Discussion 

Cardiac tamponade is the most frequent lethal complication after catheter ablation and is an independent predictor for mortality(5,6). Standard non-surgical management after cardiac perforation includes percutaneous pericardiocentesis. The risk of late term tamponade still exists combined with the inherent risks of the procedure such as pleural, liver or cardiac puncture. It gives a false sense of security and prolongs the interval until surgical exploration, which is still necessary in up to 50% of cases(1,7). This study analysed the feasibility of VATS exploration after cardiac perforation. It concludes that VATS leads to a significantly lower 30-day mortality but there are no differences to all-round mortality, length of ICU or hospital stay. Since this is a novel technique, there is little to no available reference literature.
Thoracoscopy avoids the supplementary burden of a full sternotomy and obsoletes its inherent risks such as wound infection of sternal detachment. In contrast to other authors(8), we believe thoracoscopy is faster than a full sternotomy in a dedicated minimally invasive cardiothoracic centre, allowing to quickly estimate the size of the problem and avoiding a full sternotomy for minor perforations.
Almost all possible perforation sites are thoracoscopically accessible. As stated before, most perforations occur at the left atrium or left atrial appendage, which is easily accessible by left sided thoracoscopy even on the beating heart. Should the damage done exceed the limitations of VATS, conversion to full sternotomy is still possible as happened twice in the sternotomy cohort. One case was converted due to massive right ventricle wall rupture after perforating the interventricular septum. Another case was converted to full sternotomy due to the proximity of the perforation to the right coronary artery, requiring closer inspection and complex reconstruction.
Ischemic cerebral and cardiac damage are among the most common causes of death after ablation(6). Most common reason for prolonged ischemic interval are delayed transport to the operating theatre. Femoral cannulation by percutaneous puncture and Seldinger technique can even be done outside the operating theatre, minimizing this ischemic interval. We experience that the longer the delay, the poorer the neurological prognosis.
Lastly, thoracoscopy is an accessible and reproducible method with minimal economic burden. Its main downside is a steep learning curve, emphasizing the need for proper training in centres dedicated to minimally invasive cardiac surgery.
There are several limitations to be adressed. Firstly, the patient group is rather small and single centre. To our knowledge, there are no other centres with the same approach to these cardiac emergencies. Secondly, patients were not randomised. VATS was only performed when the surgeon capable of it was on call for these emergencies. However, there was no patient preselection for either group, confirmed by the absence of differences in the baseline characteristics. For example, one could argue that the more obese patient would be difficult to explore thoracoscopically or that the more critique patient is preselected for sternotomy. However, the results deny any treatment allocation. Thirdly, the delay between perforation recognition and surgical exploration could not be withdrawn from our database, which undeniably correlates with (neurological) outcome.