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

The pathophysiological role of myocardial catecholamines in cardiomyopathies is still not completely understood. We therefore 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 [LVEFJ 75–3 ± 9–8%) and in 32 patients with dilated cardiomyopathy (DCM) (87–5 males, mean age 43–1 ± 12–5 years, LVEF34–9 ± 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–melhyl 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–' ft DCM, P < 001; and MEC: 91–6 ± 13–9 ng.g– -1 ft HCM vs 35–8 ± 6–2 ng.g-1 ft DCM, P < 001). 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– -1 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 ± 6–3%), 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.