Submitted on November 12, 2002
Accepted on January 24, 2003
Power spectral and Poincare plot characteristics in sinus node dysfunction
Lennart Bergfeldt1* and Yoshiyuki Haga2
1 Department of Cardiology, Karolinska Institutet, Stockholm, Sweden
2 Department of Surgery II, National Defense Medical College, Saitama, Japan
* To whom correspondence should be addressed. E-mail: lennart.bergfeldt{at}.
A salient feature of the normal sinus node activity is its prominent beat-to-beat variability, which shows self-similarity on different time-scales (fractal dynamics). However, in patients with sinus node dysfunction short-term time sinus cycles show exaggerated variability, the characteristics of which has not been analyzed. Therefore, Poincare plots and power spectral analysis were applied to short-term variations of sinus cycles in 30 patients with and 30 patients without sinus node disease. Three patterns of behavior were observed in sick sinus patients: [type 1] completely normal (n=3), [type 2] random-like pattern in the Poincare plots with "white noise" power spectra (n=9), and [type 3] a transitional pattern, characterized by remnants of normal behavior mixed with scattered points (n=18). In controls only type 1 (n=27) and type 3 (n=3) patterns were observed, p<0.0001. - The power spectral changes in sinus node dysfunction is thus characterized by a loss of the inverse power law relationship (1/f) , which both has implications for heart rate variability analysis and might offer a new diagnostic approach.
