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Congestive heart failure: systolic and diastolic function
1Bowman Gray School of Medicine, Department of Internal Medicine, Winston-Salem, NC 27157-1045.
Insights
Congestive heart failure arises from impaired left ventricular systolic (emptying) and diastolic (filling) function. Understanding both is crucial for diagnosing and treating this condition.
Area of Science:
- Cardiology
- Heart Failure Pathophysiology
Background:
- Congestive heart failure (CHF) is increasingly recognized as resulting from disorders in both left ventricular systolic and diastolic function.
- Evaluating the filling and emptying characteristics of the left heart is essential for understanding hemodynamic abnormalities in CHF.
Purpose of the Study:
- To provide a conceptual framework for classifying and understanding the pathophysiology of CHF based on systolic and diastolic dysfunction.
- To define systolic and diastolic dysfunction and their interrelationships.
Main Methods:
- Definition of systolic dysfunction as impaired left ventricular (LV) emptying, indicated by a decreased ejection fraction (<50%).
- Definition of diastolic dysfunction as impaired LV filling requiring elevated pulmonary venous pressure, clinically manifesting as pulmonary congestion.
- Identification of causes for systolic dysfunction (impaired contractility, increased afterload, structural abnormalities) and diastolic dysfunction (obstruction, reduced distensibility, external compression).
Main Results:
- Systolic dysfunction is characterized by reduced ejection fraction and can stem from myocardial issues, afterload, or structural problems.
- Diastolic dysfunction leads to pulmonary congestion and often occurs secondary to systolic dysfunction, with dyspnea as a common symptom.
- Diastolic dysfunction with normal systolic function can result from filling obstructions, reduced LV distensibility, or compression.
Conclusions:
- Both systolic and diastolic left ventricular function are critical in the development of congestive heart failure.
- Understanding the distinct mechanisms of systolic and diastolic dysfunction is key to effective diagnosis and treatment strategies.
- Treatment of diastolic dysfunction involves addressing underlying causes such as ischemia, improving systolic function, managing blood pressure, and reducing cardiac volume.
Abstract:
There is increasing recognition that disorders of both left ventricular systolic and diastolic function can result in congestive heart failure. As such, consideration of both the filling and emptying characteristics of the left heart is needed to evaluate the hemodynamic abnormalities present in this syndrome. Considerations of the systolic (emptying) and diastolic (filling) pumping characteristics of the left heart also provides a conceptual basis to classify and understand the pathophysiology of congestive heart failure. In this context, systolic dysfunction can be defined as impaired emptying of the LV, apparent as a decreased (< 50%) effective ejection fraction (forward stroke volume divided by end-diastolic volume). Systolic dysfunction may result from impaired myocardial contractile function, increased left ventricular afterload, and/or structural abnormalities of the left heart. Diastolic dysfunction can be defined as a condition in which filling of the LV sufficient to produce an adequate cardiac output requires an elevated pulmonary venous pressure. Thus, diastolic dysfunction is clinically manifested as pulmonary congestion. Defined in this manner, the most common cause of diastolic dysfunction is systolic dysfunction. In fact, the most common symptom of patients with systolic dysfunction is dyspnea from the resulting diastolic dysfunction. Diastolic dysfunction in the setting of normal systolic function may be due to obstruction of left ventricular filling, impaired left ventricular distensibility, or extensive external compression of the LV. Treatment of diastolic dysfunction can be accomplished by relieving myocardial ischemia, improving systolic function, lowering arterial systolic pressure, and decreasing cardiac distention.