When drug therapy for lung disease affects the heart.

The development of effective drugs for chronic lung disease, especially bronchodilator aerosols, has been a boon to patients and physicians alike, but these agents also may provoke arrhythmias. Fluorocarbon propellants, once regarded as harmless, are now known to disrupt cardiac function, sensitizing the heart to the arrhythmic effects of sympathomimetic amines. Catecholamine drugs as a group have a strong impact on heart rate and contractility. But the danger of rhythm disturbances often can be reduced by cutting the dosage or choosing a preparation with more beta 2 activity. Methylxanthines, generally safer than catecholamines, nevertheless must be used with caution and preferably alone in patients with heart and lung disease.