Quantitative electrocardiographic measures and long-term mortality in exercise test patients with clinically normal resting electrocardiograms

Fluoxetine Treatment Decreases Cardiac Vagal Input and Alters the Serotonergic Modulation of the Parasympathetic Outflow in Diabetic Rats

Comorbid diabetes and depression constitutes a major health problem, worsening associated cardiovascular diseases. Fluoxetine's (antidepressant) role on cardiac diabetic complications remains unknown. We determined whether fluoxetine modifies cardiac vagal input and its serotonergic modulation in male Wistar diabetic rats. Diabetes was induced by alloxan and maintained for 28 days. Fluoxetine was administered the last 14 days (10 mg/kg/day; p.o). Bradycardia was obtained by vagal stimulation (3, 6 and 9 Hz) or i.v. acetylcholine administrations (1, 5 and 10 μg/kg). Fluoxetine treatment diminished vagally-induced bradycardia. Administration of 5-HT originated a dual action on the bradycardia, augmenting it at low doses and diminishing it at high doses, reproduced by 5-CT (5-HT_1/7 agonist). 5-CT did not alter the bradycardia induced by exogenous acetylcholine. Decrease of the vagally-induced bradycardia evoked by high doses of 5-HT and 5-CT was reproduced by L-694,247 (5-HT_1D agonist) and blocked by prior administration of LY310762 (5-HT_1D antagonist). Enhancement of the electrical-induced bradycardia by 5-CT (10 μg/kg) was abolished by pretreatment with SB269970 (5-HT₇ receptor antagonist). Thus, oral fluoxetine treatment originates a decrease in cardiac cholinergic activity and changes 5-HT modulation of bradycardic responses in diabetes: prejunctional 5-HT₇ receptors augment cholinergic-evoked bradycardic responses, whereas prejunctional 5-HT_1D receptors inhibit vagally-induced bradycardia.

Resting Electrocardiogram and Blood Pressure in Young Athletes and Non-Athletes: A 4-year follow-up

A follow-up data on electrocardiogram (ECG) and blood pressure (BP) changes in adolescent athletes are scarce. We compared ECG and BP between adolescent athletes and non-athletes in a 4-year follow-up. A total of 154 youth sports clubs (SC) in Finland and 100 secondary schools for comparison data participated in this observational follow-up study. Those who maintained or adopted SC participation are referred to as "Always athletes" (n=137), those who never participated in SC as "Never athletes" (n=108) and those who dropped out of SC during the follow-up as "Changers" (n=116). The mean age of the participants was 15.5 (0.6) years in all study groups at baseline. Resting ECG including heart rate, PR interval, QRS duration, QRS axis, QRS amplitude, T axis and QT interval and BP were measured from all participants at baseline and after follow-up. "Always athletes" had lower resting heart rate, more negative T-wave axis and higher QRS amplitude than "Never athletes" at baseline and at 4-years (P < 0.05). "Changers" had lower resting heart rate, more negative T-wave axis and higher QRS amplitude, systolic BP and pulse pressure than "Never athletes" at baseline (P < 0.05). None of the observed differences at baseline, were visible at 4-years (P > 0.05) except the difference in T-wave axis (P = 0.028). The significant group x time interaction between "Changers" and "Never athletes" was found for QRS amplitude (P = 0.017). Adolescent athletes have several training-induced cardiovascular adaptations, which return towards the levels of non-athletes after cessation of regular training. This article is protected by copyright. All rights reserved.

Resting Electrocardiogram and Blood Pressure in Young Endurance and Nonendurance Athletes and Nonathletes

CONTEXT

Much information is available on electrocardiogram (ECG) and blood pressure (BP) changes in senior athletes. However, corresponding data on adolescent athletes are scarce.

OBJECTIVE

To study the differences in resting ECG and BP values among adolescent endurance athletes, nonendurance athletes, and nonathletes.

DESIGN

Cross-sectional study.

SETTING

A total of 154 youth sports clubs in Finland and 100 secondary schools for comparison data.

PATIENTS OR OTHER PARTICIPANTS

We recruited young athletes (n = 410) aged 14 to 16 years in 10 popular sport disciplines, including winter and summer as well as team and individual sports, and categorized them as endurance or nonendurance sports. Comparison data for age-matched, non-sports club participants (n = 164) were collected via secondary schools.

MAIN OUTCOME MEASURE(S)

Resting ECG, including heart rate, PR interval, QRS duration, QRS axis, QRS amplitude, T axis, and QT interval as well as systolic and diastolic BPs.

RESULTS

No differences in any ECG variable of interest were found between the endurance and nonendurance athletes. The PR interval was longer in endurance athletes than in nonathletes (P = .05). The QRS amplitude (P = .03) was higher among nonendurance athletes than among nonathletes. Diastolic BP was lower among endurance (P = .002) and nonendurance (P = .02) athletes than among nonathletes. Endurance athletes (odds ratio [OR] = 2.85; 95% CI = 1.81, 4.50) and nonendurance athletes (OR = 2.19; 95% CI = 1.43, 3.35) were more likely to have sinus bradycardia than were nonathletes. Nonendurance athletes were more likely to have elevated systolic BP than were endurance athletes (OR = 1.70; 95% CI = 1.07, 2.72) and nonathletes (OR = 1.73; 95% CI = 1.04, 2.87).

CONCLUSIONS

Young athletes had similar ECG and BP findings independent of their sports. Physiological adaptations including sinus bradycardia, higher QRS amplitude, and lower diastolic BP, which are commonly seen in adult athletes, were also present in adolescent athletes.

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.

Health promotion activities of sports clubs and coaches, and health and health behaviours in youth participating in sports clubs: the Health Promoting Sports Club study

Introduction

Sports clubs form a potential setting for health promotion, but the research is limited. The aim of the Health Promoting Sports Club (HPSC) study was to elucidate the current health promotion activities of youth sports clubs and coaches, and to investigate the health behaviours and health status of youth participating in sports clubs compared to non-participants.

Methods and analysis

The study design employs cross-sectional multilevel and multimethod research with aspirations to a prospective cohort study in the next phase. The setting-based variables at sports clubs and coaching levels, and health behaviour variables at the individual level, are investigated using surveys; and total levels of physical activity are assessed using objective accelerometer measurements. Health status variables will be measured by preparticipation screening. The health promotion activity of sports clubs (n=154) is evaluated by club officials (n=313) and coaches (n=281). Coaches and young athletes aged 14–16 (n=759) years evaluate the coaches’ health promotion activity. The survey of the adolescents’ health behaviours consist of two data sets—the first is on their health behaviours and the second is on musculoskeletal complaints and injuries. Data are collected via sports clubs (759 participants) and schools 1650 (665 participants and 983 non-participants). 591 (418 athletes and 173 non-athletes) youth, have already participated in preparticipation screening. Screening consists of detailed personal medical history, electrocardiography, flow-volume spirometry, basic laboratory analyses and health status screening, including posture, muscle balance, and static and dynamic postural control tests, conducted by sports and exercise medicine specialists.

Ethics and dissemination

The HPSC study is carried out conforming with the declaration of Helsinki. Ethical approval was received from the Ethics Committee of Health Care District of Central Finland. The HPSC study is close-to-practice, which generates foundations for development work within youth sports clubs.

Investigation on cardiovascular risk prediction using physiological parameters

Cardiovascular disease (CVD) is the leading cause of death worldwide. Early prediction of CVD is urgently important for timely prevention and treatment. Incorporation or modification of new risk factors that have an additional independent prognostic value of existing prediction models is widely used for improving the performance of the prediction models. This paper is to investigate the physiological parameters that are used as risk factors for the prediction of cardiovascular events, as well as summarizing the current status on the medical devices for physiological tests and discuss the potential implications for promoting CVD prevention and treatment in the future. The results show that measures extracted from blood pressure, electrocardiogram, arterial stiffness, ankle-brachial blood pressure index (ABI), and blood glucose carry valuable information for the prediction of both long-term and near-term cardiovascular risk. However, the predictive values should be further validated by more comprehensive measures. Meanwhile, advancing unobtrusive technologies and wireless communication technologies allow on-site detection of the physiological information remotely in an out-of-hospital setting in real-time. In addition with computer modeling technologies and information fusion. It may allow for personalized, quantitative, and real-time assessment of sudden CVD events.

Epidemiology of arrhythmias and conduction disorders in older adults

Normal aging is associated with a multitude of changes in the cardiovascular system, including decreased compliance of blood vessels, mild concentric left ventricular hypertrophy, an increased contribution of atrial contraction to left ventricular filling, and a higher incidence of many cardiac arrhythmias, both bradyarrhythmias and tachyarrhythmias. Conduction disorders also become more common with age, and may either be asymptomatic, or cause hemodynamic changes requiring treatment. The epidemiology of common arrhythmias and conduction disorders in the elderly is reviewed.

Two-minute heart rate recovery after cycle ergometer exercise and all-cause mortality in middle-aged men

BACKGROUND

A slow heart rate recovery (HRR) after an exercise test is associated with an increased risk of all-cause mortality in asymptomatic individuals, but the data regarding additional prognostic information provided by HRR beyond other exercise test variables are inconsistent. We investigated the prognostic significance of HRR for premature death, particularly in relation to other exercise test variables.

METHODS

The study subjects were a representative population-based sample of 1102 men (42-61 years of age) without cardiovascular disease, cancer or diabetes. HRR was defined as the difference between maximal HR and HR 2 min after a maximal symptom-limited exercise test using a cycle ergometer. The association between HRR and premature mortality was examined with Cox regression models.

RESULTS

During an average follow-up of 18 years, 238 deaths occurred. HRR was an independent predictor of death [for a decrease of 12 beats min(-1) , relative risk (RR) 1.16, 95% CI 1.02-1.33, P = 0.02] after adjustment for age and established risk factors. When added in a Cox model with chronotropic response (decrease of 12 beats min(-1) , RR 1.09, 95% CI 0.93-1.27, P = 0.26) or cardiorespiratory fitness (decrease of 12 beats min(-1) , RR 1.12, 95% CI 0.98-1.30, P = 0.08), the association between a slow HRR and an increased risk of death was clearly weaker.

CONCLUSION

A slow 2-min HRR after a cycle ergometer exercise test was an independent predictor of death in healthy middle-aged men after accounting for demographic and clinical characteristics. However, it was no longer predictive after accounting for chronotropic response and exercise capacity.

Use of reclassification for assessment of improved prediction: an empirical evaluation

BACKGROUND

An increasing number of studies evaluate the ability of predictors to change risk stratification and alter medical decisions, i.e. reclassification performance. We examined the reported design and analysis of recent studies of reclassification and the robustness of their claims for improved reclassification.

METHODS

Two independent investigators searched PubMed and citations to the article that introduced the currently most popular reclassification metric (net reclassification index, NRI) to identify studies performing reclassification analysis (January 2006-January 2010). We focused on articles that included any analyses comparing the performance of a baseline predictive model vs the baseline model plus some additional predictor for a prospectively assessed outcome. We recorded information on the baseline model used, outcomes assessed, choice of risk thresholds and features of reclassification analyses.

RESULTS

Of 58 baseline models used in 51 eligible papers, only 14 (24%) were previously described, used as described and had same outcomes as originally intended. Calibration was examined in 53% of the studies. Sixteen studies (31%) provided a reference for the choice of risk thresholds and only six used the previously proposed categories or justified the use of alternative thresholds. Only 14 studies (27%) stated that the chosen risk thresholds had different therapeutic intervention implications. NRI was calculated in 38 studies and was smaller in studies with adequately referenced or justified risk thresholds vs others (P < 0.0001).

CONCLUSIONS

Reclassification studies would benefit from more rigorous methodological standards; otherwise claims for improved reclassification may remain spurious.

Electrocardiographic changes with the onset of diabetes and the impact of aerobic exercise training in the Zucker Diabetic Fatty (ZDF) rat

Background

Early markers of diabetic autonomic neuropathy (DAN) in an electrocardiogram (ECG) include elevated R wave amplitudes, widening of QT_c intervals and decreased heart rate variability (HRV). The severity of DAN has a direct relationship with mortality risk. Aerobic exercise training is a common recommendation for the delay and possible reversal of cardiac dysfunction. Limited research exists on ECG measures for the evaluation of aerobic exercise training in Zucker Diabetic Fatty (ZDF) rat, a model of type 2 diabetes. The objective of this study was to assess whether aerobic exercise training may attenuate diabetes induced ECG changes.

Methods

Male ZDF (obese fa/fa) and control Zucker (lean fa/+) rats were assigned to 4 groups: sedentary control (SC), sedentary diabetic (SD), exercised control (EC) and exercised diabetic (ED). The exercised groups began 7 weeks of treadmill training after the development of diabetes in the ED group. Baseline (prior to the training) and termination measurements included body weight, heart weight, blood glucose and glycated hemoglobin levels and ECG parameters. One way repeated measures ANOVA (group) analyzed within and between subject differences and interactions. Pearson coefficients and descriptive statistics described variable relationships and animal characteristics.

Results

Diabetes caused crucial changes in R wave amplitudes (p < 0.001), heart rate variability (p < 0.01), QT intervals (p < 0.001) and QT_c intervals (p < 0.001). R wave amplitude augmentation in SD rats from baseline to termination was ameliorated by exercise, resulting in R wave amplitude changes in ED animals similar to control rats. Aerobic exercise training neither attenuated QT or QT_c interval prolongation nor restored decreases in HRV in diabetic rats.

Conclusion

This study revealed alterations in R wave amplitudes, HRV, QT and QT_c intervals in ZDF rats. Of these changes, aerobic exercise training was able to correct R wave amplitude changes. In addition, exercise has beneficial effect in this diabetic rat model in regards to ECG correlates of left ventricular mass.

Application of the Seattle Heart Failure Model in ambulatory patients presented to an advanced heart failure therapeutics committee

BACKGROUND

We sought to assess the predictive value of the Seattle Heart Failure Model (SHFM) when applied to ambulatory patients with advanced heart failure (HF) presented to an advanced HF therapeutics committee at a tertiary care US institution.

METHODS AND RESULTS

We evaluated model discrimination and calibration in 215 consecutive ambulatory patients who were presented to the Cleveland Clinic advanced HF therapeutics committee between 2004 to 2007 for evaluation for advanced options including transplantation and ventricular assist device (VAD). Analyses were stratified by committee decision (not listed versus listed United Network of Organ Sharing [UNOS] Status 2). Eighty-five percent had 1 or no missing SHFM variables. The primary outcome was a composite of all-cause mortality, VAD, or urgent (UNOS Status 1) transplantation. During a median follow-up of 24 months, 68 died, 18 received VAD support, and 81 underwent heart transplantation. Discrimination was modest both for those not listed (c-index, 0.683 at 1 year and 0.648 at 2 years), and for those listed UNOS status 2 (c-index, 0.629 at 1 year and 0.628 at 2 years). Calibration was acceptable among those patients not listed for heart transplantation but with substantial underestimation of risk (ie, overestimation of survival free of VAD or urgent transplantation) among UNOS status 2 patients.

CONCLUSIONS

In ambulatory patients presented to an advanced HF therapeutics committee for evaluation for heart transplantation, the SHFM offers modest discrimination of risk for the primary composite outcome of mortality, VAD, or urgent transplantation, with underestimation of risk in those patients listed for nonurgent transplantation. Interpretation of risk prediction by the SHFM in this patient population must be done with caution.