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.