title: Use of sympathomimetic drugs leads to increased risk of hospitalization for arrhythmias in patients with congestive heart failure.
abstract: BACKGROUND
  Sympathomimetic agents have a direct positive chronotropic effect on heart rate and may cause hypokalemia, even when administered by inhalation. In selected patients (e.g., patients with congestive heart failure [CHF]) this can lead to arrhythmias. Despite the potential adverse effects of these agents, they are used frequently in patients with CHF, due to a high incidence of respiratory comorbidity. This study investigates the effects of sympathomimetics on the incidence of hospitalizations for arrhythmias in patients with CHF.
  
  
  METHODS
  In a cohort of 1208 patients with a validated hospital discharge diagnosis of CHF, we identified 149 cases with a readmission for arrhythmias, and compared these in a nested matched case-control design with 149 controls from the remainder of the cohort with no hospital readmission for any cardiac cause. Conditional logistic regression was used to calculate the risk for hospitalization for arrhythmias associated with exposure to sympathomimetic agents, expressed as odds ratios.
  
  
  RESULTS
  Of 149 case patients, a total of 33 (22.1%) were treated with any sympathomimetic agent, and 6 patients (4.0%) were treated with systemic sympathomimetics. The use of any sympathomimetic drug was associated with an increased risk of admission for arrhythmia (odds ratio, 4.0; 95% confidence interval, 1.0-15.1). For systemic sympathomimetic drugs, the corresponding odds ratio was 15.7 (95% confidence interval, 1.1-228.0).
  
  
  CONCLUSIONS
  The results of this study strongly suggest an increased risk of hospitalization for arrhythmias in patients with CHF treated with sympathomimetic drugs. Sympathomimetics should be given under close surveillance to patients with CHF.
authors.affiliation: Universiteit Utrecht, Pharmacoepidemiology and Pharmacotherapy, PO Box 80082, 3508 TB Utrecht, The Netherlands. m.bouvy@pharm.uu.nl
authors.forename: M L
authors.initials: ML
authors.lastname: Bouvy
authors.forename: E R
authors.initials: ER
authors.lastname: Heerdink
authors.forename: M L
authors.initials: ML
authors.lastname: De Bruin
authors.forename: R M
authors.initials: RM
authors.lastname: Herings
authors.forename: H G
authors.initials: HG
authors.lastname: Leufkens
authors.forename: A W
authors.initials: AW
authors.lastname: Hoes
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000139:chemically induced*; D016022:Case-Control Studies; D005260:Female; D006333:Heart Failure / Q000188:drug therapy*; D006760:Hospitalization; D006801:Humans; D008297:Male; D009426:Netherlands; D013566:Sympathomimetics / Q000009:adverse effects* / Q000627:therapeutic use
chemical_list: D013566:Sympathomimetics