Cardiac arrhythmias are not always a sign of disease, but it is always worth knowing their background. Why arrhythmia can occur in a structurally healthy heart and how to proceed then is explained by Paweł Życiński, MD, PhD, from the Department of Cardiology and Department of Cardiology at the Medical University of Łódź, member of the Board of the Heart Rhythm Section of the Polish Cardiac Society.
Doctor, what is an arrhythmia? Is it a disease?
In the most general terms, an arrhythmia is a condition where our heart works erratically, too fast or too slowly. It is important to know that cardiac arrhythmia, or in other words arrhythmia, is a broad term that encompasses different types of heart rhythm disturbances. Importantly, they are not always dangerous and are not always indicative of a disease.
The term arrhythmia refers to the structure and physiology of the heart as an organ. A healthy heart has its own stimulus-conduction system, which functions in such a way that we hardly feel its work. When we feel an uneven or fast heartbeat, we clearly feel a change. Sometimes we are disturbed by a feeling of palpitations or a strong and powerful heartbeat. There may be a strange cough, trouble swallowing, a sense of "obstruction" in the chest, pain, shortness of breath, weakness, fear and anxiety, or even unconsciousness or fainting.
What could such a condition mean?
If our heart is working too fast, i.e. the heart rhythm is faster than 100 beats per minute, we speak of tachycardia, i.e. various types of tachycardia. If the heart works at a rate of less than 60 or 50 beats per minute, we are talking about bradycardia, i.e. the heart working too slowly.
The feeling of an uneven or abnormal heartbeat is one of the most common reasons for a cardiology consultation. It is worth emphasising: the symptoms of arrhythmia do not necessarily indicate a medical condition. On the other hand, there are heart rhythm disorders, such as silent atrial fibrillation, which are not felt by the patient, but are therefore no less dangerous. Undiagnosed and untreated atrial fibrillation can lead to such serious complications as ischaemic stroke. It is therefore certainly worth consulting a doctor about obviously worrying signals and carrying out regularly recommended check-ups.
What will the first consultation with a cardiologist consist of?
During the first visit, the cardiology specialist will first of all try to take as thorough a medical history as possible. He or she will ask the patient about any worrying symptoms related to both heart function and general health, as well as any accompanying conditions. The patient will be asked about any history of cardiovascular disease in the immediate family - genetic heart disease may also be a background of arrhythmia. The doctor will try to distinguish whether the patient's symptoms are related to a structural heart disease (for example, ischaemic heart disease, valvular defects, cardiomyopathies, myocarditis, heart failure, hypertension) or not. The second group of causes of arrhythmia occurrence is a group of secondary, non-cardiac causes.
What else besides cardiovascular disease can cause arrhythmia?
Very many factors! These can be, for example, endocrine disorders, related to abnormal functioning of the thyroid and endocrine system: hyperthyroidism or hypothyroidism. In women, a common cause of cardiac arrhythmias can be anaemia caused by excessively heavy monthly bleeding. The background to the development of arrhythmias can be kidney disorders, electrolyte disorders, including, for example, too low levels of potassium and magnesium. Arrhythmias can occur as a result of very intense physical exertion. Sometimes, cardiac arrhythmias occur at high altitudes, such as in high mountains.
Another group of factors that can contribute to the development of arrhythmias are lifestyle factors. Healthy heart function is definitely harmed by stimulants, including alcohol, poor diet, abnormal body weight and sleep disturbances. Psychological factors are also important. Excessive stress or emotional problems can often be a trigger for such disorders. During the medical visit, it will also be important to take a medical history of the medicines the patient is taking and the dietary supplements that are often abused in our country - it happens that arrhythmia can be a side effect of some medication.
In such cases, is it enough to eliminate risk factors for arrhythmia development - for example, stop or change a certain medication, avoid high altitude hikes?
The prescription is not always so simple. It is important to know exactly the cause of the arrhythmia and the nature of the heart rhythm disturbance present in the patient. We need to be sure of the nature of the disorder - whether it definitely requires further diagnosis and therapy. Accurate diagnosis can make a difference to health and even life! This is all the more important as sometimes arrhythmias can occur in structurally healthy hearts and are not always easy to register at the time of occurrence. Sometimes the diagnosis of cardiac arrhythmias can be arduous and time-consuming, but the symptoms reported by the patient should never be underestimated.
So what does an arrhythmic investigation look like?
In order to exclude the aforementioned primary causes of arrhythmia, the doctor refers the patient for diagnostics. Among other things, he or she orders basic biochemical tests (morphology, electrolytes, creatinine, TSH, glucose), ECG, echocardiography, Holter ECG and, if necessary, more detailed imaging or stress tests. If these do not show abnormalities, we look further for the cause of the heart rhythm disturbance. Let me give an example. In one of our patients, a twenty-something healthy and fit male, there were no obvious symptoms of arrhythmia. However, the patient was referred for a cardiology consultation because of an abnormal recording on a follow-up ECG. It turned out that the man had pre-excitation syndrome, meaning that there is a so-called accessory conduction pathway in the heart. An accessory pathway is a band of extra (unnecessary) tissue in the heart that can conduct electrical impulses. Usually, most abnormalities of this type are detected during childhood, but sometimes the diagnosis is found in an adult patient. Either way, such a condition can mean danger for the patient - even though the patient feels well.
What are the risks for the patient?
In certain specific situations, such as under conditions of strenuous exercise, a patient with an accessory conduction pathway may trigger an atrial arrhythmia, which may travel further into the cardiac chambers and even result in cardiac arrest. The risk is therefore very serious and should not be underestimated.
How can the patient be protected from the dangerous effects of a dangerous arrhythmia?
It all depends on the type of heart rhythm disturbance. As I mentioned, in many cases, arrhythmias do not require therapy. A consultation with the patient, explaining the nature of the disorder and reassuring the patient is sufficient. Sometimes therapy is necessary: the use of drugs, treatments or implantable devices. In our patient's case, we will help by performing an electrophysiological study and, in all likelihood, an ablation procedure for the underlying arrhythmia. During this procedure, a radiofrequency current will be used to 'inactivate' the part of the heart tissue responsible for the abnormal conduction of electrical impulses. This is an example of a form of therapy that, in certain cases, can help to completely cure a patient of a specific heart rhythm disorder, and in other situations often offers efficacy far superior to pharmacotherapy - despite the low surgical risk.
Danish footballer Christian Eriksen suffered a sudden cardiac arrest during a match and it was decided to implant a device - a cardioverter defibrillator. How does this system work?
This case was associated with sudden cardiac arrest (probably ventricular fibrillation) during exercise. Often such patients have a structurally sound heart on examination. Not in all such situations are we able to know the cause of the arrhythmia. Most often, previously unrecognised cardiomyopathies (for example, hypertrophic cardiomyopathy) or electrical diseases of the heart, so-called channelopathies, are responsible for such situations. As a result of abnormal functioning of the ion channels in the myocardial cells, which may become apparent in specific situations, for example during increased physical exertion, myocardial repolarisation may be impaired and, secondarily, dangerous ventricular arrhythmias may occur. Significantly, in patients with such conditions, the risk of recurrence of life-threatening arrhythmias and sudden cardiac arrest is relatively high. Depending on individual indications and in consultation with the patient, decisions are often made to implant an Implantable Cardioverter Defibrillator (ICD). The purpose of this system is to monitor and analyse the patient's heart rhythm and, in the event of a life-threatening ventricular arrhythmia, to deliver therapy within seconds by pacing or by discharge (shock), interrupting the dangerous arrhythmia and "resetting" the heart, as it were. Nowadays, cardiologists even have subcutaneous systems at their disposal that do not unduly restrict the patient's activity. It is heartening that in the above-mentioned situation, the footballer was saved, then secured and returned to his passion and sporting competition.
The possibilities for treating and protecting patients with arrhythmias seem impressive.
Indeed, as cardiologists, we are delighted with the wide spectrum of treatment options in the field of cardiac rhythm disorders. In the arsenal of electrophysiology and electrotherapy, there are precise and complex yet increasingly safe and effective ablation procedures or increasingly effective, 'intelligent' and smaller, 'patient-friendly' implantable devices. These technological advances mean that we can now treat arrhythmias for which medicine did not know the answer only a few years ago. This is fascinating and encouraging, but at the same time, certain issues remain unchanged in the field of cardiac arrhythmias. These include the role of primary and secondary prevention, including cooperation between the doctor-patient pair on modifiable risk factors. Abandoning stimulants, taking care of one's diet and daily hygiene, but also, on the other hand, taking responsibility for one's therapy, educating oneself about one's disease and the possibilities of improving one's condition and well-being cannot be overestimated. Even the best medication will not help if it is not taken continuously. The effects of ablation procedures will be short-lived if the patient does not change their lifestyle. This is not only confirmed by successive scientific guidelines - the latest recommendations even emphasise it more and more! This is absolutely worth bearing in mind: the state of your health should be nurtured and improved every day through the right, rational decisions. For a healthy heart!