 (1.18-1.91), respectively. Women with major ECG abnormalities were more likely to have a CACS of 101-400, the PRs (95% CI) comparing major ECG abnormalities to the reference group was 1.75 (1.18-2.57). NSSTTA were not associated with any CACS level in women.

CONCLUSIONS

NSSTTA and major ECG abnormalities are associated with CAC in men, though NSSTTA were not associated with CAC in women, suggesting that NSSTTA should be considered sex-specific risk factors for coronary artery disease in men, but not in women.

Cold indoor temperatures and their association with health and well-being: a systematic literature review

OBJECTIVE

The study aimed to identify, appraise and update evidence on the association between cold temperatures (i.e. <18°C) within homes (i.e. dwellings) and health and well-being outcomes.

STUDY DESIGN

This study was a systematic review.

METHODS

Seven databases (MEDLINE, Embase, Cochrane Database of Systematic Reviews, CINAHL, APA PsycInfo, Applied Social Sciences Index and Abstracts, Coronavirus Research Database) were searched for studies published between 2014 and 2022, which explored the association between cold indoor temperatures and health and well-being outcomes. Studies were limited to those conducted in temperate and colder climates due to the increased risk of morbidity and mortality during winter in those climatic zones. Studies were independently quality assessed using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies.

RESULTS

Of 1209 studies, 20 were included for review. Study outcomes included cardiovascular (blood pressure, electrocardiogram abnormalities, blood platelet count), respiratory (chronic obstructive pulmonary disease symptoms, respiratory viral infection), sleep, physical performance and general health. Seventeen studies found exposure to cold indoor temperatures was associated with negative effects on health outcomes studied. Older individuals and those with chronic health problems were found to be more vulnerable to negative health outcomes.

CONCLUSION

Evidence suggests that indoor temperatures <18°C are associated with negative health effects. However, the evidence is insufficient to allow clear conclusions regarding outcomes from specific temperature thresholds for different population groups. Significant gaps in the current evidence base are identified, including research on the impacts of cold indoor temperatures on mental health and well-being, studies involving young children, and the long-term health effects of cold indoor temperatures.

Longitudinal association of premature atrial contractions with atrial fibrillation and brain ischemia in people with type 2 diabetes: The Hoorn Diabetes Care System cohort

Background

Premature atrial contractions (PACs) are potential markers for imminent onset of both atrial fibrillation (AF) and brain ischemia (BI; transient ischemic attack [TIA] or ischemic stroke). We investigated the association of PACs with incident AF and BI events separately, and of incident AF with BI events in people with type 2 diabetes (T2D) without pre-existing AF or cerebrovascular disease.

Methods

A prospective longitudinal study of 12,242 people with T2D without known AF or cerebrovascular disease from the Hoorn Diabetes Care System cohort. Annual measurements (1998-2018) included cardiovascular risk factors, over 85,000 ECGs, and self-reported cardiovascular events. We assessed the association of PACs with incident AF and BI events and of incident AF with BI events using time-dependent Cox-regression models, adjusted for time-varying cardiovascular risk factors and medication use (Hazard Ratios with 95%CIs).

Results

The baseline mean age was 62.2 ± 11.9 years. During a median follow-up of 7.0 (IQR 3.4-11.0) years, 1031 (8.4 %) participants had PACs, and 566 (4.6 %) had incident AF at any of the median 6 (IQR 3-10) annual ECG recordings. BI events occurred in 517 (4.2 %) people (304 TIAs, 213 ischemic strokes). After adjustment, PACs were associated with incident AF (Hazard Ratio, 1.96 (95%CI, 1.53-2.50)), but not with overall BI events (1.09 (0.76-1.56)), or with TIA (0.91 (0.57-1.46)) or ischemic stroke (1.50 (0.88-2.54)) separately. AF was not associated with BI events (0.95 (0.55-1.63)).

Conclusions

In people with T2D without a history of AF or BI events, PACs are associated with a two-fold increased risk of incident AF.

Electrocardiogram changes as predictors for new imaging findings in repeat transthoracic echocardiography

Aim: To determine if electrocardiogram (EKG) findings may be a useful tool to predict changes in repeat transthoracic echocardiogram (TTE). Methods: We evaluated patients who underwent TTE during hospitalization and their EKGs, and whether findings differed between studies. Results: Of 229 hospitalized patients who underwent repeat TTE, 183 (80%) were abnormal. Each minor and major EKG abnormality resulted in a 1.8 (1.2 to 2.6; p = 0.002) and 2.1 (1.3 to 3.3; p < 0.001) increased odds of abnormal imaging on TTE, respectively. The negative likelihood ratio for an unchanged EKG to predict an unchanged TTE was 0.68 (95% CI = 0.62 to 0.73). Conclusion: Among hospitalized patients with prior imaging results, an unchanged EKG predicts an unchanged TTE.

The evolution of electrocardiographic abnormalities in the elderly with Chagas disease during 14 years of follow-up: The Bambui Cohort Study of Aging

BACKGROUND

The natural history of Chagas disease (ChD) in older ages is largely unknown, and it is a matter of controversy if the disease continues to progress in the elderly.

OBJECTIVE

To investigate the evolution of electrocardiographic abnormalities in T. cruzi chronically infected community-dwelling elderly compared to non-infected (NChD) subjects and how it affects this population's survival in a follow-up of 14 years.

METHODS AND RESULTS

A 12-lead ECG of each individual of the Bambui Cohort Study of Aging was obtained in 1997, 2002, and 2008, and the abnormalities were classified using the Minnesota Code. The influence of ChD on the ECG evolution was assessed by semi-competing risks considering a new ECG abnormality as the primary event and death as the terminal event. A Cox regression model to evaluate the population survival was conducted at a landmark point of 5.5 years. The individuals of both groups were compared according to the following categories: Normal, Maintained, New, and More by the development of ECG major abnormalities between 1997 and 2002. Among the participants, the ChD group had 557 individuals (median age: 68 years) and NChD group had 905 individuals (median age: 67 years). ChD was associated with a higher risk of development of a new ECG abnormality [HR: 2.89 (95% CI 2.28-3.67)]. The development of a new major ECG abnormality increases the risk of death ChD patients compared to those that maintain a normal ECG [HR: 1.93 (95% CI 1.02-3.65)].

CONCLUSION

ChD is still associated with a higher risk of progression to cardiomyopathy in the elderly. The occurrence of a new major ECG abnormality in ChD patients predicts a higher risk of death.

Major and minor ECG abnormalities depending on regional living conditions in Russia

The goal of our study was to explore the effect of living conditions on the odd of major and minor ECG abnormalities on a large region scale in Russia. For the analysis, cross-sectional data of the Russian study, ESSE-RF 2013-2014, were used. They were collected on a sample of 16,400 subjects from 10 regions of the Russia. ECG abnormalities were grouped into two categories: Major and Minor (sensu the 2009 version of the Minnesota Code Classification System). Regional living conditions were considered comprehensively via five indices combining 33 characteristics of the regions. The estimates were presented as odds ratios and their 95% confidence intervals. The prevalence values of major abnormalities in the sample were 8.4% among women and 9.4% among men (p = 0.021). The prevalence of minor abnormalities constituted 34.1% and 45.9%, respectively (p < 0.001). In men, the odd of major ECG abnormalities increased with the demographic depression growth (1.08: 1.04-1.12) and with industrial development growth in the region (1.12: 1.07-1.17). In women, an increase in the odd of major ECG abnormalities was directly associated with industrial development (1.12: 1.07-1.16) and inversely related to the economic development in the region (0.94: 0.89-0.99). The odd of minor ECG abnormalities in men and women declined with the growth of the regional economic development: OR of 0.95: 0.93-0.98, and OR of 0.92: 0.87-0.99, respectively. The study demonstrated an effect of regional living conditions of the Russian population on the odd of major and minor ECG abnormalities. The most stable and logically explainable relationships were obtained for industrial and economic characteristics of living conditions.

Comparing the effectiveness of asynchronous e-modules and didactic lectures to teach electrocardiogram interpretation to first year US medical students

BACKGROUND

Medical students are expected to be competent in interpreting electrocardiograms (ECGs) by the time they graduate, but many are unable to master this skill. Studies suggest that e-modules are an effective way to teach ECG interpretation, however they are typically evaluated for use during clinical clerkships. We sought to determine if an e-module could replace a didactic lecture to teach ECG interpretation during a preclinical cardiology course.

METHODS

We developed an asynchronous, interactive e-module that consisted of narrated videos, pop-up questions and quizzes with feedback. Participants were first year medical students who were either taught ECG interpretation during a 2-hour didactic lecture (control group) or were given unlimited access to the e-module (e-module group). First-year internal medicine residents (PGY1 group) were included to benchmark where ECG interpretation skills should be at graduation. At three time-points (pre-course, post-course, and 1-year follow-up), participants were evaluated for ECG knowledge and confidence. A mixed-ANOVA was used to compare groups over time. Students were also asked to describe what additional resources they used to learn ECG interpretation throughout the study.

RESULTS

Data was available for 73 (54%) students in the control group, 112 (81%) in the e-module group and 47 (71%) in the PGY1 group. Pre-course scores did not differ between the control and e-module groups (39% vs. 38%, respectively). However, the e-module group performed significantly better than the control group on the post-course test (78% vs. 66%). In a subsample with 1-year follow-up data, the e-module group's performance decreased, and the control group remained the same. The PGY1 groups' knowledge scores were stable over time. Confidence in both medical student groups increased by the end of the course, however only pre-course knowledge and confidence were significantly correlated. Most students relied on textbooks and course materials for learning ECG, however online resources were also utilized.

CONCLUSIONS

An asynchronous, interactive e-module was more effective than a didactic lecture for teaching ECG interpretation, however continued practice is needed regardless of how students learn to interpret ECGs. Various ECG resources are available to students to support their self-regulated learning.

Characterization and Validation of Flexible Dry Electrodes for Wearable Integration

When long-term biosignal monitoring is required via surface electrodes, the use of conventional silver/silver chloride (Ag/AgCl) gelled electrodes may not be the best solution, as the gel in the electrodes tends to dry out over time. In this work, the electrical behaviour and performance of dry electrodes for biopotential monitoring was assessed. Three materials were investigated and compared against the gold-standard Ag/AgCl gelled electrodes. To characterize their electrical behaviour, the impedance response over the frequency was evaluated, as well as its signal to noise ratio. The electrodes' performance was evaluated by integrating them in a proven electrocardiogram (ECG) acquisition setup where an ECG signal was acquired simultaneously with a set of dry electrodes and a set of standard Ag/AgCl gelled electrodes as reference. The obtained results were morphologically compared using the Normalised Root Mean Squared Error (nRMSE) and the Cosine Similarity (CS). The findings of this work suggest that the use of dry electrodes for biopotential monitoring is a suitable replacement for the conventional Ag/AgCl gelled electrodes. The signal obtained with dry electrodes is comparable to the one obtained with the gold standard, with the advantage that these do not require the use of gel and can be easily integrated into fabric to facilitate their use in long-term monitoring scenarios.

Longitudinal association of ECG abnormalities with major adverse cardiac events in people with type 2 diabetes: The Hoorn Diabetes Care System cohort

AIMS

To investigate the association of (changes in) ECG abnormalities with incident major adverse cardiac events (MACE) in people with type 2 diabetes (T2D) without pre-existing cardiovascular disease (CVD).

METHODS

A prospective longitudinal study of 11,993 people with T2D without known CVD from the Hoorn Diabetes Care System cohort. Annually repeated measurements (1998-2018), included cardiovascular risk factors, over 70,000 ECGs, and self-reported cardiovascular events. ECG abnormalities were classified according to the Minnesota Classification as prolonged PR duration, prolonged QRS duration, left QRS-axis, QS pattern, ST-segment/T-wave abnormalities, or tall R-wave. The association of ECG abnormalities with MACEs was assessed using time-dependent Cox-regression models, adjusted for time-varying cardiovascular risk factors and medication use (Hazzard Ratios with 95%CIs).

RESULTS

During a median follow-up of 6.6 (IQR, 3.1-10.7) years, 5445 (45.4%) of the participants had an ECG abnormality (prevalent or incident) at any of the median 6 (IQR, 3-10) annual ECG recordings, and 905 people (7.5%) had a MACE (529 CHD, 250 HF, 126 SCA). After adjustment, most ECG abnormalities were associated with HF: prolonged QRS duration (HR, 4.01 (95%CI, 2.67-6.03)), QS pattern (2.68 (0.85-8.49)), ST-segment/T-wave abnormalities (4.26 (2.67-6.80)), and tall R-wave (2.23 (1.33-3.76)). Only QS pattern (2.69 (1.20-6.03)), and ST-segment/T-wave abnormalities (2.11 (1.48-3.02)) were associated with CHD. These associations were robust across age, sex, hypertension, or estimated CVD risk subgroups.

CONCLUSION

In people with T2D without pre-existing cardiovascular disease, ECG abnormalities related to decelerated conduction, ischemia and hypertrophy are predominantly early signs of emerging HF, while only abnormalities related to ischemic disorders are signs of CHD.

Prognostic Modelling Studies of Coronary Heart Disease—A Systematic Review of Conventional and Genetic Risk Factor Studies

This study aims to provide an overview of multivariable prognostic modelling studies developed for coronary heart disease (CHD) in the general population and to explore the optimal prognostic model by comparing the models’ performance. A systematic review was performed using Embase, PubMed, Cochrane, Web of Science, and Scopus databases until 30 November 2019. In this work, only prognostic studies describing conventional risk factors alone or a combination of conventional and genomic risk factors, being developmental and/or validation prognostic studies of a multivariable model, were included. A total of 4021 records were screened by titles and abstracts, and 72 articles were eligible. All the relevant studies were checked by comparing the discrimination, reclassification, and calibration measures. Most of the models were developed in the United States and Canada and targeted the general population. The models included a set of similar predictors, such as age, sex, smoking, cholesterol level, blood pressure, BMI, and diabetes mellitus. In this study, many articles were identified and screened for consistency and reliability using CHARM and GRIPS statements. However, the usefulness of most prognostic models was not demonstrated; only a limited number of these models supported clinical evidence. Unfortunately, substantial heterogeneity was recognized in the definition and outcome of CHD events. The inclusion of genetic risk scores in addition to conventional risk factors might help in predicting the incidence of CHDs; however, the generalizability of the existing prognostic models remains open. Validation studies for the existing developmental models are needed to ensure generalizability, improve the research quality, and increase the transparency of the study.

Electrocardiographic abnormalities in childhood cancer survivors treated with cardiotoxic therapy: a systematic review

PURPOSE

The purpose of this study is to assess the available literature on the prevalence and risk factors of electrocardiographic (ECG) abnormalities after cardiotoxic treatment in childhood cancer survivors (CCS).

METHODS

A literature search was performed within MEDLINE, EMBASE, and CENTRAL (1966-11/2020) and reference lists of relevant studies. Studies were eligible for inclusion if they reported ECG abnormalities ≥2 years after cancer diagnosis in ≥50 CCS treated with anthracyclines, RT involving the heart region and/or mitoxantrone. Information about population, treatment, outcome, and risk factors were extracted and risk of bias was assessed.

RESULTS

Of 934 identified publications, 10 studies were included. Outcome definitions, treatment regimens, follow-up period, and risk of bias varied. These ECG abnormalities and prevalences were reported: major (5%-23%) and minor (12%) abnormalities according to the Minnesota Code, rhythm abnormalities (0%-12%), conduction abnormalities (0.3%-7.1%), depolarization abnormalities (0%), and repolarization abnormalities (0%-65%). The reported risk factors of ECG abnormalities (two studies) are male sex, anthracyclines, RT involving the heart region, and hypertension, although results were not univocal between studies and abnormalities.

CONCLUSIONS

Multiple ECG abnormalities have been described in CCS ≥2 years from diagnosis, some of which can have important implications. Future research is needed to evaluate the exact long-term incidence and risk factors, and to investigate their clinical relevance and relation with cardiac dysfunction or future cardiac events. This could improve cardiac surveillance for CCS.

Nonspecific ventricular repolarization abnormalities: A wolf in sheep's clothing

The term nonspecific ventricular repolarization abnormalities refers to a set of minor alterations of the ST segment and/or the T wave. For a long time, they have been of little clinical interest as they do not translate into specific diagnoses. It has even been asserted that they constitute benign electrocardiographic findings. Their presence has been reported in various cardiovascular and non-cardiovascular diseases. However, it is frequently identified in apparently healthy asymptomatic people. A growing number of studies demonstrate their importance as predictors of cardiovascular morbidity and mortality, expanding their spectrum towards cardiovascular prevention. In light of the body of scientific evidence, it is imperative that the traditional view of nonspecific ventricular repolarization abnormalities changes.

Prevalence of major electrocardiographic abnormalities in patients with hypertension in a primary care clinic in Hong Kong

Background

Hypertension is strongly associated with cardiovascular events. Studies have shown that electrocardiographic (ECG) abnormalities were associated with increased risks for cardiovascular events. However local data is limited. The objectives of this study were: (1) to determine the prevalence of major electrocardiographic abnormalities in patients with hypertension in primary care in Hong Kong, and (2) to determine the association of major electrocardiographic abnormalities with patients’ socio-economical background, cardiovascular disease and cardiovascular risk factors.

Methods

This was a cross-sectional study. Subjects were hypertensive patients aged between 18 and 80 who were enrolled in the Risk Assessment and Management Programme (RAMP) in a general outpatient clinic in Hong Kong. Outcome measures were prevalence of probable ischaemic heart disease (IHD), complete left bundle branch block (LBBB), left ventricular hypertrophy (LVH) and atrial fibrillation (AF) in patients with hypertension. The Pearson Chi-square test, independent t-test and Mantel–Haenszel test were used to measure the association between socioeconomic characteristics and cardiovascular risk factors, and ECG abnormalities.

Results

504 hypertensive patients aged 18–80 were recruited in a general outpatient clinic. 6.3% had probable IHD, 0.4% had complete LBBB, 4.0% had LVH and 1.0% had AF. Probable IHD was associated with smoking (P = 0.032), hypercholesterolaemia (P = 0.037) and higher 10-year CV risk (P = 0.04). Complete LBBB was associated with smoking (P = 0.021) and hypercholesterolaemia (P = 0.022). LVH was associated with male gender (P = 0.001) and longer duration of hypertension (P = 0.035). AF was not significantly associated with any of the clinical or sociodemographic parameters.

Conclusions

This study showed that a significant proportion of patients with hypertension at the primary care setting in Hong Kong had probable ischaemic heart disease, left ventricular hypertrophy and atrial fibrillation. This finding is consistent with both overseas data and historic data in Hong Kong. The detection of electrocardiographic abnormalities is helpful in hypertension management by improving risk stratification.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02662-1.

Can the ECG be used to estimate age-related survival?

BACKGROUND

There are few reports of the relationship between electrocardiogram (ECG) findings and the age-related survival of acutely ill patients.

AIM

This study compared the 1-year survival curves of patients attending two Danish emergency departments (EDs) with normal and abnormal ECGs. Patients were divided into age groups from 20 to 90 years of age, and an abnormal ECG was defined as low QRS voltage (i.e. lead I + II <1.4 mV) or QTc interval prolongation >434 ms.

METHODS

A retrospective register-based observational study on 35 496 patients attending two Danish EDs, with 100% follow-up for 1 year.

RESULTS

ECG abnormality increases linearly with age, and between 30 and 70 years of age. Patients aged 20-29 years with ECG abnormalities are more than four times more likely to die within a year than patients of the same age with a normal ECG. An individual with an abnormal ECG has the same risk of dying within a year as an individual with a normal ECG who is 10 years older. After 70 years of age this tight relationship ends, but for younger individuals with an abnormal ECG the increase in mortality is even higher.

CONCLUSION

An ECG may be a simple practical estimate of age-related survival. For a patient under 70 years, an abnormal QRS voltage or a prolonged QTc interval may increase 1-year mortality to that of a patient ∼10 years older.

Self-Reporting Technique-Based Clinical-Trial Service Platform for Real-Time Arrhythmia Detection

The analysis of the electrocardiogram (ECG) is critical for the diagnosis of arrhythmias. Recent advances in information and communications technology (ICT) have led to the development of wearable ECG devices and arrhythmia-detection algorithms. This study aimed to develop an ICT-based clinical trial service platform using a self-reporting technique for real-time arrhythmia detection. To establish a clinical-trial service platform, a mobile application (app), a demilitarized zone (DMZ), an internal network, and Amazon web services virtual private cloud (AWS-VPC) were developed. The ECG data acquired by a wearable device were transmitted to the mobile app, which collected the participants’ self-reported information. The mobile app transmitted raw ECG and self-reported data to the AWS-VPC and DMZ, respectively. In the AWS-VPC, the live-streaming and playback-reviewer services were operational to display the currently and previously acquired ECG data to clinicians through the web client. All the measured data were transmitted to the internal network, in which the arrhythmia-detection algorithm was executed and all the data were saved. The self-reporting technique and arrhythmia-detection algorithm are the key elements of this platform. In particular, subjective information of participants can be easily collected using a self-reporting technique. These features are particularly of critical importance for treating painless, sparsely occurring arrhythmias.

Integrated Sports Medicine: A First Investigation of Heart Performance in Opera Singers

INTRODUCTION

Opera singers are continuously subjected to cardiopulmonary exercise. The impact on cardiac performance has not been studied. Our aim was to verify the impact of singing on heart performance, particularly by the evaluation of ECG and deformation parameters as strain, rotation and twist.

METHODS

A population of 17 OS (opera singers) underwent a 12-lead ECG and 2D echocardiographic evaluation. A post-processing analysis of the images to obtain the deformation parameters was included. The data expressed as mean as SD were compared to a group of 15 high-level athletes (A).

RESULTS

In both groups, the ECG parameters, 2D standard systodiastolic parameters and pulmonary pressure were normal, and in the OS group-LVDd: 47 ± 2.75 mm, LVSd: 31 ± 3.38 mm, E/A: 1.08 ± 0.23, RV: 27.63 ± 3.38 mm; in the A group-LVDd: 51 ± 1.50 mm, LVSd: 32 ± 2.50 mm, E/A: 2.37 ± 0.73, RV: 25.00 ± 3.00 mm. Indexed LV mass was significantly greater in athletes, while ejection fraction (EF) results were higher in OS. Deformation parameters did not differ among the two groups, with the exclusion of GLS expressing a major value in athletes. Rotational parameters resulted in the OS group similar to the athletes.

CONCLUSIONS

OS show myocardial performance as high as the athletes. The data obtained suggest a positive impact of regular training as an opera singer. Deformation parameters highlight the fitness status in this group with a specific remodeling in RV in the presence of normal PP. Classic music singing appears to have a training effect on the heart. Further studies are necessary to confirm this hypothesis.

Prevalence of major and minor electrocardiographic abnormalities and their relationship with cardiovascular risk factors in Angolans

Aims

To identify the prevalence of major and minor electrocardiographic abnormalities and their association with the main risk factors for cardiovascular disease in a population in the province of Bengo, northern Angola.

Methods

A cross-sectional community-based study was conducted and a representative random sample stratified by sex and age was selected. In total, 2379 black individuals were included in the final analysis. A standard 12-lead ECG were recorded from all participants, analyzed and processed by the University of Glasgow software and coding by the Minnesota code.

Results

22.3% of participants had minor electrocardiographic abnormalities and 4.58% major ECG abnormalities. The most common minor ECG abnormalities were abnormal T wave inversion, minor isolated ST abnormalities and premature beats. The most common major ECG abnormalities were Left ventricular hypertrophy with major ST-T abnormalities, Ventricular conduction defects and major Q-wave abnormalities. Hypertension, diabetes mellitus, hypercholesterolemia, alcohol consumption and smoking, were significantly associated with major and minor electrocardiographic abnormalities.

Conclusions

In this study several participants had minor and major electrocardiographic abnormalities. Minor electrocardiographic abnormalities were more prevalent in men and major abnormalities in women. The electrocardiographic abnormalities had significant associations with the main cardiovascular risk factors.

Negative Risk Markers for Cardiovascular Risk Evaluation in Chinese Adults

Background

The atherosclerotic cardiovascular disease (ASCVD) risk predicted by traditional risk factors is used to guide preventive treatment. We aimed to investigate whether preferable levels of non-traditional emerging risk factors (i.e., negative risk markers) could downgrade the predicted ASCVD risk beyond traditional risk factors.

Methods

A total of 7,568 Chinese adults aged ≥ 40 years were followed up during 2010–2015. Negative risk markers including non-traditional lipids, urinary albumin-to-creatinine ratio, electrocardiogram (ECG), and measurements of atherosclerosis were evaluated using diagnostic likelihood ratio (DLR) and continuous net reclassification index (NRI) for their ability to downshift predicted CVD risk in the overall study population and in participants with intermediate (traditional risk factor predicted ASCVD risk 7.5% to 19.9%) or high risk (≥20%).

Results

During a median follow-up of 4.5 years, 416 participants developed CVD events including non-fatal myocardial infarction, non-fatal stroke, and cardiovascular death. Among negative risk markers examined, lipoprotein(a) ≤ 10th percentile (5 mg/dL), normal ECG, and carotid intima-media thickness (CIMT) ≤ 25th percentile (0.5 mm) provided moderate CVD risk reclassification and downward changes in pre- to post-test risk on top of the traditional CVD risk factors, especially in high-risk participants. The DLRs were 0.41, 0.75, and 0.41, and the NRIs were 18, 22, and 14% for lipoprotein(a), ECG, and CIMT, respectively in high-risk participants.

Conclusions

Lipoprotein(a) ≤ 5 mg/dL, normal ECG, and CIMT ≤ 0.5 mm might be used as negative non-traditional risk markers to correctly downgrade predicted ASCVD risk in Chinese adults.

Clinical values of resting electrocardiography in patients with known or suspected chronic coronary artery disease: a stress perfusion cardiac MRI study

Background

Electrocardiography (ECG) is an essential investigation in patients with chronic coronary artery disease (CAD). However, evidence regarding the diagnostic and prognostic value of ECG in this population is limited. Therefore, we sought to determine whether baseline ECG abnormalities were associated with myocardial ischemia and cardiac events in patients with known or suspected chronic CAD.

Methods

Consecutive patients with known (n = 146) or suspected chronic CAD (n = 349) referred for adenosine stress cardiac magnetic resonance (CMR) between 2011 and 2014 were enrolled. Resting ECGs were classified as major, minor, and no abnormalities. Predictors of myocardial ischemia on CMR and major adverse cardiac events (MACE) including cardiac death, nonfatal myocardial infarction, hospitalization for heart failure and late revascularization (> 180 days after CMR) were evaluated.

Results

Average age was 69 ± 11 years (51% men). One hundred and eighty-five patients (37.4%) had major and 154 (31.1%) had minor ECG abnormalities. In patients with suspected CAD, myocardial ischemia was presented in 83 patients (23.8%). Multivariable analysis demonstrated major ECG abnormality as the strongest predictor of myocardial ischemia (HR 2.51; 95% CI 1.44–4.36; p = 0.001). Adding ECG to clinical pretest probability models improved the prediction of myocardial ischemia in ROC analyses (p = 0.04). In the whole cohort (n = 495), 91 MACE occurred during the median follow-up period of 4.8 years. Multivariable analysis showed that diabetes mellites, history of heart failure, prior revascularization, left ventricular ejection fraction, ischemia, and major ECG abnormality were independent predictors of MACE.

Conclusion

Abnormal resting ECG is common in patients with known or suspected chronic CAD. ECG had important diagnostic and prognostic values in this population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02440-5.

The association between EKG abnormalities and the development of microalbuminuria in type 2 diabetes

Microalbuminuria is associated with both with chronic kidney disease and various cardiovascular abnormalities. Given the common use of electrocardiograms (EKGs) in diagnosing cardiovascular dysfunction, this study is analyzing the relationship between EKG abnormalities and diabetic nephropathy in type 2 diabetes mellitus (DM) patients. The enrollments of this study were from the 10-year follow-up data (2003-2012) of the Diabetes Management through an Integrated Delivery System project. All study subjects underwent at least 1 EKG measurement. The urinary microalbuminuria was recorded annually. The logistic regression model was used to evaluate the association between EKG abnormalities and the occurrence of diabetic nephropathy in type 2 DM patients. The total of 1189 patients with type 2 DM are included in this study and a total of 552 patients had microalbuminuria during a 10-year follow-up. A significantly higher odds ratio of microalbuminuria occurrence (4.85) was found in the patients with premature supraventricular contraction or tachycardia compared to those without EKG abnormalities. The odds ratios of microalbuminuria occurrence were 1.00, 2.43, 2.64, and 2.98, respectively, for patients with insulin resistance in the Q (quartile) 1(as the reference), Q2, Q3, and Q4, respectively. Our findings can serve as a reference for the association between EKG abnormalities and the development of microalbuminuria in type 2 diabetes.

Optimizing ECG to detect echocardiographic left ventricular hypertrophy with computer-based ECG data and machine learning

BACKGROUND

Left ventricular hypertrophy detected by echocardiography (Echo-LVH) is an independent predictor of mortality. Integration of the Philips DXL-16 algorithm into the electrocardiogram (ECG) extensively analyses the electricity of the heart. Machine learning techniques such as the C5.0 could lead to a new decision tree criterion to detect Echo-LVH.

OBJECTIVES

To search for a new combination of ECG parameters predictive of Echo-LVH. The final model is called the Cardiac Hypertrophy Computer-based model (CHCM).

METHODS

We extracted the 458 ECG parameters provided by the Philips DXL-16 algorithm in patients with Echo-LVH and controls. We used the C5.0 ML algorithm to train, test, and validate the CHCM. We compared its diagnostic performance to validate state-of-the-art criteria in our patient cohort.

RESULTS

We included 439 patients and considered an alpha value of 0.05 and a power of 99%. The CHCM includes T voltage in I (≤0.055 mV), peak-to-peak QRS distance in aVL (>1.235 mV), and peak-to-peak QRS distance in aVF (>0.178 mV). The CHCM had an accuracy of 70.5% (CI95%, 65.2-75.5), a sensitivity of 74.3%, and a specificity of 68.7%. In the external validation cohort (n = 156), the CHCM had an accuracy of 63.5% (CI95%, 55.4-71), a sensitivity of 42%, and a specificity of 82.9%. The accuracies of the most relevant state-of-the-art criteria were: Romhilt-Estes (57.4%, CI95% 49-65.5), VDP Cornell (55.7%, CI95%47.6-63.7), Cornell (59%, CI95%50.8-66.8), Dalfó (62.9%, CI95%54.7-70.6), Sokolow Lyon (53.9%, CI95%45.7-61.9), and Philips DXL-16 algorithm (54.5%, CI95%46.3-62.5).

CONCLUSION

ECG computer-based data and the C5.0 determined a new set of ECG parameters to predict Echo-LVH. The CHCM classifies patients as Echo-LVH with repolarization abnormalities or LVH with increased voltage. The CHCM has a similar accuracy, and is slightly more sensitive than the state-of-the-art criteria.

A Prediction Model of Incident Cardiovascular Disease in Patients with Sleep-Disordered Breathing

(1) Purpose: this study proposes a method of prediction of cardiovascular diseases (CVDs) that can develop within ten years in patients with sleep-disordered breathing (SDB). (2) Methods: For the design and evaluation of the algorithm, the Sleep Heart Health Study (SHHS) data from the 3367 participants were divided into a training set, validation set, and test set in the ratio of 5:3:2. From the data during a baseline period when patients did not have any CVD, we extracted 18 features from electrography (ECG) based on signal processing methods, 30 ECG features based on artificial intelligence (AI), ten clinical risk factors for CVD. We trained the model and evaluated it by using CVD outcomes result, monitored in follow-ups. The optimal feature vectors were selected through statistical analysis and support vector machine recursive feature elimination (SVM-RFE) of the extracted feature vectors. Features based on AI, a novel proposal from this study, showed excellent performance out of all selected feature vectors. In addition, new parameters based on AI were possibly meaningful predictors for CVD, when used in addition to the predictors for CVD that are already known. The selected features were used as inputs to the prediction model based on SVM for CVD, determining the development of CVD-free, coronary heart disease (CHD), heart failure (HF), or stroke within ten years. (3) Results: As a result, the respective recall and precision values were 82.9% and 87.5% for CVD-free; 71.9% and 63.8% for CVD; 57.2% and 55.4% for CHD; 52.6% and 40.8% for HF; 52.4% and 44.6% for stroke. The F1-score between CVD and CVD-free was 76.5%, and it was 59.1% in class four. (4) Conclusion: In conclusion, our results confirm the excellence of the prediction model for CVD in patients with SDB and verify the possibility of prediction within ten years of the CVDs that may occur in patients with SDB.

Echocardiographic and Electrocardiographic Abnormalities Among Elderly Adults With Cardiovascular Disease in Rural South Africa

BACKGROUND

Sub-Saharan Africa is undergoing an epidemiological transition fueled by the interaction between infectious and cardiovascular diseases. Our cross-sectional study aimed to characterize the spectrum of abnormalities suggesting end-organ damage on ECG and transthoracic echocardiograms (TTE) among older adults with cardiovascular diseases in rural South Africa.

METHODS

The prevalence of ECG and TTE abnormalities was estimated; χ2 analyses and multivariable logistic regressions were performed to test their association with sex, hypertension, and other selected comorbidities.

RESULTS

Overall, 729 ECGs and 155 TTEs were completed, with 74 participants completing both. ECG evaluation showed high rates of left ventricular hypertrophy (LVH, 36.5%) and T wave abnormalities (13.6%). TTE evaluation showed high rates of concentric LVH (31.6%), with moderate-severe (56.8%) diastolic dysfunction. Participants with hypertension showed more cardiac remodeling on ECG by LVH (45.4% versus 22.1%, P<0.01), and TTE by concentric LVH (42.5% versus 8.2%, P<0.01) and increased left ventricular mass (58.5% versus 20.4%, P<0.0001). In multivariable logistic regression, systolic blood pressure remained significantly associated with LVH on ECG (adjusted odds ratio, 1.03 per mm Hg [95% CI, 1.03-1.04], P<0.0001) and increased left ventricular mass on TTE (adjusted odds ratio, 1.04 per mm Hg [95% CI, 1.01-1.06], P=0.001). Male participants (n=326, 40.2%) were more likely than females (n=484, 59.8%) to show ECG abnormalities like LVH (45% versus 30.8%, P<0.01), whereas females were more likely to show TTE abnormalities like concentric LVH (40.8% versus 13.5%, P<0.01) and increased left ventricular mass (58.4% versus 23.1%, P<0.0001). Similar results were confirmed in multivariable models.

CONCLUSIONS

Our findings suggest that cardiovascular diseases are widespread in rural South Africa, with a larger burden of hypertensive heart disease than previously appreciated, and define the severity of end-organ damage that is already underway. Local health systems must adapt to face the growing burden of hypertension, as suboptimal rates of hypertension diagnosis and treatment may dramatically increase the heart failure burden.

Evaluation of Cardiac Scan in Diagnosing Coronary-artery Disease

BACKGROUND

With the evaluation of focal epicardial coronary stenosis and non-obstructive atherosclerosis, the cardiac scans play a significant role in diagnosing coronary artery disease (CAD). Moreover, the advancements in the imaging techniques leading to improved risk assessment and timely therapies help in early diagnosis of CAD with greater accuracy.

AIMS

To evaluate the role of cardiac scan in diagnosing CAD.

METHODS

Recruited 100 individuals without any history of CAD that refers to the assessment of suspected angina, conducted the prospective study. Electrocardiogram (ECG) findings assisted in the evaluation of left bundle branch blockage, abnormalities of ST-segment, and pathological Q waves.

RESULTS

The results depicted negative N.M findings among 38 respondents; whereas, ischemia and myocardial infarctions were diagnosed in 26% and 19% of the respondents, respectively. The majority of the males (59) were positive in contrast to 37 females with positive results. Similarly, 24 respondents were presented with mild dilated left atria (LA), 37 respondents suffered from impaired relaxation pattern of left ventricular (LV) diastolic filling; while, 40 of the respondents had normal global LV systolic function.

CONCLUSION

The study results have concluded that non-invasive, low-risk, and cost-effective technique like ECG is an important beneficial advancement in the diagnosis of CAD.

De novo electrocardiographic abnormalities in persons living with HIV

Persons living with HIV (PLWH) may have increased incidence of cardiovascular events and longer QTc intervals than uninfected persons. We aimed to investigate the incidence and risk factors of de novo major electrocardiogram (ECG) abnormalities and QTc prolongation in well-treated PLWH. We included virologically suppressed PLWH without major ECG abnormalities, who attended the 2-year follow-up in the Copenhagen comorbidity in HIV infection (COCOMO) study. ECGs were categorized according to Minnesota Code Manual. We defined de novo major ECG abnormalities as new major Minnesota Code Manual abnormalities. Prolonged QTc was defined as QTc > 460 ms in females and QTc > 450 ms in males. Of 667 PLWH without major ECG abnormalities at baseline, 34 (5%) developed de novo major ECG abnormalities after a median of 2.3 years. After adjustment, age (RR: 1.57 [1.08-2.28] per decade older), being underweight (RR: 5.79 [1.70-19.71]), current smoking (RR: 2.34 [1.06-5.16]), diabetes (RR: 3.89 [1.72-8.80]) and protease inhibitor use (RR: 2.45 [1.27-4.74) were associated with higher risk of getting de novo major ECG abnormalities. Of PLWH without prolonged QTc at baseline, only 11 (1.6%) participants developed de novo prolonged QTc. Five percent of well-treated PLWH acquired de novo major ECG abnormalities and protease inhibitor use was associated with more than twice the risk of de novo major ECG abnormalities. De novo prolonged QTc was rare and did not seem to constitute a problem in well-treated PLWH.

Electrocardiogram abnormalities in residents in cold homes: a cross-sectional analysis of the nationwide Smart Wellness Housing survey in Japan

Background

Excess winter mortality caused by cardiovascular disease is particularly profound in cold houses. Consistent with this, accumulating evidence indicates that low indoor temperatures at home increase blood pressure. However, it remains unclear whether low indoor temperatures affect other cardiovascular biomarkers. In its latest list of priority medical devices for management of cardiovascular diseases, the World Health Organization (WHO) included electrocardiography systems as capital medical devices. We therefore examined the association between indoor temperature and electrocardiogram findings.

Methods

We collected electrocardiogram data from 1480 participants during health checkups. We also measured the indoor temperature in the living room and bedroom for 2 weeks in winter, and divided participants into those living in warm houses (average exposure temperature ≥ 18 °C), slightly cold houses (12–18 °C), and cold houses (< 12 °C) in accordance with guidelines issued by the WHO and United Kingdom. The association between indoor temperature (warm vs. slightly cold vs. cold houses) and electrocardiogram findings was analyzed using multivariate logistic regression models, with adjustment for confounders such as demographics (e.g., age, sex, body mass index, household income), lifestyle (e.g., eating habit, exercise, smoking, alcohol drinking), and region.

Results

The average temperature at home was 14.7 °C, and 238, 924, and 318 participants lived in warm, slightly cold, and cold houses, respectively. Electrocardiogram abnormalities were observed in 17.6%, 25.4%, and 30.2% of participants living in warm, slightly cold, and cold houses, respectively (p = 0.003, chi-squared test). Compared to participants living in warm houses, the odds ratio of having electrocardiogram abnormalities was 1.79 (95% confidence interval: 1.14–2.81, p = 0.011) for those living in slightly cold houses and 2.18 (95% confidence interval: 1.27–3.75, p = 0.005) for those living in cold houses.

Conclusions

In addition to blood pressure, living in cold houses may have adverse effects on electrocardiogram. Conversely, keeping the indoor thermal environment within an appropriate range through a combination of living in highly thermal insulated houses and appropriate use of heating devices may contribute to good cardiovascular health.

Trial registration

The trial was retrospectively registered on 27 Dec 2017 to the University hospital Medical Information Network Clinical Trials Registry (UMIN-CTR, https://www.umin.ac.jp/ctr/, registration identifier number UMIN000030601).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12199-021-01024-1.

Combining Optical Character Recognition With Paper ECG Digitization

Objective: We propose a MATLAB-based tool to convert electrocardiography (ECG) waveforms from paper-based ECG records into digitized ECG signals that is vendor-agnostic. The tool is packaged as an open source standalone graphical user interface (GUI) based application. Methods and procedures: To reach this objective we: (1) preprocess the ECG records, which includes skew correction, background grid removal and linear filtering; (2) segment ECG signals using Connected Components Analysis (CCA); (3) implement Optical Character Recognition (OCR) for removal of overlapping ECG lead characters and for interfacing of patients’ demographic information with their research records or their electronic medical record (EMR). The ECG digitization results are validated through a reader study where clinically salient features, such as intervals of QRST complex, between the paper ECG records and the digitized ECG records are compared. Results: Comparison of clinically important features between the paper-based ECG records and the digitized ECG signals, reveals intra- and inter-observer correlations of 0.86–0.99 and 0.79–0.94, respectively. The kappa statistic was found to average at 0.86 and 0.72 for intra- and inter-observer correlations, respectively. Conclusion: The clinically salient features of the ECG waveforms such as the intervals of QRST complex, are preserved during the digitization procedure. Clinical and Healthcare Impact: This open-source digitization tool can be used as a research resource to digitize paper ECG records thereby enabling development of new prediction algorithms to risk stratify individuals with cardiovascular disease, and/or allow for development of ECG-based cardiovascular diagnoses relying upon automated digital algorithms.

Relationship Between Sarcopenia and Electrocardiographic Abnormalities in Older People: The Bushehr Elderly Health Program

Background: Sarcopenia is characterized by low skeletal muscle mass and function, which is associated with cardiovascular risk factors and may even be related to adverse cardiovascular events and mortality. This study aimed to evaluate whether sarcopenia is related to electrocardiographic (ECG) abnormalities in a large sample of older adults.

Methods: We performed a cross-sectional study based on the data collected during the Bushehr Elderly Health (BEH) cohort study. Body composition was measured by dual X-ray absorptiometry (DXA) and muscle strength was measured using a digital dynamometer for each hand of every participant. A person who had low muscle strength, as well as low muscle mass was identified as having sarcopenia. The subjects were classified into three groups according to the Minnesota Code (MC) as major, minor ECG abnormalities and participants with no abnormalities ECG.

Results: Of the 2,426 participants, 354 (14.6%) had major ECG abnormalities and 193 (8%) had minor ECG abnormalities. Sarcopenia was associated with an increased risk of major ECG abnormality in all models. After adjustment for confounders of CHD in full model, the OR for major ECG abnormality was 1.47 (95% CI 1.11–1.95) in those with sarcopenia. Low muscle strength and low muscle performance were both with an increased risk of major ECG abnormality in all models. Sarcopenia and low muscle strength increased 28% and 62% risk of any ECG abnormality in the full models [sarcopenia: 1.28(1.01–1.63), low muscle strength: 1.62(1.30–2.03)], respectively.

Conclusions: This study showed that sarcopenia and its components are associated with ECG abnormalities in Iranian older people. Although some older adults have higher cardiovascular risk factors, these data showed that further factors such as sarcopenia may be identified as a particular risk factor for future cardiovascular events. Therefore, sarcopenia could be added to the screening of the older population to reduce the risk of cardiovascular events.

Association between marijuana use and electrocardiographic abnormalities by middle age: the Coronary Artery Risk Development in Young Adults (CARDIA) study

AIMS

To evaluate the prevalence of electrocardiogram (ECG) abnormalities in marijuana users as an indirect measure of subclinical cardiovascular disease (CVD).

DESIGN

Longitudinal and cross-sectional secondary data analysis from the CARDIA (Coronary Artery Risk Development in Young Adults) study.

SETTING

Four communities in the United States.

PARTICIPANTS

A total of 2585 participants from the 5115 black and white men and women recruited at age 18-30 years in 1985 to 1986 in CARDIA.

MEASUREMENTS

ECG abnormalities coded as minor and major abnormalities with the Minnesota code of electrocardiographic findings at year 20. Self-reported current (past 30 days) and computed cumulative life-time marijuana use (one 'marijuana-year' corresponds to 365 days of use) through assessments every 2-5 years. We fitted logistic regression models adjusting for sex, race, center, education, age, tobacco smoking, physical activity, alcohol use and body mass index.

FINDINGS

Among the 2585 participants with an ECG at year 20, mean age was 46, 57% were women, 45% were black; 83% had past exposure to marijuana and 11% were using marijuana currently. One hundred and seventy-three participants (7%) had major abnormalities and 944 (37%) had minor abnormalities. Comparing current with never use in multivariable-adjusted models, the odds ratio (OR) for major ECG abnormalities was 0.60 [95% confidence interval (CI) = 0.32-1.15] and for minor ECG abnormalities 1.21 (95% CI = 0.87-1.68). Results did not change after stratifying by sex and race. Cumulative marijuana use was not associated with ECG abnormalities.

CONCLUSION

In a middle-aged US population, life-time cumulative and occasional current marijuana use were not associated with increases in electrocardiogram abnormalities. This adds to the growing body of evidence that occasional marijuana use and cardiovascular disease events and markers of subclinical atherosclerosis are not associated.

Prevalence of ECG abnormalities in people with type 2 diabetes: The Hoorn Diabetes Care System cohort

AIMS

The American Diabetes Association, and the joint European Society of Cardiology and European Association for the Study of Diabetes guidelines recommend a resting ECG in people with type 2 diabetes with hypertension or suspected cardiovascular disease (CVD). However, knowledge on the prevalence of ECG abnormalities is incomplete. We aimed to analyse the prevalence of ECG abnormalities and their cross-sectional associations with cardiovascular risk factors in people with type 2 diabetes.

METHODS

We used data of the Diabetes Care System cohort obtained in 2018. ECG abnormalities were defined using the Minnesota Classification and categorised into types of abnormalities. The prevalence was calculated for the total population (n = 8068) and the subgroup of people without a history of CVD (n = 6494). Logistic regression models were used to asses cross-sectional associations.

RESULTS

Approximately one-third of the total population had minor (16.0%) or major (13.1%) ECG abnormalities. Of the participants without a CVD history, approximately one-quarter had minor (14.9%) or major (9.1%) ECG abnormalities, and for those with hypertension or very high CVD risk, the prevalence was 27.5% and 39.6%, respectively. ECG abnormalities were significantly and consistently associated with established CVD risk factors.

CONCLUSIONS

Resting ECG abnormalities are common in all people with type 2 diabetes (29.1%), including those without a history of CVD (24.0%), and their prevalence is related to traditional cardiovascular risk factors such as older age, male sex, hypertension, lower HDL cholesterol, higher BMI, and smoking behaviour.

Effect of QT interval prolongation on cardiac arrest following liver transplantation and derivation of a risk index

Liver transplantation (LT) has a 4-fold higher risk of periprocedural cardiac arrest and ventricular arrhythmias (CA/VAs) compared with other noncardiac surgeries. Prolongation of the corrected QT interval (QTc) is common in patients with liver cirrhosis. Whether it is associated with an increased risk of CA/VAs following LT is unclear. Rates of 30-day CA/VAs post-LT were assessed in consecutive adults undergoing LT between 2010 and 2017. Pretransplant QTc was measured by a cardiologist blinded to clinical outcomes. Among 408 patients included, CA/VAs occurred in 26 patients (6.4%). QTc was significantly longer in CA/VA patients (475 ± 34 vs 450 ± 34 ms, P < .001). Optimal QTc cut-off for prediction of CA/VAs was ≥480 ms. After adjustment, QTc ≥480 ms remained the strongest predictor for the occurrence of CA/VAs (odds ratio [OR] 5.2, 95% confidence interval [CI] 2.2-12.6). A point-based cardiac arrest risk index (CARI) was derived with the bootstrap method for yielding optimism-corrected coefficients (2 points: QTc ≥480, 1 point: Model for End-Stage Liver Disease [MELD] ≥30, 1 point: age ≥65, and 1 point: male). CARI score ≥3 demonstrated moderate discrimination (c-statistic 0.79, optimism-corrected c-statistic 0.77) with appropriate calibration. QTc ≥480 ms was associated with a 5-fold increase in the risk of CA/VAs. The CARI score may identify patients at higher risk of these events. Whether heightened perioperative cardiac surveillance, avoidance of QT prolonging medications, or beta blockers could mitigate the risk of CA/VAs in this population merits further study.

Clinical Implications of Fragmented QRS Complex as an Outcome Predictor in Children with Idiopathic Dilated Cardiomyopathy

Fragmented QRS (fQRS) is an easily evaluated noninvasive parameter in electrocardiograms (ECGs) for predicting cardiac adverse events. Our study aimed to evaluate whether fQRS could be used as a risk factor to predict a major adverse cardiac event (MACE) in children with idiopathic dilated cardiomyopathy (DCM). Our retrospective study enrolled 63 patients aged ≤ 19 years who were newly diagnosed with idiopathic DCM at Samsung Medical Center from 2003 to 2014, and followed up until December 2018. Demographic data, ECGs, and echocardiography were reviewed and analyzed for their possible links with adverse outcomes. The median age was 14.0 months and the median length of follow-up was 65.0 months. Age, QRS duration, and ejection fraction in M-mode at diagnosis were significantly different between the fQRS and non-fQRS groups (P = 0.026; P = 0.001; and P = 0.020). Significant difference between the fQRS and non-fQRS groups was found in patients with a MACE (P = 0.016, odd ratio 3.643) or any arrhythmias (P = 0.008, odd ratio 6.563). The MACE-free survival rate showed a significant difference in terms of fQRS (P = 0.003; P = 0.007; and P = 0.027). In univariate analyses, age, QRS duration, corrected QT, positive fQRS, and the number of leads with fQRS were significant predictors of MACEs. Among the above factors, positive fQRS at diagnosis was a strongly significant predictor of adverse outcomes in multivariate analyses (hazards ratio 94.529, P = 0.001). Fragmented QRS complex at diagnosis could be used as a strong predictor for cardiac adverse outcomes in pediatric patients with idiopathic DCM.

Association Between ECG Abnormalities and Fatal Cardiovascular Disease Among Patients With and Without Severe Mental Illness

Background

ECG abnormalities are associated with adverse outcomes in the general population, but their prognostic significance in severe mental illness (SMI) remains unexplored. We investigated associations between no, minor, and major ECG abnormalities and fatal cardiovascular disease (CVD) among patients with SMI compared with controls without mental illness.

Methods and Results

We cross‐linked data from Danish nationwide registries and included primary care patients with digital ECGs from 2001 to 2015. Patients had SMI if they were diagnosed with schizophrenia, bipolar disorder, or severe depression before ECG recording. Controls were required to be without any prior mental illness or psychotropic medication use. Fatal CVD was assessed using hazard ratios (HRs) with 95% CIs and standardized 10‐year absolute risks. Of 346 552 patients, 10 028 had SMI (3%; median age, 54 years; male, 45%), and 336 524 were controls (97%; median age, 56 years; male, 48%). We observed an interaction between SMI and ECG abnormalities on fatal CVD (P<0.001). Severe mental illness was associated with fatal CVD across no (HR, 2.17; 95% CI, 1.95–2.43), minor (HR, 1.90; 95% CI, 1.49–2.42), and major (HR, 1.40; 95% CI, 1.26–1.55) ECG abnormalities compared with controls. Across age‐ and sex‐specific subgroups, SMI patients with ECG abnormalities but no CVD at baseline had highest standardized 10‐year absolute risks of fatal CVD.

Conclusions

ECG abnormalities conferred a poorer prognosis among patients with SMI compared with controls without mental illness. SMI patients with ECG abnormalities but no CVD represent a high‐risk population that may benefit from greater surveillance and risk management.

Influence of Optimization Design Based on Artificial Intelligence and Internet of Things on the Electrocardiogram Monitoring System

With the increasing emphasis on remote electrocardiogram (ECG) monitoring, a variety of wearable remote ECG monitoring systems have been developed. However, most of these systems need improvement in terms of efficiency, stability, and accuracy. In this study, the performance of an ECG monitoring system is optimized by improving various aspects of the system. These aspects include the following: the judgment, marking, and annotation of ECG reports using artificial intelligence (AI) technology; the use of Internet of Things (IoT) to connect all the devices of the system and transmit data and information; and the use of a cloud platform for the uploading, storage, calculation, and analysis of patient data. The use of AI improves the accuracy and efficiency of ECG reports and solves the problem of the shortage and uneven distribution of high-quality medical resources. IoT technology ensures the good performance of remote ECG monitoring systems in terms of instantaneity and rapidity and, thus, guarantees the maximum utilization efficiency of high-quality medical resources. Through the optimization of remote ECG monitoring systems with AI and IoT technology, the operating efficiency, accuracy of signal detection, and system stability have been greatly improved, thereby establishing an excellent health monitoring and auxiliary diagnostic platform for medical workers and patients.

Prevalences and associated factors of electrocardiographic abnormalities in Chinese adults: a cross-sectional study

Background

Electrocardiogram (ECG) is widely used to screen cardiac diseases. To date, no large population study has provided estimates of the prevalences of ECG findings in China. We aim to investigate the prevalences and associated factors of ECG abnormalities in a general population of Chinese adults.

Methods

ECG data were obtained from 34,965 participants in the 2007–2008 China National Diabetes and Metabolic Disorders Study. ECG abnormalities were classified according to the Minnesota coding (MC) criteria. Prevalences of variant ECG abnormalities were calculated. The associations between ECG abnormalities and gender, age and other risk factors for cardiovascular diseases (CVD) were analyzed by multivariate logistic regression test.

Results

The prevalences of major arrhythmias were 1.70, 2.37 and 1.04% in the whole population, men and women, respectively. Atrial fibrillation/flutter was found in 0.35% of men and 0.20% of women. ST depression and T abnormalities accounted for 10.96, 7.54 and 14.32% in the whole population, men and women, respectively. Independent of gender and other CVD risk factors, older age significantly increased the odds of having atrial fibrillation/flutter, complete left bundle branch block, complete right bundle branch block, sinus tachycardia, atrial/junctional/ventricular premature beats, ST depression and T abnormalities, tall R wave left, left/right atrial hypertrophy, left axis deviation and low voltage. Hypertension, overweight, obesity and hypercholesterolemia all independently increased the odds of having ST depression and T abnormalities. History of cardiovascular/cerebrovascular diseases was positively associated with major arrhythmias, ST depression and T abnormalities and tall R wave left.

Conclusions

This study provides estimates of the prevalences of ECG findings in a large population of Chinese adults. Gender, age, CVD risk factors and history of cardiovascular/cerebrovascular diseases were significantly associated with ECG abnormalities.