Chronic heart failure (CHF)
Definition
Chronic heart failure is a progressive condition in which the heart is unable to maintain adequate cardiac output to meet the body’s metabolic needs, or does so at the expense of elevated filling pressures, developing over weeks to years.
Classification
By side of heart involvement
By predominant functional impairment
By output
Etiology
Cardiac causes
- Ischemic heart disease (most common in developed countries).
- Chronic hypertension → left ventricular hypertrophy and failure.
- Valvular heart diseases (aortic or mitral regurgitation/stenosis).
- Cardiomyopathies (dilated, hypertrophic, restrictive).
- Congenital heart defects.
Non-cardiac contributors (worsen existing HF)
- Anemia.
- Thyrotoxicosis.
- Chronic lung diseases (cor pulmonale).
- Renal failure → fluid overload.
Pathogenesis
Primary event
Myocardial injury or chronic overload → reduced cardiac pump function.
Neurohormonal and compensatory mechanisms
- 1 Sympathetic nervous system activation
↑ heart rate, contractility, vasoconstriction → initial support but increases myocardial oxygen demand and afterload.
- 2 Renin-angiotensin-aldosterone system (RAAS) activation
Sodium and water retention → ↑ preload → pulmonary and systemic congestion.
- 3 Antidiuretic hormone (ADH) release
Water retention → hyponatremia, volume overload.
- 4 Cardiac remodeling
Hypertrophy and dilation → initially compensate but ultimately lead to
worsening dysfunction and arrhythmias.
Clinical manifestations
Left- sided chronic HF
- Dyspnea on exertion → orthopnea → paroxysmal nocturnal dyspnea.
- Fatigue, exercise intolerance.
- Nocturnal cough, possible hemoptysis (pulmonary congestion).
- Basal lung crackles.
Right- sided chronic HF
- Peripheral pitting edema (ankles, legs).
- Hepatomegaly → right upper quadrant discomfort, congestive hepatopathy ("nutmeg liver").
- Jugular venous distension.
- Ascites.
- Anorexia, nausea (gut congestion).
General symptoms (any CHF)
- Cachexia (advanced stages).
- Cold extremities (poor perfusion).
- Weight gain (fluid retention) or weight loss (catabolic state).
Summary table
Conclusion
Chronic heart failure is a progressive syndrome driven by compensatory neurohormonal mechanisms that initially support but ultimately worsen cardiac function, leading to pulmonary and systemic congestion as well as reduced perfusion.
Let me know if you'd also like a flowchart of compensatory mechanisms, or "left vs right symptoms cheat sheet"!
Here’s a complete, clear, and detailed note on abdominal pain, including classification, etiology, and pathogenesis — fully academic but easier to understand and memorize.