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Comparative value of eight M-mode echocardiographic formulas for determining left ventricular stroke volume. A
Insights
Echocardiographic formulas for calculating left ventricular stroke volume (SV) are unreliable in patients with asymmetrical heart contractions. However, the Teichholz formula provides a clinically useful estimate of SV in patients with symmetrical contractions.
Area of Science:
- Cardiology
- Medical Imaging
- Diagnostic Techniques
Background:
- Accurate measurement of left ventricular stroke volume (SV) is crucial for cardiovascular assessment.
- Echocardiography is a non-invasive imaging technique used to evaluate cardiac function.
- Various echocardiographic formulas exist to estimate SV, but their accuracy can be variable.
Purpose of the Study:
- To compare the accuracy of eight different echocardiographic formulas for calculating left ventricular stroke volume (SVE) against invasive reference methods.
- To evaluate the influence of left ventricular contraction patterns on the reliability of echocardiographic SV estimations.
- To identify the most accurate echocardiographic formula for estimating SV in specific patient populations.
Main Methods:
- Sixty-six patients underwent M-mode echocardiography prior to cardiac catheterization.
- Left ventricular stroke volume was calculated using eight echocardiographic formulas (SVE).
- Invasive stroke volume was determined by thermodilution (SVT) and left ventricular cineangiography (SVA).
Main Results:
- Four formulas calculating mitral or aortic flow showed poor correlation with invasive methods (r = 0.10 to 0.54).
- Left ventricular formulas using diameter measurements demonstrated weak correlations (r = 0.22 to 0.47) in patients with asymmetrical contractions.
- In patients with symmetrical contractions, two formulas, including the Teichholz formula, showed favorable correlations (r = 0.84-0.86) comparable to invasive techniques.
Conclusions:
- Echocardiographic estimation of left ventricular stroke volume is unreliable in patients with asymmetrical ventricular contraction.
- The Teichholz formula demonstrated the best performance among tested formulas for SV estimation.
- The Teichholz formula can provide a clinically useful estimate of stroke volume in patients with symmetrical or near-symmetrical left ventricular contraction.
Abstract:
Sixty-six consecutive patients without left ventricular volume overload, significant arrhythmia or significant pericardial effusion were examined by M-mode echocardiography immediately before diagnostic left- and right-heart catheterization. Using various echocardiographic measurements, left ventricular stroke volume (SV) was calculated according to eight different echocardiographic formulas (SVE) that have been proposed previously. At catheterization SV was also determined by thermodilution (SVT) and by single-plane left ventricular cineangiography in the right anterior oblique projection (SVA). When comparing SVE with SVT, the four formulas developed to calculate mitral or aortic flow failed (r = 0.10 to 0.54). As expected, poor correlations (r = 0.22 to 0.47) were also found when formulas used to calculate ventricular volumes from the ventricular diameter or SV from the change in diameter (left ventricular formulas) were used in coronary patients with grossly asymmetrical ventricular contraction patterns. When the use of the left ventricular formulas was confined to patients with symmetrical or almost symmetrical contraction, two formulas yielded favorable correlations of r = 0.84, SEE = 12.7 ml and r = 0.86, SEE = 12.2 ml, respectively. These correlations were comparable to the correlation between our two invasive reference techniques (r = 0.81; SEE = 12.2 ml). The comparison between SVE and SVA confirmed the results of the thermodilution study, though the correlations were generally weaker. We conclude that the formula of Teichholz et al., which was the best of all tested formulas, may be used to obtain a clinically useful estimate of SV in patients in whom symmetrical or almost symmetrical left ventricular contraction can be anticipated.