title: Impact of heart rate variability in patients with normal sinus rhythm on image quality in coronary magnetic angiography.
abstract: OBJECTIVE
  To evaluate the influence of heart rate variability on image quality in patients with suspected coronary artery disease during magnetic resonance coronary angiography (MRCA).
  
  
  METHODS
  The coronary images from 70 patients who underwent target-volume MRA were retrospectively analyzed. Two independent observers evaluated image quality using a score from 0 (nonvisible) to 4 (excellent quality). Images were grouped into good (score > 2) and poor image quality (score 0-2). Five parameters (effective scan duration, navigator efficiency, mean heart rate, acquisition window, and heart rate variability) were evaluated.
  
  
  RESULTS
  In all, 56 of the 70 patients (80%) were scored as good and 14 as poor image quality. Only the navigator efficiency, heart rate variability, and acquisition window showed statistically significant for the prediction of image quality, with navigator efficiency being the strongest predictor. Subgroup analysis showed that patients with navigator efficiency >60% had good image quality independent of the heart rate variability. In patients with navigator efficiency < or =60%, heart rate variability is the only remaining significant parameter (P = 0.03).
  
  
  CONCLUSIONS
  Navigator efficiency was the most important predictor of MRCA image quality. Heart rate variability is the most important predictor of image quality in patients with a navigator efficiency < or =60%.
authors.affiliation: Department of Internal Medicine/Cardiology, German Heart Institute, Berlin, Germany. ttarinee@googlemail.com
authors.forename: Tarinee
authors.initials: T
authors.lastname: Tangcharoen
authors.forename: Cosima
authors.initials: C
authors.lastname: Jahnke
authors.forename: Uwe
authors.initials: U
authors.lastname: Koehler
authors.forename: Bernhard
authors.initials: B
authors.lastname: Schnackenburg
authors.forename: Christoph
authors.initials: C
authors.lastname: Klein
authors.forename: Eckart
authors.initials: E
authors.lastname: Fleck
authors.forename: Eike
authors.initials: E
authors.lastname: Nagel
mesh_terms: D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies