Cardiac ablation, also known as catheter ablation, is a procedure used to treat and correct abnormal heart rhythms (arrhythmias). There are many different types of arrhythmias, and they include:
- tachyarrhythmias (the heart beats too fast)
- bradyarrhythmias (the heart beats too slowly)
Arrhythmias have the potential to become life-threatening as abnormal heart rhythms may impair the function of the heart and result in there being less blood pumped to the rest of the body.
The treatment of various tachyarrhythmias may include medications and/or cardiac ablation. Certain arrhythmias are better treated with cardiac ablation, while others may be treated with a course of medications. Moreover, cardiac ablation is usually recommended for cases where the arrhythmias do not get better after a trial of medication.
During the procedure, a small, thin, flexible tube called a catheter will be passed through a blood vessel (artery or vein) in the groin and guided upwards into the heart using fluoroscopy or X-rays. Once in the heart, after ascertaining the cause of tachyarrhythmias, tiny scars will be created using heat (radiofrequency ablation) or cold energy (cryoablation) over the cardiac tissue causing abnormal heart rhythms, scarring these small tissues and thus, restoring the heart back to its normal rhythm.
After cardiac ablation, you may also be recommended some oral medication such as short-term or long-term blood thinners, as well as instituting certain lifestyle changes (e.g. more exercise, quitting smoking) to help better control your condition.
An electrophysiology study (EP study) is used to study the electrical conduction system in the heart. EP studies are useful in helping to detect any abnormal heart rhythms (arrhythmias) present, as well as detecting the source of the abnormal heart rhythm. This can help determine the treatment of arrhythmias, which includes cardiac ablation therapy.
An EP study is usually done before a cardiac ablation procedure to help doctors better understand the conduction system within the patient’s heart, before deciding on their treatment. Other indications for an EP study include helping to evaluate the risks of sudden cardiac death in patients at risk of ventricular tachyarrhythmia. EP Studies may also be done to assess the conduction system of the heart in patients with slow heartbeats.
During an EP study, thin wires containing electrodes are inserted into a vein located in the groin area. Other areas that EP studies can be done include certain veins within the neck. The wire will then be passed through the vein into the heart, with x-rays used to guide the path of the wire (similar to the process of cardiac ablation, as mentioned above). It is a painless procedure and takes 1-2 hours.
Once the electrodes are in the heart, the doctors can then begin to analyse your heart rhythm. Some other adjuncts that can be performed include:
- Taking a baseline measurement of the heart’s electrical system (intracardiac electrogram).
- Examining the response of cardiac contractions to certain medications.
- Cardiac mapping refers to mapping the heart’s anatomy and vasculature to determine the best areas to perform cardiac ablation.
If the results during an EP study suggest that cardiac ablation is necessary, the procedure can be done directly after the EP study. If not, the medical team may move on to prescribe other forms of treatment to help with your heart condition.
Cardiac ablation is primarily used to treat arrhythmias. There are many types of arrhythmias, and they can be categorised based on the locations in the heart:
Upper chambers of the heart (atrium)
● Atrial fibrillation (AF)
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- AF refers to a type of arrhythmia where the heart rhythm is irregularly irregular, as the atria of the heart emit uncoordinated electrical signals.
- AF is a dangerous arrhythmia as it can increase the risk of stroke, heart attack, and other symptoms such as palpitations, fatigue, shortness of breath and loss of consciousness. Long-standing AF can lead to heart failure in certain cases.
- AF can be treated with medication, with cardiac ablation as a treatment option as well. Cardiac ablation in AF usually targets either the pulmonary vein or AV node, or a maze procedure can also be performed, whereby scar tissue is created in the atria to block stray heart signals causing AF.
● Supraventricular tachycardia (SVT)
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- SVT refers to abnormally fast heart beats that affect the upper chambers of the heart. It results from reentry along an abnormal or extra pathway in the heart conduction system.
● Atrial flutter
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- Typical atrial flutter is a kind of reentry arrhythmia arising from the right upper chamber of the heart or right atrium. The treatment of choice for atrial flutter is catheter ablation.
● Wolf-Parkinson-White syndrome (WPW)
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- WPW is a rarel condition often diagnosed in childhood to young adulthood. It is more often present in young boys. WPW is an extra electrical pathway present within the heart, which often overrides normal heart signals and can lead to very fast heart rates as electrical signals ricochet between the atria and ventricles.
- Cardiac ablation is useful in WPW as it helps to scar up this extra signalling pathway to block conduction through it, restoring the heart back to its normal rhythm.
Lower chambers of the heart (ventricles)
● Premature Ventricular Contractions (PVCs)
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- PVCs refer to ectopic heartbeats that originate from the ventricle, and which happen slightly earlier than the normal heartbeat resulting in an additional heartbeat signal detected on the ECG, thus disrupting the heart’s normal rhythm.
● Ventricular tachycardia (VT)
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- This refers to unusually fast heartbeats that originate in the ventricles, which can rapidly progress into life-threatening arrhythmias such as ventricular fibrillation (VF).
Before the procedure, you will be asked to fast for ≥6h beforehand. You may also be asked to stop taking certain medications such as blood thinners, based on your current long-term medication regime.
Once the procedure is complete, you will be taken into a recovery room for a few hours. Most will be discharged at the end of the day, although some patients may need to be admitted overnight for further monitoring.
In conclusion, cardiac ablation is a minimally invasive procedure used to treat abnormal heart rhythms. It may be an option for patients who have been diagnosed with arrhythmias in conjunction with medication treatment. Any recommendations and suitability for cardiac ablation will be discussed with you by your medical team beforehand.
