title: Magnetocardiographic mapping of QRS fragmentation in patients with a history of malignant tachyarrhythmias.
abstract: BACKGROUND
  The identification of patients at increased risk for ventricular tachycardia or ventricular fibrillation (VT/VF) and sudden cardiac death has consequences for therapeutic options and thus may reduce mortality in patients with coronary artery disease (CAD).
  
  
  OBJECTIVE
  We hypothesized that the intra-QRS fragmentation in magnetocardiographic recordings is increased in patients with CAD and with a history of VT/VF.
  
  
  METHODS
  Multichannel magnetocardiography (MCG) was carried out in 34 healthy controls, 42 patients with CAD without a history of VT/VF, and 43 patients with CAD and with a history of VT/VF. The intra-QRS fragmentation was quantified by a new fragmentation score. Its spatial distribution was investigated using two-dimensional (2-D) contour maps according to the sensor position of the 49-channel magnetogradiometer.
  
  
  RESULTS
  Patients with CAD and with a history of VT/VF had significantly increased QRS fragmentation compared with patients with CAD without VT/VF or controls (72.9+/-37.5, 48.5+/-14.3, and 42.5+/-7.8, respectively: p <0.05). The area of high fragmentation in 2-D contour maps was twice as large in patients with than in those without a history of VT/VF (represented by the number of MCG channels with high fragmentation: 26.3+/-15.5 vs. 12.4+/-9.9, p<0.0001). Patients prone to VT/VF could be identified with a sensitivity of 64% and a specificity of 90%.
  
  
  CONCLUSIONS
  In patients with CAD and with a history of VT/VF, intra-QRS fragmentation is increased and the area of high fragmentation in 2-D contour maps is enlarged. These findings may be helpful in identifying patients with CAD at risk for malignant tachyarrhythmias.
authors.affiliation: University Clinic Benjamin Franklin, Free Berlin University, 2nd Medical Clinic, Department of Cardiology and Pulmonary Disease, Berlin, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Gödde
authors.forename: R
authors.initials: R
authors.lastname: Agrawal
authors.forename: H P
authors.initials: HP
authors.lastname: Müller
authors.forename: K
authors.initials: K
authors.lastname: Czerski
authors.forename: P
authors.initials: P
authors.lastname: Endt
authors.forename: U
authors.initials: U
authors.lastname: Steinhoff
authors.forename: M
authors.initials: M
authors.lastname: Oeff
authors.forename: H P
authors.initials: HP
authors.lastname: Schultheiss
authors.forename: S
authors.initials: S
authors.lastname: Behrens
mesh_terms: D000328:Adult; D000465:Algorithms; D003327:Coronary Disease / Q000150:complications; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006801:Humans; D008280:Magnetics; D008297:Male; D008875:Middle Aged; D012815:Signal Processing, Computer-Assisted; D013610:Tachycardia / Q000150:complications / Q000503:physiopathology*; D014693:Ventricular Fibrillation / Q000150:complications / Q000503:physiopathology*