Myocardial catecholamines in primary heart muscle disease: fact or fancy?

The pathophysiological role of myocardial catecholamines in cardiomyopathies is still not completely understood. We there-fore assessed myocardial catecholamine concentrations (MCC) in 34 patients with hypertrophic cardiomyopathy (HCM) (76.5% males; mean age 46.7 +/- 11.6 years; left ventricular ejection fraction [LVEF] 75.3 +/- 9.8%) and in 32 patients with dilated cardiomyopathy (DCM) (87.5% males, mean age 43.1 +/- 12.5 years, LVEF 34.9 +/- 8.3%). Initial assessment included clinical work up, cardiac catheterization and endomyocardial biopsy. Myocardial norepinephrine (MNEC), epinephrine (MEC), and dopamine (MDC) concentrations in endomyocardial biopsy samples were measured using the catechol-O- methyl transferase radioenzymatic method. Significantly higher MNEC and MEC were demonstrated in HCM than in DCM patients (MNEC: 781.9 +/- 125.8 ng.g-1 fresh myocardial tissue (ft) HCM vs 262.6 +/- 68.9 ng.g-1 ft DCM, p < 0.01; and MEC: 91.6 +/- 13.9 ng.g-1 ft HCM vs 35.8 +/- 6.2 ng.g-1 ft DCM, P < 0.01). The difference in MDC did not reach statistical significance (76.1 +/- 8.3 ng.g-1 ft HCM vs 70.1 +/- 11.8 ng.g ft DCM; P > 0.05). In addition, we compared the MCC levels in 24 patients, clinically presented as dilated cardiomyopathy categorized according to the various aetiologies: 12/24 with primary DCM (75.0% males, mean age 49.6 +/- 9.5 years; LVEF 25.8 +/- 63%), 7/24 with alcohol-induced heart disease (85.7% males, mean age 46.8 +/- 7.1 years; LVEF 26.4 +/- 4.6%), and 5/24 with hypertensive heart disease (100% males, 45.1 +/- 10.6 years; LVEF 25.6 +/- 9.1%), but no significant difference was found among them (P > 0.05). There was no significant difference in tissue dopamine concentrations.