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The systolic arterial pressure/end-systolic volume relationship in patients with severe left ventricular dysfunction
Insights
Noninvasive measurements of the end-systolic pressure/end-systolic volume relationship effectively distinguish normal from severely impaired left ventricles. This method provides a linear assessment of cardiac function, aiding in diagnosis.
Area of Science:
- Cardiology
- Physiology
- Medical Imaging
Background:
- The end-systolic pressure/end-systolic volume (ESP/ESV) relationship is a key indicator of left ventricular performance.
- Assessing this relationship noninvasively could offer a valuable diagnostic tool.
Purpose of the Study:
- To determine if noninvasive measurements of the ESP/ESV relationship can differentiate normal individuals from those with severe left ventricular dysfunction.
- To evaluate the linearity and characteristics of the ESP/ESV relationship in different cardiac states.
Main Methods:
- Evaluated the relationship between arterial systolic pressure and radionuclide estimates of end-systolic volume.
- Utilized cuff sphygmomanometry for systolic pressure and phenylephrine to increase arterial pressure in 12 normal subjects and 24 patients.
- Acquired data at rest, after atropine, and during induced pressure changes.
Main Results:
- The peak-systolic pressure/end-systolic volume (SP/ESV) relationship was linear (r ≥ 0.91) in all subjects.
- Normal subjects exhibited a steeper slope (73 +/- 21.7) and higher zero pressure intercept (49.8 +/- 30 mm Hg) compared to myopathic patients (20.8 +/- 8.7 mm Hg/volume unit/m2 and 27.1 +/- 44.2 mm Hg, respectively).
- Normal subjects had higher resting ejection fraction (EF) and smaller end-diastolic volume (EDV).
Conclusions:
- Noninvasive determination of the SP/ESV relationship is linear and effectively distinguishes normal from severely impaired left ventricles.
- This method provides a reliable, noninvasive assessment of left ventricular systolic performance.
- Findings support the clinical utility of noninvasive ESP/ESV assessment for diagnosing cardiac dysfunction.
Abstract:
Performance of the intact left ventricle is well-defined by the end-systolic pressure/end-systolic volume relationship that appears independent of preload and afterload. To determine whether noninvasive measurements of this relationship could distinguish normal from abnormal subjects, we evaluated the relationship between arterial systolic pressure (determined by cuff sphygnomanometry) and radionuclide estimates of end-systolic volume in 12 normal subjects and 24 patients with severe left ventricular dysfunction. Data were acquired at rest, after atropine injection, and then during at least three increments of arterial pressure (average total increase approximately 45 mm Hg) using phenylephrine. The relationship between peak-systolic pressure (SP) and end-systolic volume (ESV) was found to be linear in all subjects (r greater than or equal to 0.91). The slope of this line was steeper in normal subjects than in myopathic patients (73 +/- 21.7 vs 20.8 +/- 8.7 mm Hg/volume unit/m2, P less than 0.001) and the zero pressure intercept also was greater (49.8 +/- 30 mm Hg vs 27.1 +/- 44.2 mm Hg, P less than 0.01). Similarly, resting ejection fraction (EF) was greater in the normals (0.71 +/- 0.88 vs 0.21 +/- 0.07% P less than 0.001) and end-diastolic volume (EDV) was smaller (4.14 +/- 0.88 vs 6.58 +/- 0.65 volume units, P less than 0.01). Systolic pressure/end-systolic volume relationship determined by these noninvasive methods was linear in both patients with severely reduced cardiac function and normal control subjects, clearly distinguishing normal from severely impaired left ventricles.(ABSTRACT TRUNCATED AT 250 WORDS)