Arrhythmias are a common heart condition which can be defined as an irregularity of the heart rhythm. An estimated 1.5% to 5% of Malaysians have arrhythmias. However, some people do not present with any symptoms, making it difficult to estimate the actual disease burden.
Arrhythmias occur when the electrical signals that coordinate the heart’s beat do not function properly. The faulty signalling causes the heart to beat either too fast, too slow or irregularly. When the heart beats too fast it is known as tachycardia and when the heart beats too slow it is known as bradycardia. Atrial fibrillation, which is the most common type of arrhythmia, is a condition where the heart beats are irregular.
Arrhythmias can be broadly classified into either atrial or ventricular arrhythmias. Certain atrial arrhythmias have no obvious causes whereas ventricular arrhythmias are usually related to a dysfunction of the heart muscles known as cardiomyopathy. There are various causes of cardiomyopathy, of which Ischemic Heart Disease is the most common form. Ischemic Heart Disease is due to narrowing of the coronary blood vessels. Non-ischemic heart diseases do cause a reduction in the heart pump and thus may lead to arrhythmias.
A normal functioning heart has a normal regular rhythm called the sinus rhythm. This is when there is an organised transmission of electrical activity through the heart via its conduction system to ensure systematic pumping of the heart muscles. This conduction system regulates the normal beating of the heart and appropriately raises and reduces the rate of the heart based on an individual’s needs.
In contrast to that, an arrhythmia is abnormal because it interferes with this normal conduction. It causes symptoms such as a fluttering sensation in the chest, racing heartbeat, slow heartbeat, chest pain, shortness of breath, anxiety, fatigue, light headedness or dizziness, sweating, fainting (syncope) or near fainting. Clinical signs of an arrhythmia can be slow or fast heartbeat or low blood pressure. Patients with an arrhythmia will have ECG changes which will help in determining the type of arrhythmia and the appropriate treatment modality.
According to Dr. Rohith, the severity of the case depends on the type of arrhythmia. Atrial arrhythmias are generally benign, apart from Atrial Fibrillation which carries an increased risk of developing a stroke. Ventricular arrhythmias are generally serious and are usually related to an issue with the cardiac muscle (cardiomyopathy).
There are several risk factors that determine whether someone is prone to develop an arrhythmia. Depending on the type of arrhythmias, there are certain risk factors associated. Ventricular arrhythmias are generally associated with ischemic heart disease and carry the similar risk factors such as diabetes mellitus, hypertension, high cholesterol and an unhealthy lifestyle. Atrial arrhythmias generally do not have risk factors associated with them and can also be seen in healthy individuals.
If a patient is having symptoms suggestive of an arrhythmia, it is prudent to get it checked immediately to ascertain the cause of the problem. This allows the clinician an opportunity to correctly identify the problem and initiate appropriate treatment. As mentioned earlier, the most common arrhythmia is atrial fibrillation and the most serious complication associated with atrial fibrillation is stroke. Thus, these patients need to be on some form of anticoagulation. Treatment of atrial fibrillation is highly complex and it is advised that each patient consult their cardiologist to plan a suitable treatment modality. Ventricular arrhythmias can be life threatening and lead to sudden cardiac death. If a rapid heartbeat is incessantly left untreated it can lead to a condition called tachycardia induced cardiomyopathy. If a slow heartbeat is the culprit, patients tend to feel giddy and this can lead to falls. Depending on the diagnosis and condition, patients and their families would be counselled accordingly and a discussion regarding pacemaker implantation would ensue.
Certain types of arrhythmias are seen more commonly in the younger age group such as AV Node Re-entrant Tachycardia (AVNRT) that causes a very high heart rate. Ventricular tachycardias are generally seen in an older population set. A slow heartbeat is also generally seen in an older population.
Prevention is possible if the cause of the arrhythmia is due to ischemic heart disease. Unfortunately, not all rhythm disturbances can be avoided when their cause is also relatively unknown. Some types of arrhythmias are age related such as bradycardia caused by sick sinus syndrome which is generally a degenerative disease of the sinus node.
There are certain screening procedures to diagnose an arrhythmia. A good screening tool is an ECG. If there are no findings on the ECG and the patient is still symptomatic, they can be investigated with an event recorder such as a Holter or even an Implantable Loop Recorder.
Treatment modalities are dependent on the type of arrhythmia seen. For slow heart rates (bradycardias), one option of treatment is implantation of a pacemaker. For fast heart rates (tachycardias), options of treatment include medication to slow down the heart rate or regularise the heart rate and procedures (electrophysiology study and radiofrequency ablation) to remove or regularise these abnormal rhythms.
An electrophysiological study is a test that looks at the electrical activity of the heart, allowing the doctor to diagnose and analyse fast or abnormal heart rhythms. It is able to give a detailed information about the conduction system of the heart and is able to diagnose arrhythmias. It involves a fine tube called a catheter being inserted into the heart via a blood vessel (vein or artery) in the groin. The end of this catheter has a special electrode tip which stimulates the heart and records the electrical activity allowing the doctor to identify where any abnormalities may be coming from.
Radiofrequency ablation is a treatment that aims to control or correct an abnormal heart rhythm. It is carried out in the same way as an electrophysiological study (EPS) by inserting catheters into the heart via the groin. Radiofrequency energy (heat) is then used to destroy the small area in the heart where the abnormal electrical activity is coming from. This can be done at the same time as the EPS or on a separate occasion.
For more information about Institut Jantung Negara, you may call us at 03-2617 8200 or email at heart@ijn.com.my
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