Heart failure (HF), also called Congestive Heart/Cardiac Failure (CHF/CCF) occurs when the heart is unable to pump adequate blood into the arteries, and the backlog of blood in the heart leads to congestion and backpressure into the lungs and the veins.
Ejection fraction (EF), measured by echocardiography, is the percentage of how much blood the left ventricle pumps out with each contraction. Based on this, HF is of the following types:
- Heart failure with reduced ejection fraction (HFrEF) or systolic heart failure: EF is 40% or less, signifying deficient pumping action possibly due to weak or damaged cardiac muscles.
- Heart failure with preserved ejection fraction (HFpEF) or diastolic heart failure: EF is 50% or more, signifying that even though pumping is effective, there is a deficient filling of the ventricle, possibly due to muscle stiffness resulting from disease, damage or scarring.
- EF of 41-49% is considered borderline.
HF is usually chronic (occurs over a period of time) but can sometimes be acute (occurs suddenly or over a short span of time). HF is sometimes mentioned as left-sided or right-sided. Left-sided HF is more common and occurs earlier, usually caused by coronary artery disease (CAD), or long-term high blood pressure. Right-sided HF generally develops as a result of advanced left-sided HF and backpressure causing congestion in the lung (pulmonary hypertension).
Causes of HF
- Myocardial infarction – An episode of a massive MI where large parts of the cardiac muscles (myocardium) are damaged due to oxygen deprivation. It can cause acute heart failure.
- Coronary Artery Disease (CAD) – As discussed above, this causes a decrease in the heart’s ability to proportionally step up oxygen supply in response to increased load due to the arteries containing plaques (atherosclerosis) that narrows them.
- Prolonged hypertension – Increased BP leads to an increased load on the heart as it has to pump against higher pressure and resistance.
- Heart rhythm abnormalities (arrhythmia). Sudden highly fast and irregular heartbeat (atrial/ventricular fibrillation) can cause acute heart failure).
- Myocarditis and cardiomyopathy – This refers to inflammation or disease, causing damage to the heart muscles (myocardium), seen due to viral infection (viral/post-viral myocarditis), injury, or degeneration.
- Cardiac valve abnormalities or damage to valves caused by infection (endocarditis).
- Pericardial effusion or constrictive pericarditis.
Symptoms of HF
- breathlessness (especially on lying down) or on exertion
- swelling of legs/ankles/feet/abdomen/face-eyelids
- lack of appetite
- increased need to pass urine (especially at night)
Medical management includes medicines that –
- Decrease the cardiac load by improving BP control and heart function (RAAS inhibitor drugs – ACE inhibitors and ARBs)
- Dilating the arteries and the veins (vasodilators like CCB group of drugs)
- Decreasing heart rate (beta-blockers)
- Eliminating excess fluid (diuretics)
The above are also drugs used to manage high BP.
New drugs called angiotensin receptor neprilysin inhibitors (ARNI: Sacubitril-Valsartan) are also available now for heart failure not responding well to these medicines.
Oxygen therapy may be needed in people who have significant congestion of blood in the lungs, due to reduced pumping of the left side of the heart.
Heart failure increases the risk of blood clotting (thrombosis) due to stagnation of blood flow. This can increase the chance of detached clots (emboli) lodging in the brain arteries and causing stroke. Therefore antiplatelet and anticoagulant medicines (blood thinners) are given in such patients as a preventive measure.