Arrhythmias
Einstein Health Glossary
ICD 10 - I49
What it is
Arrhythmias are changes in the heart’s normal rhythm. In most people, the heart beats between 60 and 100 times per minute, with variations depending on rest or physical activity. Disruptions in this rhythm can cause the heart to beat too fast (tachycardia) or too slow (bradycardia). Most arrhythmias are benign and do not cause symptoms, but others may lead to palpitations, fainting, and even risk of death.
Arrhythmias can originate in the upper part of the heart (atria or supraventricular) or the lower part (ventricles). Among supraventricular arrhythmias, notable types include atrial extrasystoles, paroxysmal tachycardias (short circuits in the heart), accessory pathways (Wolff-Parkinson-White syndrome), atrial tachycardia, atrial flutter, and atrial fibrillation. Atrial fibrillation is quite common in clinical practice. It is a rhythm disorder characterized by rapid and uncoordinated contractions of the atria, affecting a large portion of the population, especially the elderly.
In the ventricles, the most frequent arrhythmia is the extrasystole, an abnormal beat that feels like a pause or jolt in the heart, which usually does not require treatment. Ventricular tachycardia, on the other hand, can sometimes impair heart function, causing palpitations, dizziness, and even fainting, requiring immediate medical attention. In extreme cases, it can lead to cardiac arrest and sudden cardiac death. Many of these cases could be prevented with early diagnosis.
Causes
A large number of arrhythmias have no clearly defined cause, and some are congenital. Others result from problems in the heart muscle, such as heart attack, heart failure, or Chagas disease. Heart valve disorders are also commonly associated with arrhythmias.
The heart’s rhythm can also be affected by the use of medications or by conditions such as thyroid dysfunction, anemia, dehydration, infections, stress, physical activity, and anxiety.
Symptoms
The main symptoms include palpitations, weakness, dizziness, sweating, fainting, mental confusion, shortness of breath, general discomfort, and a feeling of heaviness in the chest. However, it’s important to note that many arrhythmias do not cause any symptoms.
In cases of atrial fibrillation and atrial flutter, the arrhythmia can lead to the formation of blood clots in the heart, which may cause strokes. Malignant ventricular tachycardias, on the other hand, can impair heart function and lead to sudden death. In such cases, immediate medical attention is crucial.
Diagnosis
The initial evaluation includes a clinical assessment, physical examination, and electrocardiogram (ECG). In some cases, more detailed investigation is needed, such as an exercise stress test, a Holter monitor — which records the patient’s heartbeats during daily activities over a 24-hour period — or a Web-Loop, also known as an event monitor, which can transmit the ECG trace via the internet at the moment symptoms occur. In cases of fainting, a tilt table test may be necessary.
When the problem cannot be identified through these non-invasive methods, an electrophysiological study may be performed. This is a specialized cardiac catheterization used to evaluate heart rhythm disorders. During this procedure, catheters with electrodes are inserted into the heart through a vein in the groin to diagnose and locate the origin of the arrhythmia.
Treatment
Many arrhythmias do not require treatment. Depending on the type and severity of the arrhythmia, medication may be necessary, along with lifestyle changes. The reversal of certain arrhythmias, such as atrial flutter, may require the application of an electric shock to the chest (electrical cardioversion), a procedure performed under sedation and often on an outpatient basis. In some cases of tachycardia (rapid heartbeat), catheter ablation is highly effective and often curative. This technique involves cauterizing the arrhythmia’s origin during an electrophysiological study.
In cases of bradycardia (slow heartbeat), pacemakers — devices that emit electrical impulses to correct rhythm disturbances — can be implanted under the skin, offering excellent rhythm control. These devices are now very small and do not interfere with the patient’s lifestyle.
For patients with severe ventricular tachycardia (life-threatening), a special pacemaker called an implantable cardioverter-defibrillator (ICD) can be implanted. It detects abnormal heart rhythms and delivers a life-saving shock to restore normal rhythm.
There are also special pacemakers known as cardiac resynchronization therapy (CRT) devices, used to treat certain forms of heart failure (weakened hearts). In these cases, the heart does not pump blood effectively because the muscle contracts in a disorganized manner. The pacemaker helps correct this disorder (dyssynchrony).
Prevention
In addition to regular physical activity and a balanced diet (with low intake of salt and fats), regular medical check-ups are essential, as well as controlling risk factors for conditions such as diabetes, obesity, hypertension, and smoking.