Air Pollution in Patients With Heart Failure

D espite recent advances in the treatment of heart failure with reduced ejection fraction (HFrEF), adverse event rates remain high with >50% mortality at 5 years (1). The progressive nature of HFrEF coupled with high mortality and rehospitalization rates (2) mandates greater attention to previously underappreciated etiologies of heart failure (HF) exacerbation, including environmental exposures. The adverse cardiovascular effects of air pollution have been described in a series of epidemiological studies (3,4). Potential mechanisms for the association include endothelial dysfunction, systemic inflammation, increased blood pressure, altered coagulation, arrhythmia, and ischemia (3). HF patients appear to experience stronger negative effects of air pollution than do those with other cardiovascular conditions (5). Short-term air pollution exposure, specifically particulate matter <2.5 mm (PM2.5), is associated with increased HF hospitalization and mortality (6,7). However, the majority of studies to date investigating air pollution in HF patients have been limited by retrospective and noninterventional designs.