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Changes in blood pressure and heart period variability in patients with recent acute myocardial infarction
1Second Department of Medicine, Albert Szent-Györgyi Medical University, Szeged, Hungary.
Insights
Patients with acute myocardial infarction exhibit significantly reduced blood pressure variability and heart period variability. This finding suggests altered cardiovascular regulation following a heart attack, potentially linked to reduced left ventricular compliance.
Area of Science:
- Cardiology
- Physiology
- Biomedical Engineering
Background:
- Decreased heart period variability and baroreflex sensitivity are documented in acute myocardial infarction (AMI).
- Blood pressure variability (BPV) is a major determinant of heart period variability (HPV).
- BPV characteristics during the acute phase of AMI remain understudied.
Purpose of the Study:
- To investigate blood pressure variability and heart period variability in patients with acute myocardial infarction.
- To compare cardiovascular variability parameters between AMI patients and healthy controls.
Main Methods:
- Short-term measurements of finger blood pressure and heart period variability were analyzed in 11 AMI patients and 13 age-matched controls.
- Frequency domain analysis (total, low, and high frequency components) was applied to assess BPV and HPV.
- Spectral powers were logarithmically transformed (Ln) for analysis.
Main Results:
- AMI patients showed significantly decreased HPV across all frequency components compared to controls.
- Significantly reduced BPV was observed in AMI patients in total, low, and high frequency components.
- Specific values for Ln(total power), Ln(low-frequency power), and Ln(high-frequency power) were significantly lower in AMI patients for both HPV and BPV.
Conclusions:
- Acute myocardial infarction is associated with significantly reduced blood pressure variability and heart period variability.
- Hypothesized mechanisms for reduced BPV in AMI include relative stroke volume invariance and reduced left ventricular compliance.
- These findings highlight altered cardiovascular autonomic regulation in the acute phase of myocardial infarction.
Abstract:
1. A decreased heart period variability and baroreflex sensitivity in patients with acute myocardial infarction have already been documented. Since one of the major determinants of heart period variability is blood pressure variability, it would be important to know the characteristics of blood pressure regulation in this setting. The changes in blood pressure variability during the acute phase of myocardial infarction have not yet been studied. 2. We investigated the blood pressure variability and the heart period variability in 11 patients with acute myocardial infarction 3 to 5 days after their admission. Thirteen age matched patients with no evidence signs of ischaemic heart disease or previous myocardial infarction served as controls. We used the frequency domain indexes of short term measurements of finger blood pressure variability and heart period variability. The spectral powers for both heart period variability and blood pressure variability were divided into three major components: total frequency (0.01-0.4 Hz), low frequency (0.04-0.15 Hz) and high frequency (0.15-0.4 Hz). 3. All of the frequency-domain components of the heart period variability were significantly decreased in patients with recent acute myocardial infarction compared to the controls: Ln(total power): 5.68 +/- 0.24 vs. 7.21 +/- 0.29, Ln(low-frequency power): 4.31 +/- 0.28 vs. 7.05 +/- 0.53, Ln(high-frequency power): 3.50 +/- 0.33 vs. 5.48 +/- 0.32. Acute myocardial infarction patients showed a significantly reduced blood pressure variability in all frequency components compared to the controls: Ln(total power): 4.21 +/- 0.18 vs. 6.79 +/- 0.48, Ln(low-frequency power): 2.40 +/- 0.24 vs. 4.36 +/- 0.21, Ln(high-frequency power): 3.31 +/- 0.25 vs. 5.66 +/- 0.38. 4. We hypothesize that the reduced blood pressure variability in the acute phase of myocardial infarction could be related to a relative invariance of stroke volume. The underlying mechanism is the reduced left ventricular compliance.