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Clinical Articles

Air Pollution Raises Arrhythmia Risk In MI Patients

Autonomic dysregulation and arrhythmia can occur in selected patients with coronary artery disease (CAD) when they are exposed to air pollution, according to a recently published randomized longitudinal study conducted in Padua.

Epidemiological studies show that peak exposure to air pollution is associated with increased morbidity and mortality from cardiovascular events. Panel and controlled exposure studies show that particular matter (PM) may influence the parasympathetic regulation of the heart. The aim of this study was to concurrently measure individual exposure to PM of various sizes, heart rate variability (HRV) and electrical instability in patients with myocardial infarction.

It is unclear what chemical component of particulate matter (PM) is responsible for these adverse cardiovascular effects, but smaller size PM appears to be more strongly correlated. Further difficulties in assessing exposure arise when data are derived from fixed monitoring stations because of differences between outdoor and indoor PM pollution, the latter of which often is the more relevant.

Systemic inflammation and prothrombotic conditions that are elicited by PM in the lung are thought to represent the underlying mechanism of cardiotoxicity, but other mechanisms have been inferred, whereby inflammation and thrombosis may simply co-exist.

Personal exposures to PM10, PM2.5, and PM0.25, was measured over 24 h in 39 patients (36 males, 3 females, mean age 60.3 years), with prior myocardial infarction (> 6 months). Simultaneously, a 24 h ECG was recorded and then analysed for heart rate variability (HRV) and ventricular arrhythmias. Breath condensate and blood samples also were collected at the end of monitoring to measure several indexes of inflammation. Negative correlation was found between HRV and exposure to PM0.25 in a group of patients not taking ß-blockers. More severe ventricular arrhythmias were observed at the highest concentrations of PM10 and PM2.5. Indexes of inflammation in either breath condensate or blood did not correlate with PM exposures.

The study shows that exposure to ultrafine particles is associated with autonomic dysregulation in selected patients with myocardial infarction. More severe arrhythmias occur at the highest exposure to large particles. Nevertheless, the underlying mechanisms remain hypothetical because inflammation may be evoked by PM or be related to the disease itself, these workers conclude.

Reference:

Individual exposure to particulate matter and the short-term arrhythmic and autonomic profiles in patients with myocardial infarction. Folino F, Scapellato L, Canova C, et al. European Heart Journal (2009) 30, 1614-1620.

Published on: August 19, 2009

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ENDORSED BY

  • ArrhythmiaAlliance
  • Stars
  • Anticoagulation Europe
  • Atrial Fibrillation Association
 

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