Epidemiology
Heart failure is the most common indication for hospitalization for a circulatory condition in the US, and the second most common cause of hospitalization overall among patients >65 years.[4]
From 2017 to 2020, approximately 6.7 million adults ages ≥20 years had heart failure in the US.[5] The prevalence of heart failure increases with increasing age. In the US, among people ages 40 to 59 years, the prevalence of heart failure is about 2.3% in males and 1.2% in females, whereas among people ages ≥80 years the prevalence of heart failure is about 10.9% in males and 7.1% in females; however, the population attributable risk of modifiable risk factors such as obesity, hypertension, diabetes and smoking is greater among young (ages <55 years) compared with older (ages ≥75 years) individuals.[6][5] Women present with heart failure later in life and survival is generally more favorable; however, they present with more comorbidities and with lower patient-reported health status than men.[2] In the US, heart failure incidence is higher in black patients compared to white patients, and rates of heart failure hospitalization and mortality are also higher.[2]
Heart failure is a global disease. The prevalence of heart disease is about 1.3% in China, 6.7% in Malaysia, 1% in Japan, 4.5% in Singapore, 0.12% to 0.44% in India, 1% in South America, and 1% to 2% in Australia.[7] Global improvements in AHF survival between 1980 and 2017 have been linked to increased use of neurohormonal antagonist drugs (renin-angiotensin-aldosterone inhibitors).[8]
Risk factors
In patients hospitalized for acute heart failure, around 75% have a history of prior heart failure.[11]
Coronary artery disease accounts for around 50% of all patients with acute heart failure.[11][12][13][14] Chronic myocardial ischemia results in myocardial damage with progressive decline in left ventricular (LV) systolic function. Subendocardial ischemia also causes an increase in LV end diastolic pressure leading to pulmonary edema in the presence of normal LV systolic function.
Acute coronary ischemia can lead to acute heart failure either due to pump failure or papillary muscle destruction/rupture. In the case of pump failure, the LV function is depressed, but in cases of heart failure associated with papillary muscle rupture, the measured LV function may appear preserved.
A history of hypertension is present in 72% of patients in the US and 60% of patients in Europe.[11][13][14]
Hypertension predisposes to the development of heart failure by increasing the afterload on the ventricles, which induces left ventricular hypertrophy, which in turn leads to left ventricular (LV) dysfunction, an increased risk of myocardial infarction, and significant arrhythmias.
In patients with noncompliant ventricles, an abrupt or significant increase in blood pressure increases the LV end diastolic pressure, precipitating acute heart failure.
About 23% of patients in the US and 34% in Europe have valvular disease as an associated condition.[11][14] Both significant stenotic and regurgitant lesions can lead to heart failure.
Although rheumatic valvular disease is now rarely found in western countries, calcific valvular heart disease, in particular aortic stenosis, is commonly encountered.
In patients with significant valvular disease, the heart failure will not improve until the underlying valvular disease has been corrected.
A large pericardial effusion can present with symptoms or signs of acute heart failure.
Pericardial constriction, such as tuberculosis pericarditis or the effects of radiation therapy, can also present with acute heart failure.
There are many causes of myocarditis, of which a viral etiology appears to be the most common. There is usually a prodrome of a nonspecific illness characterized by fatigue, mild dyspnea, and myalgias.
Cardiac arrhythmias, including tachyarrhythmia and bradyarrhythmia, are risk factors for acute heart failure. Atrial fibrillation is present in approximately 35% of cases.[15] Concomitant atrial fibrillation and heart failure predicts increased all-cause mortality across all categories of heart failure.[16]
Present in 31% of cases.[11]
Related directly to ischemia and renal failure.
Precipitating factor in patients with acute on chronic heart failure.
Present in 22% of cases.[17]
Obesity is a risk factor for hypertension and coronary artery disease, and is also associated with increased risk of heart failure. However, there is evidence that patients with heart failure and obesity have better clinical outcomes compared to patients with normal weight and similar degrees of heart failure (the “obesity paradox”).[24]
Studies show that higher body mass index is more strongly associated with the risk of heart failure with preserved ejection fraction (HFpEF) than with heart failure with reduced ejection fraction (HFrEF).[25][26]
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