title: Hypotension during dobutamine stress transesophageal echocardiography: relationship with provoked left ventricular obstruction.
abstract: BACKGROUND
  The mechanism of hypotension during dobutamine stress (DS) echocardiography is unknown. The role of left ventricular outflow tract (OT) or midcavitary (MID) obstruction provoked during stress in this process remains controversial. We hypothesized that left ventricular OT obstruction would account for hypotension as opposed to MID obstruction.
  
  
  METHODS
  Multiplane DS transesophageal echocardiography (TEE) was performed in 142 adult patients who displayed no resting obstruction or DS-provoked ischemia. TEE was used to identify the precise site of obstruction. Dobutamine was infused from 5 to 40 microg/kg/min and atropine as needed. Continuous wave Doppler was performed from appropriate views to assess for obstruction.
  
  
  RESULTS
  Ventricular obstruction was provoked at the OT in 13 patients, MID in 10 patients, and at both sites in 4 patients. A total of 115 patients without dobutamine-induced obstruction served as control subjects. Systolic blood pressure at rest was similar in all groups, but decreased to a greater magnitude from rest to peak stress in the OT (-20 +/- 40 mm Hg) and MID (-29 +/- 38 mm Hg) groups as compared with the control group (8 +/- 30 mm Hg). A hypotensive response (ie, decrease in systolic blood pressure > or = 20 mm Hg from baseline to peak stress) was significantly greater in OT (69%, P = .001) and MID (60%, P < .05) groups as compared with the control group (19%). Heart rate and ejection fraction at rest or peak did not differ among groups. Among clinical and hemodynamic variables, left ventricular OT (relative risk 5.9; 95% confidence interval 1.9-18; P < .002) and MID (relative risk 3.6; 95% confidence interval 1.1-12; P < .05) obstructions were the only predictors for a hypotensive response.
  
  
  CONCLUSIONS
  Hypotension during DS TEE occurs commonly when ventricular obstruction is provoked. These data support a causal relationship between a provoked ventricular obstruction and hypotension during DS TEE.
authors.affiliation: Division of Cardiology, Department of Medicine, University of Louisville, Louisville, Kentucky 40292, USA.
authors.forename: Tariq S
authors.initials: TS
authors.lastname: Siddiqui
authors.forename: Buddhadeb
authors.initials: B
authors.lastname: Dawn
authors.forename: Marcus F
authors.initials: MF
authors.lastname: Stoddard
mesh_terms: D000368:Aged; D004280:Dobutamine / Q000009:adverse effects*; D017548:Echocardiography, Transesophageal / Q000009:adverse effects*; D005080:Exercise Test / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007022:Hypotension / Q000000981:diagnostic imaging / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D013223:Statistics as Topic; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000209:etiology*; D014694:Ventricular Outflow Obstruction / Q000000981:diagnostic imaging / Q000209:etiology*
chemical_list: D004280:Dobutamine