Diastolic dysfunction causes: Difference between revisions
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**Myocardial stiffness can be secondary to cardiac muscle hypertrophy (for example as seen in [[hypertension]]). | **Myocardial stiffness can be secondary to cardiac muscle hypertrophy (for example as seen in [[hypertension]]). | ||
**Myocardial stiffness can be the result of [[infiltrative diseases]] like [[amyloidosis]]. | **Myocardial stiffness can be the result of [[infiltrative diseases]] like [[amyloidosis]]. | ||
**Scarred heart muscle, occurring after a heart attack, | **Scarred heart muscle, occurring after a heart attack, are relatively stiff. | ||
**[[Diabetes]] can be a cause of cardiac stiffness as a result of [[glycosylation]] of the heart muscle. | **[[Diabetes]] can be a cause of cardiac stiffness as a result of [[glycosylation]] of the heart muscle. | ||
*'''3- Extrinsic constraints:''' | *'''3- Extrinsic constraints:''' | ||
**Extrinsic constraints can be seen in pericardial compression. | **Extrinsic constraints can be seen in pericardial compression. | ||
*'''4- Chamber dilatation:''' | *'''4- Chamber dilatation:''' | ||
**Severe systolic dysfunction that has led to ventricular dilation can be associated with diastolic dysfunction. When the ventricle has been stretched to a certain point, any further attempt to stretch it more, as by blood trying to enter it from the left atrium, meets with increased resistance and thus | **Severe systolic dysfunction that has led to ventricular dilation can be associated with diastolic dysfunction. When the ventricle has been stretched to a certain point, any further attempt to stretch it more, as by blood trying to enter it from the left atrium, meets with increased resistance and thus decreased compliance. | ||
*5'''- Miscelleneous:''' | *5'''- Miscelleneous:''' | ||
**In [[mitral stenosis]], blood cannot readily flow out from the [[left atrium]] into the [[left ventricle]] since the valve between those two heart chambers is blocked which causes the blood to back up into the left atrium and, eventually, the lungs. [[Pulmonary edema]] may result. | **In [[mitral stenosis]], blood cannot readily flow out from the [[left atrium]] into the [[left ventricle]] since the valve between those two heart chambers is blocked which causes the blood to back up into the left atrium and, eventually, the lungs. [[Pulmonary edema]] may result. | ||
Revision as of 02:41, 20 October 2012
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Assistant Editor(s)-in-Chief: Rim Halaby
Overview
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 and they include impaired myocardial relaxation, increased myocardial stiffness and extrinsic constraint on the heart.
Causes
- 1- Impaired extent and/or speed of myocardial relaxation:
- Myocardial relaxation is an ATP dependent process regulated by the rate of re-uptake of cytoplasmic calcium into the sarcoplasmic reticulum.
- Low concentration of calcium, as seen in ischemia, is associated with a slowed down myocardial relaxation.
- 2- Increased myocardial stiffness:
- Myocardial stiffness can be secondary to cardiac muscle hypertrophy (for example as seen in hypertension).
- Myocardial stiffness can be the result of infiltrative diseases like amyloidosis.
- Scarred heart muscle, occurring after a heart attack, are relatively stiff.
- Diabetes can be a cause of cardiac stiffness as a result of glycosylation of the heart muscle.
- 3- Extrinsic constraints:
- Extrinsic constraints can be seen in pericardial compression.
- 4- Chamber dilatation:
- Severe systolic dysfunction that has led to ventricular dilation can be associated with diastolic dysfunction. When the ventricle has been stretched to a certain point, any further attempt to stretch it more, as by blood trying to enter it from the left atrium, meets with increased resistance and thus decreased compliance.
- 5- Miscelleneous:
- In mitral stenosis, blood cannot readily flow out from the left atrium into the left ventricle since the valve between those two heart chambers is blocked which causes the blood to back up into the left atrium and, eventually, the lungs. Pulmonary edema may result.
- Diastolic dysunction secondary to mitral stenosis is especially seen when the heart rate is elevated, as occurs in exercise and pregnancy. Thus, there will be insufficient time for the blood to traverse the narrowed passageway (i.e. mitral valve) between the left atrium and left ventricle.[1]
References
- ↑ Mann D.L., Chakinala M. (2012). Chapter 234. Heart Failure and Cor Pulmonale. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo (Eds), Harrison's Principles of Internal Medicine, 18e.