Pathophysiology 1. Frank-Starling's Law of the heart a. The cardiac output is a function of the preload, the afterload, and myocardial contractility b Preload: the volume and pressure of blood in the ventricle at the end of diastole c. Afterload the arterial resistance
Pathophysiology • 1. Frank-Starling’s Law of the heart a. The cardiac output is a function of the preload, the afterload, and myocardial contractility. b.Preload: the volume and pressure of blood in the ventricle at the end of diastole. c. Afterload :the arterial resistance
Cardiac output or ventricular performance Afterload Contractility Or reload Fig 3.17 Starlings Law. Normal (A), mild(B), moderate(C)and severe(D) heart failure. Ventricular performance is related to the degree of myocardial stretching. An increase in preload (end-diastolic volume end-diastolic pressure, filling pressure or atrial pressure)will therefore enhance function: however, overstretching causes marked deterioration In heart failure the curve moves to the right and becomes flatter. An increase in myocardial contractility or a reduction in afterload(arterial resistance/blood pressure) will shift the curve upwards and to the left
最大活 2正常活动 1正常静息 左室作功 心肌收缩性 活动 3’心衰活动 静息 3心衰静息 E 4静息 致死性心肌受损 呼吸困 肺水肿 左室张末容量 图32-1正常和心力衰竭时对机体活动时的代偿 情况
1 正常静息 2 正常活动 3’ 心衰活动 3 心衰静息 心肌收缩性 B A D C 左室舒张末容量 图3–2–1 正常和心力衰竭时对机体活动时的代偿 情况 最大活 动 活动 静息 左 室 作 功 呼吸困 难 肺水肿 E 4 静息 致死性心肌受损
2. RAAS in heart failure 心力衰竭 心肌细胞死亡 心肌细胞死亡 ↑心肌能量消耗 ↓心排血量 ↑心肌能量消耗 ↑后负荷 神经体液兴奋 心肌松弛性变力效应 SAS 血管收缩 ↑胞浆Ca 心律失常 猝死 InSP3 cAMP InSP3 循环 心脏 图3-2-2肾素一血管紧张素和交感一肾 上腺素能系统激活时对心脏代偿功能的影响
心肌细胞死亡 心力衰竭 心肌细胞死亡 + + ↑心肌能量消耗 ↑后负荷 血管收缩 ↓心排血量 神经体液兴奋 RAS SAS InSP3 循环 ↑心肌能量消耗 ↑胞浆Ca2+ cAMP InSP3 心脏 ↓心肌松弛性 ↑变力效应 + － — 心律失常 猝死 图3–2–2 肾素—血管紧张素和交感—肾 上腺素能系统激活时对心脏代偿功能的影响 2. RAAS in Heart Failure
2. RAAS in heart failure Angiotensinogen Renin Angiotensin I Angiotensin converting enzyme Angiotensin Il Aldosterone Direc vasoconstriction Afterload Activation of sympathetic nervous system Preload Salt and water retention Release of anti- diuretic hormone Contractility Potassium loss 3. 18 The renin-angiotensin-aldosterone system in heart failure. Impaired renal perfusion and diuretic therapy lead to the release of renin secondary changes in the afterload, preload and myocardial contractility
• 2. RAAS in Heart Failure