Changes in spontaneous variability of ventricular ectopic activity as a function of time in patients with chronic arrhythmias.

Abstract

Previous determinations of spontaneous variability in ventricular arrhythmia have often been based on measurements from consecutive days in small patient populations, whereas clinical determinations of drug efficacy typically compare measurements at intervals of 1 week and longer to baseline. We, therefore, sought to determine whether spontaneous arrhythmia variability changes as a function of time during periods ranging from 1 day to 1 year or longer. The percent reduction in the frequency of total premature ventricular complexes (PVCs) and repetitive ventricular beats required to show true drug effect rather than spontaneous variability in PVCs was determined in 47 consecutive patients with chronic ventricular arrhythmias who underwent multiple ambulatory monitor recordings while off active drug treatment (during placebo therapy). The variability in PVC rate was determined during the intervals of 1 day, 1 week, 2 weeks, 3 weeks, 4 weeks, and 1 year or longer. The percent reductions in total PVCs required to exceed the 95% confidence limits of spontaneous variability at these intervals were 55%, 85%, 86%, 93%, 96%, and 96%, respectively. Corresponding values for repetitive beats were 75%, 95%, 92%, 95%, 94%, and 98%, respectively. The percent increase in total PVCs and repetitive beats required to establish "arrhythmia aggravation" caused by an antiarrhythmic drug with a 95% confidence limit also was calculated for this study population and was 124% and 303%, respectively, at 1-day intervals and 2,269% and 4,091%, respectively, at l-year (or longer) intervals for the 24-hour monitor recordings. Variability was not substantially affected by underlying heart disease or ejection fraction. PVC rate showed a modest negative correlation with variability (r=0.3). Thus, variability is substantially greater at 1 week, the usual time for clinical assessment of antiarrhythmic drug efficacy, than at 1 day (p<0.01). Suppression of more than 85% of total PVCs and more than 95% of repetitive beats appears to be necessary after 1-2 weeks to be confident of a true drug effect. Even greater variability is observed after 1 month and up to 1 year so that reductions of up to 95% in total PVCs and 98% in repetitive beats may represent spontaneous change. True antiarrhythmic drug effects and also proarrhythmic effects may be better assessed by reducing the time (to .2-4 days) between drug-free (baseline) and drug-testing recordings and by reassessing efficacy during short drug-washout periods during the course of long-term treatment than by the common practice of comparing multiple consecutive baseline recordings with distant treatment recordings. (Circulation 1988;78:286-295) A mbulatory electrocardiographic recording is used widely for detecting arrhythmias and for guiding antiarrhythmic therapy since Holter' first suggested its potential value. The frequency of ventricular arrhythmia occurrence and its

Repeatability of ectopic beats from 48‐hr ambulatory electrocardiography: The Atherosclerosis Risk in Communities (ARIC) Study

“…12 Similarly, correlations between PVCs on 24-hour ambulatory ECG recording taken 1, 2, 3 and 4 weeks apart were >0.87, however, correlations between weekly measures and PVCs measured 1 year later were weak (range 0.33 to 0.60) among 47 participants with frequent PVCs (≥30 PVCs/hr). 10 The sample size in the study was reduced at each follow-up and only 6 participants were measured at one year. All these studies, however, reported correlation coefficients, which do not speak to repeatability; correlations only indicate the strength of a linear relationship between two variables.…”

National Russian Guidelines on Application of the Methods of Holter Monitoring in Clinical Practice

“…Рядом авторов исследована межсуточная вариабельность частоты и типа аритмий, выявляемых в различных группах больных [21,[168][169][170][171][172][173][174][175]. Также имеются ограничения и при долговременной воспроизводимости частоты и типа желудочковых аритмий [176][177][178][179][180][181].…”

Spontaneous variability in ventricular ectopic activity during chronic antiarrhythmic therapy.

“…Notice that on-drug recordings are referenced to the one or two consecutive off-drug baseline recordings in all analyses and that off-drug recordings have been shown to show substantial variability over time. 32 The pattern of variability during follow-up was used to classify long-term response of individual patients into six mutually exclusive categories, as defined in the legend to Figure 2. Both total and repetitive PVCs were used in this classification, and the K statistic was used to test the association between the classes for total and repetitive PVCs.…”