What is Cardiac Ablation?
The regular heart rhythm is due to the normal function of the heartís electrical conduction system. The electrical impulses generated from the Sinoatrial Node reach the heart muscle via a proper path. The normal function helps to maintain a regular heartbeat and normal heart muscle contraction. Any disturbance in this path or any other new source of generation of an electrical impulse causes abnormal heart rhythm which is called an arrhythmia.
Cardiac Ablation involves identifying and destroying the abnormal rhythm-producing heart tissue. It is a minimally invasive procedure but sometimes it is done through an open heart method.
Radiofrequency Ablation (RFA): Radiofrequency energy is used to damage the abnormal heart tissue. It is the most frequently used technique.
Cryoablation: Cryothermal energy damages the abnormal heart tissue by freezing and forming ice crystals.
The arrhythmias treatable with ablation are:
- Atrial Fibrillation, an abnormal heart rhythm disorder arising from the upper chamber of the heart, which leads to the quivering of the upper chambers instead of the normal contraction. There are many complications like clot formation, stroke, etc. due to improper contraction of the upper heart chamber. It is the most common arrhythmia.
- Atrial Flutter, an abnormal heart rhythm arising from the upper heart chamber leading to rapid contraction of the atria.
- Wolff-Parkinson-White syndrome is a condition where there is an accessory electrical pathway between the heartís upper and lower chambers.
- Ventricular Tachycardia, the electrical heart rhythm disorder where impulses are generated from the lower heart chambers and cause rapid heart contractions. It is a life-threatening condition.
- AV Nodal Re-entrant Tachycardia, in which an accessory path is present adjacent to or within the AV node and leads to a re-entry circuit.
There are many medications to treat arrhythmias but ablation is required when:
- Medications show no efficiency in controlling the abnormal rhythm.
- The patients donít tolerate the medication.
- The patientís condition warrants ablation as the best option. (Like in Wolff-Parkinson-White syndrome).
- The condition is life-threating or results in a sudden cardiac arrest.
This procedure is done in the Electrophysiology laboratory or Catheterization laboratory in the hospital. The procedure usually takes 2-4 hours. The blood pressure, heart rate, Electrocardiogram and oxygen levels are monitored.
The procedure is performed under aseptic precautions and conscious sedation. The groin area is disinfected and the local anesthetic agent is given to numb the area in the groin where a tube-like structure called sheath is inserted into the blood vessel. Through the sheath, thin flexible tubes known as catheters are passed into the blood vessel in the groin, then guided till the heart. The doctor may inject the dye through the catheter, which helps in the visualization of blood vessels and the heart.
The catheters carry electrodes, which send electrical impulses and stimulate the tissue to help in the detection of abnormal tissue. The catheters are connected to monitors that display electrical activity of the tissue. Once the abnormal loci are found, the catheter can generate radiofrequency energy to burn the abnormal tissue.
Pulmonary Vein Isolation
Atrial fibrillation arises due to abnormal electrical impulses, generated near the root of the pulmonary veins (blood vessel which carries pure blood from lungs to heart) in the left atrium. Pulmonary vein isolation is a cardiac ablation procedure where the tissue around the 4 pulmonary veins in the left atrium (upper heart chamber) is ablated. This prevents the abnormal impulses from spreading and hence stops the atrial fibrillation.
Before the Cardiac Ablation Procedure
- Fasting for at least 8 hours before the procedure is necessary.
- Tell your doctor about your health issues like kidney problems, diabetes, etc. and about your medications.
- Blood tests, an electrocardiogram (ECG) to see the heartís electrical activity and an echocardiogram (ECHO) to determine the size of the heart chambers and their function are recommended. Prothrombin Time and Internal Normalized Ratio to measure the clotting properties of the blood is necessary before the procedure.
- During the appointment before the procedure, the doctor will suggest you the necessary treatment changes.
- If you have any health issues like fever, flu, cough, etc. before the procedure, report them to your doctor.
- Take the suggested medications on the day of the procedure.
After the Cardiac Ablation Procedure
- After the procedure, the nurse shall apply pressure at the puncture site to prevent bleeding.
- You will be asked to lie down for 4-6 hours to prevent bleeding from the puncture site. After a few hours, the nurse will remove the sheath near the groin.
- You will be allowed to drink clear liquids initially and later progressed to eat semisolids and solids.
- The nurse will monitor your heart, blood pressure and the puncture site.
- Discharge is mostly done on the next day.
- You will be explained about the medications and follow-up visits at the time of discharge.
- Monitor the puncture site for bleeding once you are at home. A small amount of oozing is normal, apply mild pressure for 5 minutes with a piece of gauze or apply a Band-Aid.
- Tiredness after the procedure is common but lasts for only a few days. Avoid pulling, pushing and lifting heavy weights. Only light activity is allowed for 2 days, and after a week, the patient can get back to normal activity.
- Drive after 2 days and only if you are comfortable.
- Seek medical attention if there is a red lump formation near the puncture site or bleeding that is not controlled. In the case of severe chest discomfort, dizziness, loss of consciousness and fast irregular heartbeat, consult emergency room or your doctor.
Cardiac Ablation Procedure Benefits
- It is a safe procedure.
- It is a minimally invasive procedure.
- The patient can get back to the normal activity within a few days.
- It is effective and has a huge success rate.
Cardiac Catheter Ablation is a safe procedure; though rare, the following are the risks of the procedure:
- Bleeding or hematoma (blood coagulation in the tissues leading to a lump formation) at the puncture site at the groin.
- Puncture to the heart leading to cardiac tamponade (blood around the heart, sufficient enough to prevent normal function).
- Damage to the heart valves.
- Vagal or Phrenic nerve damage.
- Pulmonary Vein Stenosis (narrowing) in the case of Pulmonary Vein Isolation.
- Complete Heart Block (the normal electrical impulses get blocked) or worsening of the arrhythmia.
- Esophageal Injury and atrio-esophageal fistula (an abnormal communication between heartís upper chamber and food pipe)
- Damage to the blood vessels.
- Thromboembolic events (health conditions due to the freely moving blood clot in the blood vessels).
- Radiation exposure.
- Damage to the kidney due to the dye used.
- Heart attack.
- Death is a rare risk.
- Stroke (the blood vessels of the brain get blocked leading to decreased brain blood supply).
Cardiac ablation involves identifying and destroying the abnormal impulse generating heart tissue. It is a safe and effective procedure for the treatment of the arrhythmia. It is a minimally invasive procedure; the hospital stay is minimal and the patient can get back to normal activity within a few days.
Latest Publications and Research on Cardiac AblationFrom early beginnings to elaborate tools: contribution of German electrophysiology to the interventional treatment of cardiac arrhythmias : The German Cardiac Society welcomes ESC in Munich 2018. - Published by PubMed
Intravascular imaging, histopathological analysis, and catecholamine quantification following catheter-based renal denervation in a swine model: the impact of prebifurcation energy delivery. - Published by PubMed
High-Normal Thyroid-Stimulating Hormone Shows a Potential Causal Association With Arrhythmia Recurrence After Catheter Ablation of Atrial Fibrillation. - Published by PubMed
Amiodarone Refractory Electrical Storm Post-Revascularization for Anterior ST Elevation Myocardial Infarction: A Case Report and Brief Review of the Literature. - Published by PubMed
Procedural and anatomical predictors of renal denervation efficacy using two radiofrequency renal denervation catheters in a porcine model. - Published by PubMed