Background Long-term administration of oral β₂-adrenergic receptor agonists (β₂-AG) in patients with bronchial asthma (BA) causes disastrous events such as sudden death and heart attack. However, long-term effects of β₂-AG on cardiac function have not been previously quantified. Methods Seventy-four patients with BA with regular long-term use of oral β₂-AG (group A) and 69 patients with BA without β₂- AG (group B) were examined in medical records of outpatient clinics from 1985 to 1999. In the prospective study, echocardiography was performed in 48 consecutive patients from January to April 1999. There were 26 patients with regular oral use of β₂-AG (group a) and 22 patients without β₂-AG (group b). Twenty-one age-matched normal volunteers without heart or pulmonary diseases were used as control subjects (group c). Oral β₂-AG was withdrawn from remedies in 11 patients of group a, and echocardiographic studies were repeated 2 weeks after its cessation. Results Events related to heart failure were more frequently seen in group A than in group B (14% vs 1%, P < .01). The echocardiographic study showed that indexes of left ventricular diastolic but not systolic function were significantly deteriorated in group a, along with a markedly reduced level of plasma norepinephrine concentration (P < .05 vs groups b and c). When heart rate was adjusted to 90 beats/min during isoproterenol infusion, left ventricular diastolic function remained deteriorated in group a (P < .05 vs groups b and c). In 11 patients of group a, the cessation of β₂-AG for 2 weeks resulted in an improvement of left ventricular diastolic function and in an increase of plasma norepinephrine level (P < .01). Conclusions Long-term use of oral β₂-AG impaired left ventricular diastolic function in patients with BA, and the cessation of β₂-AG reversed diastolic pump performance to the normal level. (Am Heart J 2001;142:e11.)