Heart failure is the end stage of cardiac disease after the myocardium has used all its reserve and compensatory mechanisms. Once overt signs appear, half of patients die within 5 years despite medical management.32 Heart failure is most often a consequence of hypertension, CHD, valve deformity, diabetes, or cardiomyopathy. The various etiologies tend to coexist. CHD, frequently accompanied by hypertension, is responsible in more than 50 percent of cases and has been increasing in prevalence among new cases of heart failure. Left ventricular hypertrophy, hypertension, and valvular diseases are diminishing determinants. The risk of cardiac failure is increased two- to sixfold with CHD, angina conferring half the risk compared with MI. The dominant cause continues to be hypertension, which precedes failure in 75 percent of patients.
An estimated 4.8 million Americans have CHF.2 The prevalence increases with age to exceed 10 percent after age 60 (see Fig. 1-9). Each year there are an estimated 400,000 new cases.2 In 1997, there were 43,000 deaths nominally classified to heart failure as the underlying cause and about another 200,000 where heart failure was listed on the death certificates as a secondary cause. The death rate increased in most years between 1968 and 1997. The rate of hospitalizations for heart failure increased between three and four times between 1970 and 1997 in patients aged 45 to 64 and 65 and over.2,8 In 1997, heart failure was the first-listed discharge diagnosis in 957,000 hospital discharges and a secondary diagnosis in another 2.1 million discharges.8 Twenty percent of all hospital discharges of patients aged 65 and over had heart failure as a primary or secondary diagnosis. The percentage of CHF patients who died in hospitals, however, decreased from 11.3 percent in 1981 to 5.0 percent in 1996.1 Visits to physicians' offices for CHF increased from 1.7 million in 1980 to 3.2 million in 1995. The prevalence is similar in men and women, but it is higher in blacks than whites. It increased substantially as measured in national surveys in 19761980 and 1988-1994 (see also Chaps. 23 and 41).
Based on the Framingham Study, heart failure is equally frequent in men and women, and the annual occurrence approaches 10 per 1000 population after 65 years of age (see Table 1-1). Survival following the diagnosis of heart failure is worse in men than in women, but even in women fewer than 15 percent survive much longer than 8 to 12 years (see Table 1-6). The prognosis is not much better than for most forms of cancer. The 1-year fatality rate for heart failure is high, with one in five patients dying. Sudden death is a common mode of exitus, occurring at six to nine times the general population rate. With an increasing geriatric population, heart failure is a formidable problem.
There is little indication that the declines in death rates from heart disease in general and from CHD in particular in the United States have been accompanied by an improvement in the incidence of heart failure.33 This cannot be readily explained. Some postulate that improved survival of patients with angina, MI, and hypertensive heart disease may result in an increased prevalence of chronic heart disease and ultimately heart failure. Data from the Framingham Study indicate very little improvement to date in the ominous outlook following the onset of CHF. The median survival of 652 incident cases of CHF was only 1.7 years in men and 3.2 years in women,33 and the overall survival rates at 5 years were only 25 percent for men and 38 percent for women. The mortality increased with age in both sexes. If one adjusts for age, no significant changes in the prognosis of CHF are evident over the past four decades despite improvements in treatment. Advances in treatment of hypertension, myocardial ischemia, and valvular heart disease have not resulted in dramatic improvements in survival once heart failure ensues.
Despite the availability of potent glycosides, diuretics, and antihypertensive agents, heart failure continues at a high incidence.34 Because of the high attributable risk of hypertension and CHD, their prevention and effective treatment would appear to be required to make a significant impact on the incidence of congestive heart failure.
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Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...