Computer characterization of sinus rhythm

Sinus rhythm tracings, including sinus tachycardia and bradycardia, are characterized quantitatively by means of an ECG measurement program which has been subjected to rigorous evaluation. The analysis is performed on tracings of short duration (10 sec). The features of regularity and stability are considered for the R wavetrain. Regularity is evaluated from the normalized differences between sucessive RR intervals. Stability is determined by the ratio of maximum and minimum RR interval durations. Due to the difficulities of automatic beat-to-beat detection and measurement of P waves, an estimate of the PR interval is obtained from a pseudo-PR interval determined from certain features of the P and R wavetrains. The constancy of this pseudo-PR interval is evaluated, and its absolute value is uded as a characteristic of the type of sinus rhythm.