Diastolic dysfunction overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Assistant Editor(s)-in-Chief: Rim Halaby
Overview
Congestive heart failure and cardiac dysfunction are not interchangeable definitions. Whereas heart failure is a clinical definition that illustrates the occurrence of symptoms of fatigue, dyspnea, and fluid overload; cardiac dysfunction is a mechanical definition that includes abnormalities in heart contraction (called systolic dysfunction) or abnormalities in heart relaxation and filling (called diastolic dysfunction) or both.
Therefore, diastolic dysfunction refers to a mechanical dysfunction of the heart during the diastolic phase of the cardiac cycle in the presence or absence of any clinical symptoms. When clinical symptoms are present on top of the mechanical dysfunction of the heart, the condition is called diastolic heart failure[1].
Diastole is the phase of the cardiac cycle when the heart ( i.e. ventricle) is not contracting but is actually relaxed and filling with blood that is being returned to it, either from the body (into right ventricle) or from the lungs ( into left ventricle). The mechanical abnormality in diastolic dysfunction is characterized by a decrease in the ventricular filling in the context of an elevated left ventricular end diastolic pressure and a normal ejection fraction.
Diastolic dysfunction is caused by decrease cardiac muscle relaxation or increased stiffness. The ejection fraction of the heart is preserved in this type of dysfunction.
Systolic and diastolic dysfunction commonly occur in conjunction with each other.
Classification
There are four basic echocardiographic patterns of diastolic heart failure, which are graded I to IV.
Pathophysiology
Diastolic dysfunction is the impairment of the heart muscle in its ability to properly relax and fill with blood during diastole. Diastolic dysfunction is mainly the result of either impaired myocardial relaxation or increased cardiac muscle stiffness. As a result, the pressure in the left ventricle increases at the end of diastole and causes a build up of pressure in the left atrium and consequently in the pulmonary circulation. The result is pulmonary edema and dyspnea.
Causes
Diastolic dysfunction is the mechanical abnormality of the heart to properly relax and fill with blood during diastole. Several medical conditions may lead to diastolic dysfunction.
References
- ↑ Zile MR, Brutsaert DL (2002). "New concepts in diastolic dysfunction and diastolic heart failure: Part I: diagnosis, prognosis, and measurements of diastolic function". Circulation. 105 (11): 1387–93. PMID 11901053.