Baroreflex sensitivity following acute upper-body exercise in the cold among stable coronary artery disease patients

Background: A cold environment and exercise separately affect the autonomic nervous system (ANS), baroreflex sensitivity (BRS), and blood pressure variability (BPV) but their combined effects on post-exercise recovery are not known. Our cross-over trial examined these responses following upper-body static and dynamic exercise performed in a cold and neutral environment in patients with coronary artery disease (CAD). Methods: 20 patients with stable coronary artery disease performed both graded static (10%-30% of maximal voluntary contraction) and dynamic (light, moderate and high perceived intensity) upper-body exercise at -15°C and +22°C for 30 min. Electrocardiogram and continuous blood pressure were measured to compute post-exercise (10 and 30 min after exercise) spectral powers of heart rate (HR), blood pressure variability and BRS at low (0.04-0.15 Hz) and high (0.15-0.4 Hz) frequencies. Results: Static upper-body exercise performed in a cold environment increased post-exercise high frequency (HF) spectral power of heart rate (HF RR) (p < 0.001) and reduced heart rate (p = 0.001) and low-to-high frequency (LF/HF) ratio (p = 0.006) more than in a neutral environment. In addition, post-exercise mean BRS (p = 0.015) and high frequency BRS (p = 0.041) increased more following static exercise in the cold than in a neutral environment. Dynamic upper-body exercise performed in a cold environment reduced post-exercise HF BRS (p = 0.019) and systolic blood pressure (p = 0.003). Conclusion: Static upper-body exercise in the cold increased post-exercise BRS and overall vagal activity but without reduced systolic blood pressure. Dynamic upper-body exercise in the cold reduced post-exercise vagal BRS but did not affect the other parameters. The influence of cold exposure on post-exercise autonomic and cardiovascular responses following static upper-body exercise require further studies. This information helps understanding why persons with cardiovascular diseases are vulnerable to low environmental temperature. ClinicalTrials.gov: NCT02855905 (04/08/2016).

Characteristics of women with ischemic sudden cardiac death

BACKGROUND

Sudden cardiac death (SCD) is a significant mode of death causing 15-20% of all deaths in high-income countries. Coronary artery disease (CAD) is the most common cause of SCD in both sexes, and SCD is often the first manifestation of underlying CAD in women. This case-control study aimed to determine the factors associated with SCD due to CAD in women.

METHODS

The study group consisted of women with CAD-related SCD (N = 888) derived from the Fingesture study conducted in Northern Finland from 1998 to 2017. All SCDs underwent medicolegal autopsy. The control group consisted of women with angiographically verified CAD without SCD occurring during the 5-year-follow-up (N = 610). To compare these groups, we used medical records, autopsy findings, echocardiograms, and electrocardiograms (ECGs).

RESULTS

Subjects with SCD were older (73.2 ± 11.3 vs. 68.8 ± 8.0, p < 0.001) and were more likely to be smokers or ex-smokers (37.1% vs. 27.6%, p = 0.045) compared to control patients. The proportion of subjects with prior myocardial infarction (MI) was higher in controls (46.9% vs. 41.4% in SCD subjects, p = 0.037), but in contrast, SCD subjects were more likely to have underlying silent MI (25.6% vs. 2.4% in CAD controls, p < 0.001). Left ventricular hypertrophy (LVH) was more common finding in SCD subjects (70.9% vs. 55.1% in controls, p < 0.001). Various electrocardiographic abnormalities were more common in subjects with SCD, including higher heart rate, atrial fibrillation, prolonged QTc interval, wide or fragmented QRS complex and early repolarization. The prevalence of Q waves and T inversions did not differ between the groups.

CONCLUSIONS

Underlying LVH and previous MI with myocardial scarring are common and often undiagnosed in women with CAD-related SCD. These results suggest that untreated CAD with concomitant myocardial disease is an important factor in SCD in women.

Lower hemoglobin levels associate with higher baroreflex sensitivity and heart rate variability

The aim of this study was to cross-sectionally examine whether hemoglobin (Hb) levels within the normal variation associate with heart rate variability (HRV) measures and baroreflex sensitivity (BRS). The study population included 733 Finnish subjects of the OPERA cohort (aged 41-59 yr, 53% males, 51.7% treated for hypertension) of whom HRV was measured from a standardized 45-min period and whose Hb levels were within the Finnish reference intervals. The low Hb tertile (mean Hb, 135 g/L) had an overall healthier metabolic profile compared with the high Hb tertile (mean Hb, 152 g/L). BRS was higher in the low Hb tertile compared with the high Hb tertile (P < 0.05). R-R interval (RRi) and standard deviation (SD) of the RRi (SDNN)index were the longest in the low Hb tertile regardless of posture. Of the spectral components of HRV, HF power was the highest in the low Hb tertile regardless of posture (P < 0.05). In a stepwise logistic regression model, BRS associated negatively with Hb levels after adjusting for covariates (B = -0.160 [-0.285; -0.035]). Similar associations were observed for SDNNindex when lying down (B = -0.105 [-0.207; -0.003]) and walking (B = -0.154 [-0.224; -0.083]). For HF power negative associations with Hb levels were observed when lying down (B = -0.110 [-0.180; -0.040]), sitting (B = -0.150 [-0.221; -0.079]), and in total analysis (B = -0.124 [-0.196; -0.053]). Overall, lower Hb levels associated independently with healthier cardiac autonomic function.NEW & NOTEWORTHY Heart rate variability (HRV) and baroreflex sensitivity (BRS), which can be measured noninvasively, can predict cardiac and metabolic diseases. Our findings show that within normal variation subjects with lower hemoglobin (Hb) levels have an overall healthier HRV profile and increased cardiac parasympathetic activity in middle age, independent of age, sex, smoking status, and key metabolic covariates. These findings support our previous findings that Hb levels can be used in assessing long-term risks for cardiometabolic diseases.

Endothelin-1 is associated with mortality that can be attenuated with high intensity statin therapy in patients with stable coronary artery disease

BACKGROUND

All coronary artery disease (CAD) patients do not benefit equally of secondary prevention. Individualized intensity of drug therapy is currently implemented in guidelines for CAD and diabetes. Novel biomarkers are needed to identify patient subgroups potentially benefitting from individual therapy. This study aimed to investigate endothelin-1 (ET-1) as a biomarker for increased risk of adverse events and to evaluate if medication could alleviate the risks in patients with high ET-1.

METHODS

A prospective observational cohort study ARTEMIS included 1946 patients with angiographically documented CAD. Blood samples and baseline data were collected at enrollment and the patients were followed for 11 years. Multivariable Cox regression was used to assess the association between circulating ET-1 level and all-cause mortality, cardiovascular (CV) death, non-CV death and sudden cardiac death (SCD).

RESULTS

Here we show an association of circulating ET-1 level with higher risk for all-cause mortality (HR: 2.06; 95% CI 1.5-2.83), CV death, non-CV death and SCD in patients with CAD. Importantly, high intensity statin therapy reduces the risk for all-cause mortality (adjusted HR: 0.05; 95% CI 0.01-0.38) and CV death (adjusted HR: 0.06; 95% CI 0.01-0.44) in patients with high ET-1, but not in patients with low ET-1. High intensity statin therapy does not associate with reduction of risk for non-CV death or SCD.

CONCLUSIONS

Our data suggests a prognostic value for high circulating ET-1 in patients with stable CAD. High intensity statin therapy associates with reduction of risk for all-cause mortality and CV death in CAD patients with high ET-1.

Use of psychotropic medication in victims of sudden cardiac death with nonischemic heart disease

BACKGROUND

Nonischemic heart disease (NIHD) is the underlying pathology in about 20% of sudden cardiac deaths (SCDs). Psychotropic medication has been reported as a risk factor for SCD among patients with coronary artery disease, but similar information concerning NIHD is scarce.

OBJECTIVES

We evaluated the use of psychotropic medication in victims of SCD due to NIHD and compared it to the general medication use in Finland.

METHOD

Study population was derived from the Finnish Genetic Study of Arrhythmic Events (Fingesture) (n = 5,869, mean age 65±12, 79% males; 1,404 victims of SCD due to NIHD, mean age 57±13, 77% males). All deaths occurred in Northern Finland during 1998-2017. All victims underwent a medico-legal autopsy. Data on use of medication was defined using post-mortem toxicology results and patient records. Subjects with neither toxicological analysis nor information of medication use available were excluded. Information on general medication use was derived from Finnish Statistics on Medicines 2018 and presented as defined daily dose/1000 inhabitants/day.

RESULTS

Psychotropic medication was used by 579 (41%) subjects with NIHD, whereas in the general population only 12% were estimated to use psychotropics. The results were similar in subgroups of psychotropic medication: 27% vs 2.3% for benzodiazepines, 19% vs 7.5% for antidepressants and 18% vs 2.2% for antipsychotics.

CONCLUSIONS

Use of psychotropic medication is common in victims of SCD due to NIHD compared to the general population.

Leisure time and occupational physical activity, overall and cardiovascular mortality: a 24-year follow-up in the OPERA study

BACKGROUND

In earlier studies, the health benefits of physical activity have only been related to leisure time physical activity (LTPA). High occupational physical activity (OPA) might even be harmful. The current physical activity recommendations do not separate the OPA and LTPA. We investigated the effect of LTPA and OPA on cardiovascular morbidity and mortality during long-term follow-up. We also examined how heavy work affects the benefits of leisure time exercise.

MATERIAL AND METHODS

The study was part of the OPERA study and the baseline examinations were conducted between the years 1991 and 1993. The Follow-up of events continued until the end of the year 2020. Study subjects (n = 1044) were divided into four groups according to their LTPA ("no exercise", "irregular", "regular" and "heavy regular") and into three groups according to their OPA ("no activity", "mild" and "heavy"). The amount of exercise was self-reported and the exercise status was defined at the beginning of the study. Study subjects were followed up for their overall mortality (26 years), fatal and non-fatal CVD events (24 and 20 years) and heart failure (20 years). The survival analysis was performed using Kaplan-Meier curves and Cox-proportional hazard models.

RESULTS

"Heavy" OPA group subjects belonging to the "irregular" (less than 1-2 times 30 min exercise per week) LTPA group experienced the lowest overall mortality compared to other LTPA groups. Also, overall mortality was increased in the "mild" (p = 0.002) and CVD mortality in the" heavy" (p = 0.005) OPA group compared to "no activity". The incidence of heart failure was increased in the "no exercise" LTPA compared to the "heavy regular" (p = 0.015) group.

CONCLUSIONS

Study subjects who were in physically demanding occupations (heavy OPA) seemed to benefit from less LTPA than WHO currently recommends. Thus we suggest targeting different LTPA recommendations to different OPA groups.

Carotid and femoral bruits as cardiovascular risk indicators in a middle-aged Finnish population: A 20-year prospective study

BACKGROUND

Effective treatment and prevention of cardiovascular (CV) diseases requires reliable methods of assessing individual CV event risk. Although standardized risk calculators like Systematic Coronary Risk Evaluation (SCORE) are sufficient in most instances, sometimes more specific clinical examination is needed to determine the most optimal intervention and its intensity.

AIM

To study whether carotid and femoral bruits provide prognostic information on CV events, CV mortality and all-cause mortality beyond traditional CV risk factors.

METHODS

1045 subjects (49.8% men), aged 51.3 ± 5.97 years were clinically examined in the beginning of 1990's. The subjects were followed for over 20 years and data on CV events and causes of deaths was collected.

RESULTS

During the follow-up period, 241 (23.1%) of the subjects died and 82 (34.6%) of the deaths were of CV origin. Carotid bruits were a significant risk factor for CV deaths only if subjects with previous CV events were included. After adjusting for age, sex, systolic blood pressure, smoking, diabetes, LDL cholesterol, coronary artery disease and stroke, carotid bruits posed a hazard ratio (HR) (95% confidence interval) of 4.15 (2.39-8.52) p<0.001 for CV deaths. After excluding subjects with previous CV events (after which n = 941) neither carotid nor femoral bruits were statistically associated with CV events or all-cause mortality. Adding carotid or femoral bruits in the baseline risk model with traditional CV risk factors did not improve C-statistic, reclassification, or discrimination of the subjects.

CONCLUSIONS

Carotid and femoral bruits do not provide clinically useful information in a pure primary prevention setting. Carotid bruits might be useful in evaluating the overall CV risk in a population where recurrent CV events may occur.

Sudden cardiac death after alcohol intake: classification and autopsy findings

Alcohol is known to have an immediate effect on cardiac rhythm, and previous studies have found that a notable proportion of sudden cardiac deaths (SCD) occur after alcohol intake. The objective of the present study was to investigate the association between the timing of alcohol intake and SCD. Our study population is drawn from the Fingesture study, which includes 5869 consecutive SCD cases from Northern Finland who underwent medicolegal autopsy 1998–2017. Toxicological analysis was performed if there was any suspicion of toxic exposure, or if there was no obvious immediate cause of SCD at autopsy. We found that 1563 (27%) of all SCD victims had alcohol in blood or urine at autopsy (mean age (61 ± 10 years, 88% male). Eighty-six percent of alcohol-related SCD victims had higher urine alcohol concentration than blood alcohol concentration, referring to the late-stage inebriation. These results suggest that the majority of alcohol-related SCDs occur at the late stage of inebriation.

Plaque histology and myocardial disease in sudden coronary death: the Fingesture study

AIMS

At least 50% of deaths due to coronary artery disease (CAD) are sudden cardiac deaths (SCDs), but the role of acute plaque complications on the incidence of sudden death in CAD is somewhat unclear. The present study aimed to investigate plaque histology and concomitant myocardial disease in sudden coronary death.

METHODS AND RESULTS

The study population is derived from the Fingesture study, which has collected data from 5869 consecutive autopsy-verified SCD victims in Northern Finland (population ≈600 000) between 1998 and 2017. In this substudy, histological examination of culprit lesions was performed in 600 SCD victims whose death was due to CAD. Determination of the cause of death was based on the combination of medical records, police reports, and autopsy data. Plaque histology was classified as either (i) plaque rupture or erosion, (ii) intraplaque haemorrhage, or (iii) stable plaque. The mean age of the study subjects was 64.9 ± 11.2 years, and 82% were male. Twenty-four per cent had plaque rupture or plaque erosion, 24% had an intraplaque haemorrhage, and 52% had a stable plaque. Myocardial hypertrophy was present in 78% and myocardial fibrosis in 93% of victims. The presence of myocardial hypertrophy or fibrosis was not associated with specific plaque histology.

CONCLUSION

Less than half of sudden deaths due to CAD had evidence of acute plaque complication, an observation which is contrary to historical perceptions. The prevalence of concomitant myocardial disease was high and independent of associated plaque morphology.

Temporal Trends in the Incidence and Characteristics of Sudden Cardiac Death Among Subjects Under 40 Years of Age in Northern Finland During 1998-2017

Background: Although the mean age of sudden cardiac death (SCD) victims has increased during recent decades, overall incidence has remained relatively stable. Small but very important proportion of SCDs occur in subjects under 40 years of age and temporal trends in the incidence and characteristics of SCD in this age group are not well known. Methods: The Fingesture study has prospectively gathered data from 5,869 consecutive autopsy verified SCD victims in Northern Finland during 1998-2017. On the basis of Finnish law, all who die unexpectedly undergo autopsy. Results: Out of total 5,869 SCDs, 160 occurred in subjects under 40 years of age (3%) indicating a total incidence of 2.9/100,000/year. Incidence decreased during the study period; 4.0/100,000/year (n=50) in 1998-2002, 3.7/100,000/year (n=45) in 2003-2007, 2.5/100,000/year (n=36) in 2008-2012 and 1.5/100,000/year (n=29) in 2013-2017. Coronary artery disease (CAD) was the cause of death in 46 SCD victims (29%). Among non-ischemic causes, most common were obesity-related hypertrophic myocardial disease (24%), primary myocardial fibrosis (19%) and hypertensive myocardial disease (6%). The incidence of SCD caused by CAD decreased as follows; 1.5/100,000/year in 1998-2002, 1.2/100,000/year in 2003-2007, 0.6/100,000/year in 2008-2012 and 0.2/100,000/year in 2013-2017. Proportion of male gender (81%) and obesity as a comorbidity (body mass index >30 kg/m2, 40%) remained relatively stable during the period (p=0.58 and p=0.79, respectively). Conclusions: The incidence of SCD in subjects under 40 years of age has decreased in Northern Finland during 1998-2017. According to autopsy data, most of the deaths are due to non-ischemic myocardial diseases and relative proportion of CAD has decreased.

Cardiovascular responses to dynamic and static upper-body exercise in a cold environment in coronary artery disease patients

Purpose

Upper-body exercise performed in a cold environment may increase cardiovascular strain, which could be detrimental to patients with coronary artery disease (CAD). This study compared cardiovascular responses of CAD patients during graded upper-body dynamic and static exercise in cold and neutral environments.

Methods

20 patients with stable CAD performed 30 min of progressive dynamic (light, moderate, and heavy rating of perceived exertion) and static (10, 15, 20, 25 and 30% of maximal voluntary contraction) upper body exercise in cold (− 15 °C) and neutral (+ 22 °C) environments. Heart rate (HR), blood pressure (BP) and electrocardiographic (ECG) responses were recorded and rate pressure product (RPP) calculated.

Results

Dynamic-graded upper-body exercise in the cold increased HR by 2.3–4.8% (p = 0.002–0.040), MAP by 3.9–5.9% (p = 0.038–0.454) and RPP by 18.1–24.4% (p = 0.002–0.020) when compared to the neutral environment. Static graded upper-body exercise in the cold resulted in higher MAP (6.3–9.1%; p = 0.000–0.014), lower HR (4.1–7.2%; p = 0.009–0.033), but unaltered RPP compared to a neutral environment. Heavy dynamic exercise resulted in ST depression that was not related to temperature. Otherwise, ECG was largely unaltered during exercise in either thermal condition.

Conclusions

Dynamic- and static-graded upper-body exercise in the cold involves higher cardiovascular strain compared with a neutral environment among patients with stable CAD. However, no marked changes in electric cardiac function were observed. The results support the use of upper-body exercise in the cold in patients with stable CAD.

Trial registration

Clinical trial registration NCT02855905 August 2016.

Coronary Artery Disease as the Cause of Sudden Cardiac Death Among Victims < 50 Years of Age

Coronary artery disease (CAD) is the most common cause of sudden cardiac death (SCD). Atherosclerosis increases with age, but also many victims of SCD in young and middle-aged population have CAD at autopsy. The purpose of this study was to determine the characteristics and autopsy findings of SCD due to CAD among victims of SCD under the age of 50. Fingesture is a population-based study consisting of consecutive series of victims of autopsy verified SCD in Northern Finland between the years 1998 to 2017 (n = 5,869). Histological examinations were part of all autopsies and a toxicology investigation was performed if needed. Analyses included information accumulated from death certificates, medical records, autopsy data, standardized questionnaire to the closest family members of the victims of SCD and police reports of the conditions of the death. Overall, 10.4% of all SCDs occurred among victims under the age of 50 years (610 victims). Most common underlying cause of SCD among these younger SCD victims was CAD (43.6%). The prevalence of CAD as the cause of SCD became more common in young SCD victims after the age of 35 years. The mean age of ischemic SCD victims was 44±5 years and most were men (89.5%). Most victims (90.2%) had no clinical diagnosis of CAD, however 33.8% had an autopsy evidence of silent myocardial infarction. SCD occurred during physical activity in 24.1%. Three-vessel disease was detected in 44.4% of the study victims. Cardiac hypertrophy (58.3%) and myocardial fibrosis (82.6%) were also common. At least 1 cardiovascular risk factor was present in 64.7% of SCD victims. In conclusion, most SCDs among victims < 50 years of age are due to CAD.

Central aortic hemodynamics following acute lower and upper-body exercise in a cold environment among patients with coronary artery disease

Exercise is beneficial to cardiovascular health, evidenced by reduced post-exercise central aortic blood pressure (BP) and wave reflection. We assessed if post-exercise central hemodynamics are modified due to an altered thermal state related to exercise in the cold in patients with coronary artery disease (CAD). CAD patients (n = 11) performed moderate-intensity lower-body exercise (walking at 65–70% of HR_max) and rested in neutral (+ 22 °C) and cold (− 15 °C) conditions. In another protocol, CAD patients (n = 15) performed static (five 1.5 min work cycles, 10–30% of maximal voluntary contraction) and dynamic (three 5 min workloads, 56–80% of HR_max) upper-body exercise at the same temperatures. Both datasets consisted of four 30-min exposures administered in random order. Central aortic BP and augmentation index (AI) were noninvasively assessed via pulse wave analyses prior to and 25 min after these interventions. Lower-body dynamic exercise decreased post-exercise central systolic BP (6–10 mmHg, p < 0.001) and AI (1–6%, p < 0.001) both after cold and neutral and conditions. Dynamic upper-body exercise lowered central systolic BP (2–4 mmHg, p < 0.001) after exposure to both temperatures. In contrast, static upper-body exercise increased central systolic BP after exposure to cold (7 ± 6 mmHg, p < 0.001). Acute dynamic lower and upper-body exercise mainly lowers post-exercise central BP in CAD patients irrespective of the environmental temperature. In contrast, central systolic BP was elevated after static exercise in cold. CAD patients likely benefit from year-round dynamic exercise, but hemodynamic responses following static exercise in a cold environment should be examined further.

Clinical trials.gov: NCT02855905 04/08/2016.

Early Growth Patterns and Cardiac Structure and Function at Midlife: Northern Finland 1966 Birth Cohort Study

OBJECTIVES

To evaluate the influence of early growth patterns that have previously been associated with later cardiometabolic risk on cardiac left ventricular (LV) structure and function in midlife.

STUDY DESIGN

A subpopulation of the Northern Finland Birth Cohort 1966 took part in follow-up, including echocardiography (n = 1155) at the age of 46 years. Body mass index (BMI) growth curves were modeled based on frequent anthropometric measurements in childhood. Age and BMI at adiposity peak (n = 482, mean age 9.0 months) and at adiposity rebound (n = 586, mean age 5.8 years) were determined. Results are reported as unstandardized beta (β) or OR with 95% CIs for 1 SD increase in early growth variable.

RESULTS

Earlier adiposity rebound was associated with increased LV mass index (β = -4.10 g/m² (-6.9, -1.3); P = .004) and LV end-diastolic volume index (β = -2.36 mL/m² (-3.9, -0.84); P = .002) as well as with eccentric LV hypertrophy (OR 0.54 [0.38, 0.77]; P = .001) in adulthood in males. BMI at adiposity rebound was directly associated with LV mass index (β = 2.33 g/m² [0.80, 3.9]; P = .003). Higher BMI at both adiposity peak and at adiposity rebound were associated with greater LV end-diastolic volume index (β = 1.47 mL/m²; [0.51, 2.4], β = 1.28 mL/m² [0.41, 2.2], respectively) and also with eccentric LV hypertrophy (OR 1.41 [1.10, 1.82], OR 1.53 [1.23, 1.91], respectively) and LV concentric remodeling (OR 1.38 [1.02, 1.87], OR 1.40 [1.06, 1.83], respectively) in adulthood (P < .05 for all). These relationships were only partly mediated by adult BMI.

CONCLUSIONS

Early growth patterns in infancy and childhood contribute to cardiac structure at midlife.

Physical Activity and the Risk for Sudden Cardiac Death in Patients With Coronary Artery Disease

BACKGROUND

The association between leisure-time physical activity (LTPA) and the risk of sudden cardiac death (SCD) in coronary artery disease patients is not well known. We aim to assess whether there is an association between LTPA and the risk of SCD and non-SCD in patients with coronary artery disease.

METHODS

Patients with angiographically verified coronary artery disease (n=1946) underwent a clinical evaluation, including filling in an LTPA questionnaire and extensive risk profiling at the baseline. The patients were classified into 4 groups according to LTPA: (1) inactive; (2) irregularly active; (3) active, exercise regularly 2× to 3× weekly; (4) highly active, exercise regularly ≥4× weekly. Age, sex, body mass index, left ventricular ejection fraction, type 2 diabetes mellitus, history of myocardial infarction, Canadian Cardiovascular Society grading of angina pectoris class, and exercise capacity were used as covariates in the multivariate Cox regression analysis.

RESULTS

During follow-up (median 6.3 years), 52 SCDs and 49 non-SCDs occurred. Inactive patients had increased risk for SCD compared with active patients (hazard ratio, 2.45 [95% CI, 1.01-5.98]; P<0.05). A significant LTPA×Canadian Cardiovascular Society grading of angina pectoris class interaction was observed in SCD risk (P=0.019 in highly active patients). LTPA was not associated with SCD in patients with Canadian Cardiovascular Society grading of angina pectoris class 1 (n=1107, 18 events). Among patients with Canadian Cardiovascular Society grading of angina pectoris class 2 or higher (n=839, 34 events), increased risk for SCD was encountered in highly active patients (hazard ratio, 7.46 [95% CI, 2.32-23.9]; P<0.001) and inactive patients (hazard ratio, 3.64 [95% CI, 1.16-11.5]; P<0.05) as compared to active patients. A linear association was observed between LTPA and non-SCD; those with high LTPA had the lowest risk for non-SCD.

CONCLUSIONS

Inactive coronary artery disease patients had increased risk for SCD. In subgroup analysis among symptomatic patients, the risk of SCD was increased in highly active and inactive patients compared with active patients. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01426685.

Sudden Cardiac Death in Women

BACKGROUND

Despite recent progress in profiling of risk for sudden cardiac death (SCD) and prevention and intervention of cardiac diseases, SCD remains a major cause of death. Among women, the incidence of SCD is significant, but lower than in men, particularly in the premenopausal and early postmenopausal years. Possibly, as a consequence of the difference in population burden, the mechanisms and risk markers of SCD are not as well defined for women. The aim of this study was to determine the autopsy findings and causes of death among women in a large SCD population. Additionally, we sought to classify prior ECG characteristics in male and female subjects with SCD.

METHODS

The Fingesture study has systematically collected clinical and autopsy data from subjects with SCD in Northern Finland between 1998 and 2017. The cohort consists of 5869 subjects with SCD. Previously recorded ECGs were available and analyzed in 1101 subjects (18.8% of total population; and in 25.3% of women).

RESULTS

Female subjects with SCD were significantly older than men: 70.1±13.1 years versus 63.5±11.8 years (mean ± standard deviation, P<0.001). The most frequently identified cause of death was ischemic heart disease in both sexes: 71.7% among women versus 75.7% among men, P=0.005. In contrast, women were more likely to have nonischemic cause of SCD than men (28.3% versus 24.3%, P=0.005). The prevalence of primary myocardial fibrosis was higher among women (5.2%, n=64) than in men (2.6%, n=120; P<0.001). Female subjects with SCD were more likely to have normal prior ECG tracings (22.2% versus 15.3% in men, P<0.001). A normal ECG was even more common among nonischemic female subjects with SCD (27.8% versus 16.2% in men, P=0.009). However, ECG markers of left ventricular hypertrophy, with or without repolarization abnormalities, were more common among women (8.2%; 17.9%) than in men (4.9%; 10.6%, P=0.036; P<0.001, respectively).

CONCLUSIONS

Women were considerably older at the time of SCD and more commonly had nonischemic causes. Women were also more likely to have a prior normal ECG than men, but an increased marker for SCD risk based on ECG criteria for left ventricular hypertrophy with repolarization abnormalities was more commonly observed in women.

Good safety practice in a randomized controlled trial (CadColdEx) involving increased cardiac workload in patients with coronary artery disease

Background

Methodological information acknowledging safety of cardiac patients in controlled medical experiments are lacking. The descriptive report presents one good practice for considering safety in a randomized controlled study involving augmented cardiovascular strain among persons with coronary artery disease (CAD).

Methods

The patients were pre-selected by a cardiologist according to strictly defined selection criteria. Further confirmation of eligibility included screening of health. In addition, assessments of physical capacity by a graded bicycle ergometer test were implemented and safety monitored by an exercise physiologist and medical doctor. In this context, an emergency simulation was also carried out. A total of 18 CAD patients each underwent four different experimental interventions where either temperature (+ 22 °C and − 15 °C) and the level of exercise (rest and brisk walking) were employed for 30 min in random order (72 experiments). Baseline (20 min) and follow-up (60 min) measurements were conducted resting at + 22 °C. ECG, and brachial blood pressure were measured and perceived exertion and symptoms of chest pain inquired throughout the experiments. An emergency nurse was responsible for the health monitoring and at least two persons followed the patient throughout the experiment. A medical doctor was available on call for consultation. The termination criteria followed the generally accepted international guidelines for exercise testing and were planned prior to the experiments.

Results

The exercise test simulation revealed risks requiring changes in the study design and emergency response. The cardiovascular responses of the controlled trials were related to irregular HR, ST-depression or post-exercise hypotension. These were expected and the majority could be dealt on site by the research personnel and on call consultation. Only one patient was encouraged to seek for external health care consultation.

Conclusions

Appropriate prospective design is a key to safe implementation of controlled studies involving cardiac patients and stimulation of cardiovascular function. This includes careful selection of participants, sufficient and knowledgeable staff, as well as identifying possible emergency situations and the required responses.

Trial registration

ClinicalTrials ID: NCT02855905.

Childhood growth patterns and cardiovascular autonomic modulation in midlife: Northern Finland 1966 Birth Cohort Study

OBJECTIVES

To test the hypothesis that age and body mass index (BMI) at BMI peak during infancy and at BMI rebound in childhood are related to cardiovascular autonomic modulation in adulthood.

METHODS

At the age of 46 years, a sample (n = 5861) of the participants of the Northern Finland Birth Cohort 1966 took part in follow-up examinations. Heart rate variability (HRV), baroreflex sensitivity (BRS) and low-frequency oscillations of systolic blood pressure (LF_SBP) were measured during sympathetic stimulus by standing. BMI at various ages was calculated from frequent anthropometric measurements collected from child welfare clinical records. BRS and LF_SBP were available for 1243 participants with BMI peak data and 1524 participants with BMI rebound data, and HRV for 2137 participants with BMI peak data and 2688 participants with BMI rebound data.

RESULTS

Age at BMI rebound had a significant inverse association with LF_SBP (beta = -0.071, p = 0.006) after all adjustments (p < 0.001) and was also directly associated with BRS (beta = 0.082, p = 0.001) independently of birth and maternal factors (p = 0.023). BMI at BMI peak and at BMI rebound was inversely associated with high-frequency component of HRV (HF) (beta = -0.045, p = 0.036 for BMI at peak; beta = -0.043, p = 0.024 for BMI at rebound) and directly associated with the ratio of low- and high-frequency components of HRV (LF/HF ratio) (beta = 0.084, p = < 0.001 for BMI at peak; beta = 0.069, p < 0.001 for BMI at rebound). These associations remained significant after all adjustments (p < 0.05 for all).

CONCLUSIONS

This novel study shows that younger age at BMI rebound and higher BMI at BMI peak and at BMI rebound are associated with higher levels in markers suggestive of augmented sympathetic and reduced vagal cardiovascular modulation in midlife.

Cardiovascular responses to cold and submaximal exercise in patients with coronary artery disease

Regular year-round exercise is recommended for patients with coronary artery disease (CAD). However, the combined effects of cold and moderate sustained exercise, both known to increase cardiac workload, on cardiovascular responses are not known. We tested the hypothesis that cardiac workload is increased, and evidence of ischemia would be observed during exercise in the cold in patients with CAD. Sixteen men (59.3 ± 7.0 yr, means ± SD) with stable CAD each underwent 4, 30 min exposures in a randomized order: seated rest and moderate-intensity exercise [walking, 60%-70% of max heart rate (HR)] performed at +22°C and -15°C. Systolic brachial blood pressure (SBP), HR, electrocardiogram (ECG), and skin temperatures were recorded throughout the intervention. Rate pressure product (RPP) and ECG parameters were obtained. The combined effects of cold and submaximal exercise were additive for SBP and RPP and synergistic for HR when compared with rest in a neutral environment. RPP (mmHg·beats/min) was 17% higher during exercise in the cold (18,080 ± 3540) compared with neutral (15,490 ± 2,940) conditions ( P = 0.001). Only a few ST depressions were detected during exercise but without an effect of ambient temperature. The corrected QT interval increased while exercising in the cold compared with neutral temperature ( P = 0.023). Recovery of postexercise blood pressure was similar regardless of temperature. Whole body exposure to cold during submaximal exercise results in higher cardiac workload compared with a neutral environment. Despite the higher RPP, no signs of myocardial ischemia or abnormal ECG responses were observed. The results of this study are useful for planning year-round exercise-based rehabilitation programs for stable CAD patients.

Association of sST2 and hs-CRP levels with new-onset atrial fibrillation in coronary artery disease

BACKGROUND

The data on biomarkers as predictors of atrial fibrillation (AF) in patients with coronary artery disease (CAD) are limited.

METHODS

A total of 1946 patients with CAD were recruited to the ARTEMIS study. At baseline, the study patients underwent clinical and echocardiographic examinations and had laboratory tests. The patients (n=1710) with the information about the occurrence of new-onset AF during the follow-up were included in the present analysis.

RESULTS

During 5.7±1.5years of follow-up, 143 (8.4%) patients developed a new-onset AF. Higher values of soluble ST2 (sST2) (20.2±10.8 vs. 17.5±7.2ng/mL, p=0.005), high-sensitivity troponin T (hs-TnT) (11.9±10.2 vs. 10.3±8.3ng/L, p=0.005), high-sensitivity C-reactive protein (hs-CRP) (3.3±5.9 vs. 2.0±4.4mg/L, p<0.001) and brain natriuretic peptide (BNP) (85.6±77.5 vs. 64.9±73.5ng/L, p<0.001) had significant associations with the occurrence of new-onset AF. In the Cox clinical hazards model, higher age (p=0.004), greater weight (p=0.045), larger left atrial diameter (p=0.001), use of asthma/chronic obstructive pulmonary disease medication (p=0.001) and lack of cholesterol lowering medication (p=0.008) had a significant association with the increased risk of AF. When the biomarkers were tested in the Cox clinical hazards model, sST2 (HR=1.025, 95% CI=1.007-1.043, p=0.006) and hs-CRP (HR=1.027, 95% CI=1.008-1.047, p=0.006) retained their significant power in predicting AF.

CONCLUSION

A biomarker of fibrosis, sST2, and a biomarker of inflammation, hs-CRP, predict the risk of occurrence of new-onset AF in patients with CAD. These biomarkers contributed to the discrimination of the AF risk model, but did not improve it markedly.

Non-alcoholic fatty liver disease with and without metabolic syndrome: Different long-term outcomes

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) and metabolic syndrome (MetS) are both shown to increase the risk of cardiovascular diseases and type 2 diabetes. However, there is a great overlap between these two diseases. The present study was aimed to examine the cardiovascular and metabolic prognosis of non-alcoholic fatty liver disease with and without metabolic syndrome.

METHODS

Middle-aged subjects (n=958) were divided into four subgroups, those with NAFLD and MetS, those with NAFLD or MetS, and healthy controls. The baseline characteristics of the subgroups were analyzed. The follow-up time for cardiovascular events was about 16years. After approximately 21years the cardiac ultrasound and laboratory parameters were re-analyzed and new type 2 diabetes cases were recorded.

RESULTS

Those with both diseases were at the greatest risk for cardiovascular events (p<0.001). Compared to healthy controls, only those with MetS, with or without NAFLD, were at increased risk for the development of type 2 diabetes (p<0.001) and for an increase in left ventricular mass index (p=0.001 and p=0.005, respectively). The cardiovascular and metabolic risk in subjects with NAFLD only was quite similar to that in healthy controls. The I148M variant of the patatin-like phospholipase domain-containing 3 gene (PNPLA3 polymorphism) was most present in those with NAFLD only (p=0.008).

CONCLUSIONS

NAFLD with MetS implies a considerable risk for cardiovascular diseases, type 2 diabetes and the increase of left ventricular mass index whereas NAFLD without MetS does not.

Association between Birth Characteristics and Cardiovascular Autonomic Function at Mid-Life

Background

Low birth weight is associated with an increased risk of cardiovascular diseases in adulthood. As abnormal cardiac autonomic function is a common feature in cardiovascular diseases, we tested the hypothesis that low birth weight may also be associated with poorer cardiac autonomic function in middle-aged subjects.

Methods

At the age of 46, the subjects of the Northern Finland Birth Cohort 1966 were invited to examinations including questionnaires about health status and life style and measurement of vagally-mediated heart rate variability (rMSSD) from R-R intervals (RRi) and spontaneous baroreflex sensitivity (BRS) in both seated and standing positions. Maternal parameters had been collected in 1965–1966 since the 16^th gestational week and birth variables immediately after delivery. For rMSSD, 1,799 men and 2,279 women without cardiorespiratory diseases and diabetes were included and 902 men and 1,020 women for BRS. The analyses were adjusted for maternal (age, anthropometry, socioeconomics, parity, gestational smoking) and adult variables (life style, anthropometry, blood pressure, glycemic and lipid status) potentially confounding the relationship between birth weight and autonomic function.

Results

In men, birth weight correlated negatively with seated (r = -0.058, p = 0.014) and standing rMSSD (r = -0.090, p<0.001), as well as with standing BRS (r = -0.092, p = 0.006). These observations were verified using relevant birth weight categories (<2,500 g; 2,500–3,999 g; ≥4,000 g). In women, birth weight was positively correlated with seated BRS (r = 0.081, p = 0.010), but none of the other measures of cardiovascular autonomic function. These correlations remained significant after adjustment for potential confounders (p<0.05 for all).

Conclusions

In men, higher birth weight was independently associated with poorer cardiac autonomic function at mid-life. Same association was not observed in women. Our findings suggest that higher, not lower, birth weight in males may contribute to less favourable cardiovascular autonomic regulation and potentially to an elevated cardiovascular risk in later life.

Antiepileptic medications and the risk for sudden cardiac death caused by an acute coronary event: a prospective case-control study

BACKGROUND

Epilepsy is associated with sudden death, but the reasons for this association are not well known. Objective We studied the role of antiepileptic drugs (AEDs) as a factor contributing to sudden cardiac death (SCD) in The Finnish Study of the Genotype and Phenotype Characteristics of Sudden Cardiac Death (FinGesture).

METHODS AND RESULTS

The FinGesture study compares the characteristics of victims of SCD caused by an autopsy-verified acute coronary event (cases) vs. survivors of an acute coronary event (ACS) (controls). The study population comprised 3737 cases (mean age 64 ± 12 y) and 3081 controls (mean age 66 ± 12 y). The use of AED was obtained from death certificates, autopsy/hospital records, national drug imbursement register, and interviews with the relatives. AEDs were more commonly used by the victims of SCD vs. controls (5.5% vs. 2.2%, adjusted odds ratio 2.7, 95% CI; 1.9-3.9; p < 0001). The use of AED for non-epilepsy indications was also more common in the cases than in controls (1.5% vs. 1.0%, p = 0.005).

CONCLUSION

A higher rate of AED was observed in victims of SCD than in a control group of ACS patients. Concomitant use of AED could be responsible for a small fraction of deaths due to acute coronary events. Key message Epilepsy has been associated with sudden cardiac death. The use of antiepileptic drugs seems to be associated with an increased risk of sudden cardiac death during a coronary event. Physicians should be aware of the risk related to antiepileptic drugs especially when used for other reasons than epilepsy.

Sudden cardiac death during physical exercise: Characteristics of victims and autopsy findings

OBJECTIVE

To provide data on the risk factors and characteristics of subjects who experience sudden cardiac death (SCD) during physical exercise.

METHODS AND RESULTS

We assessed the characteristics and the medico-legal autopsy findings of SCD victims who had experienced a witnessed fatal cardiac arrest at rest (n = 876) or in relation to physical exercise (n = 328) in the Finnish Study of Genotype and Phenotype Characteristics of SCD (FinGesture). A total of 876 (73%) witnessed SCDs occurred at rest (R group) and 328 (27%) during or immediately after physical exercise (PE group). Male gender was more common in the PE group compared to the R group (309/328, 94% versus 678/876, 77%, P < 0.001). Coronary artery disease was a more common structural heart disease than non-ischemic disease at autopsy when SCD was exercise-triggered (299/328, 91% versus 657/876, 75%, P < 0.001). Myocardial scarring and cardiac hypertrophy were more commonly found at autopsy in the PE group (194/328, 59% versus 370/876, 42%, P < 0.001; 243/328, 74% versus 585/876, 67%, P = 0.012, respectively). Skiing, cycling, and snow shoveling were the most common modes of exercise at the time of SCD.

CONCLUSIONS

SCD during or immediately after exercise is related to male gender, ischemic heart disease, cardiac hypertrophy, and myocardial scarring.

Heart Rate Turbulence and T-Wave Alternans in Patients with Coronary Artery Disease: The Influence of Diabetes

BACKGROUND

Patients with diabetes mellitus (DM) have a higher risk of sudden cardiac death. Factors associated with the risk profiles of coronary artery disease (CAD) patients with DM are not well established. Heart rate turbulence (HRT) and T-wave alternans (TWA) are often used to predict arrhythmia events.

METHODS AND RESULTS

HRT and TWA were measured in two independent groups: the ARTEMIS cohort study and the REFINE-ICD randomized trial. ARTEMIS assesses risk 3-12 months after coronary angiography in patients with CAD. The initial 1001 patients in ARTEMIS, 526 with and 475 without DM, are included in this analysis. REFINE-ICD compares usual care versus usual care plus ICD therapy in patients with left ventricular (LV) ejection fraction (EF) values of 36-50% assessed 2-15 months after myocardial infarction. The initial 275 patients screened in REFINE ICD are included in this analysis. Abnormal HRT plus TWA was more common in patients with versus without DM in ARTEMIS (125/526, 24% vs 63/475, 13%; P < 0.001) and REFINE-ICD (43/55, 78% vs 55/220, 25%; P < 0.001), respectively. Abnormal HRT plus TWA was also more common in patients with LVEF values < 50% (28%) vs ≥ 50% (18%; P < 0.001) in ARTEMIS and LVEF values below the population median of 42% (60/138, 43%) versus above the median (38/137, 28%; P < 0.01) in REFINE-ICD.

CONCLUSIONS

Abnormal HRT plus TWA is more common in CAD patients with DM compared with the patients without DM and is related to the severity of LV dysfunction.

CLINICAL TRIAL REGISTRATION INFORMATION

http://www.clinicaltrials.gov, NCT01426685; http://www.clinicaltrials.gov, NCT00673842.

Heart rate variability findings as a predictor of atrial fibrillation in middle-aged population

BACKGROUND

Autonomic nervous system modifies atrial electrophysiologic properties and arrhythmia vulnerability.

METHODS

Heart rate (HR) variability, an indicator of cardiac autonomic regulation, was measured in 784 subjects (mean age 51 ± 6 years; 54% males) from a standardized 45-minute period in a study population (n = 1,045), which consisted of randomly selected hypertensive and age- and sex-matched control subjects at the time of recruitment in 1991-1992 (the OPERA study).

RESULTS

During a mean follow-up of 16.5 ± 3.5 years, 76 subjects (9.7%) had developed symptomatic atrial fibrillation (AF), needing hospitalization. HR did not predict the occurrence of AF. Among the various spectral and time-domain HR variability indexes, only the low-frequency (LF) spectral component independently predicted AF. In the Cox regression analysis, the hazard ratio of reduced HR corrected LF (LFccv ≤ 1.59%, optimal cutoff from the ROC curve) in predicting the AF was 3.28 (95% CI: 2.06-5.24; P < 0.001). In the multiple Cox regression model, including LFccv and other predictors of AF, such as age, gender, hypertension, history of coronary artery disease, systolic and diastolic blood pressure, body mass index, β-blocking, angiotensin converting enzyme inhibitor and aspirin medication, left atrial size, left ventricular mass index, and left ventricular size obtained by echocardiography, only LFccv (hazard ratio 2.81; 95% CI: 1.64-4.81; P < 0.001), age (P = 0.006), and systolic blood pressure (P = 0.02) remained as significant predictors of AF.

CONCLUSIONS

Impaired LF oscillation of HR predicts new-onset AF in a middle-aged population emphasizing the important role of autonomic nervous system in the genesis of symptomatic AF.

Measurement of heart rate variability by methods based on nonlinear dynamics

Heart rate (HR) variability has been conventionally analyzed with time and frequency domain methods, which measure the overall magnitude of R-R interval fluctuations around its mean value or the magnitude of fluctuations in some predetermined frequencies. Analysis of HR dynamics by methods based on chaos theory and nonlinear system theory has gained recent interest. This interest is based on observations suggesting that the mechanisms involved in cardiovascular regulation likely interact with each other in a nonlinear way. Furthermore, recent observational studies suggest that some indexes describing nonlinear HR dynamics, such as fractal scaling exponents, may provide more powerful prognostic information than the traditional HR variability indexes. In particular, short-term fractal scaling exponent measured by detrended fluctuation analysis method has been shown to predict fatal cardiovascular events in various populations. Approximate entropy, a nonlinear index of HR dynamics, which describes the complexity of R-R interval behavior, has provided information on the vulnerability to atrial fibrillation. There are many other nonlinear indexes, eg, Lyapunov exponent and correlation dimensions, which also give information on the characteristics of HR dynamics, but their clinical utility is not well established. Although concepts of chaos theory, fractal mathematics, and complexity measures of HR behavior in relation to cardiovascular physiology or various cardiovascular events are still far away from clinical medicine, they are a fruitful area for future research to expand our knowledge concerning the behavior of cardiovascular oscillations in normal healthy conditions as well as in disease states.

In situ bioremediation through mulching of soil polluted by a copper-nickel smelter

Bioremediation of a heavy metal-polluted soil was investigated in a 3-yr field experiment by adding mulch to a polluted forest floor. The mulch consisted of a mixture of compost and woodchips. The remediation treatment decreased the toxicity of the soil solution to bacteria as determined by the [3H]-thymidine incorporation technique, that is, by measuring the growth rate of soil bacteria extracted from unpolluted humus after exposing them to soil solution containing heavy metals from the experimental plots. Canonical correlation analysis was performed in order to identify the chemical and microbiological changes in the soil. The pH of the mulched organic layer increased by one unit. The concentration of complexed Cu increased and that of free Cu2+ decreased in the soil solution from the mulch treatment. According to basal respiration and litter decomposition, microbial activity increased during the 3 yr following the remediation treatment. The [3H]-thymidine incorporation technique was also used to study the growth rate and tolerance of bacteria to Cu. The bacterial growth rate increased and the Cu tolerance decreased on the treated plots. The structure of the microbial community, as determined by phospholipid fatty acid (PLFA) analysis, remained unchanged. The results indicate that remediation of the polluted soil had occurred, and that adding a mulch to the forest floor is a suitable method for remediating heavy metal-polluted soil.

Effect of Cd-containing wood ash on the microflora of coniferous forest humus

The use of wood ash in forestry has been questioned because the cadmium (Cd) concentration of ash, which varies between 1 and 20 mg kg(-1) ash, exceeds the level allowed for fertilizers (3 mg kg(-1)) used in agriculture. To investigate the combined and separated effects of Cd and ash on the forest humus microflora, pumice or wood ash, spiked with a water-soluble (CdCl(2)) or -insoluble (CdO) form of Cd at three levels (0, 400 and 1000 mg kg(-1)), were applied at a fertilization level of 5000 kg ha(-1) in a laboratory microcosm study. The trial consisted of 60 microcosms (five replications per treatment), which were incubated in darkness at +20 degrees C and a constant relative air humidity of 60%. After two months the humus in the microcosms was sampled. Analyses of CO(2) evolution to measure the overall microbial activity and of phospholipid fatty acid (PLFA) pattern to measure microbial community structure were performed. The substrate-use patterns of Biolog EcoPlates were analyzed as a measure of bacterial functionality. Finally the bacterial (3)H-thymidine incorporation in the presence of different concentrations of Cd and the number of colony forming units (cfu) of bacteria on nutrient agar in the presence of 0, 5 and 20 mg Cd l(-1) agar were applied to measure Cd tolerance. The use of pumice (pH of humus under the pumice 4.0) did not induce any changes in the above variables compared to two untreated microcosms (humus pH 3.9). Pumice was therefore used to distribute the Cd evenly over the humus surface in order to estimate the possible effect of Cd without ash (pH of humus under the ash 7.0). The application of ash increased the microbial activity, changed the PLFA and substrate-use patterns and increased cfu compared to the humus under pumice. The form and level of Cd in the ash had no further effect on this result. In the humus under pumice the level, but not the form of Cd decreased the microbial activity and changed the PLFA pattern compared to the unspiked pumice. None of the treatments induced bacterial tolerance to Cd. Ash thus protected the humus microflora from the harmful effects of Cd.