title: Heart rate variability and heat sensation during CT coronary angiography: Low-osmolar versus iso-osmolar contrast media.
abstract: BACKGROUND
  During computed tomography coronary angiography (CTCA) unexpected changes in heart rate while scanning may affect image quality.
  
  
  OBJECTIVE
  To evaluate whether an iso-osmolar contrast medium (IOCM, iodixanol) and a low-osmolar contrast medium (LOCM, iomeprol) affect heart rate and experienced heat sensation differently.
  
  
  METHODS
  One hundred patients scheduled for CTCA were randomized to receive either iodixanol 320 mgI/ml or iomeprol 400 mgI/ml. Depending on their heart rate, the patients were assigned to one of five scanning protocols, each optimized for different heart rate ranges. During scanning the time between each heart beat (hb) was recorded, and the corresponding heart rate was calculated. For each contrast medium (CM) the average heart rate, the variation in heart rate from individual mean heart rate, and the mean deviation from the predefined scanning protocol were calculated. Experience of heat was obtained immediately after scanning by using a visual analog scale (VAS). Examination quality was rated by two radiologists on a three-point scale.
  
  
  RESULTS
  The mean variation in heart rate after IOCM was 1.4 hb/min and after LOCM it was 4.4 hb/min (NS). The mean deviations in heart rate from that in the predefined scanning protocol were 2.0 hb/min and 4.7 hb/min, respectively (NS). A greater number of arrhythmic hb were observed after LOCM compared with IOCM (P<0.001). There was no statistically significant difference in image quality. The LOCM group reported a stronger heat sensation after CM injection than the IOCM group (VAS =36 mm and 18 mm, P<0.05).
  
  
  CONCLUSIONS
  At clinically used concentrations the IOCM, iodixanol 320 mgI/ml, does not increase the heart rate during CTCA and causes less heart arrhythmia and less heat sensation than the LOCM, iomeprol 400 mgI/ml.
authors.affiliation: Department of Clinical Science, Intervention and Technology at Karolinska Institutet, Karolinska University Hospital in Huddinge, Stockholm, Sweden. anders.svensson@karolinska.se
authors.forename: Anders
authors.initials: A
authors.lastname: Svensson
authors.forename: Jonaz
authors.initials: J
authors.lastname: Ripsweden
authors.forename: Andreas
authors.initials: A
authors.lastname: Rück
authors.forename: Peter
authors.initials: P
authors.lastname: Aspelin
authors.forename: Kerstin
authors.initials: K
authors.lastname: Cederlund
authors.forename: B Torkel
authors.initials: BT
authors.lastname: Brismar
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media / Q000008:administration & dosage*; D017023:Coronary Angiography; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006358:Hot Temperature; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007479:Iopamidol / Q000008:administration & dosage / Q000031:analogs & derivatives*; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D010147:Pain Measurement; D012684:Sensory Thresholds / Q000187:drug effects; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed; D014283:Triiodobenzoic Acids / Q000008:administration & dosage*
chemical_list: D003287:Contrast Media; D014283:Triiodobenzoic Acids; C057937:iomeprol; C044834:iodixanol; D007479:Iopamidol