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Use of apexcardiography to evaluate left ventricular diastolic compliance in human beings
Insights
The A/D ratio of the left apexcardiogram is a valuable noninvasive measure of left ventricular diastolic compliance. This ratio, along with the A/H ratio, shows significant changes in patients with heart failure.
Area of Science:
- Cardiology
- Biomedical Engineering
- Physiology
Background:
- Assessing left ventricular diastolic compliance is crucial for diagnosing and managing heart conditions.
- Noninvasive methods are preferred for patient comfort and frequent monitoring.
- Existing methods for measuring diastolic compliance can be invasive or complex.
Purpose of the Study:
- To investigate the relationship between left apexcardiogram amplitude ratios and left ventricular diastolic compliance.
- To determine if apexcardiogram ratios can serve as reliable noninvasive markers of diastolic function.
- To compare the efficacy of different apexcardiogram ratios in reflecting diastolic compliance.
Main Methods:
- Simultaneous high-fidelity recordings of left apex tracings and left ventricular pressure were obtained.
- Measurements included the A wave amplitude to total diastolic deflection (A/D) ratio, A wave amplitude to total height (A/H) ratio, and D/H ratio.
- These ratios were analyzed in normal subjects, patients without left ventricular disease, and patients with congestive cardiomyopathy.
Main Results:
- The A/D and A/H ratios were significantly elevated in patients with congestive cardiomyopathy compared to normal subjects.
- The D/H ratio remained within normal limits across all patient groups.
- The A/D ratio demonstrated a stronger correlation with specific compliance (r = -0.87) than the A/H ratio (r = -0.53).
Conclusions:
- The A/D ratio of the left apexcardiogram is a sensitive and noninvasive indicator of left ventricular diastolic compliance.
- The A/H ratio also shows potential as a noninvasive measure, though less strongly correlated than A/D.
- These apexcardiogram-derived ratios offer a practical approach to assessing diastolic function in clinical settings.
Abstract:
The relation between various relative amplitude measurements of the left apexcardiogram and internally derived indexes of diastolic compliance of the left ventricle was studied in 29 patients. Simultaneous high fidelity recordings of the left apex tracing and left ventricular pressure were obtained in 11 patients without left ventricular disease (group I) and 18 patients with congestive cardiomyopathy (group II). In 204 normal subjects the ratio of the A wave amplitude to the total diastolic deflection (A/D ratio) of the left apexcardiogram was 31.4 +/- 11.4 (mean +/- standard deviation) percent, the ratio of the A wave amplitude to the total height (A/H ratio) 8.9 +/- 4.3 percent and the D/H ratio 30.4 +/- 14.7 percent. The A/D and A/H ratios were significantly (P less than 0.001 and P less than 0.005) increased in group II (69.2 +/- 12.2 percent and 16.8 +/- 8.2 percent, respectively); they were within normal limits in group I. In contrast, the D/H ratio was within normal limits in both groups of patients. The A/D ratio correlated significantly better with specific compliance (deltaV/deltaP.V) (r = -0.87) than did the A/H ratio (r = -0.53), whereas similar correlations were obtained with end-diastolic volume compliance (dV/dPV) (r = -0.61 and r = - 0.64, respectively). In contrast, the D/H ratio correlated significantly only with end-diastolic distensibility index (dV/dP) (r = -0.52). It is concluded that A wave amplitude/total diastolic deflection (A/D) ratio and, to a lesser degree, the A wave amplitude/total height (A/H) ratio of the left apexcardiogram correspond best to diastolic compliance and are useful noninvasive measurements of this property of the left ventricle.