Abnormal myocardial contractile responses in patients with idiopathic dilated cardiomyopathy / 中华超声影像学杂志

ABSTRACT

Objective To investigate abnormal myocardial contractile responses induced by dobutamine in patients with idiopathic dilated cardiomyopathy (DCM).Methods Eighteen DCM patients underwent low dosage dobutamine stress echocardiography (5,10,20 ?g?kg~ -1?min~ -1).Transthoracic echocardiogram was recorded with the use of a HP Sonos 5500 color echocardiographic diagnostic system.Wall motions in 16 myocardial segments were assessed using a four-point scale recommended by the American Society of Echocardiography.During dobutamine infusion,abnormally contracting segments were classified into four different patterns of contractile response: improved,unchanged,worsened and biphasic.Unchanged,worsened and biphasic segments were defined as abnormal contractile responses.Worsened and biphasic segments were judged to be ischemia-like responses.Results All patients showed abnormal myocardial contractile responses of wall motions (100%),and thirteen were ischemia-like responses ( 72.2%).In total 225 segments,126 segments showed abnormal contractile responses ( 56.0%).Among them,97 segments were unchanged segments ( 43.1%),29 segments were ischemia-like responses ( 12.9%),in which 16 segments were worsened ( 7.1%),and 13 segments were biphasic ( 5.8%).The statistical analysis showed that incidence of improved segments was highest in two point segments( 62.1%) compared with three point and four point segments; incidence of ischemia-like responses was highest in three point segments( 24.6%); incidence of unchanged segments was highest in four point segments( 68.4%).Conclusions DCM has the abnormal myocardial contractile responses induced by dobutamine stress echocardiography.It indicates there is the ischemia-like energy mismatch between demand and supply in DCM,which would be related to etiology and progress of DCM.