Frequency Distribution, Variance, and Moving Average of Left Ventricular Rhythm and Contractility during Atrial Fibrillation in Dog.
- 1 January 2002
- journal article
- Published by Physiological Society of Japan in The Japanese Journal of Physiology
- Vol. 52 (1), 41-49
- https://doi.org/10.2170/jjphysiol.52.41
Abstract
Mean levels of left ventricular rhythm and contractility averaged over arrhythmic beats would characterize the average cardiac performance during atrial fibrillation (AF). However, no consensus exists on the minimal number of beats for their reliable mean values. We analyzed their basic statistics to find out such a minimal beat number in canine hearts. We produced AF by electrically stimulating the atrium and measured left ventricular arrhythmic beat interval (RR) and peak isovolumic pressure (LVP). From these, we calculated instantaneous heart rate (HR = 60,000/RR), contractility (E(max) = LVP/isovolumic volume above unstressed volume), and beat interval ratio (RR1/RR2). We found that all their frequency distributions during AF were variably nonnormal with skewness and kurtosis. Their means +/- standard deviations alone cannot represent their nonnormal distributions. A 90% reduction of variances of E(max) and RR1/RR2 required a moving average of 15 and 24, respectively, arrhythmic beats on the average, whereas that of RR and HR required 60 beats on the average. These results indicate that a statistical characterization of arrhythmic cardiodynamic variables facilitates better understanding of cardiac performance during AF.Keywords
This publication has 24 references indexed in Scilit:
- Peak Endocardial Acceleration Reflects Heart Contractility Also in Atrial FibrillationPacing and Clinical Electrophysiology, 2000
- Temporal Organization of Atrial Activity and Irregular Ventricular Rhythm During Spontaneous Atrial Fibrillation:Journal of Cardiovascular Electrophysiology, 2000
- Effect of rhythm regularization on left ventricular contractility in patients with atrial fibrillation.The American Journal of Cardiology, 2000
- Left ventricular beat to beat performance in atrial fibrillation: dependence on contractility, preload, and afterloadHeart, 1999
- Optimal sampling interval to estimate heart rate at rest and during exercise in atrial fibrillationThe American Journal of Cardiology, 1989
- Is the pulse in atrial fibrillation irregularly irregular?Heart, 1986
- Atrial fibrillation: Minimal sampling interval to estimate average rateJournal of Electrocardiology, 1984
- Analysis of R-R Intervals in Patients with Atrial Fibrillation at Rest and During ExerciseCirculation, 1970
- Probabilistic Characterization of R-R IntervalsCardiovascular Research, 1969
- Study of Ventricular Response in Atrial FibrillationCirculation Research, 1961