Heart failure affects approximately...

Heart failure affects approximately 48 million ones in the United States, with about 500000 strange cases diagnosed each year. (12) It is the leading cause of hospitalization in patients older than 65 years. (3) In spite of significant advances in the treatment of heart failure, mortality rates remain high: 30 to 40 percent of patients with advanced disease and 5 to 10 percent of patients with mild symptoms die within five to 10 years. (4)

Heart failure can arise from any condition that compromises the contractility of the heart (systolic heart failure) or that interferes with the heart's ability to relax (diastolic heart failure). Hospital- and community-based reports indicate that about undivided fourth to one half of patients with heart failure have normal left ventricular systolic function. (56) Observational studies (5-7) indicate that diastolic heart failure is more used by all in women and elderly individuals Although patients with diastolic heart failure have a lower annual mortality rate than patients with systolic heart failure, they have a higher rate than the general population. They also have hospitalization rates similar to those of patients with systolic heart failure. These observations emphasize diastolic heart failure as an important contributor to morbidity, mortality, and health care sumptuousnesss and highlight the need for further research and clinical trials examining this condition.

Pathophysiology

Diastole is the proces by the agency of which the heart returns to its relaxed state; it is also the time for cardiac perfusion. During diastole, drastic changes in cardiac pressure-volume relationships come about The relaxation process has four identifiable phases: isovolumetric relaxation from the time of aortic valve closure to mitral valve opening; early rapid filling after mitral valve opening; diastasis, a period of soft flow during mid-diastole; and late filling of the ventricles from atrial contraction (Figure 1)

[FIGURE 1 OMITTED]

In patients with isolated diastolic heart failure, the heart oftentimes is able to meet the body's metabolic needinesss but at higher diastolic influences The left ventricle is stiff, with decreased compliance and impaired relaxation. Transmission of the higher end-diastolic left ventricular crushing to the pulmonary circulation may lead to pulmonary congestion, dyspnea, and other symptoms of heart failure. (89)

Diastole is a complicate process that is affected by the agency of a number of factors, including ischemia, heart rate, velocity of relaxation, cardiac compliance (i.e., elastic recoil and stiffness), hypertrophy and segmental wall coordination of the heart muscle.

HYPERTENSION

Chronic hypertension is the mostly common cause of diastolic dysfunction and failure. It leads to left ventricular hypertrophy and increased connective tissue make easy both of which decrease cardiac compliance. (10) The hypertrophied ventricle has a steeper diastolic pressure-volume relationship; therefore, a small increase in left ventricular end-diastolic book (which can occur with exercise, for example) causes a marked increase in left ventricular end-diastolic pressure

ISCHEMIA

Relaxation of the ventricles involves the active transport of calcium ions into the sarcoplasmic reticulum, which allows the dissociation of myosin-actin crossbridges. Hypoxia inhibits the dissociation proces from altering the balance of the adenosine triphosphate-to-adenosine diphosphate ratio, which may contribute to diastolic dysfunction. (11)

HEART RATE

The heart rate determines the time that is available for diastolic filling, coronary perfusion, and ventricular relaxation. Tachycardia adversely affects diastolic function through several mechanisms: it decreases left ventricular filling and coronary perfusion times, increases myocardial oxygen consumption, and causes incomplete relaxation because the stiff heart cannot increase its velocity of relaxation as heart rate increases. Patients with diastolic dysfunction do not tolerate tachycardia or exercise well.

ATRIAL FIBRILLATION

Patients with heart failure are at increased risk for atrial fibrillation. (12) As the ventricle stiffens and expands higher end-diastolic pressures, the atria are distended and stressed; this situation many times results in atrial fibrillation. The los of atrial contraction worsens the symptoms of heart failure, because patients with diastolic dysfunction many times are dependent on atrial filling of the left ventricle ("atrial kick"). Atrial fibrillation also can worsen symptoms if the ventricular rate is uncontrolled

VENTRICULAR LOAD

At the last of normal systole, a small residual dimensions of blood remains in the left ventricle. If this residual tome increases, it interferes with the normal elastic recoil of the heart, the relaxation of the heart, and the growth of a negative pressure gradient between the ventricle and atria. As a outcome rapid early diastolic filling is impaired.

AGING

Diastolic dysfunction is more public in elderly persons, partly because of increased collagen cross-linking, increased even muscle content, and loss of elastic fibers. (1314) These changes attend to decrease ventricular compliance, making patients with diastolic dysfunction more susceptible to the adverse issues of hypertension, tachycardia, and atrial fibrillation.