Due to their high prevalence and common risk factors, chronic obstructive pulmonary disease (COPD) and coronary heart disease as well as arterial hypertension often occur concomitantly. In the pharmacological treatment of COPD with bronchodilators, an increased risk of arrhythmia can be expected in patients with cardiac comorbidity, particularly when theophylline is used. The bronchodilators of first choice are inhaled a nticholinergic agents, followed by inhaled beta(2)-sympathomimetics. Systemic glucosteroids should preferably not be employed in long-term therapy of COPD. Measures for prevention and treatment of arrhythmias in patients with COPD and cardiac comorbidity include effective therapy of the cardiac disease, correction of arterial hypoxemia and hypokalemia, if necessary reduction of the dose of bronchodilators, and antiarrhythmic therapy to manage hemodynamically significant arrhythmias.