Congestive heart failure pathophysiology
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Associate Editor-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]; Saleh El Dassouki, M.D [3], Atif Mohammad, MD
Overview
Heart failure may result from an abnormality of any one of the anatomical structures of the heart; the pericardium, the myocardium, the endocardium, valvular heart disease or disorders of the great vessels. Heart failure was once thought to be secondary to a depressed left ventricular ejection fraction. However, studies have shown that approximately 50% of patients who are diagnosed with heart failure have a normal ejection fraction (diastolic dysfunction). Patients may be broadly classified as having heart failure with depressed left ventricular ejection fraction (systolic dysfunction) or normal/preserved ejection fraction (diastolic dysfunction). Systolic and diastolic dysfunction commonly occur in conjunction with each other.
Pathophysiology
- Left ventricular systolic dysfunction is associated with a reduction in stroke volume, the amount of blood the heart ejects with each heart beat.
- Cardiac output can be maintained if LV dilation occurs and stroke volume is preserved even though the LVEF is low.
- As LV dilation occurs, functional mitral regurgitation (MR) may develop despite an anatomically normal mitral valve.
- The ejection fraction is usually below 35% in symptomatic patients.
- Rales usually develop if the pulmonary capillary wedge pressure is >25 mm Hg. Rales may not be present in the patient with chronic heart failure. Rales may develop at even lower pressures if LV function deteriorates suddenly.
- Dyspnea and orthopnea occur due to interstitial edema at lower pressures.
- Hypoperfusion at rest is suggested by cool extremities, altered mentation, and declining renal function.
- Left atrial dilation may lead to atrial fibrillation which occurs in 20% of patients with congestive heart failure. Atrial fibrillation diminishes left ventricular filling through the loss of the atrial kick (the atrial contraction) and due to an increase in the heart rate.
Pathology
Microscopic Pathology
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HEART: Congestive heart failure, hydropic change
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HEART: Congestive heart failure, hydropic change
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HEART: Congestive heart failure, hydropic change
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HEART: Congestive heart failure, hydropic change
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HEART: Congestive heart failure, hydropic change
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HEART: Congestive heart failure, hydropic change
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Lung, congestion, heart failure cells (hemosiderin laden macrophages)
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Lung, Congestive Heart Failure, bone marrow embolus
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Lung, pulmonary edema in patient with congestive heart failure due to heart transplant rejection
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HEART: Congestive heart failure, hydropic change
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HEART Congestive heart failure, hydropic change
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Spleen, congestion, congestive heart failure