Additionally, BNP can be used to differentiate between causes of dyspnea due to heart failure from other causes of dyspnea. If myocardial infarction is suspected, various cardiac markers may be used. BNP is a better indicator than N-terminal pro-BNP  for the diagnosis of symptomatic heart failure and left ventricular systolic dysfunction. In symptomatic people, BNP had a sensitivity of 85% and specificity of 84% in detecting heart failure; performance declined with increasing age.Hyponatremia (low serum sodium concentration) is common in heart failure. Vasopressin levels are usually increased, along with renin, angiotensin II, and catecholamines to compensate for reduced circulating volume due to inadequate cardiac output. This leads to increased fluid and sodium retention in the body; the rate of fluid retention is higher than the rate of sodium retention in the body, this phenomenon causes hypervolemic hyponatremia (low sodium concentration due to high body fluid retention). This phenomenon is more common in older women with low body mass. Severe hyponatremia can result in accumulation of fluid in the brain, causing cerebral edema and intracranial hemorrhage. Angiography
Angiography is the X-ray imaging of blood vessels, which is done by injecting contrast agents into the bloodstream through a thin plastic tube (catheter), which is placed directly in the blood vessel. X-ray images are called angiograms. Heart failure may be the result of coronary artery disease, and its prognosis depends in part on the ability of the coronary arteries to supply blood to the myocardium (heart muscle).
Although some people survive many years, progressive disease is associated with an overall annual mortality rate of 10%.Around 18 of every 1000 persons will experience an ischemic stroke during the first year after diagnosis of HF. As the duration of follow-up increases, the stroke rate rises to nearly 50 strokes per 1000 cases of HF by 5 years. Epidemiology
In 2022, heart failure affected about 64 million people globally. Overall, around 2% of adults have heart failure and in those over the age of 65, this increases to 6–10%. Above 75 years old, rates are greater than 10%.Rates are predicted to increase. Increasing rates are mostly because of increasing lifespan, but also because of increased risk factors (hypertension, diabetes, dyslipidemia, and obesity) and improved survival rates from other types of cardiovascular disease (myocardial infarction, valvular disease, and arrhythmias). Heart failure is the leading cause of hospitalization in people older than 65. United States
In the United States, heart failure affects 5.8 million people, and each year 550,000 new cases are diagnosed. In 2011, heart failure was the most common reason for hospitalization for adults aged 85 years and older, and the second-most common for adults aged 65–84 years. An estimated one in five adults at age 40 will develop heart failure during their remaining lifetimes and about half of people who develop heart failure die within 5 years of diagnosis. Heart failure is much higher in African Americans, Hispanics, Native Americans, and recent immigrants from the Eastern Bloc countries such as Russia.