title: Bachmann Bundle and its arterial supply: imaging with multidetector CT--implications for interatrial conduction abnormalities and arrhythmias.
abstract: OBJECTIVE
  To retrospectively investigate anatomy of Bachmann Bundle (BB) and its vascular supply at 64-section multidetector computed tomography (CT) in healthy patients and patients with abnormalities.
  
  
  METHODS
  The institutional review board approved this HIPAA-compliant study and waived informed consent. Clinical histories, electrocardiograms (ECGs), and coronary 64-section multidetector CT angiograms in 317 patients were reviewed (healthy group, 164; group with abnormalities, 153). Among patients with abnormalities, 68 had atrial fibrillation (AF) or interatrial conduction block (IAB) (P wave duration, >or=120 msec), 46 had severe coronary artery disease (CAD) (>or=70% stenosis of coronary artery giving rise to sinuatrial node [SAN] artery), and 39 had severe CAD and an abnormal ECG (AF or IAB). Length, anteroposterior and superoinferior diameters, attenuation, and vascular supply of BB were studied. Student t test for continuous variables and contingency tables for categorical variables were used.
  
  
  RESULTS
  BB was visualized, to greater degree, in the healthy group (90.2% vs 73.9% for group with abnormalities, P < .001). Visualization of BB was similar among subgroups with abnormalities: 71.7% in patients with severe CAD, 73.5% in patients with abnormal ECG, and 76.9% in patients with severe CAD and abnormal ECG. BB measurements were similar for both groups. Patients with nonvisualized BB displayed lower overall mean attenuation in the region, with -30.6 HU +/- 33.4 (standard deviation), but mean attenuation in healthy patients was 51.3 HU +/- 59.9 (P < .001). This finding suggests fatty infiltration. BB and BB region were mainly supplied by the right SAN artery (55.5%), followed by the left SAN artery (39.6%) and both SAN arteries (4.9%). In the group with abnormalities, there was a significant difference for SAN artery nonvisualization between those with and without identifiable BB (P = .001).
  
  
  CONCLUSIONS
  BB and its vascular supply can easily be demarcated on cardiac CT images. BB was visualized less in patients with severe CAD and abnormal ECG, a finding that suggests that disease of BB fibers may play a role in development of atrial arrhythmias.
authors.affiliation: Department of Radiological Sciences, University of California, Irvine Medical Center, 101 The City Drive, Rte 140, Orange, CA 92868-3298, USA. fsaremi@uci.edu
authors.forename: Farhood
authors.initials: F
authors.lastname: Saremi
authors.forename: Stephanie
authors.initials: S
authors.lastname: Channual
authors.forename: Subramaniam
authors.initials: S
authors.lastname: Krishnan
authors.forename: Swaminatha V
authors.initials: SV
authors.lastname: Gurudevan
authors.forename: Jagat
authors.initials: J
authors.lastname: Narula
authors.forename: Amir
authors.initials: A
authors.lastname: Abolhoda
mesh_terms: D001145:Arrhythmias, Cardiac / Q000000981:diagnostic imaging*; D016001:Confidence Intervals; D017023:Coronary Angiography; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D003330:Coronary Vessel Anomalies / Q000000981:diagnostic imaging*; D004562:Electrocardiography; D005260:Female; D006325:Heart Atria / Q000002:abnormalities* / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*