Supraventricular Tachycardia (SVT) is an abnormally fast heart rhythm that originates in the upper chambers of the heart or the atrioventricular (AV) node. Episodes of SVT, characterized by a sudden rapid heartbeat, can be disruptive and cause symptoms like palpitations, shortness of breath, or dizziness. Catheter ablation is a common, minimally invasive treatment that aims to permanently cure this irregular rhythm by targeting the small area of misfiring tissue. While the procedure is widely considered safe and highly effective, like any medical intervention, it carries risks that patients must understand.
What Is Catheter Ablation
Catheter ablation is performed by an electrophysiologist in a specialized cardiac lab. The process begins with the insertion of thin, flexible tubes, called catheters, into a blood vessel, typically in the groin area. These catheters are then carefully threaded through the vascular system and guided up to the heart chambers using advanced imaging technologies like fluoroscopy.
Once inside the heart, the catheters perform an electrophysiology study, mapping the heart’s electrical activity to precisely locate the tissue responsible for the abnormal electrical signals. After the target site is identified, the catheter tip delivers controlled energy to destroy, or ablate, this tissue. The energy used is usually heat (radiofrequency ablation) or extreme cold (cryoablation), creating a small scar that blocks the faulty electrical circuit.
Statistical Safety and Mortality Rates
SVT catheter ablation carries a very low risk, particularly when performed at high-volume centers by experienced teams. Major complications, defined as events requiring significant intervention or prolonged hospitalization, occur in approximately 1 to 3% of cases. A large-scale analysis involving over 10,000 SVT ablations documented an overall complication rate of just 0.5%.
The most severe outcome, all-cause in-hospital mortality, is extremely rare, often cited at less than 0.1%. In one comprehensive study, the mortality rate was found to be 0.02%. The risk profile is not uniform, as it can be influenced by the specific type of SVT being treated, the patient’s age, and their overall health status.
Understanding Specific Procedure Risks
Several specific adverse events are associated with the procedure that patients should be aware of. Since the procedure involves accessing the vascular system, minor complications at the access site are the most common, including bruising, bleeding, or localized pain in the groin area. More serious vascular complications, such as the formation of an arteriovenous fistula or pseudoaneurysm, are uncommon, occurring in less than 0.5% of cases.
A more serious, yet infrequent, risk involves the possibility of cardiac perforation, where the catheter tip inadvertently creates a small hole in the heart wall. This can lead to cardiac tamponade, which occurs in about 0.3% of SVT ablations and requires immediate drainage. Damage to the heart’s normal electrical wiring, particularly the atrioventricular (AV) node, is also a concern. This may necessitate the permanent implantation of a pacemaker and occurs in less than 1% of cases.
Other extremely rare but serious risks include stroke, which can occur if a clot forms on a catheter and travels to the brain, and, for left-sided SVT ablations, pulmonary vein stenosis. The risk of stroke is estimated to be around 0.2% in a broader analysis of all ablation types.
Weighing Success Against the Dangers
Success rates for the most common types of SVT, such as Atrioventricular Nodal Reentrant Tachycardia (AVNRT) and Atrioventricular Reentrant Tachycardia (AVRT), are high, often reported in the range of 95 to 98%. This high efficacy offers the potential for a complete, permanent cure, eliminating symptoms and the need for daily medication.
The alternative to ablation is typically long-term treatment with antiarrhythmic medications, which carry their own risks, including systemic side effects and potential long-term toxicity. These medications only manage the rhythm and do not cure the underlying electrical problem. Untreated or poorly managed SVT also poses dangers, including a reduced quality of life and, in rare instances, the development of tachycardia-induced cardiomyopathy. For most patients, the probability of a permanent cure combined with the low incidence of serious complications makes catheter ablation a favorable option compared to the risks of lifelong dependency on medication or living with an uncontrolled arrhythmia.