title: Effect of cardiac resynchronisation therapy on coronary blood flow in patients with non-ischaemic dilated cardiomyopathy.
abstract: BACKGROUND
  Cardiac resynchronisation therapy (CRT) has beneficial effects on cardiac function, exercise tolerance, symptoms, and prognosis. Coronary blood flow impairment has been observed in patients with non-ischaemic dilated cardiomyopathy (DCM) despite angiographically normal coronary arteries. No data are available on coronary blood flow and coronary flow reserve (CFR) measured by intracoronary Doppler in different coronary arteries in patients with DCM and left bundle branch block (LBBB) before and during treatment with CRT.
  
  
  OBJECTIVE
  Thus, the major aim of our study was to assess the effect of CRT on coronary blood flow in patients with non-ischaemic DCM and to compare coronary blood flow and CFR measured in the 3 major coronary arteries (left anterior descending [LAD], left circumflex [LCX], and right coronary artery [RCA]).
  
  
  METHODS
  Twenty one patients with DCM and LBBB (mean left ventricular ejection fraction 26 ± 7%, 5 females, mean age 57.8 ± 8.1 years) were studied. Average peak velocity, diastolic/systolic velocity ratio and CFR were measured using intracoronary Doppler before and 6-9 months after implantation of CRT-D or CRT-P.
  
  
  RESULTS
  In patients with a clinical improvement (71.4%), CFR increased in LAD. CFR measured in LCX and RCA did not improve either in the overall study group or in patients with a clinical improvement. The observed increase in CFR in LAD correlated only with reduction of QRS duration.
  
  
  CONCLUSIONS
  In non-ischaemic DCM, CFR is reduced only in LAD. A significant improvement of CFR in LAD after CRT correlates with reduction of QRS duration.
authors: Department of Cardiology, Pomeranian Medical University, Szczecin, Poland. jar.kazmierczak@o2.pl.
authors: Jarosław
authors: J
authors: Kaźmierczak
authors: Małgorzata
authors: M
authors: Peregud-Pogorzelska
authors: Jarosław
authors: J
authors: Gorący
authors: Andrzej
authors: A
authors: Wojtarowicz
authors: Radosław
authors: R
authors: Kiedrowicz
authors: Zdzisława
authors: Z
authors: Kornacewicz-Jach
mesh_terms: D000368:Aged; D001783:Blood Flow Velocity; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D002311:Cardiomyopathy, Dilated / Q000503:physiopathology* / Q000628:therapy*; D004452:Echocardiography; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006801:Humans; D008297:Male; D008875:Middle Aged