Forget about all the love songs that say skipping a heartbeat when you find love is romantic. In reality, it’s extremely dangerous to have such an abnormal heart rate. Keep reading to find out why you should never shrug off symptoms of irregular heart rhythms.

Apart from chest pain and dyspnoea, dizziness and palpitation are other common complaints in patients attending the cardiology clinic. These symptoms can occur following a change of posture, physical exertion and even external factors such as caffeine and alcohol intake. However, at times there may not be any obvious precipitating factor.

Many types of heart disease can give rise to these symptoms. Abnormality arising from the heart conduction system is one of the lesser known etiology, which can hinder appropriate treatment to be given to patients. The heart is built with blood vessels supplying oxygen and nutrients to the heart itself and an electrical conduction system that coordinates the heart beats. A healthy functioning of the heart conduction system allows the heart to beat at an appropriate rate based on our daily activities, in an orderly manner. If there’s any malfunction of this system, the heart rate can end up being too slow or too fast.

Slow Heart Rate
There’s a structure that lies within the right atrium, namely SA Node, that serves as the heart’s natural pacemaker. It works hand in hand with another structure downstream of the conduction system, known as the AV node, to ensure the heart beats at an appropriate rate. However, often with ageing, degenerative changes set in and may affect the function of these two important structures, causing an inappropriate slow heart rate. Patients may be asymptomatic at the beginning, but due to the progressive nature of the changes, they may end up suffering from episodes of dizziness and syncope. This can lead to potentially catastrophic outcomes if left untreated.

There are many methods used to detect such conditions at the early stage of the disease, which include a 12-lead electrocardiogram (ECG) and 24-hour Holter monitoring. These tests can show the range of heart rate at a glance and over a period of 24 hours. When needed, further testing which includes an implantable loop recorder and Electrophysiology Study (EPS) can also help to detect abnormality within the heart conduction system. Once the diagnosis is made, definite treatment for slow heart rate often lies in implanting an artificial pacemaker. This smart device will take over the role of SA and AV nodes, allowing the heart to beat in an orderly manner at an acceptable rate.

Fast Heart Rate
In some patients, they may complain of palpitation, which can occur intermittently or rather frequently. Often such complaints will be trivialised and in the long run, can lead to various complications pertaining to heart function.

Besides this, many other factors result in palpitation, which includes premature ventricular complexes (PVCs), atrial fibrillation, supraventricular tachycardia and ventricular tachycardia. Such conditions arise because of abnormality within the myocardial cells and the heart conduction system, that leads to abnormally fast heart rates or abnormal beats. When these problems are not resolved and treated early, heart failure can set in and may become irreversible.

In order to make a diagnosis, preliminary testing with ECG and 24-hour Holter can be done. However, the more definitive investigation modality will be Electrophysiology Study (EPS). This procedure will involve the use of specialized tools and equipment that can evaluate the heart conduction system and enable localizing the abnormal circuit within the heart chambers. These abnormal circuits are often the root cause of the abnormal rapid heart rate. Subsequently, therapeutic measures can be instituted during the procedure itself to eliminate such circuits. This measure is known as radiofrequency ablation (RFA). Overall, the EPS and RFA are done in the same sitting, in an effective and safe manner. When successful, it is potentially curative for the abnormal rapid heart rate condition. In some patients, a successful procedure can allow them to be taken off the medications needed previously to treat this abnormal heart rate, which may have potential medicine related adverse events.

Conclusion
Often symptoms related to the abnormal heart rhythm are ignored, and this can potentially cause problems in the near future. Therefore, it is advisable for anyone who suffers at one point in time symptoms of palpitation or giddiness to consult their cardiologist for further assessment so that appropriate therapy can be given. If in doubt, it is always advisable to see your cardiac electrophysiologist early for consultation.

Dr Gary Lee Chin Keong,
Consultant Cardiologist & Electrophysiologist MBBS (IMU); MRCP (UK).
Fellowship In Cardiac Electrophysiology & Pacing (NUH, S’pore)