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Left ventricular filling rate at rest and during exercise in patients with previous myocardial infarction
P Assennato1, B Candela, E Hoffmann
1Facoltà di Medicina e Chirurgia, Università di Palerma, Italy.
Insights
Coronary artery disease significantly impairs left ventricular filling rate (PFR). Dynamic exercise unmasks these PFR abnormalities, particularly in anterior myocardial infarction patients, alongside increased end-systolic volume.
Area of Science:
- Cardiology
- Nuclear Medicine
- Cardiovascular Physiology
Background:
- Coronary artery disease (CAD) is a leading cause of heart dysfunction.
- Left ventricular filling rate (PFR) is a critical indicator of diastolic function.
- The impact of dynamic exercise on PFR in myocardial infarction (MI) patients requires further elucidation.
Purpose of the Study:
- To quantify left ventricular filling rate variations in patients with coronary artery disease using radionuclide techniques.
- To assess the effects of dynamic exercise on left ventricular diastolic function in these patients.
Main Methods:
- Radionuclide ventriculography was employed in 91 subjects (46 anterior MI, 30 inferior MI, 15 controls).
- Left ventricular time-activity curves were analyzed for peak filling rate (PFR), relative end-diastolic volume (rEDV), and relative end-systolic volume (rESV).
- Measurements were taken at rest and during symptom-limited dynamic exercise.
Main Results:
- Patients with previous myocardial infarction exhibited significantly lower PFR compared to healthy controls.
- Dynamic exercise revealed abnormal PFR in a substantial proportion of MI patients, more pronounced in anterior MI.
- An increase in relative end-systolic volume (rESV) during exercise was observed in anterior MI patients.
Conclusions:
- Myocardial infarction leads to significant alterations in left ventricular diastolic function, specifically PFR.
- Dynamic exercise is effective in unmasking latent PFR abnormalities not evident at rest.
- Exercise-induced increases in rESV may contribute to the observed PFR alterations in MI patients.
Abstract:
The purpose of this investigation was to define, with radionuclide technique, the variation on left ventricular filling rate in patients with coronary artery disease, and to determine the effects of dynamic exercise on this variation. The study was carried out on 91 subjects, 46 patients with anterior and 30 with inferior previous transmural myocardial infarction; 15 healthy subjects were studied as control group. All the patients underwent coronary angiography and left ventriculography. From the left ventricular time activity curve we considered the diastolic parameters of the peak filling rate (PFR). We considered also the relative end-diastolic volume (rEDV) and the relative end-systolic volume (rESV). These parameters were determined at rest and at the fifth minute of a symptom limited dynamic exercise taken in the supine position, on an ergometric bicycle. In normal subjects rest mean PFR values is 3.08 +/- 0.51 edv/s, during exercise occurs a physiological increase and mean PFR values becomes 5.48 +/- 1 edv/s. The patients with previous myocardial infarction show a PFR significantly smaller than in normal subjects. Abnormal PFR indices during exercise are present in a large number of these patients and the higher anomalies of PFR during exercise were found among patients with anterior myocardial infarction. In these patients we found an increase of rESV during exercise. In conclusion myocardial infarction induces significant alterations of the PFR; physical exercise reveals PFR alterations not exhibited at rest and rESV increase during exercise could be responsible for the PFR alteration observed.