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GLOSSARY OF TERMS USED IN TIME SERIES ANALYSIS
OF CARDIOVASCULAR DATA
HEART RATE TURBULENCE

The physiological response of the sinus node to premature ventricular contractions characterized by a short acceleration followed by a deceleration of the heart rate.

Heart Rate Turbulence is quantified by the onset and the slope.

Turbulence Onset (TO): difference (in %) between the sum of the two normal RR intervals following (RR1 and RR2) and the sum of the two normal RR intervals preceding (RR-1 and RR-2) the premature ventricular contraction.

TO = [(RR1+RR2) - (RR-1+RR-2)]  /  (RR-1+RR-2) * 100

TO> 0 means deceleration, TO<0  means acceleration of the sinus rhythm.

The Turbulence Slope (TS):  the steepest slope of the linear regression line for each sequence of five consecutive normal intervals following the premature ventricular contraction in the local averaged tachogram.

TO and TS were shown to be important predictors of of mortality after myocardial infarction, and that dysfunctions of the arterial baroreflex may be responsible for abnormal values of turbulence.

Links
Heart Rate Turbulence: The Site, by the Working Group of Biological Signal Analyses of the Technische Universitat Munchen

References
Schmidt G et al (1999) Heart-rate turbulence after ventricular premature beats as a predictor of mortality after acute myocardial infarction. Lancet
Mrowka R at al (2000) Blunted arterial baroreflex causes "pathological" heart rate turbulence. Am J Physiol Regulatory Integrative Comp Physiol

(PC 07-09-2003)

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