Volume end systolic

Notes CO cardiac output VR venous return HR heart rate SV stroke volume EDV end-diastolic volume ESV end-systolic volume O blood flow AP pressure gradient R resistance r vessel radius P systolic pressure Piiastoik- diastolic pressure MAP mean arterial pressure TPR total peripheral resistance, P venous pressure Era- right atrial pressure Rv venous resistance. 

This trace shows the volume of the left ventricle throughout the cycle. The important point is the atrial kick seen at point a. Loss of this kick in atrial fibrillation and other conditions can adversely affect cardiac function through impaired LV filling. The maximal volume occurs at the end of diastolic filling and is labelled the left ventricular end-diastolic volume (LVEDV). In the same way, the minimum volume is the left ventricular end-systolic volume (LVESV). The difference between these two values must, therefore, be the stroke volume (SV), which is usually 70 ml as demonstrated above. The ejection fraction (EF) is the SV as a percentage of the LVEDV and is around 60% in the diagram above. 

Frames corresponding to end diastole and end systole are identified from each cine sequence and regions-of-interest (ROI) drawn around the left ventricular (LV) epi- and endocardial borders using ParaVision software (Bruker). The area of the ROIs is summed and multiplied by the inter-slice distance (5 mm) to calculate the end diastolic and end systolic volumes (EDV and ESV) of the whole ventricle and lumen. Other cardiac parameters are calculated as follows ... 

Burns RJ, Gibbons RJ, Yi Q, et al. The relationships of left ventricular ejection fraction, end-systolic volume index and infarct size to six-month mortality after hospital discharge following myocardial infarction treated by thrombolysis. J Am... 

WuE, Ortiz JT, Tejedor P, et al. Infarct size by contrast enhanced cardiac magnetic resonance is a stronger predictor of outcomes than left ventricular ejection fraction or end-systolic volume index prospective cohort study. Heart 2008 94(6) 730—6. 

Chronic hypertension, such as during obesity or in neurohormonal imbalances (Crowley et al., 2006), results in increased pressure in the aorta (pressure overload). The aortic valve opens at the start of systole and blood is forced from the LV into the aorta as the heart contracts as a result of higher pressure in the ventricle than the aorta. When the aortic valve closes at the end of systole, the remaining volume of blood in the LV is known as end-systolic volume (ESV). The resistance to blood flow from the LV is a result of pressure in the aorta and is known as afterload. When afterload is increased as a result of hypertension, the amount of blood ejected from the LV with each contraction, or stroke volume (S V=EDV - ESV), is reduced and ESV is increased, increasing wall stress and resulting in concentric hypertrophy of the LV. 

CRT also appears to confer long-term benefits on cardiac function. Several studies support a positive effect of CRT on cardiac remodeling. Yu et al. assessed CRT patients serially over 3 months. They found that there was progressive improvement in EF, LV end systolic volume, and LV end diastolic volumes (12). The MIRACLE trial similarly found progressive improvement of these parameters over 6 months of CRT patients (11). We frequently see patients continue to have symptomatic improvement several months after the procedure. 

Carabello BA, Nolan SP, McGuire LA (1981) Assessment of preoperative left ventricular function in patients with mitral regurgitation Value of the end-systolic stress-end-systolic volume ratio. Circulation 64 1212-1217... 

The mean correlation coefficient was 0.985 0.004 (SE). The result demonstrates that, as far as prediction of 5V is concerned, our linear end-systolic volume-elastance model is reasonably accurate despite its neglection of a slight afterload dependence (a small sift of V with changes in afterload resistance and characteristic impedance) (Maughan et ai, 1984). 

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