The role of dobutamine stress echocardiography in idiopathic dilated cardiomyopathy.
In patients with chronic heart failure, myocardial contractile responsiveness to dobutamine is diminished as a result of beta-receptor desensitization due to chronic adrenergic activation. Changes in beta-receptor effector mechanisms are more marked in idiopathic dilated cardiomyopathy (IDCM) than in ischemic dilated cardiomyopathy. As the magnitude of the dobutamine effect is proportional to the severity of left ventricular systolic dysfunction, the heterogeneous cardiotonic effects of dobutamine in IDCM may represent different evolutive stages of a progressive disease process. On the basis of this pathophysiologic background, some studies were undertaken to investigate the prognostic and functional implications of dobutamine stress echocardiography (DSE) in IDCM. Prognostic studies consistently suggest that myocardial response to dobutamine is related to the clinical outcome. However, the limited number of patients and events in the individual studies are important limitations. Moreover, the impact of beta-blockers on the potential ability of DSE to predict the prognosis needs to be assessed. A few studies also suggest that changes in left ventricular systolic function parameters following dobutamine infusion are related to exercise tolerance, as assessed by peak exercise oxygen consumption and functional recovery of the failing myocardium. The data suggest that DSE is a promising method, which may improve the risk stratification process in patients with IDCM and provide further insights into the pathophysiologic mechanisms underlying progressive systolic pump dysfunction and exercise intolerance. Further studies are however needed to define the role of DSE in IDCM.
Scrutinio
Domenico
D
Divisione di Cardiologia Riabilitativa Fondazione S. Maugeri, IRCCS Via per Mercadante, km 2 70020 Cassano Murge. dscrutinio@fsm.it
Napoli
Venanzio F
VF
Ricci
Antonio
A
Rizzon
Paolo
P
D002311:Cardiomyopathy, Dilated / Q000000981:diagnostic imaging* / Q000503:physiopathology; D025401:Echocardiography, Stress; D006801:Humans; D009200:Myocardial Contraction / Q000502:physiology*; D011379:Prognosis; D016277:Ventricular Function, Left / Q000502:physiology*