Total Thoracoscopic Maze Outcomes
Two studies from The Ohio State University have been published on earlier iterations of the total thoracoscopic maze. In the first,¹ 87.5% of a group of patients, nearly all of whom had longstanding persistent atrial fibrillation (no paroxysmal), remained in normal sinus rhythm at 6 months postoperatively without the use of rhythm-control medications.
Rhythm surveillance consisted of a week of continuous self-actuated event monitoring at 3, 6, and 13 months postoperatively. The notable result of this study is that the high success rate in this most difficult group of patients was achieved prior to the availability of a linear ablation device designed for the extended lesions on the left atrium. Moreover, the verification technique employed in this study, electrogram attenuation, has been discarded in favor of the more rigorous standard of bidirectional block.
In the second study,² 91% of a similar group consisting almost entirely of people with longstanding persistent atrial fibrillation remained in normal sinus rhythm at 6 months without the use of rhythm-control medicines and with the same surveillance protocol. Again, these results do not reflect the advancements in both lesion creation and verification achieved in the summer of 2008. With these advances, the success in treating atrial fibrillation in the most difficult patients is expected to increase further.
Comparison with Percutaneous (Catheter) Ablation
Percutaneous ablation, also known as catheter ablation describes a procedure in which long catheters are inserted into the femoral vein and advanced into the heart. Indirect imaging, such as echocardiography and x-ray fluoroscopy, and electrical sensing are used to position the ablation catheter. Current techniques direct ablations to the inside surfaces of the heart to target specific anatomic structures, such as the pulmonary veins, and areas of electrical instability as detected by a sensing catheter.
However, extended lines to isolate arrhythmogenic areas of the heart are created not as true continuous lesions, as in the total thoracoscopic maze surgery, but as a series of spot ablations directed by necessarily imprecise imaging modalities. Without direct visualization of the ablation, and without a true linear ablation probe, the extended lesions performed with a catheter do not block errant electrical signals with the same reliability as those used in the total thoracoscopic maze.
In fact, in all patients referred The Ohio State University after failed catheter ablation, intraoperative testing of the pulmonary vein isolation from their previous catheter ablation has consistently demonstrated failure of isolation. The inability of catheter ablation to achieve this most basic goal of any anti-arrhythmia procedure illustrates the significant limitations of the technique.
These limitations emerge particularly in outcomes in patients with persistent, or non-self-terminating, atrial fibrillation. As reported recently in the journal Circulation: Arrhythmia and Electrophysiology, only 40% of this group of patients was successfully treated with a single catheter ablation. The reason for the substantial difference in outcomes between the total thoracoscopic maze and catheter ablation is clear. In comparison to the linear ablation technology of the total thoracoscopic maze, the spot ablation techniques of catheter ablation are inefficient and unreliable for isolating arrhythmia-generating regions of the heart.
More Information
For more details about atrial fibrillation treatments, including the total thoracoscopic maze procedure, request a phone consultation with Dr. John Sirak or call his appointment phone at 614-293-5502.
1. Sirak et al., Toward a Definitive, Totally Thoracoscopic Procedure for Atrial Fibrillation. Annals of Thoracic Surgery 2008; 86, 1960-64.
2. Sirak et al., Toward a Definitive, Totally Thoracoscopic Procedure for Atrial Fibrillation. American Heart Association Scientific Sessions 2008, Poster Presentation.
