The fluoroalkane gases used to propel aerosols were toxic to the hearts of 34 mice, sensitizing them to asphyxiainduced sinus bradycardia, atrioventricular block, and T-waue depression. Cardiac sensitization was rapid, long-lasting, and lethal. It also occurred in rats and dogs. The propellants are postulated to possess a spectrum of cardiotoxic effects capable, in various species, of causing bradyarrhythmias, tachyarrhythmias, or myocardial depression. In humans the cardiac toxicity of aerosol propellants, particularly during asphyxia, may be a cause of sudden death in youths who "turn on" by inhaling propellants and in patients with asthma who make excessive use of bronchodilator aerosols. To a degree presently unknown, cardiac toxicity, including arrhythmias, due to propellant inhalation may be a potential hazard to frequent users of pressurized aerosol dispensers.
Taylor GJ, Harris WS. Cardiac Toxicity of Aerosol Propellants. JAMA. 1970;214(1):81-85. doi:10.1001/jama.1970.03180010023004