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Intraoperative electrical ablation of ventricular arrhythmias: a "closed heart" procedure
E Downar1, L Mickleborough, L Harris
1Department of Medicine, Toronto General Hospital, Ontario, Canada.
Insights
A novel "closed heart" technique for mapping and ablating ventricular arrhythmias avoids ventriculotomy. This minimally invasive approach shows promise for treating ventricular tachycardia without increasing patient risk.
Area of Science:
- Cardiovascular Surgery
- Electrophysiology
- Medical Devices
Background:
- Traditional surgical ablation for ventricular arrhythmias necessitates a ventriculotomy, increasing patient morbidity and mortality risk.
- This risk is amplified when operating on friable myocardium.
Observation:
- A new "closed heart" technique utilizing a 112-electrode balloon array introduced via a transmitral approach was developed.
- This array allows for safe, repeated electrical discharges up to 150 J per electrode within the left ventricle.
Findings:
- In four patients with coronary artery disease (no ventricular aneurysm), seven ventricular tachycardias were mapped and treated.
- Successful ablation was achieved in 7-16 minutes per patient, with arrhythmia freedom in three survivors for 4-11 months post-procedure.
Implications:
- This technique offers a less invasive surgical option for ventricular tachycardia treatment, potentially reducing complications.
- It is particularly suitable for patients without left ventricular aneurysms.
Abstract:
Both intraoperative endocardial mapping and surgical ablation for ventricular arrhythmias have until now required a ventriculotomy. Such an incision may be associated with an increase in morbidity and mortality, especially when performed through friable myocardium. A "closed heart" technique of intraoperative endocardial mapping and ablation of ventricular arrhythmias was developed in which a balloon array of 112 electrodes was introduced into the left ventricular cavity by a transmitral approach. The array permitted safe delivery of repeated electrical discharges of up to 150 J at each electrode. In four patients with coronary artery disease and no ventricular aneurysm, this "closed heart" technique was used to map and treat seven distinct ventricular tachycardias. The time taken to map each tachycardia varied from 3 to 13 minutes. Between 100 and 150 J was then delivered at each of 10 to 42 electrode sites, and the ablation procedure took 7 to 16 minutes per patient to complete. One patient died 24 hours postoperatively from preexisting thrombocytopenic purpura. There was no significant deterioration in left ventricular function in the three survivors and all have remained arrhythmia free, without antiarrhythmic agents, for 4 to 11 months. This technique offers a new method of surgical treatment of ventricular tachycardia without ventriculotomy, and is particularly suited to patients without a discernible left ventricular aneurysm.