Spectral analysis of radial pulse in patients with acute, uncomplicated myocardial infarction
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1Division of Cardiology, Veterans General Hospital, Kaohsiung, Taiwan, Republic of China.
Insights
This study analyzed arterial pulse frequency spectra in myocardial infarction patients, revealing specific changes in pulse wave components (C2 and C3) correlating with effective renal plasma flow. These findings suggest a non-invasive method for assessing heart attack recovery.
Area of Science:
- Cardiology
- Biomedical Engineering
- Physiology
Background:
- Acute myocardial infarction (MI) presents unique physiological challenges.
- Non-invasive monitoring of cardiovascular dynamics is crucial for patient management.
- Arterial pulse wave analysis offers potential insights into cardiac function.
Purpose of the Study:
- To investigate the frequency spectrum of arterial pulses in patients with acute myocardial infarction.
- To compare pulse wave analysis in MI patients with control groups undergoing cardiac procedures.
- To explore the relationship between pulse wave spectral changes and renal function post-MI.
Main Methods:
- Radial pulse recordings were taken from 17 acute MI patients and 3 control groups.
- Discrete Fourier transformation was used to obtain power spectra of pulse waves.
- Effective renal plasma flow (ERPF) was measured using I-131 labelled iodo-ortho-hippurate.
- Correlation analysis was performed between pulse wave spectral components and ERPF.
Main Results:
- Acute MI patients showed a distinct decrease in frequency moduli C2 and C3, and C0 energy, unlike control groups.
- A significant inverse correlation was found between the initial drop in C2/C3 and initially higher ERPF.
- ERPF was significantly higher at MI onset compared to one week later.
Conclusions:
- Acute myocardial infarction is associated with specific, non-invasive changes in radial pulse wave frequency spectra.
- Changes in effective renal plasma flow may influence pulse wave spectral components (C2, C3) post-MI.
- These findings suggest coupled oscillations between the aorta and nearby organs, potentially modeling a resonance circuit.
Abstract:
The aim of this study was to examine the frequency spectrum of arterial pulses in 17 patients with acute, uncomplicated myocardial infarction. Recordings of right radial pulses were taken from these patients immediately after their arrival at the emergency room. This information was considered as baseline data and was monitored at the same time each day for up to 7 days. These serial recordings of radial pulses were then analyzed together with recordings from 3 control groups of patients not suffering from myocardial infarction. These included subjects who underwent coronary arteriography (n = 24), coronary angioplasty (n = 18), and mitral valvuloplasty (n = 13). The method of analysis involved a discrete Fourier transformation of radial pulses recorded from an external pulsation transducer to obtain "power spectra" for pulse waves. There was no significant change in the power spectrum for each of the 3 control groups although significant clinical and hemodynamic improvement was observed in the coronary angioplasty and mitral valvuloplasty patients. In sharp contrast, the intensity of the frequency moduli C2 and C3 in the target group fell on arrival at the emergency room and then gradually increased while the average pulse energy (frequency modulus C0) decreased simultaneously with stable recovery from the acute myocardial infarction. In order to investigate the changes in C2 and C3 in the target group, the effective renal plasma flow (ERPF) was first determined for 10 of the 17 patients using intravenous I-131 labelled iodo-ortho-hippurate. A second reading was taken a week later. Eight of the 10 patients were found to have a relatively "higher" ERPF at the onset of acute myocardial infarction with an average reading of 450.1 +/- 168.9 ml/min, compared with the data obtained a week later (374.1 +/- 130.4 ml/min, p < 0.02). An inverse correlation existed between the percentage of "initial drop" in frequency moduli C2 and C3 in the power spectra of the radial pulses and the percentage of "initially higher" ERPF (r = -0.66 and -0.70, respectively, p < 0.05). It is concluded that there was a specific change in the power spectrum of the radial pulses which were recorded and analyzed noninvasively in patients with acute, uncomplicated myocardial infarction. Changes in the ERPF may exert an influence on the frequency moduli C2 and C3 of the power spectra of the radial pulses after heart attack, suggesting that the aorta and the closely organs may cause coupled oscillation. Theoretically this structure is equivalent to a resonance circuit.