Characterization of atrial fibrillation using the surface ECG: time-dependent spectral properties.
Time-frequency analysis is considered for characterizing atrial fibrillation in the surface electrocardiogram (ECG). Variations in fundamental frequency of the fibrillatory waves are tracked by using different time-frequency distributions which are appropriate to short- and long-term variations. The cross Wigner-Ville distribution is found to be particularly useful for short-term analysis due to its ability to handle poor signal-to-noise ratios. In patients with chronic atrial fibrillation, substantial short-term variations exist in fibrillation frequency and variations up to 2.5 Hz can be observed within a few seconds. Although time-frequency analysis is performed independently in each lead, short-term variations in fibrillation frequency often exhibit a similar pattern in the leads V1, V2 and V3. Using different techniques for short- and long-term analysis, it is possible to reliably detect subtle long-term changes in fibrillation frequency, e.g., related to an intervention, which otherwise would have been obscured by spontaneous variations in fibrillation frequency.
Signal Processing Group, Department Applied Electronics, Lund University, S-221 00 Lund, Sweden.
M
M
Stridh
L
L
Sörnmo
C J
CJ
Meurling
S B
SB
Olsson
D001281:Atrial Fibrillation / Q000175:diagnosis*; D002908:Chronic Disease; D004562:Electrocardiography; D006801:Humans; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted