ESSENTIALS OF DIAGNOSIS
Dyspnea on exertion and at rest, orthopnea, paroxysmal nocturnal dyspnea, and fatigue.
Elevated jugular venous pressure, basilar rales or coarse rales throughout both lung fields with wheezing, cardiomegaly, S3 gallop, hepatomegaly, and bilateral peripheral pitting edema.
Dilated left ventricle with a reduced ejection fraction on transthoracic echocardiography.
Elevated left ventricular filling pressures on cardiac catheterization.
Heart failure (HF) is a complex clinical syndrome resulting from any structural or functional myocardial dysfunction that leads to an impaired ability to circulate blood at a rate sufficient to maintain the metabolic needs of internal organs and peripheral tissues. The myocardial dysfunction is often the consequence of long-standing ischemia due to coronary artery disease or loss of myocardial mass due to prior infarction, long-standing myocardial stress due to suboptimally treated hypertension or valvular disease, or direct long-term toxin exposure (alcohol abuse, illicit substance use, or chemotherapeutic agents); rarely, fulminant infections (especially viral) can lead to autoimmune myocardial damage, and in some cases, there is no apparent cause (idiopathic cardiomyopathy, usually related to inherited or spontaneous gene mutations).
The cardinal manifestations of HF are dyspnea and fatigue (which may limit exercise tolerance) and fluid retention (which may lead to pulmonary/hepatic/splanchnic congestion and peripheral edema). Both abnormalities impair the functional capacity and quality of life of affected patients, but they may not necessarily dominate the clinical picture at the same time.
The prevalence of HF in the United States is around 5.8 million patients, with projections showing a 46% increase from 2012 to 2030 resulting in over 8 million people with HF. Approximately 45% have reduced ejection fraction/systolic dysfunction. There are an estimated 870,000 new HF cases annually.
At age 40, the lifetime risk for HF is as high in women as in men, and is approximately one in five. Although over 75% of HF patients have antecedent hypertension or coronary artery disease, the population attributable risk (PAR) is different in men and women; the PAR for HF associated with coronary artery disease is 39% in men and 18% in women, whereas the PAR associated with hypertension is 39% in men and 59% in women, emphasizing the crucial need for population-based strategies to prevent the development of HF.
Multiethnic epidemiologic studies showed that the highest risk for developing HF is in African Americans (highest in young women and middle-aged men), followed by Hispanics/Latinos, Caucasians, and Chinese. This higher risk likely reflects differences in the prevalence of hypertension and diabetes mellitus and in socioeconomic status between different ethnicities.
Although the survival after HF diagnosis has improved, the 5-year mortality is still close to 50%, and over a quarter million deaths every year have antecedent HF. In addition, HF is one of the leading causes of hospitalization in the United States, with over one million hospitalizations a year (a figure that has ...