The research shows that the changes observed within a few months help predict whether the arrhythmia may reappear and demonstrates, for the first time, direct benefits to the heart muscle.
The study, published in Circulation, was led by Dr Ivo Roca, cardiologist and arrhythmia specialist at Hospital Clínic Barcelona and researcher in the IDIBAPS group Biopathology and treatment of cardiac arrhythmias. Several professionals from the Arrhythmia Section and the Cardiac Imaging Section of the ICCV Cardiology Department also participated.
What is ventricular tachycardia?
Ventricular tachycardia (VT) is an arrhythmia in which the ventricles —the lower chambers of the heart— beat very fast and irregularly.This rapid rhythm reduces the heart’s ability to pump blood effectively and may cause palpitations, dizziness, shortness of breath, loss of consciousness, and even be life-threatening if untreated.
Most cases occur in people with structural heart disease, especially after a heart attack. In these situations, the scar tissue left in the heart muscle can promote the formation of abnormal electrical circuits that trigger the arrhythmia.
Radiofrequency ablation is one of the main therapeutic options to reduce VT episodes. However, little is known about how scar tissue evolves in the months and years after the procedure and whether these changes relate to long-term treatment effectiveness.
Assessing scar evolution after ablation
To address these questions, the research team prospectively studied 51 patients undergoing their first VT ablation. All patients underwent a cardiac MRI before the ablation, a second MRI 3–6 months after the procedure, and a third MRI 18–24 months later.
This approach made it possible to assess how the scar evolved over time and how these changes related to arrhythmia recurrence.
Long-lasting changes in scar tissue after ablation
The results show that ablation produces a homogenisation of the scar, meaning a more stable organisation of scar tissue that reduces the risk of new arrhythmias. This effect remains stable over time.
Key findings included:
- An increase in the densest portion of the scar, as a direct effect of the procedure.
- A progressive reduction over two years in the intermediate tissue zone, which is more prone to generating arrhythmias.
- A marked and sustained decrease in conduction channels, the “electrical corridors” capable of triggering ventricular tachycardia.
These findings suggest that ablation-induced changes are long-lasting and contribute to stabilising the heart’s electrical substrate.
Follow-up MRI helps predict recurrence
One of the most relevant findings is that the MRI performed 3 to 6 months after ablation offers information that helps anticipate recurrence risk.
Patients with two or more conduction channels on this early follow-up scan had a significantly higher risk of experiencing new VT episodes. Conversely, those showing a marked reduction in these channels had a more favourable clinical course.
“The results suggest that post‑ablation MRI may be a key tool to personalise follow‑up and tailor treatment to each patient’s risk,” explains Dr Roca.
Ventricular remodelling: an added benefit
Beyond changes in scar tissue, the study observed a significant reduction in left ventricular volume on long-term follow-up. This indicates positive structural remodelling, even in patients who experienced some recurrence. This is the first time such a long-term benefit has been demonstrated in a clinical study worldwide.
This additional benefit may be related to the reduction in arrhythmic burden after ablation and opens new avenues for research into the impact of these procedures on heart function.
Implications for managing ventricular tachycardia
The study provides new evidence supporting the role of cardiac MRI as a non-invasive tool to:
- assess the impact of ablation,
- understand scar evolution,
- identify early the risk of recurrence,
- and personalise treatment strategies.
“This is the first study to systematically analyse long-term scar evolution after ventricular tachycardia ablation, offering valuable insights to improve patient care,” concludes Ivo Roca.
Study reference:
Roca-Luque I, Garre P, Vázquez-Calvo S, Ortiz-Pérez JT, Prat-González S, Perea RJ, Falzone PV, Guichard JB, Regany-Closa M, Althoff TF, Guasch E, Tolosana JM, Arbelo E, Sánchez-Somonte P, Quinto L, Borràs R, Domingo R, Niebla M, García-Alvarez A, Sitges M, Brugada J, Mont L, Porta-Sánchez A. PAM-VT 2 Study: Long-Term Scar Evolution and Ablation Lesion Assessment by Late Gadolinium Enhancement Cardiac Magnetic Resonance After Ventricular Tachycardia Ablation. Circulation. 2026 Mar 24;153(12):874-886. doi: 10.1161/CIRCULATIONAHA.125.074748.
