Aerosol Propellants: Cardiac Toxicity and Long Biological Half-Life

To the Editor.—  In the editorial (222:827-828, 1972), "Cardiac Toxicity of Aerosol Propellants," Silverglade defended the safety of fluorocarbon propellants when used properly in asthmatic patients. Statements that failure to reproduce the cardiac toxicity in animals as originally reported by Taylor and Harris (214:81, 1970) have been criticized by Harris (223:1508, 1973). This communication supplements Harris' comments and points to potential danger of these propellants in susceptible individuals.An important and excellent study by Flowers and Horan (219:33, 1972) showed the cardiac toxicity of the propellants to be prolonged and lethal. Eight dogs, despite the stopping of exposure to the propellants at the earliest detectable moment of sinus slowing and the reinstitution of artificial ventilation, died once the cardiac abnormal sequence began. This, of course, supports many investigations from the Harris' laboratory.The rapid elimination, short halflives, and hence the unlikelihood of accumulation of the propellants in animals and humans