Changes in Blood Pressure and Heart Period Variability in Patients with Recent Acute 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.

Carvedilol recovers normal blood pressure variability in rats with myocardial infarction

“…Our study showed an overall decrease of BPV in the rats with healed MI, a finding partially prevented in the infarcted group submitted to the chronic use of carvedilol. Our data agreed with a previous study (Kardos et al, 1996) that also found decreased BPV in patients 3-5 days after infarction. BPV is linked to beat-to-beat changes in stroke volume.…”

“…Our study assessed the effect of chronic treatment with carvedilol on BPV in rats underwent MI. Previous studies (Detollenaere et al, 1993;Kardos et al, 1996;Mostarda et al, 2010) evaluated BPV in MI, but to our knowledge, this was the first study that investigated the effect of long-term treatment with carvedilol on BPV in an experimental infarction model.…”

Time course of changes in heart rate and blood pressure variability in rats with myocardial infarction

“…Data obtained by Kardos et al (30) show attenuation of the power spectrum 3 to 5 days after infarction in patients compared with controls, indicating that sympathetic activation may contribute to this finding but is not solely responsible for the post-infarction tachycardia. We also observed this finding in our study in rats free from the influence of drugs that affect autonomic modulation.…”

“…Kardos et al (30) observed that patients in the acute phase of infarction (3 to 5 days) show reduction in all of the spectral components of BPV compared with healthy individuals. They suggested that poor adaptation of the stroke volume of the infarcted heart is the cause of this finding.…”

Differences between diabetic and non-diabetic hypertensive patients with first acute non-ST elevation myocardial infarction and predictors of in-hospital complications

“…To the best of our knowledge, the predictive value of SBP variability for in-hospital morbidity has never been reported; BP variability has been evaluated in the acute phase of myocardial infarction in only one study on 11 patients without providing any information about its impact on clinical outcome [25].…”