Markers of cardiovascular autonomic dysfunction predict COPD in middle-aged subjects

Association between admission heart rate and in-hospital mortality in patients with acute exacerbation of chronic obstructive pulmonary disease and respiratory failure: a retrospective cohort study

BACKGROUND

Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) combined with respiratory failure (RF) is a chronic respiratory disease that seriously endangers human health. This study aimed to specifically evaluate the relationship between admission heart rate (AHR) and in-hospital mortality in patients with combined AECOPD and RF to better inform clinical treatment.

METHODS

This retrospective cohort study included 397 patients admitted to a Chinese hospital between January 2021 and March 2023. The primary outcome measure was all-cause in-hospital mortality. Multivariate logistic regression analyses were performed to calculate adjusted hazard ratios (OR) with corresponding 95% confidence intervals (CI), and curve fitting and threshold effect were performed to address nonlinear relationships.

RESULTS

In total, 397 patients with AECOPD/RF were screened. The mean (± SD) age of the study cohort was 72.6 ± 9.5 years, approximately 49.4% was female, and the overall in-hospital mortality rate was 5%. Multivariate logistic regression analysis and smooth curve fitting revealed a nonlinear association between AHR and in-hospital mortality in the study population, with 100 beats/min representing the inflection point. Left of the inflection point, the effect size (OR) was 0.474 (95% CI 0.016 ~ 13.683; p = 0.6635). On the right side, each 1 beat/min increase in AHR resulted in an effect size (OR) of 1.094 (95% CI 1.01 ~ 1.186; p = 0.0281).

CONCLUSIONS

Results of the present study demonstrated a nonlinear relationship between AHR and in-hospital mortality in patients with AECOPD/RF. When AHR was < 100 beats/min, it was not statistically significant; however, AHR > 100 beats/min was a predictor of potential mortality, which increased by 9.4% for every 1 beat/min increase in AHR.

Importance of resting heart rate

Resting heart rate is a determinant of cardiac output and physiological homeostasis. Although a simple, but critical, parameter, this vital sign predicts adverse outcomes, including mortality, and development of diseases in otherwise normal and healthy individuals. Temporal changes in heart rate can have valuable predictive capabilities. Heart rate can reflect disease severity in patients with various medical conditions. While heart rate represents a compilation of physiological inputs, including sympathetic and parasympathetic tone, aside from the underlying intrinsic sinus rate, how resting heart rate affects outcomes is uncertain. Mechanisms relating resting heart rate to outcomes may be disease-dependent but why resting heart rate in otherwise healthy, normal individuals affects outcomes remains obscure. For specific conditions, physiologically appropriate heart rate reductions may improve outcomes. However, to date, in the normal population, evidence that interventions aimed at reducing heart rate improves outcomes remains undefined. Emerging data suggest that reduction in heart rate via vagal activation and/or sympathetic inhibition is propitious.

Cardiovascular Autonomic Function and Incident Chronic Obstructive Pulmonary Disease Hospitalizations in Atherosclerosis Risk in Communities

Rationale: The autonomic nervous system extensively innervates the lungs, but its role in chronic obstructive pulmonary disease (COPD) outcomes has not been well studied. Objective: We assessed relationships between cardiovascular autonomic nervous system measures (heart rate variability [HRV] and orthostatic hypotension [OH]) and incident COPD hospitalization in the multicenter ARIC (Atherosclerosis Risk In Communities) study. Methods: We used Cox proportional hazards regression models to estimate hazard ratios and 95% confidence intervals between baseline (1987-1989) autonomic function measures (HRV measures from 2-minute electrocardiograms and OH variables) and incident COPD hospitalizations through 2019. Adjusted analyses included demographic data, smoking status, lung function, comorbidities, and physical activity. We also performed analyses stratified by baseline airflow obstruction. Results: Of the 11,625 participants, (mean age, 53.8 yr), 56.5% were female and 26.3% identified as Black. Baseline mean percentage predicted forced expiratory volume in 1 second was 94 ± 17% (standard deviation), and 2,599 participants (22.4%) had airflow obstruction. During a median follow-up time of 26.9 years, there were 2,406 incident COPD hospitalizations. Higher HRV (i.e., better autonomic function) was associated with a lower risk of incident COPD hospitalization. Markers of worse autonomic function (OH and greater orthostatic changes in systolic and diastolic blood pressure) were associated with a higher risk of incident COPD hospitalization (hazard ratio for the presence of OH, 1.5; 95% confidence interval, 1.25-1.92). In stratified analyses, results were more robust in participants without airflow obstruction at baseline. Conclusions: In this large multicenter prospective community cohort, better cardiovascular autonomic function at baseline was associated with a lower risk of subsequent hospitalization for COPD, particularly among participants without evidence of lung disease at baseline.

Sinus Tachycardia: a Multidisciplinary Expert Focused Review

Sinus tachycardia (ST) is ubiquitous, but its presence outside of normal physiological triggers in otherwise healthy individuals remains a commonly encountered phenomenon in medical practice. In many cases, ST can be readily explained by a current medical condition that precipitates an increase in the sinus rate, but ST at rest without physiological triggers may also represent a spectrum of normal. In other cases, ST may not have an easily explainable cause but may represent serious underlying pathology and can be associated with intolerable symptoms. The classification of ST, consideration of possible etiologies, as well as the decisions of when and how to intervene can be difficult. ST can be classified as secondary to a specific, usually treatable, medical condition (eg, pulmonary embolism, anemia, infection, or hyperthyroidism) or be related to several incompletely defined conditions (eg, inappropriate ST, postural tachycardia syndrome, mast cell disorder, or post-COVID syndrome). While cardiologists and cardiac electrophysiologists often evaluate patients with symptoms associated with persistent or paroxysmal ST, an optimal approach remains uncertain. Due to the many possible conditions associated with ST, and an overlap in medical specialists who see these patients, the inclusion of experts in different fields is essential for a more comprehensive understanding. This article is unique in that it was composed by international experts in Neurology, Psychology, Autonomic Medicine, Allergy and Immunology, Exercise Physiology, Pulmonology and Critical Care Medicine, Endocrinology, Cardiology, and Cardiac Electrophysiology in the hope that it will facilitate a more complete understanding and thereby result in the better care of patients with ST.

Orthostatic Hypotension: Management of a Complex, But Common, Medical Problem

Orthostatic hypotension (OH), a common, often overlooked, disorder with many causes, is associated with debilitating symptoms, falls, syncope, cognitive impairment, and risk of death. Chronic OH, a cardinal sign of autonomic dysfunction, increases with advancing age and is commonly associated with neurodegenerative and autoimmune diseases, diabetes, hypertension, heart failure, and kidney failure. Management typically involves a multidisciplinary, patient-centered, approach to arrive at an appropriate underlying diagnosis that is causing OH, treating accompanying conditions, and providing individually tailored pharmacological and nonpharmacological treatment. We propose a novel streamlined pathophysiological classification of OH; review the relationship between the cardiovascular disease continuum and OH; discuss OH-mediated end-organ damage; provide diagnostic and therapeutic algorithms to guide clinical decision making and patient care; identify current gaps in knowledge and try to define future research directions. Using a case-based learning approach, specific clinical scenarios are presented highlighting various presentations of OH to provide a practical guide to evaluate and manage patients who have OH.

Susceptibility to diarrhea is related to hemodynamic markers of sympathetic activation in the general population

Objectives: Functional gastrointestinal (GI) symptoms, such as IBS (irritable bowel syndrome), have been suggested to be associated with autonomic neuropathy. We therefore examined associations between hemodynamic indices of autonomic control, functional GI symptoms and stress in a population-based cohort.Methods and materials: The study included 2094 participants of the Malmö Offspring Study (mean age 40.6 ± 13.8 years, 53.9% women). 509 (24.3%) reported having GI symptoms the last 2 weeks, without having organic GI disease, and 347 subjects (16.6%) reported IBS. Office and ambulatory 24-h systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate were measured. Associations between hemodynamic parameters and abdominal pain, diarrhea, constipation, bloating and flatulence, vomiting and nausea and psychological well-being according to the visual analog scale for IBS (VAS-IBS), and stress, were performed by Spearman's correlation test and linear regression models.Results: Subjects who reported GI symptoms had lower office supine and standing DBP and lower 24 h SBP and DBP compared with those without GI symptoms. Regarding specific symptoms, diarrhea was correlated with 24-h measurements of SBP (rs = 0.197), DBP (rs = 0.173) and heart rate (rs = 0.134). Subjects with the most severe diarrhea had higher 24-h SBP (125.2 vs. 119.0 mmHg; p = .038), DBP (74.0 vs. 69.0 mmHg; p = .033) and heart rate (74.5 vs 71.1 beats/minute; p = .048), after adjustments for confounders, compared to the other. There were no associations between other GI symptoms, IBS, stress and hemodynamic alterations.Conclusion: Functional diarrhea was associated with hemodynamic indices of sympathetic activation, supporting a possible role of the autonomic nervous system in diarrhea.

Time-updated resting heart rate predicts mortality in patients with COPD

High resting heart rate (RHR) is associated with higher mortality in the general population and in cardiovascular disease. Less is known about the association of RHR with outcome in chronic obstructive pulmonary disease (COPD). In particular, the time-updated RHR (most recent value before the event) appears informative. This is the first study to investigate the association of time-updated RHR with mortality in COPD. We compared the baseline and time-updated RHR related to survival in 2218 COPD patients of the German COSYCONET cohort (COPD and Systemic Consequences-Comorbidities Network). Patients with a baseline RHR > 72 beats per minute (bmp) had a significantly (p = 0.049) higher all-cause mortality risk (adjusted hazard ratio (HR) of 1.37 (1.00-1.87) compared to baseline RHR ≤ 72 bpm. The time-updated RHR > 72 bpm was markedly superior (HR 1.79, 1.30-2.46, p = 0.001). Both, increased baseline and time-updated RHR, were independently associated with low FEV1, low TLCO, a history of diabetes, and medication with short-acting beta agonists (SABAs). In conclusion, increased time-updated RHR is associated with higher mortality in COPD independent of other predictors and superior to baseline RHR. Increased RHR is linked to lung function, comorbidities and medication. Whether RHR is an effective treatment target in COPD, needs to be proven in controlled trials.

High prevalence of undiagnosed COPD among patients evaluated for suspected myocardial ischaemia

Objective

Chronic obstructive pulmonary disease (COPD) and coronary artery disease (CAD) are leading causes of global morbidity and mortality. Despite the well-known comorbidity between COPD and CAD, the presence of COPD may be overlooked in patients undergoing coronary evaluation. We aimed to assess the prevalence of undiagnosed COPD among outpatients evaluated due to suspected myocardial ischemia.

Methods

Among 500 outpatients who were referred to myocardial perfusion imaging due to suspected stable myocardial ischaemia, 433 patients performed spirometry. Of these, a total of 400 subjects (age 66 years; 45% women) had no previous COPD diagnosis and were included in the current study. We compared the prevalence of previously undiagnosed COPD according to spirometry criteria from The Global Initiative for Chronic Obstructive Lung Disease (GOLD) or lower limit of normal (LLN) and reversible myocardial ischaemia according to symptoms and clinical factors.

Results

A total of 134 (GOLD criteria; 33.5 %) or 46 patients (LLN criteria; 11.5%) had previously undiagnosed COPD, whereas 55 patients (13.8 %) had reversible myocardial ischaemia. The presenting symptoms (chest discomfort, dyspnoea) did not differ between COPD, myocardial ischaemia and normal findings. Except for smoking, no clinical factors were consistently associated with previously undiagnosed COPD.

Conclusions

Among middle-aged outpatients evaluated due to suspected myocardial ischaemia, previously undiagnosed COPD is at least as common as reversible myocardial ischaemia and the presenting symptoms do not differentiate between these entities. Patients going through a coronary ischaemia evaluation should be additionally tested for COPD, especially if there is a positive history of smoking.