Additional content is available online at Elsevier eBooks1 1147

Apuntes

Additional content is available online at Elsevier eBooks+ 1147 KEY POINTS • Heart failure with a reduced ejection fraction is initiated after an initial index event leads to a decline in the pumping capacity of the heart. • The circulatory changes that arise from impaired myocardial pump function are sensed by peripheral arterial baroreceptors as underfilling of the circulation, which leads to activation of the sympathetic nervous system (SNS). • Activation of the SNS leads to increase in cardiac output; however, sustained activation of the SNS leads to myocardial injury, activation of the renin-angiotensin-aldosterone system (RAAS) and peripheral vasoconstriction. • RAAS activation facilitates retention of sodium and water by the kidney, which can lead to volume overload. RAAS activation also leads to oxidative stress, myocardial fibrosis renal mechanisms, and myocardial inflammation. • Activation of the SNS and RAA neurohormonal systems leads to change in the biology of the cardiac myocyte, as well as changes in the extracellular matrix. • The failing heart undergoes left ventricular (LV) remodeling, which refers to the alterations in LV mass, volume, shape, and composition tha...