Magnetocardiographic mapping of QRS fragmentation in patients with a history of malignant tachyarrhythmias.
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.
Gödde
P
P
University Clinic Benjamin Franklin, Free Berlin University, 2nd Medical Clinic, Department of Cardiology and Pulmonary Disease, Berlin, Germany.
Agrawal
R
R
Müller
H P
HP
Czerski
K
K
Endt
P
P
Steinhoff
U
U
Oeff
M
M
Schultheiss
H P
HP
Behrens
S
S
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*