Catheter ablation of intramural outflow tract premature ventricular complexes: a multicentre study
Matthew Hanson1, Piotr Futyma2, Weeranun Bode3
1Division of Cardiology, Queen's University, 76 Stuart Street, Kingston, Ontario K7L 2V7, Canada.
Insights
Ablating deep intramural premature ventricular complexes (PVCs) is challenging but achievable. This study shows that specialized ablation techniques can significantly reduce PVC burden, though repeat procedures may be needed.
Area of Science:
- Cardiology
- Electrophysiology
- Cardiac Ablation
Background:
- Outflow tract ventricular arrhythmias can originate from deep intramural sources, making ablation difficult.
- Intramural premature ventricular complexes (PVCs) present unique challenges for catheter ablation due to their location.
Purpose of the Study:
- To evaluate the acute and long-term outcomes of patients undergoing ablation for intramural outflow tract PVCs.
- To assess the efficacy of various ablation techniques in managing these challenging arrhythmias.
Main Methods:
- A multicenter study included 92 patients with intramural outflow tract PVCs, defined by specific activation criteria or septal vein recordings.
- Direct mapping of the intramural septum was performed in 32% of patients.
- Specialized ablation techniques, including sequential unipolar, low-ionic irrigation, and bipolar ablation, were frequently employed.
Main Results:
- Acute PVC suppression was achieved in 75% of patients, reducing the mean PVC burden significantly.
- The mean follow-up was 15 months, with 16 patients requiring repeat ablation.
- Inferior axis and LBBB pattern were common in the studied PVCs.
Conclusions:
- Ablation of intramural PVCs is technically demanding.
- Acute arrhythmia elimination is successful in approximately 75% of cases.
- Non-conventional ablation approaches are often required for successful treatment of intramural PVCs.
Aims:
Ablation of outflow tract ventricular arrhythmias may be limited by a deep intramural location of the arrhythmogenic source. This study evaluates the acute and long-term outcomes of patients undergoing ablation of intramural outflow tract premature ventricular complexes (PVCs).
Methods And Results:
This multicenter series included patients with structurally normal heart or nonischemic cardiomyopathy and intramural outflow tract PVCs defined by: (a) ≥ 2 of the following criteria: (1) earliest endocardial or epicardial activation < 20ms pre-QRS; (2) Similar activation in different chambers; (3) no/transient PVC suppression with ablation at earliest endocardial/epicardial site; or (b) earliest ventricular activation recorded in a septal coronary vein. Ninety-two patients were included, with a mean PVC burden of 21.5±10.9%. Twenty-six patients had had previous ablations. All PVCs had inferior axis, with LBBB pattern in 68%. In 29 patients (32%) direct mapping of the intramural septum was performed using an insulated wire or multielectrode catheter, and in 13 of these cases the earliest activation was recorded within a septal vein. Most patients required special ablation techniques (one or more), including sequential unipolar ablation in 73%, low-ionic irrigation in 26%, bipolar ablation in 15% and ethanol ablation in 1%. Acute PVC suppression was achieved in 75% of patients. Following the procedure, the PVC burden was reduced to 5.8±8.4%. The mean follow-up was 15±14 months and 16 patients underwent a repeat ablation.
Conclusion:
Ablation of intramural PVCs is challenging; acute arrhythmia elimination is achieved in 3/4 patients, and non-conventional approaches are often necessary for success.
Related Concept Videos
01:25ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias
01:29Disturbances in Heart Rhythm
Arrhythmias are categorized by their speed, rhythm, and origin. A slow heart...
01:30Acute Coronary Syndrome III: Diagnostic Studies
01:29Cardiomyopathy III: Hypertrophic Cardiomyopathy