Variability and spectral analysis of cardiac rhythm in diagnosis of dysfunction of the sinus node

Assessment of heart rate variability and spectral analysis of cardiac rhyth m in patients with sick sinus node syndrome and vagotonic dysfunction showe d that organic sinus node disease is associated with significant decrease o f variability and relative preponderance of low frequency spectrum. In vago tonic dysfunction heart rate variability increases and high frequency spect rum predominates. A conclusion is made of the necessity to use mathematical analysis of cardiac rhythm in diagnosis of sinus node dysfunctions.