HTHSCI 2H03 Chapter Notes - Chapter 4: Mitral Valve Stenosis, Congenital Heart Defect, Peripheral Edema

• School: McMaster University
• Department: Health Sciences
• Course: HTHSCI 2H03
• Professor: kirsten

Document Summary

Heart failure: the i(cid:374)a(cid:271)ilit(cid:455) of the heart to pu(cid:373)p e(cid:374)ough (cid:271)lood to satisf(cid:455) the (cid:271)od(cid:455)"s de(cid:373)a(cid:374)d for o(cid:454)(cid:455)ge(cid:374) Risk factors: cardiovascular disease, previous myocardial infarction, diabetes, mitral stenosis, cardiomyopathies, congenital heart disease. Preload: degree to which the muscle fibers are stretched before the heart contracts (systole) Increased preload results in increased blood volume (eg. fluid retention by renin- angiotensin- aldosterone) Increase in venous pressure through decreased venous compliance or increased ventricular compliance that results in greater filling of the ventricles. Increased afterload causes the blood to back up into the peripheral circulation, causing peripheral edema in the lower limbs, making the heart work harder. Hypertonic heart: constant pressure and demand can remodel the tissue by making it compensate to work hard, walls may grow thicker and use elasticity leading to the inability of this tissue to expand and pump effectively. Left: backs up in the lungs, more common. Diastolic dysfunctions: preload (stretch) determines ventricular function.