Are Ambient Ultrafine, Accumulation Mode, and Fine Particles Associated with Adverse Cardiac Responses in Patients Undergoing Cardiac Rehabilitation?

Department of Community and Preventive Medicine, and.
Environmental Health Perspectives (Impact Factor: 7.98). 04/2012; 120(8):1162-9. DOI: 10.1289/ehp.1104262
Source: PubMed


Background: Mechanisms underlying previously reported air pollution and cardiovascular (CV) morbidity associations remain poorly understood.
Objectives: We examined associations between markers of pathways thought to underlie these air pollution and CV associations and ambient particle concentrations in postinfarction patients.
Methods: We studied 76 patients, from June 2006 to November 2009, who participated in a 10-week cardiac rehabilitation program following a recent (within 3 months) myocardial infarction or unstable angina. Ambient ultrafine particle (UFP; 10–100 nm), accumulation mode particle (AMP; 100–500 nm), and fine particle concentrations (PM2.5; ≤ 2.5 μm in aerodynamic diameter) were monitored continuously. Continuous Holter electrocardiogram (ECG) recordings were made before and during supervised, graded, twice weekly, exercise sessions. A venous blood sample was collected and blood pressure was measured before sessions.
Results: Using mixed effects models, we observed adverse changes in rMSSD [square root of the mean of the sum of the squared differences between adjacent normal-to-normal (NN) intervals], SDNN (standard deviation of all NN beat intervals), TpTe (time from peak to end of T-wave), heart rate turbulence, systolic and diastolic blood pressures, C-reactive protein, and fibrinogen associated with interquartile range increases in UFP, AMP, and PM2.5 at 1 or more lag times within the previous 5 days. Exposures were not associated with MeanNN, heart-rate–corrected QT interval duration (QTc), deceleration capacity, and white blood cell count was not associated with UFP, AMP, and PM2.5 at any lag time.
Conclusions: In cardiac rehabilitation patients, particles were associated with subclinical decreases in parasympathetic modulation, prolongation of late repolarization duration, increased blood pressure, and systemic inflammation. It is possible that such changes could increase the risk of CV events in this susceptible population.


Available from: David Q Rich
  • Source
    • "Pope et al. [[42]] found reductions in HRV associated with increases in concentrations of particulate matter less than or equal to 2.5 μm (PM2.5) in elderly subjects. Rich et al. [[43]] studied 76 patients in a cardiac rehabilitation program who had a recent myocardial infarction or unstable angina. Exposures to fine particles and UFP were associated with decreases in parasympathetic modulation, prolongation of late repolarization duration, increased blood pressure, and systemic inflammation. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Background Diabetes may confer an increased risk for the cardiovascular health effects of particulate air pollution, but few human clinical studies of air pollution have included people with diabetes. Ultrafine particles (UFP, ¿100 nm in diameter) have been hypothesized to be an important component of particulate air pollution with regard to cardiovascular health effects.Methods17 never-smoker subjects 30¿60 years of age, with stable type 2 diabetes but otherwise healthy, inhaled either filtered air (0¿10 particles/cm3) or elemental carbon UFP (~107 particles/cm3, ~50 ug/m3, count median diameter 32 nm) by mouthpiece, for 2 hours at rest, in a double-blind, randomized, crossover study design. A digital 12-lead electrocardiogram (ECG) was recorded continuously for 48 hours, beginning 1 hour prior to exposure.ResultsAnalysis of 5-minute segments of the ECG during quiet rest showed reduced high-frequency heart rate variability with UFP relative to air exposure (p¿=¿0.014), paralleled by non-significant reductions in time-domain heart rate variability parameters. In the analysis of longer durations of the ECG, we found that UFP exposure increased the heart rate relative to air exposure. During the 21- to 45-hour interval after exposure, the average heart rate increased approximately 8 beats per minute with UFP, compared to 5 beats per minute with air (p¿=¿0.045). There were no UFP effects on cardiac rhythm or repolarization.Conclusions Inhalation of elemental carbon ultrafine particles alters heart rate and heart rate variability in people with type 2 diabetes. Our findings suggest that effects may occur and persist hours after a single 2-hour exposure.
    Particle and Fibre Toxicology 07/2014; 11(1):31. DOI:10.1186/s12989-014-0031-y · 7.11 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The US Environmental Protection Agency funded five academic research centers in 2005 to address uncertainties in the health effects caused by airborne particulate matter (PM) as suggested by the 1998 National Research Council report, “Research Priorities for Airborne Particulate Matter.” The centers employed multidisciplinary teams of epidemiologists, toxicologists, atmospheric scientists, engineers, and chemists to approach four key research themes: susceptibility to PM, biological mechanisms of PM response, exposure–response relationships, and source linkages. This review presents selected accomplishments in these categories from the past 5-year period. Publications from the centers are summarized to provide both an overview of the accomplishments to date and easy reference to much of the original literature published by the centers. Numerous investigators worked together within and across centers to investigate the relationships between atmospheric PM and health effects, including (a) the role of reactive oxygen species, inflammation, the nervous system, and the cardiovascular system, (b) particle characteristics such as size, composition, source, and temporal pattern of exposure, and (c) phenotypic and genotypic characteristics of the population that influence the level of exposure and risk in response to a given exposure.
    Air Quality Atmosphere & Health 06/2012; 6(2). DOI:10.1007/s11869-012-0181-8 · 1.80 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The main objectives of this study are to (1) characterize chemical constituents of particulate matter (PM) and (2) compare overall differences in PM collected from eight US. counties. This project was undertaken as a part of a larger research program conducted by the Johns Hopkins Particulate Matter Research Center (JHPMRC). The goal of the JHPMRC is to explore the relationship between health effects and exposure to ambient PM of differing composition. The JHPMRC collected weekly filter-based ambient fine particle samples from eight US. counties between January 2008 and January 2010. Each sampling effort consisted of a 5-6-week sampling period. Filters were analyzed for 25 metals using inductively coupled plasma mass spectrometry (ICP-MS). Overall compositional differences were ranked by principal component analysis (PCA). The results showed that weekly concentrations of each element varied 3-40 times between the eight counties. PCA showed that the first five principal components explained 85% of the total variance. The authors found significant overall compositional differences in PM as the average of standardized principal component scores differed between the counties. These findings demonstrate PCA is a useful tool to identify the differences in PM compositional mixtures by county. These differences will be helpful for epidemiological and toxicological studies to help explain why health risks associated with PM exposure are different in locations with similar mass concentrations of PM.
    Journal of the Air & Waste Management Association (1995) 07/2012; 62(7):773-82. DOI:10.1080/10962247.2012.676593 · 1.34 Impact Factor
Show more