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Early time course of heart rate variability after thrombolytic and delayed interventional therapy for acute
1Department of Internal Medicine III, Friedrich Schiller University, Jena, Germany. Ulrich.Lotze@med.uni-jena.de
Insights
Heart rate variability (HRV) analysis reveals prolonged cardiac autonomic imbalance after myocardial infarction (MI), even with successful reperfusion therapy. Initial vagal hyperactivity in inferior MI quickly shifts to sympathetic activation.
Area of Science:
- Cardiology
- Autonomic Nervous System Research
- Medical Diagnostics
Background:
- Myocardial infarction (MI) significantly impacts cardiac autonomic function.
- Assessing heart rate variability (HRV) is crucial for understanding post-MI recovery.
- Reperfusion therapies aim to restore cardiac function but their effect on autonomic balance needs further study.
Purpose of the Study:
- To evaluate the time course of cardiac autonomic function using heart rate variability (HRV) in patients after myocardial infarction (MI).
- To compare HRV changes between anterior and inferior MI.
- To investigate the impact of percutaneous coronary intervention (PCI) on HRV recovery post-MI.
Main Methods:
- 24-hour ECG recordings were used to assess time-domain HRV parameters (SDNNi, rMSSD) in 89 MI patients.
- Measurements were taken approximately 40 hours after chest pain onset and at 4 weeks post-MI.
- Patients underwent thrombolysis and, if indicated, delayed early coronary angiography with PTCA.
Main Results:
- Patients with anterior MI showed lower HRV and left ventricular ejection fraction compared to those with inferior MI.
- Significant decreases in SDNNi and rMSSD were observed post-MI, indicating autonomic dysfunction.
- These HRV reductions were more pronounced in inferior MI and persisted at 4 weeks, suggesting prolonged autonomic imbalance.
Conclusions:
- Myocardial infarction leads to a prolonged cardiac autonomic imbalance, characterized by initial vagal hyperactivity followed by sympathetic activation.
- The autonomic dysfunction recovery is slow, even after successful reperfusion therapies like PTCA.
- HRV monitoring provides valuable insights into the complex recovery process following MI.
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.