Causes, Symptoms, and Diagnostics of HEART FAILURE (Nursing School Lessons)

Heart failure results from anything that impairs the heart's ability to pump effectively. The leading causes include myocardial infarctions (MIs), where dead muscle tissue cannot pump, and hypertension, which forces the heart to work harder against increased pressure (afterload), eventually leading to fatigue and failure. Valve disorders, causing either regurgitation or stenosis, also prevent blood from flowing correctly, leading to congestion and backup.

Diagnosis involves several key indicators. Brain Natriuretic Peptide (BNP), released when ventricles stretch due to severe volume overload, is a crucial lab value that can reach thousands in heart failure patients. A chest X-ray might reveal an enlarged heart and pulmonary edema (fluid in the lungs). An echocardiogram shows end-diastolic volume (preload), ejection fraction (often less than 50% in heart failure), and any valve disorders.

In right-sided heart failure, there's decreased blood flow to the lungs, leading to oxygenation problems and activity intolerance. Backward congestion affects the systemic circulation, causing peripheral edema, fatigue, weight gain, ascites (fluid in the gut), nausea, and jugular venous distention (JVD).

Left-sided heart failure leads to decreased perfusion to the body, manifesting as paleness, decreased peripheral pulses, slow capillary refill, and cool skin. Backward congestion impacts the lungs, resulting in pulmonary edema, characterized by a cough, pink and frothy sputum, and significant shortness of breath, often requiring patients to sleep upright. Weight loss can also occur as breathing takes precedence over eating.

A major complication of heart failure involves the kidneys. Decreased renal perfusion activates the renin-angiotensin-aldosterone system (RAAS). This system causes water retention (due to ADH and aldosterone), increasing preload. It also leads to vasoconstriction, which raises afterload and the heart's workload, and stimulates the sympathetic nervous system, further increasing heart rate and contraction. This creates a perpetuated cycle of volume overload and stress on an already overworked heart, known as the 'cycle of death'. Many heart failure therapies aim to break this cycle.