Heart Failure
- Complex clinical syndrome resulting in insufficient blood supply/oxygen to tissues and organs
- Involves diastolic or systolic dysfunction
- Ejection fraction (EF) is amount of blood pumped by LV with each heart beat
- Associated with CVDs
- Increase in incidence and prevalence
- Most common cause for hospital admission in adults over age 65
Risk factors
- Primary risk factors
- Hypertension
- Modifiable risk factor
- Properly treated and managed, incidence of HF can be reduced by 50%
- CAD
- Hypertension
- Co-morbidities contribute to development of HF
Etiology of Heart failure
- Anything that interferes with mechanisms that regulate cardiac output (CO)
- Primary causes
- Conditions that directly damage the heart
- Hypertension, including hypertensive crisis
- Coronary artery disease, including myocardial infarction
- Rheumatic heart disease
- Congenital heart defects (e.g., ventricular septal defect)
- Pulmonary hypertension
- Cardiomyopathy (e.g., viral, postpartum, substance abuse)
- Hyperthyroidism
- Valvular disorders (e.g., mitral stenosis)
- Myocarditis
- Conditions that directly damage the heart
- Precipitating causes
- Conditions that increase workload of ventricles
Cause | Mechanism |
Anemia | Decrease O2-carrying capacity of the blood stimulating Increase in CO to meet tissue demands, leading to increase in cardiac workload and increase in size of LV |
Infection | Increased O2 demand of tissues, stimulating increase CO |
Thyrotoxicosis | Changes the tissue metabolic rate, increased HR and workload of the heart |
Hypothyroidism | Indirectly predisposes to increased atherosclerosis. Severe hypothyroidism decreases myocardial contractility. |
Dysrhythmias | May decreased CO and increased workload and O2 requirements of myocardial tissue |
Bacterial endocarditis | Infection: increased metabolic demands and O2 requirements Valvular dysfunction: causes stenosis or regurgitation |
Obstructive sleep apnea | Frequent nighttime apnea results in increased afterload, intermittent hypoxia, and increased sympathetic nervous system activity. |
Pulmonary embolism | Increased pulmonary pressure resulting from obstruction leads to pulmonary hypertension, decreased CO. |
Paget’s disease | Increased workload of the heart by increased vascular bed in the skeletal muscle |
Nutritional deficiencies | May decrease cardiac function by increased myocardial muscle mass and myocardial contractility |
Hypervolemia | Increased preload causing volume overload on the RV |
