Diastolic function in left ventricular hypertrophy: clinical and experimental relationships
B H Lorell1, C S Apstein, E O Weinberg
1Cardiac Muscle Research Laboratory, Boston University School of Medicine, Massachusetts.
Insights
Distinguishing systolic and diastolic dysfunction is key for patients with left ventricular hypertrophy and heart failure. Diastolic dysfunction is suspected with elevated left ventricular diastolic pressure but normal chamber size and preserved systolic function.
Area of Science:
- Cardiology
- Heart Failure Research
- Cardiac Physiology
Background:
- Evaluating patients with left ventricular hypertrophy (LVH) and congestive heart failure (CHF) necessitates differentiating systolic dysfunction from diastolic dysfunction.
- Diastolic dysfunction, characterized by impaired relaxation and filling, is a critical consideration in CHF patients with LVH.
- Understanding the underlying mechanisms of diastolic dysfunction in LVH is crucial for effective patient management.
Purpose of the Study:
- To highlight the importance of distinguishing between systolic and diastolic etiologies in patients presenting with LVH and CHF.
- To identify clinical indicators for suspecting predominant diastolic dysfunction in this patient population.
- To review the multifaceted and controversial mechanisms contributing to diastolic dysfunction in cardiac hypertrophy.
Main Methods:
- Clinical evaluation focusing on left ventricular diastolic pressure, chamber volume/dimensions, and systolic shortening.
- Review of proposed mechanisms for diastolic dysfunction in cardiac hypertrophy.
- Consideration of factors such as left ventricular geometry, myocardial composition (fibrosis, collagen), and dynamic modulators.
Main Results:
- Predominant diastolic dysfunction should be suspected when elevated left ventricular diastolic pressure is observed alongside normal diastolic chamber volumes/dimensions and preserved systolic shortening.
- Multiple, often controversial, mechanisms contribute to diastolic dysfunction in cardiac hypertrophy.
- These include alterations in left ventricular geometry, myocardial fibrosis, collagen changes, and dynamic factors affecting relaxation.
Conclusions:
- Accurate differentiation between systolic and diastolic dysfunction is vital for managing patients with LVH and CHF.
- Hypertrophied cardiac muscle appears particularly vulnerable to diastolic dysfunction under stress, such as hypoxia or ischemia.
- Further research into the complex mechanisms of diastolic dysfunction is warranted for improved therapeutic strategies.
Abstract:
The evaluation of patients with left ventricular hypertrophy and the clinical syndrome of congestive heart failure requires the ability to distinguish between the etiologies of abnormal systolic contractile function and abnormalities of diastolic relaxation and filling. In patients with left ventricular hypertrophy and congestive heart failure, predominant diastolic dysfunction should be suspected when elevation of left ventricular diastolic pressure is detected in the presence of normal diastolic chamber volume or dimensions and preserved systolic shortening. The mechanisms which account for diastolic dysfunction in the presence of cardiac hypertrophy are controversial and are likely to be multiple. These mechanisms may include changes in left ventricular geometry, per se, changes in the composition of the left ventricular wall (fibrosis or alteration in collagen), and dynamic factors which modulate diastolic force inactivation (loading conditions, cytosolic calcium handling, cyclic AMP availability). In addition, recent studies suggest that hypertrophied cardiac muscle may be particularly susceptible to develop diastolic dysfunction in response to the stress of hypoxia or ischaemia.
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