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[Preload dependence of atrial contribution: correlation with left ventricular endo-diastolic wall stress]
Insights
High left ventricular wall stress reduces the heart
Area of Science:
- Cardiology
- Cardiac Physiology
- Echocardiography
Background:
- Atrial contribution to ventricular filling is crucial for cardiac function.
- Left ventricular end-diastolic wall stress (sigma ed) may influence atrial contribution.
- Understanding this relationship is vital for managing heart conditions.
Purpose of the Study:
- To investigate the correlation between left ventricular end-diastolic wall stress (sigma ed) and atrial contribution.
- To analyze the impact of preload and stiffness on atrial contribution.
- To determine factors influencing left ventricular filling dynamics.
Main Methods:
- Echocardiography with pulsed Doppler and cardiac catheterization with cineangiography were employed.
- Index of atrial contribution (A/R ratio) and left ventricular end-diastolic stiffness (delta P/delta V) were calculated.
- Correlations between these indices, sigma ed, m-PCWP, and LVEDP were analyzed in 35 patients.
Main Results:
- Atrial contribution (A/R) was inversely correlated with sigma ed (r = -0.75), m-PCWP (r = -0.62), and LVEDP (r = -0.59).
- A/R was also inversely correlated with left ventricular end-diastolic stiffness (delta P/delta V) (r = -0.72).
- Left ventricular end-diastolic stiffness (delta P/delta V) was significantly correlated with sigma ed (r = 0.92).
Conclusions:
- Elevated left ventricular end-diastolic wall stress diminishes atrial contribution to ventricular filling.
- Left ventricular end-diastolic stiffness is significantly determined by left ventricular end-diastolic wall stress.
- Atrial contraction effectively increases left ventricular volume only when sigma ed is low.
Abstract:
The correlation between left ventricular end-diastolic wall stress (sigma ed) and atrial contribution was investigated using echocardiography including the pulsed Doppler method and cardiac catheterization with cineangiography in 21 patients with coronary artery disease, 4 with hypertensive heart disease, 3 with hypertrophic cardiomyopathy, 3 with dilated cardiomyopathy, 4 with aortic regurgitation, and 10 normal subjects. The ratio of peak velocities (A/R) in the rapid filling phase (R) and atrial contraction phase (A) was used as the index of atrial contribution. Left ventricular end-diastolic stiffness (delta P/delta V) was calculated by the ratio of increases in left ventricular pressure and volume during the atrial contraction phase. The correlations between A/R and sigma ed, mean pulmonary capillary wedge pressure (m-PCWP), and left ventricular end-diastolic pressure (LVEDP) were analyzed in the 35 patients. Correlations between delta P/delta V and sigma ed and A/R were also analyzed. A/R was inversely correlated with sigma ed (r = -0.75), m-PCWP (r = -0.62) and LVEDP (r = -0.59), suggesting that A/R is influenced significantly by preload. A/R was also inversely correlated with delta P/delta V (r = -0.72). delta P/delta V was significantly correlated with sigma ed (r = 0.92), suggesting that sigma ed is a factor for determining left ventricular end-diastolic stiffness. Left ventricular volume can be increased in patients with low sigma ed by atrial contraction, achieving good atrial contribution. Left ventricular volume will be little increased by atrial contraction in patients with elevated sigma ed despite significant increase of left ventricular end-diastolic pressure, resulting in diminished atrial contribution.(ABSTRACT TRUNCATED AT 250 WORDS)