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Effects of ventricular ectopy on sinus R-R intervals in patients with advanced heart failure
M A Woo1, W G Stevenson, D K Moser
1School of Nursing, University of California, Los Angeles.
Objective:
To determine the effect of ventricular ectopy on subsequent sinus R-R intervals.
Design:
Comparative, repeated-measures design.
Setting:
University medical center.
Subjects:
Ten consecutive sinus R-R intervals and their standard deviations before and after ventricular ectopy from 24-hour ambulatory electrocardiogram recordings were obtained from 25 patients with heart failure (left ventricular ejection fraction 0.18 +/- 0.08; New York Heart Association Functional Class III-IV) and three healthy subjects.
Results:
The effects of 7564 single ventricular ectopic beats, 272 ventricular couplets, and 49 episodes of ventricular tachycardia in the patients with heart failure and 1369 single ventricular ectopic beats in the three healthy subjects were evaluated. Repeated-measures ANOVA indicated no significant differences in sinus R-R intervals immediately before or after ventricular ectopy. Standard deviation of sinus R-R intervals before and after ventricular ectopy did not differ significantly.
Conclusions:
Ventricular ectopy does not significantly alter subsequent sinus R-R intervals and is unlikely to affect measurement of heart rate variability, particularly by techniques that use standard deviation methods.