Over time, these increases in workload, which are mediated by long-term activation of neurohormonal systems such as the renin–angiotensin system and the sympathoadrenal system, lead to fibrosis, dilation, and structural changes in the shape of the left ventricle from elliptical to spherical.The heart of a person with heart failure may have a reduced force of contraction due to overloading of the ventricle. In a normal heart, increased filling of the ventricle results in increased contraction force by the Frank–Starling law of the heart, and thus a rise in cardiac output. In heart failure, this mechanism fails, as the ventricle is loaded with blood to the point where heart muscle contraction becomes less efficient. This is due to reduced ability to cross-link actin and myosin myofilaments in over-stretched heart muscle. Diagnosis
No diagnostic criteria have been agreed on as the gold standard for heart failure. In the UK the National Institute for Health and Care Excellence recommends measuring brain natriuretic peptide 32 (BNP) followed by an ultrasound of the heart if positive. This is recommended in those with shortness of breath. In those with worsening heart failure, both a measure of BNP and of troponin are recommended to help determine likely outcomes. Classification
One historical method of categorizing heart failure is by the side of the heart involved (left heart failure versus right heart failure).
The inclusion of regular physical conditioning as part of a cardiac rehabilitation program can significantly improve quality of life and reduce the risk of hospital admission for worsening symptoms, but no evidence shows a reduction in mortality rates as a result of exercise. Despite cardiac rehabilitation being a recommended treatment for patients with heart failure with reduced ejection fraction (HFrEF), it is still underused. The reasons why this happens are complex, heterogeneous, and encompass healthcare system-, referring physician-, program-, and patient-level barriers. According to Alexandre et al., the main reasons for HFrEF patients not being enrolled in cardiac rehabilitation were no medical referral (31%), concomitant medical problems (28%), patient refusal (11%), and geographical distance to the hospital (9%). Furthermore, whether this evidence can be extended to people with HFpEF or to those whose exercise regimen takes place entirely at home is unclear.Home visits and regular monitoring at heart-failure clinics reduce the need for hospitalization and improve life expectancy. Medication
Quadruple medical therapy using a combination of angiotensin-receptor neprilysin inhibitors (ARNI), beta blockers, mineralocorticoid receptor antagonists (MRA), and sodium glucose cotransporter-2 inhibitors (SGLT2 inhibitors) is now the standard of care as of 2021. First line medications
First-line therapy for people with heart failure due to reduced systolic function should include angiotensin-converting enzyme (ACE) inhibitors (ACE-I), or angiotensin receptor blockers (ARBs) if the person develops a long-term cough as a side effect of the ACE-I.