Venous return increased filling

Organic nitrates (A) increase blood flow, hence 02 supply, because diastolic wall tension (preload) declines as venous return to the heart is diminished. Thus, the nitrates enable myocardial flow resistance to be reduced even in the presence of coronary sclerosis with angina pectoris. In angina due to coronary spasm, arterial dilation overcomes the vasospasm and restores myocardial perfusion to normal. 02 demand falls because of the ensuing decrease in the two variables that determine systolic wall tension (afterload) ventricular filling volume and aortic blood pressure. 

After an anecdotal report of CPR performed successfully with a plumbers helper, interest was stimulated in active decompression of the chest, allowing for negative intrathoracic pressure and increased venous return [44,45]. This technique became known as active compression - decompression (ACD-CPR), and has achieved routine clinical use in some countries, such as France. While discussion continues as to whether definitive survival is increased, studies have shown that flow, filling pressure, and valve movement (as thoracic pump) is improved with respect to standard CPR. Initial reports of significant improvement of outcome have been challenged by others who were unable to find improvements [46]. ACD-CPR... 

Position head of bed flat or at a maximum of 10 degree of elevation to enhance venous return to the heart and increase left atrial filling pressure, reducing ADH release. 

Human Studies of the Consequences of AVF Creation Shortly after access creation, CO increases due to both left ventricular ejection fraction and heart rate increase [9]. These changes are probably driven by the decrease in systemic vascular resistance (caused by the arterial anastomosis of the VA) and by the increase of preload (venous return to the heart). Such changes could be considered rather physiological. However, within some weeks after access creation, Iwashima et al. [10] observed also an increase in the left ventricular diastolic diameter the indices of diastolic left ventricle function worsened, and levels of natriuretic peptides increased. The rise of B-natriuretic peptide (BNP) correlated with the diastolic function (E/A ratio, which is early/atrial left ventricular filling). Similar findings were observed in our center in a group that had their first VA with the access flow volume of only 789 361 ml/min 6 weeks after... 

Figure 10.12 shows a dynamic system in a vessel where, for example, a hlood holus volume on its passage leads to a temporal local volume increase during heart systole. The measured zone in the inner cylinder is filled with blood (inflow phase). Later, during the diastole, the blood is transported further (outflow phase), but also returned via the venous system. Figure 10.12 shows a tetrapolar electrode system for the measurement of G. 

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