title: Rapid effects of air pollution on ventricular arrhythmias.
abstract: OBJECTIVE
  Air pollution has been associated with ventricular arrhythmias in patients with implantable cardioverter defibrillators (ICDs) for exposure periods of 24-48 h. Only two studies have investigated exposure periods <24 h. We aimed to explore such effects during the 2 and 24 preceding hours as well as in relation to distance from the place of the event to the air pollution monitor.
  
  
  RESULTS
  We used a case-crossover design to investigate the effects of particulate matter <10 microm in diameter (PM10) and nitrogen dioxide (NO2) in 211 patients with ICD devices in Gothenburg and Stockholm, Sweden. Events interpreted as ventricular arrhythmias were downloaded from the ICDs, and air pollution data were collected from urban background monitors. We found an association between 2 h moving averages of PM10 and ventricular arrhythmia [odds ratio (OR) 1.31, 95% confidence interval (CI) 1.00-1.72], whereas the OR for 24 h moving averages was 1.24 (95% CI 0.87-1.76). Corresponding ORs for events occurring closest to the air pollution monitor were 1.76 (95% CI 1.18-2.61) and 1.74 (95% CI 1.07-2.84), respectively. Events occurring in Gothenburg showed stronger associations than in Stockholm.
  
  
  CONCLUSIONS
  Moderate increases in air pollution appear to be associated with ventricular arrhythmias in ICD patients already after 2 h, although future studies including larger numbers of events are required to confirm these findings. Representative geographical exposure classification seems important in studies of these effects.
authors.affiliation: Department of Cardiology, Karolinska Institutet, Stockholm South General Hospital, Stockholm, Sweden.
authors.forename: Petter L S
authors.initials: PL
authors.lastname: Ljungman
authors.forename: Niklas
authors.initials: N
authors.lastname: Berglind
authors.forename: Christina
authors.initials: C
authors.lastname: Holmgren
authors.forename: Fredrik
authors.initials: F
authors.lastname: Gadler
authors.forename: Nils
authors.initials: N
authors.lastname: Edvardsson
authors.forename: Göran
authors.initials: G
authors.lastname: Pershagen
authors.forename: Mårten
authors.initials: M
authors.lastname: Rosenqvist
authors.forename: Bengt
authors.initials: B
authors.lastname: Sjögren
authors.forename: Tom
authors.initials: T
authors.lastname: Bellander
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000397:Air Pollution / Q000009:adverse effects; D001145:Arrhythmias, Cardiac / Q000139:chemically induced*; D018592:Cross-Over Studies; D016757:Death, Sudden, Cardiac / Q000209:etiology*; D017147:Defibrillators, Implantable / Q000009:adverse effects*; D004781:Environmental Exposure / Q000009:adverse effects*; D004784:Environmental Monitoring; D005260:Female; D006323:Heart Arrest / Q000139:chemically induced; D006801:Humans; D008297:Male; D008875:Middle Aged; D009585:Nitrogen Dioxide / Q000633:toxicity*; D016017:Odds Ratio; D010083:Oxidants, Photochemical / Q000633:toxicity*; D052638:Particulate Matter / Q000633:toxicity; D013548:Sweden; D013997:Time Factors
chemical_list: D010083:Oxidants, Photochemical; D052638:Particulate Matter; D009585:Nitrogen Dioxide