Dilated cardiomyopathy with hypertension: prevalence and response to high-dose β1-adrenoceptor antagonist therapy.
ABSTRACT 1. The aim of the present study was to investigate the prevalence of hypertension in patients with dilated cardiomyopathy (DCM) and to determine the tolerance and efficacy of a high dose of the β1-adrenoceptor antagonist metoprolol in the long-term treatment of DCM patients. 2. The prevalence of hypertension in DCM patients (n = 362) and age-matched controls (n = 401) was evaluated and compared. To investigate the effects of metoprolol, DCM patients were divided into hypertensive (DCM-H) or normotensive (DCM-N) subgroups. Metoprolol was administered at a starting dosage of 6.25 mg/day and increased gradually to 250 mg/day or the maximum tolerable dose. Blood pressure (BP), heart rate (HR), left ventricular (LV) end-diastolic dimension (LVEDD), left atrial end-diastolic dimension (LAEDD), LV ejection fraction (LVEF), LV posterior wall thickness (LVPWT) and ventricular septal thickness (VST) were determined at baseline and 6 and 12 months after metoprolol treatment. 3. The prevalence of hypertension was significantly higher in DCM patients than in age-matched controls (32.8 vs 20.1%, respectively; P < 0.01). Resting HR and a family history of hypertension were highest in the DCM-H group. There were no significant differences in age, gender and occupation between the DCM-H, DCM-N and age-matched control groups. 4. The tolerable dose for metoprolol was significantly higher in the DCM-H group than the DCM-N group (189.6 ± 14.8 vs 133.9 ± 12.0 mg/day, respectively; P < 0.05). Metoprolol significantly reduced BP and HR in the DCM-H group and improved LVEDD, LAEDD and LVEF in all DCM patients, with a greater effect seen in the DCM-H group. 5. In conclusion, DCM patients have a higher prevalence of hypertension than the general population. Patients in the DCM-H subgroup were characterized by a higher resting HR and a family history of hypertension and were more tolerant of and more responsive to metoprolol treatment. These data suggest that this subgroup of DCM patients could have higher sympathetic nerve activity and is suitable for treatment with a higher dose of metoprolol.