Early Time Course of Heart Rate Variability after Thrombolytic and Delayed Interventional Therapy for Acute Myocardial Infarction

Abstract

In 89 of 97 consecutive patients with myocardial infarction (MI) undergoing thrombolysis and delayed early coronary angiography with PTCA, if indicated, heart rate variability (HRV) in time domain was evaluable 40 ± 11 h after the onset of chest pain using 24-hour ECG recordings. Patients with anterior MI (n = 40) had lower values for HRV and left ventricular ejection fraction (p < 0.05). The mean of all 5-min standard deviations of RR intervals (SDNNi) and the root-mean-square difference of successive RR intervals (rMSSD) decreased significantly (p < 0.001 each), whereas the standard deviation of all normal RR intervals and the percentage of absolute differences between successive RR intervals only showed a tendency to lower values 4 weeks after MI (p = 0.20 and 0.08, respectively). The decreases in SDNNi and rMSSD were more evident in inferior than in anterior MI. The time course of HRV following MI was similar in patients with and without PTCA. These results indicate an initial vagal hyperactivity in inferior MI, which is quickly predominated by sympathetic activation and a prolonged recovery of the cardiac autonomic imbalance after MI despite a successful combined reperfusion therapy.

Depressed heart rate response to vasodilator stress for myocardial SPECT predicts mortality in patients after myocardial infarction

“…These findings are consistent with the known association of low HR variability with larger sized infarction [18,20,23], that is credited to a heightened sympathetic drive and reduced cardiac parasympathetic outflow [18].…”

“…Analogous comparisons between decreased HR variability and infarct site have shown a complex relationship. Whereas Lotze et al and Doulalas et al observed a more evident depression of HR variability in the early phase of anterior compared to inferior wall infarction [18,19], other investigators did not find a significant difference based on infarct location [11,20]. The relation has also been reported to be time dependent, with more depressed HR variability with anterior infarction only in the very early phase [21].…”

Exercise unmasks autonomic dysfunction in swine with a recent myocardial infarction

“…Parasympathetic tone is already reduced on the day of the infarction [19,20], but may recover over a period varying from several days [19,20] to months [21][22][23][24], except in patients who subsequently develop heart failure [25]. The degree of withdrawal of parasympathetic activity following a myocardial infarction depends on the size and location of the infarcted region [26,27], and the ensuing degree of LV dysfunction [8].…”

Autonomic Responses During Acute Anterior Versus Inferior Myocardial Infarction: A Systematic Review and Meta-Analysis

“…Another study examined thrombolysis followed by rescue PCI, with HRV measurements performed beyond the acute phase, i.e., (a mean of) 40 hours after the onset of symptoms [38]. In this cohort, the same autonomic pattern was confirmed, with successful thrombolysis resulting in faster HRV recovery in inferior, as compared to anterior MI; of note, rescue PCI exerted minimal effects on HRV indices in either location [38].…”

“…The speed of this process appears to vary among revascularization strategies, i.e., primary PCI versus thrombolysis, with delayed improvement in the latter, despite transient, short-lived fluctuations [37]. Another study examined thrombolysis followed by rescue PCI, with HRV measurements performed beyond the acute phase, i.e., (a mean of) 40 hours after the onset of symptoms [38]. In this cohort, the same autonomic pattern was confirmed, with successful thrombolysis resulting in faster HRV recovery in inferior, as compared to anterior MI; of note, rescue PCI exerted minimal effects on HRV indices in either location [38].…”