title: Left ventricular function and exercise capacity in patients with slow coronary flow.
abstract: BACKGROUND
  Endothelial and microvascular dysfunction have been implicated in slow coronary flow (SCF). How and to what extent do these etiological factors affect left ventricular (LV) function and exercise capacity?
  
  
  OBJECTIVE
  The aim of the study was to evaluate LV systolic and diastolic function by pulsed tissue Doppler imaging (TDI) in SCF patients and their effects on exercise capacity.
  
  
  METHODS
  Sixty SCF patients and 20 control subjects were included in the study. Echocardiographic examination, treadmill exercise test, and TDI were performed. Isovolumic myocardial acceleration (IVA) and myocardial performance index (MPI) were measured.
  
  
  RESULTS
  TDI mean parameters for systolic and diastolic LV function were significantly impaired in SCF group with decreased Sa, IVA, Ea/Aa, and increased MPI (0.31 ± 0.06 vs. 0.26 ± 0.04, P < 0.01) compared to control. There was significant correlation between thrombolysis in myocardial infarction (TIMI) frame count and TDI mean parameters for LV systolic function (Sa & IVA, r =-0.53, P < 0.01 & r =-0.36, P < 0.05, respectively). Mean TIMI frame count was correlated with MPI and E/Ea. SCF patients had poorer peak exercise capacity than the controls (9.9 ± 1.9 METs vs. 12.7 ± 2.3, P < 0.01) with significant negative correlation with mean TIMI frame count (r =-0.46, P < 0.01).
  
  
  CONCLUSIONS
  There is impairment of LV systolic and diastolic function in SCF patients with clinical impact on exercise capacity which emphasizes the importance of close follow-up of these patients for risk stratification.
authors: Cardiology Department, Zagazig University, Egypt. islamcardio@yahoo.com
authors: Islam A
authors: IA
authors: Elsherbiny
mesh_terms: D001783:Blood Flow Velocity; D017023:Coronary Angiography; D003326:Coronary Circulation; D015150:Echocardiography, Doppler / Q000379:methods; D005080:Exercise Test / Q000379:methods / Q000706:statistics & numerical data; D017079:Exercise Tolerance; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D015588:Observer Variation; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000503:physiopathology*