title: Regional coronary flow and contractile reserve in patients with idiopathic dilated cardiomyopathy.
abstract: OBJECTIVE
  The purpose of this study was to assess regional coronary flow and contractile reserve in patients with idiopathic dilated cardiomyopathy (IDCM).
  
  
  BACKGROUND
  Although IDCM has been associated with alterations in coronary blood flow and contractile reserve, little is known about their regional distribution and correlation.
  
  
  METHODS
  Fourteen patients with IDCM and 11 control subjects underwent coronary flow velocity (APV) measurements in the left anterior descending (LAD), left circumflex (LCx), and right coronary (RCA) arteries at baseline (b) and at maximal hyperemia (h). Coronary flow reserve (CFR) was defined as h-APV/b-APV. Wall thickening was assessed in 16 segments (7 assigned to LAD, 5 to LCx, and 4 to RCA) both at rest and under peak stress during low-dose dobutamine echocardiography. Regional contractile reserve was defined as the percentage difference in wall motion score index between rest and stress in each vascular territory.
  
  
  RESULTS
  Although there were no significant differences in b-APV, patients with IDCM had significantly lower h-APV than controls in all three vascular territories and reduced CFR (LAD: 2.79 +/- 0.43 vs. 3.48 +/- 0.51, p < 0.05; LCx: 2.71 +/- 0.39 vs. 3.36 +/- 0.65, p < 0.05; and RCA: 3.43 +/- 0.55 vs. 4.02 +/- 0.73, p < 0.05). There was also a significant correlation between CFR and the corresponding contractile reserve in the vascular territory of the LAD (r = 0.75, p = 0.002) and the LCx (r = 0.64, p = 0.014).
  
  
  CONCLUSIONS
  Patients with IDCM have alterations in regional coronary flow and reduced CFR. Furthermore, the correlation between regional CFR and the corresponding contractile reserve indicates that microvascular dysfunction may have a pathophysiologic role in the evolution of the disease.
authors.affiliation: Cardiology Department, University Hospital of Heraklion, Heraklion, Greece.
authors.forename: Emmanuel I
authors.initials: EI
authors.lastname: Skalidis
authors.forename: Frangiskos I
authors.initials: FI
authors.lastname: Parthenakis
authors.forename: Alexandros P
authors.initials: AP
authors.lastname: Patrianakos
authors.forename: Michael I
authors.initials: MI
authors.lastname: Hamilos
authors.forename: Panos E
authors.initials: PE
authors.lastname: Vardas
mesh_terms: D001783:Blood Flow Velocity; D002311:Cardiomyopathy, Dilated / Q000000981:diagnostic imaging / Q000503:physiopathology*; D016022:Case-Control Studies; D017023:Coronary Angiography; D003326:Coronary Circulation / Q000502:physiology; D003331:Coronary Vessels / Q000502:physiology*; D004280:Dobutamine; D004452:Echocardiography; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011673:Pulsatile Flow
chemical_list: D004280:Dobutamine