Unedited premature beats increased the randomness of short-term R-R interval dynamics, with unedited alpha1 differing significantly between post-AMI patients who died versus survived (P<0.05).
Case-Control
Does the inclusion of unedited premature beats affect the prognostic significance of fractal scaling exponents in post-AMI and elderly populations?
Unedited premature beats increase the randomness of short-term R-R interval dynamics but do not necessarily need to be edited out when using fractal analysis for risk stratification.
p-value: p=<0.05
BACKGROUND: Premature beats (PBs) have been considered as artifacts producing a bias in the traditional analysis of heart rate (HR) variability. We assessed the effects and significance of PBs on fractal scaling exponents in healthy subjects and patients with a recent myocardial infarction (AMI). METHODS: Artificial PBs were first generated into a time series of pure sinus beats in 20 healthy subjects and 20 post-AMI patients. Thereafter, a case-control approach was used to compare the prognostic significance of edited and nonedited fractal scaling exponents in a random elderly population and in a post-AMI population. Detrended fluctuation analysis (DFA) was used to measure the short-term (alpha1) and long-term (alpha2) fractal scaling exponents. RESULTS: Artificial PBs caused a more pronounced reduction of alpha1 value among the post-AMI patients than the healthy subjects, for example, if > 0.25% of the beats were premature a > 25% decrease in the alpha1 was observed in post-AMI patients, but 4% of the premature beats were needed to cause a 25% reduction in alpha1 in healthy subjects. Both edited (1.01 +/- 0.31 vs 1.19 +/- 0.27, P < 0.01) and unedited alpha1 (0.71 +/- 0.33 vs 0.89 +/- 0.36, P < 0.05) differed between the patients who died (n = 42) and those who survived (n = 42) after an AMI. In the general population, only unedited alpha1 differed significantly between survivors and those who died (0.96 +/- 0.19 vs 0.83 +/- 0.27, P < 0.05). CONCLUSIONS: Unedited premature beats result in an increase in the randomness of short-term R-R interval dynamics, particularly in post-AMI patients. Premature beats must not necessarily be edited when fractal analysis is used for risk stratification.
Peltola et al. (Thu,) conducted a case-control in Myocardial infarction (AMI) and healthy subjects. Premature beats (PBs) vs. Pure sinus beats (edited R-R intervals) was evaluated on Short-term fractal scaling exponent (alpha1) differences between survivors and non-survivors (p=<0.05). Unedited premature beats increased the randomness of short-term R-R interval dynamics, with unedited alpha1 differing significantly between post-AMI patients who died versus survived (P<0.05).