Analysis of the spontaneous variability of ventricular arrhythmias: Consecutive ambulatory electrocardiographic recordings of ventricular tachycardia

Pratt, Craig M.; Slymen, Donald J.; Wierman, Ann; Young, James B.; Francis, Marilyn; Seals, A. Allen; Quiñones, Miguel Á.; Roberts, Robert

doi:10.1016/0002-9149(85)90568-5

Cited by 89 publications

(10 citation statements)

References 29 publications

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“…This measure was described by Morganroth et a115 and Pratt et al, 22 and it represents the percent suppression required to show a significant departure from spontaneous variability or the percent suppression required to show a true drug effect. This measure was obtained for both total PVCs per hour and repetitive ventricular beats per hour.…”

Section: Discussionmentioning

confidence: 99%

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

et al. 1988

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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

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Section: Discussionmentioning

confidence: 99%

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

et al. 1988

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“…This study used the former because of the patients' frequent VPBs in the baseline study. Since 24-hour ambulatory ECG shows day-to-day variations in the frequency of VPBs in individual patients, the criteria for efficacy were defined as a ->75% reduction in the total VPB count and a ->90% reduction in the couplet VPB count [13]. In the baseline study, frequent ventricular tacbycardias (->10 times a day) were recorded in only four patients, and we did not investigate the effect of therapies on ventricular tachycardia.…”

Section: Discussionmentioning

confidence: 99%

Efficacy of disopyramide and mexiletine used alone or in combination in the treatment of ventricular premature beats

Sakurada

Motomiya

Hiraoka

1991

Cardiovasc Drug Ther

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The efficacy of oral disopyramide and mexiletine used alone or in combination was studied in 75 patients with frequent ventricular premature beats (VPBs). The efficacy was evaluated with 24-hour ambulatory ECG and greater than or equal to 75% reduction in the number of VPBs was defined as effective. When disopyramide or mexiletine were ineffective or not tolerated, the alternative drug was administered and the efficacy was again evaluated. If the single administration of neither drug was effective, the combination of disopyramide and mexiletine was then given. Either disopyramide or mexiletine was effective in 48 patients, and neither drug was effective in 19 patients. In 19 patients unresponsive to both drugs, combination therapy was effective in six patients (32%). Both drugs caused side effects or one drug caused side effects and another drug was ineffective in eight patients. In five out of those patients, we attempted combined therapy with a reduced dosage of those drugs that caused side effects. This therapy was effective in two patients without intolerable side effects. Thus, when the single use of neither disopyramide nor mexiletine single-drug therapy is effective, it is worthwhile to try combination therapy. Also, combination therapy with a reduced dosage of the drugs that caused side effects might be the therapy of choice in patients who have developed dose-dependent side effects.

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“…'9 Comparison of these results with those of the present trial is difficult due to the low frequency of nonsustained VT in the previous study'9 and because there is a significant daily variability in the frequency of VT.22 24 In similar patients with a low frequency of VT (less than five runs of VT/day), we demonstrated that in many no VT (interpreted as " 1 00% VT suppression") is observed on a subsequent ambulatory electrocardiogram while they are on placebo.22 Our criterion for drug effect ('75% reduction in runs of nonsustained VT) was chosen to exceed known variability at the 95% confidence interval, given access to 3 days of ambulatory ECG information before and after drug therapy, which in our published experience must exceed a 68% reduction. 22 Although a 75% reduction in VT is adequate to define a "drug effect" or efficacy, it is clear that it may be clinically desirable and possibly mandatory to achieve a greater reduction in VT to decrease the incidence of sudden death, although this is not known at present. The entrance criterion of five or more runs of nonsustained VT was selected to eliminate patients with the greatest variability in VT and resulted in a patient population averaging 161 runs of VT daily.…”

Section: Discussionmentioning

confidence: 99%

Antiarrhythmic efficacy and hemodynamic effects of cibenzoline in patients with nonsustained ventricular tachycardia and left ventricular dysfunction.

Seals¹,

Haider²,

León³

et al. 1987

Circulation

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Analysis of the spontaneous variability of ventricular arrhythmias: Consecutive ambulatory electrocardiographic recordings of ventricular tachycardia

Cited by 89 publications

References 29 publications

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

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

Efficacy of disopyramide and mexiletine used alone or in combination in the treatment of ventricular premature beats

Antiarrhythmic efficacy and hemodynamic effects of cibenzoline in patients with nonsustained ventricular tachycardia and left ventricular dysfunction.

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