Heart Failure
Heart failure is a common condition where the heart does not pump sufficient blood to meet the demands of the body, over a long period of time. The condition can cause severe symptoms and can even shorten lifespan, depending on the cause, severity and success of treatment.
Heart failure is the common endpoint of many different other conditions, and can occur for example after a heart attack, as a result of heart rhythm problems, or due to diseases of the heart muscle or valves. Symptoms, timecourse and treatments may differ depending on the underlying cause but there are some common themes to all causes, and some treatments are common to all conditions.
Symptoms - When to see a cardiologist - Causes - Complications
Symptoms
The most common symptoms of heart failure are fatigue, breathlessness and reduced exercise tolerance, due to the heart being unable to keep up with the demands being made of it. As the condition worsens, the following features may also arise:
Oedema - swelling of the lower limbs and abdomen due to fluid retention. Heart failure triggers production of hormones and other substances that cause the kidneys to retain fluid.
Breathlessness on lying flat - called “orthopnoea” in anglicised Greek, is a symptom of more advanced heart failure where fluid retention leads to the lung cavity filling with water. Fluid shifts triggered by lying down worsen the problem, as fluid from the lower body gets redistributed into the chest. Patients with orthopnoea typically sleep propped up on several pillows and wake very breathless if they slide down. Sitting up relieves the breathing problems almost instantly.
Unpredictable breathlessness at night - this is a variation on “orthopnoea” called “paroxysmal nocturnal dyspnoea” which literally means “intermittent breathing difficulties at night-time”. Patients report being woken from sleep by breathing difficulties and wheezing, relieved by sitting upright and/or opening a window to get more air. This is a very typical story for heart failure.
Chest pain - advanced heart failure can cause pains similar to angina as the heart even struggles to meet it’s own blood supply needs.
Symptoms of heart failure are graded according to the New York Heart Association scoring system, classes 1 to 4. Patients with class 1 symptoms have little or no restriction on everyday activities, and may only get symptomatic on unusual levels of exertion. At the other end of the scale, patients with class 4 symptoms experience problems on little or no exertion, sometimes even at rest.
It is important to assess symptoms of heart failure accurately, as despite many other tests being available, the severity of symptoms is still one of the best ways to predict survival and complications of heart failure.
When to See a Cardiologist
A cardiologist can help make a diagnosis of heart failure and has access to tests and investigations to look for a cause. Some causes of heart failure and treatable and even reversible, whereas others are not reversible but require long term management. It is important to see a doctor with expertise in this area to ensure a correct diagnosis and evaluation for reversible causes.
Doctors will usually diagnose heart failure based on symptoms (see above), blood tests such as NTpro-BNP, and cardiac imaging with tests such as echocardiography and cardiac MRI.
If you suffer with symptoms that could be caused by heart failure then a cardiologist will have access to tests to confirm the problem or to reassure you that your symptoms are not due to the heart. If the problem does turn out to be heart failure than a cardiologist will usually arrange further tests to find the cause. These tests may include blood pressure monitors, blood tests, and ECGs. Some causes of heart failure can run in families, so a detailed family history will be saught.
Causes of Heart Failure
Most cases of newly diagnosed heart failure are “systolic” heart failure, i.e. a problem with the heart contracting to push blood forward around the circulation. A minority of new cases of heart failure are “diastolic” heart failure, caused by a failure of the heart muscle to suck in blood between beats. Systolic and diastolic heart failure have different lists of causes, and affect different groups of people. They also have different sets of treatments.
The most common cause of systolic heart failure is previous heart attack. If a heart attack is treated late, or not at all, it leads to death of some heart muscle. The muscle around the dead muscle is also affected and may contract less strongly. In very large heart attacks, even healthy muscle not affected by the original problem may, over time, begin to work less efficiently and become scarred. The capacity of the heart to pump blood is reduced and this causes heart failure.
The most common cause of diastolic heart failure is untreated or adequately treated high blood pressure (hypertension). Over time, hypertension puts additional stress on the main pumping chamber of the heart, called the left ventricle. This tends to thicken up, with very subtle scar developing within the substance of the muscle. This in time will interfere with the relaxation of the heart in between beats, leading to inefficient filling of the heart and eventually to heart failure.
Many medical conditions can cause heart failure and a complete list is not feasible. Other common causes of heart failure include:
Alcohol excess - this tends to cause systolic heart failure by weakening the heart muscle leading to enlarged (“dilated”) chambers which do not pump effectively.
Inherited heart muscle disease (inherited cardiomyopathy) - this group of conditions includes diseases which are very different to each other. Some cause systolic failure, and some others cause diastolic failure. The most common inherited cardiomyopathy is hypertrophic cardiomyopathy (HCM), which tends to cause obstruction to blood flow but can also cause both systolic and diastolic heart failure. The terminology here can be confusing, because in general inherited causes of heart failure tend to be called “cardiomyopathies” but any heart muscle disorder of any cause can also be called “cardiomyopathy”.
Arrhythmia - disorders of heart rhythm, particularly those that cause persistent racing of heart, can lead to systolic heart failure. Atrial fibrillation and atrial flutter are the most common arrhythmias to cause heart failure, but rarer conditions such as persistent atrial tachycardia, and persistent reciprocating junctional tachycardia (PJRT) also may cause weakening of the heart over time. Heart failure caused by arrhythmia tends to recover if the rhythm problem is successfully treated.
Metabolic disorders - the most common metabolic cause of heart failure is thyroid disease. The thyroid gland produces the hormone thyroxine which regulates many important processes in the body. In the heart, it influences heart rate and the strength of heart contraction. Severe overactive thyroid, or overuse of thyroxine tablets, can lead to heart failure. Some other very rare disorders of metabolism such as Fabry’s disease and Gaucher’s disease can cause cardiomyopathy.
Complications of Heart Failure
If not diagnosed and treated, heart failure tends to worsen gradually over time. This results in more severe symptoms and greater limitations for the patient. Exercise tolerance may decrease and fatigue may worsen. Symptoms such as chest pain may occur on progressively less and less exertion.
Ultimately, a failing heart may lead to severe fluid retention and, in many cases, to death.
Other complications of heart failure include fast and dangerous heart rhythms (“ventricular arrhytyhmias”) which can also be fatal. For this reason, some patients with advanced heart failure are offered defibrillator devices, if they are felt to be at high risk of potentially fatal heart rhythm disturbances.