Heart Failure PDF

NURS 7053 Advanced Pathophysiology I for DNP Students Alterations of Cardiovascular Function III - Class Notes Heart Failure The inability of the heart to maintain adequate circulatory volume and pressure, measured by a reduced cardiac output...

NURS 7053 Advanced Pathophysiology I for DNP Students Alterations of Cardiovascular Function III - Class Notes Heart Failure The inability of the heart to maintain adequate circulatory volume and pressure, measured by a reduced cardiac output (CO)/cardiac index (CI) or ejection fraction (EF). It includes changes in systolic and diastolic function. Types of Heart Failure Heart failure may be systolic, diastolic, or both Systolic dysfunction The inability of the ventricle to contract against a load resulting in decreased ejection fraction and increased left ventricular end diastolic volume (LVEDV). Diastolic dysfunction An impairment in left ventricular filling which results in decreased CO. Heart failure usually originates in one ventricle, but can ultimately affect both Left ventricular failure (left heart failure, congestive heart failure) Right ventricular failure (a.k.a. right heart failure, cor pulmonale) Duration of onset Acute heart failure Chronic heart failure 1  NURS 7053 Advanced Pathophysiology I for DNP Students Alterations of Cardiovascular Function III - Class Notes Epidemiology 6.2 million adults in U.S. living with heart failure (2020) Causes 1 in 9 deaths each year (2009) Half of people who develop heart failure die within 5 years Costs an estimated $30.7 billion dollars in U.S. each year – health care services, medications, and lost work Left Ventricular Failure General Pathophysiology Hemodynamic Alterations See figure on next page LV is unable to generate an adequate stroke volume and cardiac output Increased residual volumes in LV cause an increase in preload Pressures back up into the left atrium and eventually the pulmonary veins Increased hydrostatic pressures in pulmonary capillaries leads to pulmonary edema 2  NURS 7053 Advanced Pathophysiology I for DNP Students Alterations of Cardiovascular Function III - Class Notes Hemodynamics of LVF 3  NURS 7053 Advanced Pathophysiology I for DNP Students Alterations of Cardiovascular Function III - Class Notes Neurohormonal responses to decreased CO Decreased CO leads to a drop in arterial blood pressure (BP), which activates several compensatory mechanisms. Sympathetic nervous system response Alpha-1 effect: vasoconstriction of systemic arteries/arterioles Beta-1 effect: increased HR Renal compensation Renin-angiotensin-aldosterone system Angiotensin II: vasoconstriction of systemic arteries/arterioles Aldosterone: increased sodium/water reabsorption by kidneys 4  NURS 7053 Advanced Pathophysiology I for DNP Students Alterations of Cardiovascular Function III - Class Notes Increased BNP secretion In LVF, BNP secretion is stimulated by ventricular stretch/dilation caused by: 1) Increased LV residual volumes/preload (primarily with systolic dysfunction) 2) Renal retention of fluid (renal compensation) Elevated BNP is a laboratory indicator of systolic heart failure Detrimental effects of long-term exposure to compensatory hormones Exposure to compensatory hormones leads to long term cardiovascular injury Ventricular hypertrophy and interstitial fibrosis (catecholamines, angiotensin II, aldosterone) 5  NURS 7053 Advanced Pathophysiology I for DNP Students Alterations of Cardiovascular Function III - Class Notes Pathophysiology of Common Etiologies Abnormal Cardiac Muscle Contraction (Systolic Dysfunction) Myocardial ischemia from atherosclerosis in the coronary arteries (CAD) 6  NURS 7053 Advanced Pathophysiology I for DNP Students Alterations of Cardiovascular Function III - Class Notes Other Causes of Systolic Dysfunction Myocardial infarction Dilated cardiomyopathy 25% cases are genetic (malformed cardiac cytoskeleton proteins, mitochondrial dz…); acquired causes include parasitic/viral infection, toxic injury, pregnancy, autoimmune… Myocarditis (inflammatory cardiomyopathy) Inflammation due to viral infection or autoimmunity Obstruction to Outflow from LV Systemic hypertension 75% with CHF had a history of hypertension Other causes of outflow obstruction: aortic stenosis, isolated systemic hypertension caused by atherosclerosis of the aortic arch 7  NURS 7053 Advanced Pathophysiology I for DNP Students Alterations of Cardiovascular Function III - Class Notes Diastolic Dysfunction Note: Ejection fraction may be normal Myocardial infarction Constrictive pericarditis Inflammation of the pericardial sac often caused by bacterial, viral or fungal infection, autoimmune disease, cardiac trauma, medications, etc. Hypertrophic obstructive cardiomyopathy Genetic disease (autosomal dominant) causing abnormal thickening of the ventricular wall and septum; also involves collagen deposition in the myocardium Restrictive cardiomyopathy 8  NURS 7053 Advanced Pathophysiology I for DNP Students Alterations of Cardiovascular Function III - Class Notes Limited Ventricular Filling Mitral stenosis Volume Overload Fluid overload (causes include renal failure, IV fluid administration, failure to take diuretics…) Clinical Manifestations Pulmonary Edema Hypoxemia, tachypnea, dyspnea Hypercapnea and respiratory acidosis 9  NURS 7053 Advanced Pathophysiology I for DNP Students Alterations of Cardiovascular Function III - Class Notes Bibasilar crackles Cough Compensatory Mechanisms Tachycardia Pale, cool skin; possible mottling Decreased urine output Hypotension Mental status changes Fatigue & weakness Decreased urinary output 10