Diastolic dysfunction

Kenakin, T. P., Ambrose, J. R., and Irving, P. E. (1991). The relative efficiency of beta-adrenoceptor coupling to myocardial inotropy and diastolic relaxation Organ-selective treatment of diastolic dysfunction. J. Pharmacol. Exp. Ther. 257 1189—1197. 

Ventricular hypertrophy Maintains cardiac output Diastolic dysfunction... 

Diastolic dysfunction Abnormal filling of the ventricles during diastole. 

Heart failure (HF) is a clinical syndrome caused by the inability of the heart to pump sufficient blood to meet the metabolic needs of the body. HF can result from any disorder that reduces ventricular filling (diastolic dysfunction) and/or myocardial contractility (systolic dysfunction). 

Causes of diastolic dysfunction (restriction in ventricular filling) are increased ventricular stiffness, ventricular hypertrophy, infiltrative myocardial diseases, myocardial ischemia and infarction, mitral or tricuspid valve stenosis, and pericardial disease (e.g., pericarditis, pericardial tamponade). 

The echocardiogram is the single most useful evaluation procedure because it can identify abnormalities of the pericardium, myocardium, or heart values and quantify the left ventricular ejection fraction (LVEF) to determine if systolic or diastolic dysfunction is present. 

Bolus diuretic administration decreases preload by functional venodilation within 5 to 15 minutes and later (>20 min) via sodium and water excretion, thereby improving pulmonary congestion. However, acute reductions in venous return may severely compromise effective preload in patients with significant diastolic dysfunction or intravascular depletion. 

Diastolic dysfunction Improved hemodynamic performance -as above -improved lusitropy... 

Myocardial ischemia and infarction cause abnorma myocardial metabolism, decreased left ventricular (LV) systolic function, diastolic dysfunction, congestive heart failure, and decreased survival. Consequently, revascularization techniques, either surgical or catheter based, have become integral to treatment of severe ischemic heart disease. 

Patients with CHF and a normal ejection fraction are considered to have diastolic dysfunction. The frequency of CHF with diastolic dysfunction increases with age. Such patients benefit from treatment of the underlying cause such as hypertension or ischaemia. Inotropic agents such as digoxin should be avoided. Diuretics, -blockers, ACE inhibitors can be used. Aldosterone inhibition, using spironolactone or epleronone, may be beneficial. Carvedilol improves diastolic dysfunction in diastolic CHF. However the long-term benefit of different drug therapies has not yet been defined. 

The management of heart failure in the presence of normal systolic function is not reviewed. This form of heart failure commonly occurs in the elderly with chronic hypertension and left ventricular hypertrophy. The failure of the left ventricle to relax during diastole (diastolic dysfunction) results in elevated end diastolic... 

Heart failure is a syndrome with many causes that may involve either ventricle or both. Cardiac output is usually below the normal range. Systolic dysfunction, with reduced cardiac output and significantly reduced ejection fraction (< 45%), is typical of acute failure, especially that resulting from myocardial infarction. Diastolic dysfunction often occurs as a result of hypertrophy and stiffening of the myocardium, and although cardiac output is reduced, ejection fraction may be normal. Heart failure due to diastolic dysfunction does not usually respond optimally to positive inotropic drugs. 

Zile MR, Brutsaert DL. New concepts in diastolic dysfunction and diastolic heart failure Part I diagnosis, prognosis, and measurements of diastolic function. Circulation 2002 105 1387-1393. 

Myocardial hypertrophy The heart increases in size, and the chambers dilate. Initially, stretching of the heart muscle leads to a stronger contraction of the heart. However, excessive elongation of the fibers results in weaker contractions. This type of failure is termed systolic failure and is a result of a ventricle unable to pump effectively. Less commonly, patients with CHF may have diastolic dysfunction—a term applied when the ventricles ability to relax and accept blood is impaired by structural changes, such as hypertrophy. The thickening of the ventricular wall and subsequent decrease in ventricular volume decreases the ability of heart muscle to relax. In this case, the ventricle does not fill adequately, and the inadequacy of cardiac output is termed diastolic heart failure. 

Jougasaki, M., Nishimura, R. A., Bailey, K. R., Saito, Y, Nakao, K., Redeield, M. M. (1996). Superiority of brain natriuretic peptide as a hormonal marker of ventricular systolic and diastolic dysfunction and ventricular hypertrophy. Hypertension 28, 988-994. 

Bonow RO, Udelson JE. Left ventricular diastolic dysfunction as a cause of congestive heart failure Mechanisms and management. Ann Int Med 1992 117 502-10. 

Pouleur H. Diastolic dysfunction and myocardial energetics. Eur Heart J 1990 ll(Suppl C) 30. ... 

K. Przyklenk, P. Whittaker and R.A. Kloner, In vivo infusion of oxygen free radical substrates causes myocardial systolic but not diastolic dysfunction, Am. Heart J. 119, 807-815 (1990). 

L. F. Wexler, B. H. Lorell, S. Momomura, E. O. Weinberg, J. S. Ingwall, C. S. Apstein, Enhanced sensitivity to hypoxia-induced diastolic dysfunction in pressure-overload left ventricular hypertrophy in the rat role of high-energy phosphate depletion, Circ Res 62, 766-75 (1988). 

Heart failure can result from any disorder that affects the ability of the heart to contract (systolic function) and/or relax (diastolic dysfunction) common causes of heart failure are shown in Table 14—1 Systolic heart failure is the classic, more familiar form of the disorder, but current estimates suggest that 20% to 50% of patients with heart failure have preserved left ventricular systolic function and suffer from diastolic dysfunction. In contrast to systolic heart failure that is usually caused by previous myocardial infarction (Ml), patients with diastolic heart failure typically are elderly, female, and have hypertension and diabetes. However, systolic and diastolic dysfunction frequently coexist. The common cardiovascular diseases such as MI and hypertension can cause both systolic and diastolic dysfunction thus many patients have heart failure as a result of reduced myocardial contractility and abnormal ventricular filling. 

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