Prognostic significance of serial Q/ST-T changes by the Minnesota Code and Novacode in the Atherosclerosis Risk in Communities (ARIC) study

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.

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.

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.

Electrocardiographic Predictors of Mortality: Data from a Primary Care Tele-Electrocardiography Cohort of Brazilian Patients

Computerized electrocardiography (ECG) has been widely used and allows linkage to electronic medical records. The present study describes the development and clinical applications of an electronic cohort derived from a digital ECG database obtained by the Telehealth Network of Minas Gerais, Brazil, for the period 2010–2017, linked to the mortality data from the national information system, the Clinical Outcomes in Digital Electrocardiography (CODE) dataset. From 2,470,424 ECGs, 1,773,689 patients were identified. A total of 1,666,778 (94%) underwent a valid ECG recording for the period 2010 to 2017, with 1,558,421 patients over 16 years old; 40.2% were men, with a mean age of 51.7 [SD 17.6] years. During a mean follow-up of 3.7 years, the mortality rate was 3.3%. ECG abnormalities assessed were: atrial fibrillation (AF), right bundle branch block (RBBB), left bundle branch block (LBBB), atrioventricular block (AVB), and ventricular pre-excitation. Most ECG abnormalities (AF: Hazard ratio [HR] 2.10; 95% CI 2.03–2.17; RBBB: HR 1.32; 95%CI 1.27–1.36; LBBB: HR 1.69; 95% CI 1.62–1.76; first degree AVB: Relative survival [RS]: 0.76; 95% CI0.71–0.81; 2:1 AVB: RS 0.21 95% CI0.09–0.52; and RS 0.36; third degree AVB: 95% CI 0.26–0.49) were predictors of overall mortality, except for ventricular pre-excitation (HR 1.41; 95% CI 0.56–3.57) and Mobitz I AVB (RS 0.65; 95% CI 0.34–1.24). In conclusion, a large ECG database established by a telehealth network can be a useful tool for facilitating new advances in the fields of digital electrocardiography, clinical cardiology and cardiovascular epidemiology.

Association of T-wave abnormalities with major cardiovascular events in diabetes: the ACCORD trial

AIMS/HYPOTHESIS

T-wave abnormalities (TWA) are often found on ECG and signify abnormal ventricular repolarisation. While TWA have been shown to be associated with subclinical atherosclerosis, the relationship between TWA and hard cardiovascular endpoints is less clear and may differ in the presence of diabetes, so we sought to explore these associations in participants from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial.

METHODS

TWA were operationally defined as the presence of any Minnesota Codes 5-1 through 5-4 in any lead distribution. Multivariable Cox proportional hazards models were constructed to examine relationships between TWA and clinical cardiovascular events. Secondary analyses explored the risks conferred by major vs minor TWA, differential effects of TWA by anatomic localisation (anterolateral, inferior or anterior lead distributions), and differing associations in those with or without prevalent CVD.

RESULTS

Among 8176 eligible participants (mean 62.1 ± 6.3 SD years, 61.4% male), there were 3759 cardiovascular events, including 1430 deaths (473 of a cardiovascular aetiology), 474 heart failure events, 1452 major CHD events and 403 strokes. Participants with TWA had increased risks of all-cause mortality (HR 1.45 [95% CI 1.30, 1.62], p < 0.0001), cardiovascular mortality (HR 1.93 [1.59, 2.34], p = 0.0001), congestive heart failure (HR 2.04 [1.69, 2.48], p < 0.0001) and major CHD (HR 1.40 [1.26, 1.57], p < 0.0001), but no increased risk of stroke (HR 0.99 [0.80, 1.23], p = 0.95). Major TWA conferred a higher risk than minor TWA. When TWA were added to the UK Prospective Diabetes Study risk engine, there was improved discrimination for incident CHD events, but only for those with prevalent CVD (area under the receiver operating characteristic curve 0.5744 and 0.6030 with p = 0.0067). Adding TWA to the risk engine yielded improvements in reclassification that were of greater magnitude in those with prevalent CVD (net reclassification improvement [NRI] 0.24 [95% CI 0.16, 0.32] in those with prevalent CVD, NRI 0.14 [95% CI 0.07, 0.22] in those without prevalent CVD).

CONCLUSIONS/INTERPRETATION

The presence and magnitude of TWA are associated with increased risk of clinical cardiovascular events and mortality in individuals with diabetes and may have value in refining risk, particularly in those with prevalent CVD. Graphical abstract.

Reprint of "Electrocardiographic definition of silent myocardial infarction in population studies: A call to standardize the standards"

According to the American Heart Association, 170,000 new silent myocardial infarctions (SMI) occur annually in the United States. Prior studies from the general population also have shown that SMI is common, but the rates varied widely. Some studies reported SMI rates as low as 4% while others reported rates as high as 57% of the total MIs. Reports on the prognostic significance of SMI compared to clinically recognized MI also have been inconsistent. Although SMI could be detected using cardiac imaging, electrocardiogram (ECG) has been the most common method for detection of SMI in both clinical and research settings due to it is low-cost and wide availability. This report highlights certain ECG methodological aspects that need to be taken into consideration when interpreting findings from population studies addressing SMI. Examples from population studies will be used in this report to show how deviation and differences in applications of the ECG standard definitions of SMI, ECG processing methods, and the frequency of ECG recording in population studies could impact the results, which may explain the wide range of rates and inconsistent conclusions about the prognostic significance of SMI. A summary of the gaps in knowledge of the SMI research is provided. By highlighting the lack of uniform approach in defining SMI despite the availability of standard definitions and pointing out the gaps in knowledge, it is hoped that a call for standardizing the use of the current standards will emerge.

Major Electrocardiographic Abnormalities According to the Minnesota Coding System Among Brazilian Adults (from the ELSA-Brasil Cohort Study)

The electrocardiogram is a simple and useful clinical tool; nevertheless, few studies have evaluated the prevalence of electrocardiographic abnormalities in the Latin American population. This study aims to evaluate the major electrocardiographic abnormalities according to the Minnesota coding system in Brazilian adults, stratified by gender, age, race, and cardiovascular risk factors. Data from 14,424 adults (45.8% men, age 35 to 74 years) were obtained at baseline of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil), according to standardized protocol. The electrocardiogram were obtained with the Burdick Atria 6100 machine, stored on Pyramis System, automatically coded according to the Minnesota coding system by the Glasgow University software and then manually revised. Major abnormalities were more prevalent in men than women (11.3% and 7.9%, p <0.001). These differences were consistent through the different age groups, race, and number of cardiovascular risk factors. Electrocardiographic major abnormalities were more prevalent in black participants for both men (black: 15.1%, mixed: 10.4%, white: 11.1%, p = 0.001) and women (black: 10%, mixed: 7.6%, white: 7.2%, p = 0.004). In conclusion, in this large sample of Brazilian adults, the prevalence of major electrocardiographic abnormalities was higher among men, the elderly, black, and among people with more cardiovascular risk factors.

Usefulness of Maintaining a Normal Electrocardiogram Over Time for Predicting Cardiovascular Health

We hypothesized that maintaining a normal electrocardiogram (ECG) status over time is associated with low cardiovascular (CV) disease in a dose-response fashion and subsequently could be used to monitor programs aimed at promoting CV health. This analysis included 4,856 CV disease-free participants from the Atherosclerosis Risk in Communities study who had a normal ECG at baseline (1987 to 1989) and complete electrocardiographic data in subsequent 3 visits (1990 to 1992, 1993 to 1995, and 1996 to 1998). Participants were classified based on maintaining their normal ECG status during these 4 visits into "maintained," "not maintained," or "inconsistent" normal ECG status as defined by the Minnesota ECG classification. CV disease events (coronary heart disease, heart failure, and stroke) were adjudicated from Atherosclerosis Risk in Communities visit-4 through 2010. Over a median follow-up of 13.2 years, 885 CV disease events occurred. The incidence rate of CV disease events was lowest among study participants who maintained a normal ECG status, followed by those with an inconsistent pattern, and then those who did not maintain their normal ECG status (trend p value <0.001). Similarly, the greater the number of visits with a normal ECG status, the lower was the incidence rate of CV disease events (trend p value <0.001). Maintaining (vs not maintaining) a normal ECG status was associated with a lower risk of CV disease, which was lower than that observed in those with inconsistent normal ECG pattern (trend p value <0.01). In conclusion, maintaining a normal ECG status over time is associated with low risk of CV disease in a dose-response fashion, suggesting its potential use as a monitoring tool for programs promoting CV health.

Progression of Electrocardiographic Abnormalities in Type 1 Diabetes During 16 Years of Follow-up: The Epidemiology of Diabetes Interventions and Complications (EDIC) Study

BACKGROUND

The electrocardiogram (ECG) is an objective tool for cardiovascular disease (CVD) risk assessment.

METHODS AND RESULTS

We evaluated distribution of ECG abnormalities and risk factors for developing new abnormalities in 1314 patients with type 1 diabetes (T1D) from the Epidemiology of Diabetes Interventions and Complications (EDIC) study. Annual ECGs were centrally read. ECG abnormalities were classified as major and minor according to the Minnesota ECG Classification. At EDIC year 1 (baseline), 356 (27.1%) of the participants had at least 1 ECG abnormality (major or minor) whereas 26 (2%) had at least one major abnormality. During 16 years of follow-up, 1016 (77.3%) participants developed at least 1 new ECG abnormality (major or minor), whereas 172 (13.1%) developed at least 1 new major abnormality. Independent risk factors for developing new major ECG abnormalities were: age, current smoking, increased systolic blood pressure, and higher glycosylated hemoglobin (hazard ratio [HR] [95% CI]: 1.04 [1.02-1.06] per 1-year increase, 1.75 [1.22-2.53], 1.03 [1.01-1.05] per 1 mm Hg increase, and 1.16 [1.04-1.29] per 10% increase, respectively). Independent risk factors for developing any new ECG abnormalities (major or minor) were age and systolic blood pressure (HR [95% CI]: 1.02 [1.01-1.03] per 1-year increase and 1.01 [1.00-1.02] per 1 mm Hg increase, respectively).

CONCLUSIONS

New ECG abnormalities commonly occur in the course of T1D, consistent with the recognized increasing risk for CVD as patients age. Advanced age, increased systolic blood pressure, smoking, and higher HbA1c are independent risk factor for developing major ECG abnormalities, which underscores the importance of tight glucose control in T1D in addition to management of common CVD risk factors.

Abnormal electrocardiographic QRS transition zone and risk of mortality in individuals free of cardiovascular disease

AIMS

We examined the prognostic significance of abnormal electrocardiographic QRS transition zone (clockwise and counterclockwise horizontal rotations) in individuals free of cardiovascular disease (CVD).

METHODS AND RESULTS

A total of 5541 adults (age 53 ± 10.4 years, 54% women, 24% non-Hispanic black, 25% Hispanic) without CVD or any major electrocardiogram (ECG) abnormalities from the US Third National Health and Nutrition Examination Survey were included in this analysis. Clockwise and counterclockwise horizontal rotations were defined from standard 12-lead ECG using Minnesota ECG Classification. Mortality and cause of death were assessed through 2006. At baseline, 282 participants had clockwise rotation and 3500 had counterclockwise rotation. During a median follow of 14.6 years, 1229 deaths occurred of which 415 were due to CVD. In multivariable-adjusted Cox proportional hazard analysis and compared with normal rotation, clockwise rotation was significantly associated with increased risk of all-cause mortality {hazard ratio (HR) [95% confidence interval (CI)]: 1.43 (1.15-1.78); P = 0.002} and CVD mortality [HR (95% CI): 1.61 (1.09, 2.37) P = 0.016]. In contrast, counterclockwise rotation was associated with significantly lower risk of all-cause mortality [HR (95% CI): 0.86 (0.76, 0.97); P = 0.017] and non-significant association with CVD mortality [HR (95% CI): 1.07 (0.86, 1.33); P = 0.549]. These results were consistent in subgroup analysis stratified by age, sex, and race.

CONCLUSION

In a diverse community-based population free of CVD and compared with normal rotation, clockwise rotation was associated with increased risk of all-cause and CVD mortality while counterclockwise rotation was associated with lower risk of all-cause mortality and non-significant association with CVD mortality. These findings call for attention to these often neglected ECG markers, and probably call for revising the current definition of normal rotation.

Electrocardiogram as a screening tool in the general population: a strategic review

Sudden cardiac death (SCD) is a major public health concern, accounting for 400,000 deaths in the US each year. Clinical and autopsy studies have consistently demonstrated a predominant, common pathophysiology in Western populations, showing that the most common electrophysiological mechanism of SCD is ventricular fibrillation, and the most common pathologic substrate is coronary heart disease (CHD). In about half of SCD cases, death is the first clinical manifestation of CHD. Yet risk factors of SCD early in the natural history of conditions predisposing SCD have not been fully identified, and SCD risk stratification strategy in the general population has not been developed. ECG is an easily available, non-expensive and non-invasive tool, which carries valuable information on electrophysiological properties of the heart. However, traditional analysis of ECG includes very limited assessment of the arrhythmogenic substrate. In this review rationale for development of ECG SCD risk score for screening in the general population is discussed.

Desafios à implantação do centro de leitura de eletrocardiografia no ELSA-Brasil

O eletrocardiograma é um método estabelecido de avaliação cardiovascular de baixo custo utilizado há décadas em estudos epidemiológicos de grande porte. Apesar disso, sua utilização em estudos desse tipo se constitui em desafio, especialmente quando se pretende implantar Centro de Leitura próprio. Este artigo descreve o processo, dificuldades e desafios de implantação do Centro de Leitura em eletrocardiograma no Estudo Longitudinal de Saúde do Adulto (ELSA-Brasil). Dentre os aspectos discutidos, ressaltam-se: os critérios para escolha dos eletrocardiógrafos e da central de armazenamento e manejo dos aparelhos; o pessoal necessário; os procedimentos de aquisição e de transmissão dos eletrocardiogramas para o Centro de Leitura; os sistemas de codificação dos traçados, com ênfase para o código de Minnesota; os aspectos éticos e práticos relacionados à entrega dos laudos aos participantes do estudo; e os aspectos relacionados ao controle de qualidade.