PHAR 2006 Pathophysiology - Congestive Heart Failure PDF

PHAR 2006 Pathophysiology –Congestive Heart Failure Dr. Jacqueline E. Campbell [email protected] Heart failure Occurs when cardiac output is inadequate to provide oxygen needed by the body Acute or chronic Common causes – coronary artery disease,...

PHAR 2006 Pathophysiology –Congestive Heart Failure Dr. Jacqueline E. Campbell [email protected] Heart failure Occurs when cardiac output is inadequate to provide oxygen needed by the body Acute or chronic Common causes – coronary artery disease, HTN, MI, arrhythmia, valvular disease Diseases either impair ability of cardiac m to contract (MI, arrhythmia) or ↑ workload of heart (HTN) Signs heart failure Left sided Right sided Pulmonary oedema Congestion of liver Dyspnoea Peripheral oedema Homeostatic responses to ↓ cardiac function Mediated by sympathetic nervous Myocardial hypertrophy – mediated in system, renin- angiotensin- part by sympathetic discharge & aldosterone system angiotensin 11 ↑sympathetic tone → tachycardia, ↑ Compensatory responses temporarily peripheral vascular resistance improve cardiac output but also ↑ load ↓ renal blood flow→ aldosterone on heart → decline in cardiac function stimulation & ↑ salt & water retention Heart failure - video An Osmosis Video: Congestive Heart Failure (CHF) Explained (youtube.com) CHECKPOINT Q1. What are the clinical presentations of left ventricular heart failure?; of right ventricular heart failure? Q2. What are the four general categories that account for almost all causes of CHF? Q3. Explain the differences between the pathophysiology of CHF resulting from systolic versus diastolic dysfunction Treatment of heart failure Improving cardiac contractility ↓ preload (decrease myocardial demand for O 2) ↓ afterload Removal of retained salt & water