20.1
Heart Failure I: Introduction
Heart failure, or HF, is a clinical syndrome that occurs when structural or functional cardiac disorders impair the heart's ability to pump sufficient blood to meet the body's metabolic needs.
This condition typically results from myocardial damage, which disrupts cardiac output dependent on factors such as preload, afterload, contractility, and heart rate.
Changes in these factors can impair ventricular function, ultimately leading to heart failure.
Common causes of HF include coronary artery disease, where ischemia and myocardial infarction damage heart cells, leading to myocardial dysfunction and loss of contractility.
Hypertension increases afterload, causing myocardial hypertrophy and impaired filling, which can result in HF.
Cardiomyopathies, particularly dilated cardiomyopathy, cause myocardial necrosis and fibrosis, leading to progressive HF.
Valvular heart disease and systemic conditions such as chronic kidney disease and cardiac arrhythmias also contribute to HF.
Additionally, several factors elevate the risk of HF, including smoking, obesity, poorly managed diabetes, hypothyroidism, anemia, and pulmonary embolism.
Heart failure refers to a clinical syndrome caused by structural or functional cardiac disorders that prevent the heart from pumping an adequate amount of blood to meet the body's metabolic needs. This condition often arises from myocardial infarction or ischemia, leading to decreased cardiac output, reduced tissue perfusion, impaired gas exchange, fluid volume imbalance, and decreased functional ability.
Heart failure can result from disruptions in the mechanisms that regulate cardiac output (CO). Cardiac output is influenced by preload, afterload, myocardial contractility, and heart rate (HR), all of which determine the stroke volume (SV) or the amount of blood pumped per heartbeat. The relationship is expressed as CO = SV × HR. Alterations in any of these factors can impair ventricular function, leading to heart failure.
Risk factors
The risk of heart failure increases with age and is more common in men over 60. Factors that elevate the risk of heart failure include cigarette smoking, obesity, poorly managed diabetes, hypothyroidism, thyrotoxicosis, anemia, Paget's disease of bone, and pulmonary embolism.
Etiology
Heart failure often arises from the following conditions:
- Coronary artery disease (CAD), hypertension, cardiomyopathy, valvular disorders, and renal dysfunction with volume overload. CAD is a primary cause of heart failure, as ischemia and myocardial infarction (MI) damage heart cells, leading to myocardial dysfunction and loss of contractility.
- Hypertension increases afterload, leading to increased cardiac workload and myocardial hypertrophy, which can eventually impair the heart's ability to fill properly and lead to heart failure.
- Cardiomyopathies, particularly dilated cardiomyopathy (DCM), cause myocardial necrosis and fibrosis, often leading to progressive heart failure.
- Valvular heart disease disrupts normal blood flow, increasing cardiac workload and pressure and contributing to heart failure.
- Systemic conditions like chronic kidney disease (CKD) and cardiac arrhythmias such as atrial fibrillation also contribute to heart failure. These arrhythmias impair myocardial contraction and reduce overall cardiac efficiency.
- Additionally, factors like hypoxia, acidosis, and electrolyte imbalances can exacerbate myocardial dysfunction.
Heart failure, or HF, is a clinical syndrome that occurs when structural or functional cardiac disorders impair the heart's ability to pump sufficient blood to meet the body's metabolic needs.
This condition typically results from myocardial damage, which disrupts cardiac output dependent on factors such as preload, afterload, contractility, and heart rate.
Changes in these factors can impair ventricular function, ultimately leading to heart failure.
Common causes of HF include coronary artery disease, where ischemia and myocardial infarction damage heart cells, leading to myocardial dysfunction and loss of contractility.
Hypertension increases afterload, causing myocardial hypertrophy and impaired filling, which can result in HF.
Cardiomyopathies, particularly dilated cardiomyopathy, cause myocardial necrosis and fibrosis, leading to progressive HF.
Valvular heart disease and systemic conditions such as chronic kidney disease and cardiac arrhythmias also contribute to HF.
Additionally, several factors elevate the risk of HF, including smoking, obesity, poorly managed diabetes, hypothyroidism, anemia, and pulmonary embolism.
From Chapter 20:
Now Playing
20.1 : Heart Failure I: Introduction
Congestive Cardiac Failure
4.4K Views
20.2 : Heart Failure II: Pathophysiology
Congestive Cardiac Failure
4.7K Views
20.3 : Heart Failure III: Clinical Manifestations
Congestive Cardiac Failure
3.9K Views
20.4 : Heart Failure IV: Classification and Diagnostic Evaluation
Congestive Cardiac Failure
3.5K Views
20.5 : Heart Failure V: Medical Management
Congestive Cardiac Failure
852 Views
20.6 : Heart Failure VI: Adjunct Therapies
Congestive Cardiac Failure
804 Views
20.7 : Heart Failure VII: Nursing Interventions
Congestive Cardiac Failure
982 Views