Related Experiment Videos
[Venous flow velocity patterns and cardiac function studied by Doppler echocardiography]
1Department of Internal Medicine, Faculty of Medicine, Kyoto University.
Insights
The VI ratio, derived from hepatic venous flow velocity, effectively indicates cardiac pump function. This ratio shows strong correlations with cardiac index in various heart conditions, offering valuable diagnostic insights.
Area of Science:
- Cardiology
- Hemodynamics
- Diagnostic Imaging
Context:
- Assessing cardiac pump function is crucial for diagnosing and managing heart disease.
- Hepatic venous flow velocity (VFV) and its derived metrics offer a non-invasive window into cardiac performance.
- Understanding the relationship between VFV patterns and cardiac output is essential for refining diagnostic tools.
Purpose:
- To investigate the correlation between central venous flow velocity (VFV) parameters and cardiac pump function, specifically the cardiac index (CI).
- To evaluate the utility of the VI ratio, calculated from VFV, as an indicator of cardiac pump efficiency in patients with and without atrial fibrillation.
- To explore how changes in cardiac rhythm (sinus rhythm vs. atrial fibrillation) affect the VFV pattern and its relationship with CI.
Summary:
- Doppler echocardiography was used to record hepatic venous flow velocity in normal subjects and heart disease patients. The systolic time-velocity integral (VIs) and diastolic time-velocity integral (VId) were computed to derive the VI ratio [VIs/(VIs + VId)].
- A strong positive correlation was observed between the VI ratio and cardiac index (CI) in patients with atrial fibrillation (r = 0.80), particularly those without tricuspid regurgitation.
- In patients with sinus rhythm, an inverse correlation was found between the VI ratio and CI (r = -0.70) when the VI ratio exceeded 0.75, suggesting differing hemodynamic responses based on atrial activity.
Impact:
- The VI ratio emerges as a promising, non-invasive indicator of cardiac pump function, potentially aiding in the assessment of heart disease severity.
- Findings highlight the differential impact of atrial fibrillation and sinus rhythm on VFV patterns and their correlation with CI.
- The study suggests that the VI ratio could be a valuable addition to echocardiographic assessments for evaluating cardiac performance and predicting outcomes in heart failure.
Abstract:
To study the relations of central venous flow velocity (VFV) to cardiac pump function, hepatic venous flow velocity was recorded using Doppler echocardiography in six normal subjects and 47 patients with heart disease, of whom 28 had sinus rhythm and 19, atrial fibrillation. The area under the VFV profile during systole and diastole in a cardiac cycle was computed, and termed the VIs (systolic time-velocity integral) and VId (diastolic time-velocity integral), respectively. VIs was divided by the sum of VIs and VId [VIs/(VIs + VId)], and this was termed the VI ratio. The cardiac index (CI) was estimated by Doppler echocardiography. In normal subjects, the VFV pattern in a cardiac cycle was biphasic, the systolic VFV being dominant. In patients with atrial fibrillation, the systolic VFV was attenuated or absent, the diastolic VFV being dominant. The CI correlated well with the VI ratio (r = 0.80; p less than .001) in 14 patients with atrial fibrillation except for five patients with tricuspid regurgitation. Four patients in whom atrial fibrillation converted spontaneously to sinus rhythm showed an increase in the CI and the VI ratio according to the CI-VI ratio relationship. In patients with sinus rhythm, the CI tended to decrease as the VI ratio increased. In 15 patients who had a VI ratio of over 0.75, the CI correlated inversely with the VI ratio (r = -0.70; p less than 0.01). Three of four patients who had the VI ratio of 1.0 died of congestive heart failure. Although there was positive correlation between the CI and VI ratio in patients without effective atrial contraction, there was inverse correlation in patients with effective atrial contraction. It is suggested that the VI ratio could be a good indicator of cardiac pump function.