title: Effect of decrease in heart rate variability on the diagnostic accuracy of 64-MDCT coronary angiography.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the effect of average heart rate and heart rate variability on the diagnostic accuracy of 64-MDCT in the assessment of coronary artery stenosis.
  
  
  METHODS
  CT and invasive coronary angiography were performed on 114 patients (mean age, 62 years) referred for known coronary artery disease (n = 26), atypical chest pain (n = 58), and presurgical exclusion of coronary artery disease before abdominal aortic (n = 14) or cardiac valve (n = 16) surgery. The population was divided into two groups depending on median average heart rate (60.0 beats/min) and median heart rate variability (2.7 beats/min) during scanning. Heart rate variability was calculated as SD from the mean heart rate. Two blinded observers using a 4-point scale independently assessed the quality of images of each coronary artery segment and classified each segment as being stenosed (luminal diameter narrowing > 50%) or not. Invasive coronary angiography was used as the reference standard.
  
  
  RESULTS
  In 71 (62.3%) of the patients, 241 significant coronary artery stenoses were identified with invasive coronary angiography. In 11 (9.7%) of the patients, 1.6% (26/1,672) of the segments were not evaluable with CT. Overall sensitivity, specificity, and positive and negative predictive values in a patient-based analysis were 97%, 81%, 90%, and 95%, respectively. Image quality was better (p < 0.05) in the low average heart rate group than in the high average heart rate group, but diagnostic accuracy was comparable for the two groups. In contrast, image quality and diagnostic accuracy were significantly better (p < 0.01) among patients in the low heart rate variability group than in the high heart rate variability group.
  
  
  CONCLUSIONS
  Lower heart rate variability is associated with higher diagnostic accuracy of 64-MDCT coronary angiography.
authors.affiliation: Institute of Diagnostic Radiology, Department of Medical Radiology, University Hospital Zurich, Raemistrasse 100, 8091 Zurich, Switzerland.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Leschka
authors.forename: Hans
authors.initials: H
authors.lastname: Scheffel
authors.forename: Lars
authors.initials: L
authors.lastname: Husmann
authors.forename: Oliver
authors.initials: O
authors.lastname: Gämperli
authors.forename: Borut
authors.initials: B
authors.lastname: Marincek
authors.forename: Philipp A
authors.initials: PA
authors.lastname: Kaufmann
authors.forename: Hatem
authors.initials: H
authors.lastname: Alkadhi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D017023:Coronary Angiography / Q000379:methods*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging*; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D011856:Radiographic Image Enhancement / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D014057:Tomography, X-Ray Computed / Q000379:methods*