Figure 1.
The pressure measurement device used in this study.
The mask (a) with related tube was connected to the watch-shaped manometer (b), which was detached from an aneroid sphygmomanometer (XB-11 aneroid sphygmomanometer, Shanghai Medical Equipment Factory, Shanghai, China), and the needle of the manometer was set at 100 mmHg as the zero point. The pulse transducer (c) with wire and plug could be attached to the ultrasonographic system to display the action of the Valsalva maneuver.
Table 1.
The common characteristics of the 30 volunteers of the in vivo study.
Figure 2.
The beat-by-beat responses to Valsalva maneuver (VM) were simultaneously recorded by dual PW/PW echocardiography.
The arrows show the beginning of a 40 mmHg VM. The tricuspid inflow spectrum (upper in each panel) and mitral inflow spectrum (lower in each panel) were simultaneously recorded. The peak velocity and the velocity-time integral (VTI) of each cardiac cycle can be measured in the spectrum. The bottom is the simultaneous ECG recording.
Figure 3.
Average percent changes in peak velocity (PV) and velocity-time integral (VTI).
The average percent of each beat was calculated as (mean value of each beat/the value at rest) ×100%. The upper panel shows the average percent changes of the peak inflow velocity of mitral valve (M-PV), the mitral VTI (M-VTI). The lower panel shows the average percent changes of the peak inflow velocity of tricuspid valve (T-PV), the tricuspid VTI (T-VTI).
Figure 4.
Changes in inflow volume of left heart (L-IV) and right heart (R-IV).
The arrows below show the onset and the release of the 40 mmHg VM.
Table 2.
Inter- and intraobserver variabilities in the measurements in fifteen subjects.
Figure 5.
The fully-intrathoracic system and the partially-intrathoracic system of our hypothesis.
Anatomically and functionally, the circulatory system can be divided into two parts, the fully-intrathoracic system (the dark part) is completely in the chest cavity, while the partially-intrathoracic system (the white part) is partly in the chest cavity and is connected with the vein or artery system outside the chest cavity. These two systems are a little different in diastole and in systole. RA = Right Atrium; RV = Right Ventricle; LA = Left Atrium; LV = Left Ventricle; PA = Pulmonary Artery; AO = Aorta; PVS = Peripheral Venous System; PAS = Peripheral Arterial System.