Premorbid physical activity and prognosis after incident myocardial infarction: The atherosclerosis risk in communities study

BACKGROUND

High to moderate levels of physical activity (PA) are associated with low risk of incident cardiovascular disease. However, it is unclear whether the benefits of PA in midlife extend to cardiovascular health following myocardial infarction (MI) in later life.

METHODS

Among 1,111 Atherosclerosis Risk in Communities study participants with incident MI during Atherosclerosis Risk in Communities follow-up (mean age 73 [SD 9] years at MI, 54% men, 21% Black), PA on average 11.9 (SD 6.9) years prior to incident MI (premorbid PA) was evaluated as the average score of PA between visit 1 (1987-1989) and visit 3 (1993-1995) using a modified Baecke questionnaire. Total and domain-specific PA (sport, nonsport leisure, and work PA) was analyzed for associations with composite and individual outcomes of mortality, recurrent MI, and stroke after index MI using multivariable Cox models.

RESULTS

During a median follow-up of 4.6 (IQI 1.0-10.5) years after incident MI, 823 participants (74%) developed a composite outcome. The 10-year cumulative incidence of the composite outcome was lower in the highest, as compared to the lowest tertile of premorbid total PA (56% vs. 70%, respectively). This association remained statistically significant even after adjusting for potential confounders (adjusted hazard ratio [aHR] 0.80 [0.67-0.96] for the highest vs. lowest tertile). For individual outcomes, high premorbid total PA was associated with a low risk of recurrent MI (corresponding aHR 0.64 [0.44, 0.93]). When domain-specific PA was analyzed, similar results were seen for sport and work PA. The association was strongest in the first year following MI (e.g., aHR of composite outcome 0.66 [95% CI 0.47, 0.91] for the highest vs. lowest tertile of total PA).

CONCLUSIONS

Premorbid PA was associated positively with post-MI cardiovascular health. Our results demonstrate the additional prognostic advantages of PA beyond reducing the risk of incident MI.

Correlations between physical activity and quality of life in entrepreneurs from Wrocław, Poland

BACKGROUND

Limited physical activity is one of the main reasons for the rapid increase in the prevalence of diseases of affluence, which can lead to premature deaths in adults. Quality of life may be one of potential determinants of physical activity. The aim of this article is to identify the relationships between physical activity and quality of life in entrepreneurs from Wroclaw, Poland.

METHODS

A cross-sectional study was conducted on a group of 616 entrepreneurs (216 women and 400 men). A diagnostic survey method was used with a direct interview technique. The research tools included the International Physical Activity Questionnaire Short Form and the World Health Organization Quality of Life Questionnaire.

RESULTS

Among the studied entrepreneurs, along with their higher ratings of overall quality of life, the odds of high rather than low levels of physical activity increased nearly fivefold (OR 4.86, CI 3.34-7.07). Entrepreneurs with higher assessment levels of their perceived health condition were nearly twice as likely to report high rather than low physical activity levels (OR 1.92, CI 1.42-2.59). The conditional probability of high rather than low levels of physical activity also increased in the entrepreneurs with higher assessments of quality of life in the physical, psychological, social, and environmental domains, by 34%, 11%, 5%, and 6%, respectively.

CONCLUSION

Programs promoting physical activity among entrepreneurs, which focus on moderate and high intensity exercise, should be considered desirable in the context of the study findings. Activities aimed at improving quality of life in the physical and psychological domains as a potential determinant of the level of physical activity of entrepreneurs are also worth recommending.

Association between engagement in exercise training and peak cardiac biomarker concentrations following ST-elevation myocardial infarction

Background

Regular exercise training is an important factor in prevention of myocardial infarction (MI). However, little is known whether exercise engagement prior to MI is related to the magnitude of post-MI cardiac biomarker concentrations and clinical outcomes.

Objectives

We tested the hypothesis that exercise engagement in the week prior MI is related to lower cardiac biomarker concentrations following ST-elevated MI (STEMI).

Methods

We recruited hospitalised STEMI patients and assessed the amount of exercise engagement in the 7 days preceding MI onset using a validated questionnaire. Patients were classified as 'exercise' if they performed any vigorous exercise in the week prior MI, or as 'control' if they did not. Post-MI peak concentrations of high-sensitive cardiac troponin T (peak-hs-cTnT) and creatine kinase (peak-CK) were examined. We also explored whether exercise engagement prior MI is related to the clinical course (duration of hospitalisation and incidence of in-hospital, 30-day and 6-month major adverse cardiac events (reinfarction, target vessel revascularisation, cardiogenic shock or death)).

Results

In total, 98 STEMI patients were included, of which 16% (n=16) was classified as 'exercise', and 84% (n=82) as 'control'. Post-MI peak-hs-cTnT and peak-CK concentrations were lower in the exercise group (941 (645-2925) ng/mL; 477 (346-1402) U/L, respectively) compared with controls (3136 (1553-4969) ng/mL, p=0.010; 1055 (596-2019) U/L, p=0.016, respectively). During follow-up, no significant differences were found between both groups.

Conclusion

Engagement in exercise is associated with lower cardiac biomarker peak concentrations following STEMI. These data could provide further support for the cardiovascular health benefits of exercise training.

Sociodemographic and clinical variables as determinants of mortality and survival in patients with acute ST-elevation myocardial infarction in the Eastern Amazon

Background

The aim of this study was to analyze the influence of sociodemographic and clinical variables as determinants of mortality and survival in patients with ST-segment elevation acute myocardial infarction in the Eastern Amazon.

Design and methods

This observational, longitudinal, and retrospective study was conducted at the Gaspar Vianna Clinical Hospital Foundation in patients hospitalized from January 2017 to June 2020. Patients were divided into two groups: those who survived (G1) (n = 646) and those who died (G2) (n = 37). Sociodemographic and clinical variables associated with mortality and survival in these two groups were analyzed.

Results

Patients with STEMI who had the highest risk of death were often the oldest (G1: 61.58 ± 10.74 years; G2: 69.57 ± 9.02 years; t = -4.492; p = 0.001), with Killip III-IV classifications (OR = 0.13; 95% CI = 0.02-0.71; p = 0.03), and with diseases such as heart failure (OR = 0.07; 95% CI = 0.004-1.50; p = 0.168) or renal failure (OR = 0.03; 95% CI = 0.006-0.16; p = 0.0001). In addition, female sex (hazard ratio = 2.073; 95% CI = 1.413-5.170), Killip III-IV classifications (hazard ratio = 4.041; 95% CI = 1.703-18.883) and the presence of heart failure (hazard ratio = 34.102; 95% CI = 4.410-263.684) or renal failure (hazard ratio = 14.278; 95% CI = 3.275-62.248) shortened in-hospital survival.

Conclusions

Specific sociodemographic and clinical aspects influenced mortality and survival in patients with acute ST -elevation myocardial infarction.

Cardioprotection Attributed to Aerobic Exercise-Mediated Inhibition of ALCAT1 and Oxidative Stress-Induced Apoptosis in MI Rats

Cardiolipin (CL) plays a pivotal role in mitochondria-mediated apoptosis. Acyl-CoA: lysocardiolipin acyltransferase 1 (ALCAT1) can accelerate CL reactive oxygen production and cause mitochondrial damage. Although we have demonstrated that aerobic exercise significantly reduced ALCAT1 levels in MI mice, what is the temporal characteristic of ALCAT1 after MI? Little is known. Based on this, the effect of exercise on ALCAT1 in MI rats needs to be further verified. Therefore, this paper aimed to characterize ALCAT1 expression, and investigate the possible impact of exercise on ALCAT1 and its role in fibrosis, antioxidant capacity, and apoptosis in MI rats. Our results indicated that the potential utility of MI increased ALCAT1 expression within 1–6 h of MI, and serum CK and CKMB had significant effects in MI at 24 h, while LDH exerted an effect five days after MI. Furthermore, ALCAT1 expression was upregulated, oxidative capacity and excessive apoptosis were enhanced, and cardiac function was decreased after MI, and aerobic exercise can reverse these changes. These findings revealed a previously unknown endogenous cardiac injury factor, ALCAT1, and demonstrated that ALCAT1 damaged the heart of MI rats, and aerobic exercise reduced ALCAT1 expression, oxidative stress, and apoptosis after MI-induced cardiac injury in rats.

Prognostic implications for patients after myocardial infarction: an integrative literature review and in-depth interviews with patients and experts

Background

As patients with myocardial infarction (MI) survive for a long time after acute treatment, it is necessary to pay attention to the prevention of poor prognosis such as heart failure (HF). To identify the influencing factors of adverse clinical outcomes through a review of prospective cohort studies of post-MI patients, and to draw prognostic implications through in-depth interviews with post-MI patients who progressed to HF and clinical experts.

Methods

A mixed-method design was used that combined a scoping review of 21 prospective cohort studies, in-depth interviews with Korean post-MI patients with HF, and focus group interviews with cardiologists and nurses.

Results

A literature review showed that old age, diabetes, high Killip class, low left ventricular ejection fraction, recurrent MI, comorbidity of chronic disease and current smoking, and low socioeconomic status were identified as influencing factors of poor prognosis. Through interviews with post-MI patients, these influencing factors identified in the literature as well as a lack of disease awareness and lack of self-care were confirmed. Experts emphasized the importance of maintaining a healthy lifestyle after acute treatment with the recognition that it is a chronic disease that must go together for a lifetime.

Conclusion

This study confirmed the factors influencing poor prognosis after MI and the educational needs of post-MI patients with transition to HF. Healthcare providers should continue to monitor the risk group, which is expected to have a poor prognosis, along with education emphasizing the importance of self-care such as medication and lifestyle modification.

Increased protein S-nitrosylation in mitochondria: a key mechanism of exercise-induced cardioprotection

Endothelial nitric oxide synthase (eNOS) activation in the heart plays a key role in exercise-induced cardioprotection during ischemia-reperfusion, but the underlying mechanisms remain unknown. We hypothesized that the cardioprotective effect of exercise training could be explained by the re-localization of eNOS-dependent nitric oxide (NO)/S-nitrosylation signaling to mitochondria. By comparing exercised (5 days/week for 5 weeks) and sedentary Wistar rats, we found that exercise training increased eNOS level and activation by phosphorylation (at serine 1177) in mitochondria, but not in the cytosolic subfraction of cardiomyocytes. Using confocal microscopy, we confirmed that NO production in mitochondria was increased in response to H₂O₂ exposure in cardiomyocytes from exercised but not sedentary rats. Moreover, by S-nitrosoproteomic analysis, we identified several key S-nitrosylated proteins involved in mitochondrial function and cardioprotection. In agreement, we also observed that the increase in Ca²⁺ retention capacity by mitochondria isolated from the heart of exercised rats was abolished by exposure to the NOS inhibitor L-NAME or to the reducing agent ascorbate, known to denitrosylate proteins. Pre-incubation with ascorbate or L-NAME also increased mitochondrial reactive oxygen species production in cardiomyocytes from exercised but not from sedentary animals. We confirmed these results using isolated hearts perfused with L-NAME before ischemia-reperfusion. Altogether, these results strongly support the hypothesis that exercise training increases eNOS/NO/S-nitrosylation signaling in mitochondria, which might represent a key mechanism of exercise-induced cardioprotection.

Downregulation of Long Noncoding RNA LINC00261 Attenuates Myocardial Infarction through the miR-522-3p/Trinucleotide Repeat-Containing Gene 6a (TNRC6A) Axis

BACKGROUND

Myocardial infarction (MI) is cardiac tissue necrosis caused by acute and persistent ischemic hypoxia of the coronary arteries. This study is aimed at investigating the expression of long noncoding RNA (lncRNA) LINC00261 in MI and its effect on myocardial cells.

METHODS

qRT-PCR was performed to detect the expression levels of LINC00261, miR-522-3p, and TNRC6A in normal and MI cells. Western blotting analysis was performed to detect the expression of TNRC6A protein. Viability and apoptosis of myocardial cells after MI with the knockout of LINC00261 or TNRC6A were detected. The relationships among miR-522-3p, LINC00261, and TNRC6A in cardiomyocytes were evaluated using a double luciferase reporter gene assay. Hypoxic preconditioning in normal cells was used to construct a simulated MI environment to investigate the effect of LINC00261 on apoptosis of cardiac cells.

RESULTS

LINC00261 and TNRC6A were upregulated, while miR-522-3p was downregulated in coronary heart disease tissues with MI. Knockout of LINC00261 can increase the viability of cardiomyocytes and inhibit cell apoptosis. LINC00261 targets miR-522-3p in cardiomyocytes. In addition, miR-522-3p targets TNRC6A in cardiomyocytes. TNRC6A regulates cell viability and apoptosis of cardiomyocytes after MI, and TNRC6A-induced MI can be reversed by overexpression of miR-522-3p.

CONCLUSIONS

LINC00261 downregulated miR-522-3p in cardiomyocytes after MI by directly targeting miR-522-3p. TNRC6A is the direct target of miR-522-3p. Our results indicated that LINC00261 might serve as a therapeutic target for the treatment of MI.

Association of fatal myocardial infarction with past level of physical activity: a pooled analysis of cohort studies

AIMS

To assess the association between past level of physical activity (PA) and risk for death during the acute phase of myocardial infarction (MI) in a pooled analysis of cohort studies.

METHODS AND RESULTS

European cohorts including participants with a baseline assessment of PA, conventional cardiovascular (CV) risk factors, and available follow-up on MI and death were eligible. Patients with an incident MI were included. Leisure-time PA was grouped as sedentary (<7 MET-hours), low (7-16 MET-hours), moderate (16.1-32 MET-hours), or high (>32 MET-hours) based on calculated net weekly energy expenditure. The main outcome measures were instant and 28-day case fatality of MI. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using multivariate random-effects models. Adjustments for age, sex, CV risk factors, alcohol consumption, and socioeconomic status were made. From 10 cohorts including a total of 1 495 254 participants, 28 140 patients with an incident MI comprised the study population. A total of 4976 (17.7%) died within 28 days-of these 3101 (62.3%) were classified as instant fatal MI. Compared with sedentary individuals, those with a higher level of PA had lower adjusted odds of instant fatal MI: low PA [OR, 0.79 (95% CI, 0.60-1.04)], moderate PA [0.67 (0.51-0.89)], and high PA [0.55 (0.40-0.76)]. Similar results were found for 28-day fatal MI: low PA [0.85 (0.71-1.03)], moderate PA [0.64 (0.51-0.80)], and high PA [0.72 (0.51-1.00)]. A low-to-moderate degree of heterogeneity was detected in the analysis of instant fatal MI (I2 = 47.3%), but not in that of 28-day fatal MI (I2 = 0.0%).

CONCLUSION

A moderate-to-high level of PA was associated with a lower risk of instant and 28-day death in relation to a MI.

Self-care and related factors associated with left ventricular systolic function in patients under follow-up after myocardial infarction

BACKGROUND

Recent advances in treatment have led to long-term survival after myocardial infarction (MI), but subsequent complications such as heart failure have also increased, and, therefore, the relationship between prognosis and self-care needs to be investigated.

AIMS

This study aimed to confirm the relationship of potential variables affecting self-care of patients after MI and to determine whether self-care predicts left ventricular systolic function.

METHODS

Using a descriptive study design, a hypothetical model was constructed based on previous studies, and 191 post-MI patients were recruited from three university hospital outpatient clinics in Korea. The modified model was verified by constructing a structural equation model using AMOS version 24.0. The exogenous variables were illness perception, social support, and depression symptoms. The endogenous variables were self-efficacy, self-care compliance, and changes in left ventricular ejection fraction (LVEF).

RESULTS

The average patient age and disease duration were 66.3 (±11.5) years and 62.1 (±56.6) months, respectively. Self-care compliance was directly influenced by self-efficacy and indirectly affected by social support. Self-care compliance had a direct effect on LVEF changes, which was indirectly associated with illness perception, social support, and self-efficacy.

CONCLUSION

This study confirmed the direct effect of self-care compliance on changes in LVEF in patients under follow-up after MI. It is necessary to periodically monitor the degree of self-care in outpatients who are undergoing follow-up after MI to prevent a decrease in cardiac function. Counseling and education may be effective forms of social support to improve disease awareness and self-efficacy among patients with low self-care compliance.

Predictive Factors on the Incidence of Heart Failure in Patients with Ischemic Heart Disease: Using a 10-Year Population-Based Korea National Health Insurance Cohort Data

Early risk stratification and preventative strategies are required in patients with ischemic heart disease (IHD) to prevent heart failure (HF). We aimed to investigate the rate of progression to HF and to investigate the factors predicting the development of HF in a population with IHD for 10 years. A descriptive study was conducted using Korea National Health Insurance Service-National Sample Cohort (NHI-NSC) data (2005-2015). Among the patients diagnosed with IHD for the first time in 2005-2006, 2271 men and 2037 women who responded to the health check-up survey were finally selected. Cox Proportional Hazard regression analyses and the Kaplan-Meier survival analysis were used. HF incidence rates were 5.1% in men and 8.0% in women. The mean duration of transition to HF was 4.85 ± 2.73 years in men and 4.73 ± 2.73 years in women. The non-incidence rate of HF was higher in men than in women (Log-rank test, p = 0.0003). Bivariate analyses showed that older age, prevalence of hypertension and diabetes, less alcohol, and lower physical exercise were associated with the incidence of HF in both men and women. Multivariate analyses found that HF incidence in aged subjects ≥70 years was 1.46 times higher in men and 1.44 times higher in women compared to those in their 30 s (p < 0.001). Prevalence of hypertension reduced the incidence of HF by 0.78 and 0.87 for men and women, respectively. The prevalence of diabetes increased 1.23 times only in men. These findings suggest that special attention such as periodic counseling and education is needed to prevent progression to HF in elderly and diabetic patients during follow-up after IHD.

Exercise and cardiac health: physiological and molecular insights

The cardiac benefits of exercise have been recognized for centuries. Studies have undisputedly shown that regular exercise is beneficial for the cardiovascular system in young, old, healthy and diseased populations. For these reasons, physical activity has been recommended worldwide for cardiovascular disease prevention and treatment. Although the benefits of exercise are clear, understanding of the molecular triggers that orchestrate these effects remains incomplete and has been a topic of intense research in recent years. Here, we provide a comprehensive review of the cardiac effects of physical activity, beginning with a brief history of exercise in cardiovascular medicine and then discussing seminal work on the physiological effects of exercise in healthy, diseased and aged hearts. Later, we revisit pioneering work on the molecular mechanisms underlying the cardiac benefits of exercise, and we conclude with our view on the translational potential of this knowledge as a powerful platform for cardiovascular disease drug discovery.

Exercise training protects the heart against ischemia-reperfusion injury: A central role for mitochondria?

Ischemic heart disease is one of the main causes of morbidity and mortality worldwide. Physical exercise is an effective lifestyle intervention to reduce the risk factors for cardiovascular disease and also to improve cardiac function and survival in patients with ischemic heart disease. Among the strategies that contribute to reduce heart damages during ischemia and reperfusion, regular physical exercise is efficient both in rodent experimental models and in humans. However, the cellular and molecular mechanisms of the cardioprotective effects of exercise remain unclear. During ischemia and reperfusion, mitochondria are crucial players in cell death, but also in cell survival. Although exercise training can influence mitochondrial function, the consequences on heart sensitivity to ischemic insults remain elusive. In this review, we describe the effects of physical activity on cardiac mitochondria and their potential key role in exercise-induced cardioprotection against ischemia-reperfusion damage. Based on recent scientific data, we discuss the role of different pathways that might help to explain why mitochondria are a key target of exercise-induced cardioprotection.

Subjective reports of physical activity levels and sedentary time prior to hospital admission can predict utilization of hospital care and all-cause mortality among patients with cardiovascular disease

Background

In prevention, sedentary behaviour and physical activity have been associated with risk of cardiovascular disease and mortality. Less is known about associations with utilization of hospital care.

Aim

To investigate whether physical activity level and sedentary behaviour prior to cardiac ward admission can predict utilization of hospital care and mortality among patients with cardiovascular disease.

Methods

Longitudinal observational study including 1148 patients admitted and treated in cardiac wards in two hospitals. Subjective reports of physical activity levels and sedentary time prior to admission were collected during inpatient care and categorized as low, medium or high. The associations between physical activity level and sedentary time with hospital stay, readmission and mortality were analysed using linear, logistic and Cox regressions.

Results

Median hospital stay was 2.1 days. One higher step in the physical activity level, or lower sedentary time, was related to an approximately 0.9 days shorter hospital stay. Sixty per cent of patients were readmitted to hospital. The risk of being readmitted was lower for individuals reporting high physical activity and low sedentary time (odds ratios ranging between 0.44 and 0.91). A total of 200 deaths occurred during the study. Mortality was lower among those with high and medium physical activity levels and low sedentary time (hazard ratios ranging between 0.36 and 0.90).

Conclusion

Both physical activity level and sedentary time during the period preceding hospitalization for cardiac events were predictors of hospital utilization and mortality. This highlights the prognostic value of assessing patients’ physical activity and sedentary behaviour.

Prior exercise training and experimental myocardial infarction: A systematic review and meta-analysis

Exercising prior to experimental infarction may have beneficial effects on the heart. The objective of this study was to analyze studies on animals that had exercised prior to myocardial infarction and to examine any benefits through a systematic review and meta-analysis. The databases MEDLINE, Google Scholar, and Cochrane were consulted. We analyzed articles published between January 1978 and November 2018. From a total of 858 articles, 13 manuscripts were selected in this review. When animals exercised before experimental infarction, there was a reduction in mortality, a reduction in infarct size, improvements in cardiac function, and a better molecular balance between genes and proteins that exhibit cardiac protective effects. Analyzing heart weight/body weight, we observed the following results - Mean difference 95% CI - -0.02 [-0.61,0.57]. Meta-analysis of the infarct size (% of the left ventricle) revealed a statistically significant decrease in the size of the infarction in animals that exercised before myocardial infarction, in comparison with the sedentary animals -5.05 [-7.68, -2.40]. Analysis of the ejection fraction, measured by echo (%), revealed that animals that exercised before myocardial infarction exhibited higher and statistically significant measures, compared with sedentary animals 8.77 [3.87,13.66]. We conclude that exercise performed prior to experimental myocardial infarction confers cardiac benefits to animals.

Compositional analysis of the association between mortality and 24-hour movement behaviour from NHANES

AIMS

Previous prospective studies of the association between mortality and physical activity have generally not fully accounted for the interplay between movement behaviours. A compositional data modelling approach accounts for relative scale and co-dependency in time-use data across physical activity behaviours of the 24-hour day.

METHODS

A prospective analysis of the National Health and Nutrition Examination Survey 2005-2006 on N = 1468 adults (d = 135 deaths) in ages 50-79 years was undertaken using compositional Cox regression analysis. Daily time spent in sedentary behaviour, light intensity (LIPA) and moderate-to-vigorous physical activity (MVPA) was determined from waist-mounted accelerometer data (Actigraph 7164) and supplemented with self-reported sleep data to determine the daily time-use composition.

RESULTS

The composition of time spent in sedentary behaviour, LIPA, MVPA and sleep was associated with mortality rate after allowing for age and sex effects (p < 0.001), and remained significant when other lifestyle factors were added (p < 0.001). This was driven primarily by the preponderance of MVPA; however, significant changes are attributable to LIPA relative to sedentary behaviour and sleep, and sedentary behaviour relative to sleep. The final ratio ceased to be statistically significant after incorporating lifestyle factors. The preponderance of MVPA ceased to be statistically significant after incorporating health at outset and physical limitations on movement.

CONCLUSIONS

An association is inferred between survival rate and the physical activity composition of the day. The MVPA time share is important, but time spent in LIPA relative to sedentary behaviour and sleep is also a significant factor. Increased preponderance of MVPA may have detrimental associations at higher levels of MVPA.

Physical activity and risk of instant and 28-day case-fatality in myocardial infarction

BACKGROUND

While physical activity reduces risk of developing myocardial infarction (MI), it is unknown whether a history of physical activity is also protective of fatal arrhythmia and case-fatality in patients who have suffered an acute MI.

METHODS

104,801 individuals included in 2003-2014 in the Copenhagen General Population Study (CGPS), a prospective population-based study with self-reported leisure time physical activity (LTPA) in three categories measured at baseline, were followed until 2014 through national registries. The 1,517 individuals who suffered a first time MI during follow-up constituted the study population. Outcomes were fatal MI, defined as date of death same as date of MI (including out-of-hospital deaths) and 28-day fatality. Through multivariable analyses the association between baseline LTPA and outcomes were assessed adjusted for CVD risk factors.

RESULTS

Of 1,517 MI events, 117 (7.7%) were fatal and another 79 (5.6%) lead to death within 28 days. Median time from baseline to MI was 3.6 years (IQR 1.7-5.8). LTPA was associated with lower risk of fatal MI with odds ratios of 0.40 (95% CI: 0.22-0.73) for light and 0.41 (0.22-0.76) for moderate/high LTPA after multivariable adjustment with sedentary LTPA as reference. Age, alcohol-intake, education and smoking were identified as other predictors for fatal MI. We found no association between LTPA and 28-day case fatality.

CONCLUSIONS

Among individuals with MI, those that have engaged in any light or moderate physical activity were more likely to survive their MI. Results are consistent with effect of exercise preconditioning on risk of fatal arrhythmia.

Association between physical activity, occupational sitting time and mortality in a general population: An 18-year prospective survey in Tanushimaru, Japan

AIMS

It is well known that a decline in physical activity is associated with an increase of all-cause death including cardiovascular events and cancer. Few studies have examined the association between occupational sitting time and mortality. Therefore, we investigated this issue in a general population.

METHODS

Physical activity and occupational sitting time were measured using the Baecke physical activity questionnaire in 1999. The questionnaire generated indices in three physical activity categories: work, sport and leisure-time. A total physical activity index was calculated by adding these three indices. The Baecke physical activity questionnaire was able to evaluate occupational sitting time. Hazard ratios and 95% confidence intervals (CIs) were calculated using Cox's proportional hazard regression models.

RESULTS

We enrolled a total of 1680 participants, who were followed up for 15.9 ± 3.8 years. The final follow-up rate was 93%. During the follow-up period, 397 subjects died. A significant inverse association (p < 0.0001) was found between physical activity and mortality after adjustment for age and sex. Compared with lower levels of physical activity, the adjusted hazard ratio for mortality at higher levels of physical activity was 0.85 (95% CI: 0.78-0.92). Longer occupational sitting time was also significantly associated with higher mortality (p < 0.01). The adjusted hazard ratio for mortality at longer occupational sitting time was 1.16 (95% CI: 1.05-1.27). These findings were observed in males, but not in females.

CONCLUSIONS

Our data demonstrated that higher levels of physical activity are associated with a reduced risk of cancer and cardiovascular death. Further, longer occupational sitting time is associated with increased mortality.

Sedentary time, metabolic abnormalities, and all-cause mortality after myocardial infarction: A mediation analysis

BACKGROUND

Sedentary time was associated with myocardial infarction (MI) and metabolic diseases in previous studies.

PURPOSE

To investigate whether sedentary time measured before disease onset was associated with all-cause mortality among MI survivors and whether the sedentary time-mortality association was mediated by physical activity status and metabolic phenotypes.

METHODS

In this prospective community-based cohort including 101,510 Chinese adults, we used sedentary time, evaluated at 2006 (baseline), to predict further all-cause mortality among individuals who then developed new onset MI from 2006 to December 2013 ( n = 989). The post-MI mortality was ascertained after the first non-fatal MI until December 2014. We assessed the mediating effects of physical inactivity and metabolic factors on the sedentary time-mortality association.

RESULTS

During 7 years follow up, 180 deaths occurred among these participants with incident MI. Prolonged sedentary time was associated with a higher risk of mortality among MI survivors. The adjusted hazard ratio (HR) of mortality for sedentary time 4-8 hours/day versus <4 hours/day, was 1.62 (95% confidence interval (CI) 1.14-2.31). A high amount of sedentary time (>4 hours/day) and inactive physical activity had an increased risk of all-cause mortality (HR: 2.74, 95% CI 1.34-5.60), relative to those with sedentary time ≤4 hours/day and moderate/vigorous physical activity. Physical inactivity and metabolic factors mediated a small proportion (≤9.2 % for all) of the total association between sedentary time and post-MI mortality.

CONCLUSION

High sedentary time was significantly associated with all-cause mortality among MI survivors, independent of physical activity status and metabolic abnormalities.

Mechanisms of atrial fibrillation in athletes: what we know and what we do not know

Exercise is an emerging cause of atrial fibrillation (AF) in young individuals without coexisting cardiovascular risk factors. The causes of exercise-induced atrial fibrillation remain largely unknown, and conclusions are jeopardised by apparently conflicting data. Some components of the athlete's heart are known to be arrhythmogenic in other settings. Bradycardia, atrial dilatation and, possibly, atrial premature beats are therefore biologically plausible contributors to exercise-induced AF. Challenging findings in an animal model suggest that exercise might also prompt the development of atrial fibrosis, possibly due to cumulative minor structural damage after each exercise bout. However, there is very limited, indirect data supporting this hypothesis in athletes. Age, sex, the presence of comorbidities and cardiovascular risk factors, and genetic individual variability might serve to flag those athletes who are at the higher risk of exercise-induced AF. In this review, we will critically address current knowledge on the mechanisms of exercise-induced AF.

Signaling mediators modulated by cardioprotective interventions in healthy and diabetic myocardium with ischaemia-reperfusion injury

Ischaemic heart diseases are one of the major causes of death in the world. In most patients, ischaemic heart disease is coincident with other risk factors such as diabetes. Patients with diabetes are more prone to cardiac ischaemic dysfunctions including ischaemia-reperfusion injury. Ischaemic preconditioning, postconditioning and remote conditionings are reliable interventions to protect the myocardium against ischaemia-reperfusion injuries through activating various signaling pathways and intracellular mediators. Diabetes can disrupt the intracellular signaling cascades involved in these myocardial protections, and studies have revealed that cardioprotective effects of the conditioning interventions are diminished in the diabetic condition. The complex pathophysiology and poor prognosis of ischaemic heart disease among people with diabetes necessitate the investigation of the interaction of diabetes with ischaemia-reperfusion injury and cardioprotective mechanisms. Reducing the outcomes of ischaemia-reperfusion injury using targeted strategies would be particularly helpful in this population. In this study, we review the protective interventional signaling pathways and mediators which are activated by ischaemic conditioning strategies in healthy and diabetic myocardium with ischaemia-reperfusion injury.