Heart Failure Part 1 PDF

Health Variations 4 NURS3015 Heart Failure- Part 1  Commonwealth of Australia Copyright Act 1968 WARNING This material has been reproduced and communicated to you by or o...

Health Variations 4 NURS3015 Heart Failure- Part 1  Commonwealth of Australia Copyright Act 1968 WARNING This material has been reproduced and communicated to you by or on behalf of Western Sydney University under Part VB of the Copyright Act 1968 (the Act). The material in this communication may be subject to copyright under the Act. Any further reproduction or communication of this material by you may be the subject of copyright protection under the Act. Do not remove this notice. Congestive Cardiac Failure “Heart failure is a complex clinical syndrome that is frequently, but not exclusively, characterised by an underlying structural abnormality or cardiac dysfunction that impairs the ability of the left ventricle (LV) to fill with or eject blood, particularly during physical activity. Symptoms of CHF can occur at rest or during physical activity”(The National Heart Foundation of Australia and the Cardiac Society of Australia and New Zealand) CCF is the inability of the heart to maintain an output, at rest or during stress, necessary for the metabolic needs of the body Congestive Cardiac Failure diastolic failure/preserved ejection systolic failure/reduced ejection fraction fraction failure (HFpEF)/right heart failure (HFrEF)/left heart failure failure Physiological Terminologies End Diastolic Volume(EDV) The amount of blood returning to the heart and filling the ventricle End Systolic Volume(ESV) The volume of blood that remains in the ventricle at the end of systole Stroke Volume (SV)  Volume of blood pumped out of the heart by the left ventricle with each beat (measured in mL)  Not all the blood that is in the ventricle is ejected, Usually just over half or 1mL/kg SV= EDV-ESV =120mL/beat- 50 mL/beat =70 mL/beat Physiological Terminologies Preload The amount of blood at the end of diastole prior to contraction AND A measure of the degree of the ventricular stretch at the end of diastole prior to contraction (is influenced by the factors just prior to ventricular contraction and is determined by the end-diastolic volume (and the associated end-diastolic pressure) Contractility Ability of the myocardial fibres to shorten or contract when loaded. Determines the force of contraction Afterload The force which the ventricle has to overcome to eject blood. The resistance to the ejection of blood from the left ventricle. E.g. Systemic Vascular Resistance (SVR) Physiological Terminologies Cardiac Output (CO) The amount of blood pumped around the body in one minute CO = SV x Heart Rate (HR) E.g for a healthy person weighing 70kg SV 70mL x HR 70bpm = CO 4.9L/minute Frank-Starling law of the heart ↑ stretch= ↑cardiac output More volume (blood) in the left ventricle increases the stretch of the cardiac myocytes, which will increase the force of contraction Ejection Fraction (EF) Percentage of blood the left ventricle pumps out with each contraction OR blood ejected during systole E.g In a healthy person weighing 70kg Normal End Diastolic Volume (EDV) is about 120mls and SV 70mls the EF is 58% Normal EF is 55-70% FRANK-STARLING- mechanism Changes to the myocardial contractility Reduced contractility decreases stretch The ‘frank-starling’ mechanism is altered Buckely T, Understanding Pathophysiology, 2019 References Buckley, Tin Understanding Pathophysiology by Craft, J., Gordon, C., Heuther, S., McCance, K., Brashers, V., & Rote, N.3rd ed. Australian and New Zealand ed St. Louis, MOElsevier2019610 - 679 (chp 23) Buckley, Tin Understanding Pathophysiology by Craft, J., Gordon, C., Heuther, S., McCance, K., Brashers, V., & Rote, N.3rd ed. Australian and New Zealand ed St. Louis, MOElsevier2019563 - 609 (chp 22) Atherton, J.J., Sindone, A., De Pasquale, C.G., Driscoll, A., Macdonald, P.S., Hopper, I. & Connell, C. (2018). National Heart Foundation of Australia and Cardiac Society of Australia and New Zealand: Guidelines for the Prevention, Detection, and Management of Heart Failure in Australia 2018. Heart, Lung and Circulation. 27(10). pp. 1123-1208. doi; 10.1016/ j.hlc.2018.06.1042.