title: Low-dose dobutamine induces left ventricular mechanical dyssynchrony in patients with dilated cardiomyopathy and a narrow QRS: a study using real-time three-dimensional echocardiography.
abstract: OBJECTIVE
  The effects of inotropic agents on left ventricular (LV) synchrony in heart failure patients are still unknown. The purpose of this study was to investigate the effects of dobutamine on LV mechanical dyssynchrony and LV systolic performance in patients with dilated cardiomyopathy (DCM) and a narrow QRS using real-time three-dimensional echocardiography (RT3DE).
  
  
  RESULTS
  Thirty-three patients with idiopathic DCM and a narrow QRS underwent low-dose dobutamine stress echocardiography (LDSE) with RT3DE. A time-global LV volume curve and time-regional LV volume curves were derived from RT3DE. Regional LV stroke volumes were summed in each stage, and the dobutamine-induced increase in the sum of regional LV stroke volumes was considered as the sum of regional contractile reserve. Systolic dyssynchrony index (SDI) was calculated as follows: (standard deviation of time to minimal volume for regional LV segments)×100/RR duration. Among the 33 patients, low-dose dobutamine increased global LV stroke volume (SV) in 28 (85%), but decreased global LVSV in the remainder (15%). The sum of regional contractile reserve was modestly correlated with the dobutamine-induced increase in global LVSV (R=0.57, p<0.001). In contrast, low-dose dobutamine increased SDI in 14 (42%) patients without a significant change in QRS duration, and there was an inverse correlation between the increase in SDI and the increase in global LVSV induced by dobutamine (R=-0.67, p<0.001).
  
  
  CONCLUSIONS
  Dobutamine may induce LV mechanical dyssynchrony in a substantial proportion of patients with DCM and a narrow QRS. In such cases, regional LV contractile reserve does not fully contribute to an increase in global LVSV.
authors.affiliation: Department of Cardiology, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Yagishita-Tagawa
authors.forename: Yukio
authors.initials: Y
authors.lastname: Abe
authors.forename: Kotaro
authors.initials: K
authors.lastname: Arai
authors.forename: Daigo
authors.initials: D
authors.lastname: Yagishita
authors.forename: Atsushi
authors.initials: A
authors.lastname: Takagi
authors.forename: Kyomi
authors.initials: K
authors.lastname: Ashihara
authors.forename: Morio
authors.initials: M
authors.lastname: Shoda
authors.forename: Takahiko
authors.initials: T
authors.lastname: Naruko
authors.forename: Akira
authors.initials: A
authors.lastname: Itoh
authors.forename: Kazuo
authors.initials: K
authors.lastname: Haze
authors.forename: Junichi
authors.initials: J
authors.lastname: Yoshikawa
authors.forename: Nobuhisa
authors.initials: N
authors.lastname: Hagiwara
mesh_terms: D000328:Adult; D000368:Aged; D002311:Cardiomyopathy, Dilated / Q000188:drug therapy* / Q000503:physiopathology; D002316:Cardiotonic Agents / Q000008:administration & dosage* / Q000009:adverse effects*; D004280:Dobutamine / Q000008:administration & dosage* / Q000009:adverse effects*; D019560:Echocardiography, Three-Dimensional / Q000379:methods*; D004562:Electrocardiography; D005260:Female; D006333:Heart Failure / Q000188:drug therapy* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D018487:Ventricular Dysfunction, Left / Q000139:chemically induced* / Q000000981:diagnostic imaging*
chemical_list: D002316:Cardiotonic Agents; D004280:Dobutamine