Volume end diastolic

The contractility of the myocardium determines the ejection fraction of the heart, which is the ratio of the volume of blood ejected from the left ventricle per beat (stroke volume) to the volume of blood in the left ventricle at the end of diastole (end-diastolic volume) ... 

Under normal resting conditions in which the end-diastolic volume is 120 to 130 ml and the stroke volume is 70 ml/beat, the ejection fraction is 55 to 60% ... 

The sympathetic system also innervates vascular smooth muscle and regulates the radius of the blood vessels. All types of blood vessels except capillaries are innervated however, the most densely innervated vessels include arterioles and veins. An increase in sympathetic stimulation of vascular smooth muscle causes vasoconstriction and a decrease in stimulation causes vasodilation. Constriction of arterioles causes an increase in TPR and therefore MAP. Constriction of veins causes an increase in venous return (VR) which increases end-diastolic volume (EDV), SV (Frank-Starling law of the heart), CO, and MAP. 

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. 

A pulmonary artery (Swan-Ganz) catheter can be used to determine central venous pressure (CVP) pulmonary artery pressure CO and pulmonary artery occlusive pressure (PAOP), an approximate measure of the left ventricular end-diastolic volume and a major determinant of left ventricular preload. 

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. 

This can be equated to the end-diastolic volume and is described by the Frank-Starling mechanism. Clinically it is equated to the CVP when studying the RV or the PAOP when studying the LV. 

Undesirable effects of 3-blocking agents in angina include an increase in end-diastolic volume and an increase in ejection time, both of... 

End-diastolic volume Decrease Increase None or decrease... 

Abbreviations BM-MNC, bone marrow mononuclear cell CABO, coronary artery bypass grafting CPC, circulating progenitor cells LV. left ventricle LVED. left ventricular end-diastolic diameter LVEDV, left ventricular end-diastolic volume LVEF, left ventricular ejection fraction NYHA, New York Heart Association SKMB, skeletal myoblast. 

GTN is a nitrate. This class of drugs are potent vasodilators. At therapeutic doses the main effect of nitrates is to act on vascular smooth muscle to dilate the veins, thus reducing central venous pressure (preload) and ventricular end-diastolic volume. The overall effect is to lower myocardial contraction, wall stress and oxygen demand, thereby relieving the angina. Nitrates also promote vasodilation of the coronary blood vessels. 

Coenzyme QIO is a powerful antioxidant naturally occurring in the mitochondria of myocardium, and it is an electron carrier in the mitochondrial synthesis of ATP. Patients with heart failure have lower myocardial levels of coenzyme QIO, but supplementation has been demonstrated to have variable benefits in randomized controlled trials. One meta-analysis on the use in congestive heart failure showed improvements in stroke volume, ejection fraction, cardiac output, cardiac index, and end diastolic volume index. " Another antioxidant associated with beneficial effects in cardiac patients is lycopene, a natural constituent of tomatoes. Lycopene is the major carotenoid found in human serum, and epidemiological studies have indicated an effect of dietary supplementation in reducing heart disease. Few dietary interventions have been reported one study showed a mild but significant hypocholesterolemic effect, and another showed a significant reduction in LDL oxidation. " Animal studies show an antiatherogenic effect of DHEA, and a review of the clinical trials and studies on DHEA in males with coronary heart disease reported a favorable or neutral effect. Plasma levels of DHEA are decreased in patients with chronic heart failure in proportion to its severity. ... 

Adverse Effects. The side effects of topical minoxidil are mainly local, caused by skin irritation and contact dermatitis. Systemic side effects are uncommon because of limited percutaneous absorption, but diffuse hypertrichosis of the face and limbs has been reported with the 5% solution and was attributed to systemic absorption of the drug (84). Although topical minoxidil does not change blood pressure in healthy subjects, it increases heart rate by 3-5 beats/min and slightly increases the left ventricular end-diastolic volume, cardiac output, and left ventricular mass (85). These effects are not considered clinically significant, and the potential for cardiovascular side effects is very low. 

Hypertrophic cardiomyopathy (HCM) is a prototype for DHF The grossly thickened myocardium, structural changes, and interstitial fibrosis severely alter the passive elastic properties of the myocardium. Patients with HCM and LV outflow obstruction are sensitive to small changes in volume such that a small decrease in filling pressure can lead to a decrease in LV end-diastolic volume and a dramatic fall in stroke volume and cardiac output. 

Increased levels of angiotensin II The pericardium may have a constraining effect as LV filling pressure and end-diastolic volume increase. 

Sublingual nitroglycerin tablets or nitroglycerin spray may be used for patients who develop shortness of breath with mild exercise, and they may be used much in the same way as in patients with ischemic symptoms. Nitroglycerin will decrease LV end-diastolic volume resulting in relief of breathlessness. 

Preload—Along with afterload, it is an important determinant of cardiac output. It is the degree of stretch of the myocardial fibers (sarcomeres) at the end of diastole. As the sarcomeres are stretched, the force of contraction increases. Preload is approximated by the left ventricular end diastolic volume or pressure. 

In addition to improving symptoms, randomized clinical trials have also shown that conventionally indicated patients derive objective evidence of beneficial structural changes (often referred to as reverse remodeling) in response to CRT. Resynchronization reduces left ventricular end-systolic (10,18-19) and end-diastolic volumes (10,22,23), and increases left ventricular ejection fraction (10,21,23). The improvements in ejection fraction ranged from 2% to 7% and are noteworthy given that the baseline ejection fractions in these trials were in the range... 

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