Heart failure
Heart failure is a condition in which the heart does not perform well in its vital function of supplying blood to the body. Parts of the body may be less well supplied with blood, or blood may build up and swell.
Caring for patients with heart failure requires long-term collaboration between a team of doctors and nurses.
There can be a number of causes of deterioration in heart function. It may be a malfunction of one of the heart's ventricles or heart valves, or it may be due to a heart rhythm disorder. Heart failure can also occur if any part of the heart is compressed or if something outside the heart obstructs the flow of blood or if there is some unnatural connection between the heart parts and there is a short circuit of blood. Some causes can be removed, others are irreversible.
The most common cause of heart failure is loss of left ventricular function after a myocardial infarction. In myocardial infarction, part of the muscle of the left ventricle dies and is permanently replaced by scar tissue. The ability to expel blood from the left ventricle into the circulation of the whole body is thus reduced. A healthy heart ejects approximately 60% of the left ventricular volume during contraction; this parameter is called the left ventricular ejection fraction and is abbreviated as EFLK. The EFLK value is very important. If EFLK is less than 35% the heart is at risk of sudden cardiac arrest. If the EFLK is, for example, 20% the impairment is already very severe and the patient finds it difficult to manage even a small effort.
Cut through the heart at the level of ventricles. Left ventricle with a noticeable scar of the lower wall after a myocardial infarction.
Another common cause of decreased left ventricular ejection fraction is the so-called dilated cardiomyopathy. In this case, it is a disease of the musculature of the left ventricle itself, its blood supply is not impaired in any way, and the flow through the coronary arteries supplying the heart is unrestricted. The cause of dilated cardiomyopathy is mostly unknown. For example, there may be a history of inflammation of the heart and hereditary factors are certainly involved in its development. In dilated cardiomyopathy, the ventricles are affected in their entirety and the worse stenosis is not limited to one part as after myocardial infarction. The left ventricle is often dilated.
Comparison of a healthy heart (left) and a heart in dilated cardiomyopathy with a noticeable dilated and globularly changed left ventricle (right)
Sometimes the left ventricular stiffness weakens only transiently, and the heart muscle is as if stunned or hibernated. In this case, if the cause is resolved, left ventricular function improves again. This is, for example, a situation where part of the muscle is less well perfused when the coronary artery is narrowed, but there has not yet been a heart attack. Or in the case of an increase in heart rate lasting for several weeks in a rhythm disturbance, most often in atrial flutter. Sometimes there may be a weakening of contractility in prolonged ventricular pacing or in multiple premature ventricles contractions. If any of these causes is removed, the stunned or hibernating heart muscle will gradually recover its function and left ventricular contractility will return to normal in about 1-3 months.
Sometimes the heart fails even if the left ventricle has preserved contractility and there is no apparent other correctable cause of failure. In this case, we speak of heart failure with preserved EFLK. This condition may be caused, for example, by increased stiffness of the left ventricle, which is thus less easily filled with blood between contractions.
Heart failure is most often manifested by shortness of breath, or a feeling of oxygen deprivation with the need to breathe faster. Other symptoms include fatigue and weakness. If blood builds up somewhere in the body, it moves water from the blood to adjacent tissues and they begin to swell. Typically, the lower limbs swell. Further, the lungs may swell and the breathlessness then gets worse; in more advanced stages, fluid gets into the lung chambers and the patient coughs, cannot tolerate lying down and often has to sit up to breathe. This condition is life-threatening and if it occurs, the ambulance service should be called urgently. If the liver or stomach is swollen, then disgust may occur.
The most common manifestations of heart failure
If heart failure is detected, the cause of the heart failure is investigated and doctors try to eliminate the cause. However, the cause is not always curable and heart failure persists. In these cases, drugs are taken to lower blood pressure or to drain the blood. By lowering the blood pressure, the heart is relieved, it does not have to exert as much work and the rate of congestion in the body is reduced. Drainage drugs then drain excess water from the body from the swollen organs. The body is able to make drainage substances on its own, but their effect is no longer sufficient in the later stages of failure. In heart failure, the activity of stress hormones also increases, and this can result in life-threatening heart rhythm disturbances. Drugs that dampen the effect of these stress hormones then prolong the life of patients. Similarly, most of the blood pressure lowering drugs mentioned above and some drainage drugs also prolong the life of heart failure patients.
The European Society of Cardiology's recommended practice for the treatment of heart failure with reduced EFLK. ACEIs, angiotensin converting enzyme inhibitors; ARNIs, angiotensin receptor blockers and neprilysin inhibitors; CRT-D, defibrillator resynchronization therapy; CRT-P, pacemaker resynchronization therapy; ICD, implantable cardioverter-defibrillator; MRAs, mineralocorticoid receptor antagonists; SR, sinus rhythm.
With long-term treatment, it may happen that the condition worsens and it is necessary to temporarily increase the dose of drainage medication. This can usually be done in the home environment, but sometimes a short hospitalization and administration of drugs in injectable form is necessary. Warning signs of worsening are rapid weight gain with water loss in the body or the development of swelling of the lower limbs or worsening shortness of breath. If treatment in such cases is adjusted in time, the development of life-threatening pulmonary oedema can be prevented. Sometimes pulmonary oedema can occur even after abrupt withdrawal of blood pressure lowering drugs. Therefore, when treating heart failure, it is important to actively look for signs of deterioration and not to spontaneously discontinue the medication.
If the reduced EFLK persists at 35% or less despite treatment, implantation of an implantable cardioverter-defibrillator (ICD) is performed. This device monitors the rhythm of the heart over a long period of time and, in the event of life-threatening rhythm disturbances, terminates the condition with rapid pacing or a shock. If the left ventricular contraction is not symmetrical, the performance of the heart can be improved by implanting a pacemaker or an ICD that allows so-called biventricular pacing. With biventricular pacing, left ventricular contraction is more symmetrical and synchronous and cardiac performance improves. The physician decides whether to indicate this so-called resynchronisation therapy on the basis of the ECG, where the impaired symmetry of the left ventricular contraction is manifested as a prolongation of the QRS interval.
Schematic representation of an implantable cardioverter-defibrillator
Schematic representation of cardiac resynchronization therapy - the atrial electrode is placed in the right atrium, the right ventricle in the right ventricle and the left ventricle is inserted into the lateral cardiac vein.
Life with heart failure can be quite fulfilling. Many patients are able to cope with heavier exertion and can play sports. Regular physical activity increases whole-body performance, muscle strength and improves the patient's prognosis - this is generally true for all individuals, regardless of heart failure. If dyspnoea develops during physical activity, it is necessary to slow down or stop, but otherwise physical activity is unrestricted. Regular monitoring of blood pressure and body weight at home, for example, weekly or when there is a change in condition or development of difficulties, is appropriate. Driving is unrestricted except in exceptional circumstances. In the more advanced stages of heart failure, health checks should be intensified, signs of deterioration should be carefully monitored and treatment should be adjusted or the patient hospitalised in a timely manner.
Regular physical activity is also beneficial for patients with heart failure.
If the heart function is so low that it can no longer perform its function even with drug-induced reduction in blood pressure and drainage, then heart replacement should be considered. In younger patients without significant associated diseases, heart transplantation is a possible solution. In some cases, heart function can be replaced by mechanical systems. This is particularly appropriate in patients who have hope of improving left ventricular function or who are waiting for a suitable donor for heart transplantation. All existing systems require an external power source, and a fully implantable and stand-alone system has not yet been developed. More powerful systems such as HeartMate or HeartWest connect to the heart in the chest surgically and are connected to a control unit and batteries that the patient wears on a belt. These systems can also be used as a permanent solution. The less invasive Impella system can be inserted by catheterisation or after artery preparation by a surgeon. It is used in intensive care units, has a large external unit and can support cardiac function for up to 2 weeks.
Schematic representation of the HeartMate 3 system
