DISCUSSION
The incidence of dextrocardia with situs inversus totalis is 1/10,0000–50,000 births.(6) In such patients, the IVC might be interrupted or stenotic in 8-18% of patients, with azygos continuation present in only 0,6% of cases.7 Unless severe concomitant congenital defects occur, patients with SID showed life expectancy similar to that of the general population.8 In literature only few case reports described ablation strategies in this specific subset of patients, in which percutaneous PVs isolation can be extremely challenging. The major limitations are considered: small calibre of the entrance vessel, often complicated by tortuosity especially at the level of the azygos vein;9 difficulty in obtaining trans-septal puncture; limited manoeuvrability of the ablation/mapping system.7 For these reasons, “unconventional methods” were explored and described in literature:10,11 so far, three different PA approaches have been reported: trans-septal puncture via trans‐jugular approach through the SVC9; transaortic retrograde approach10 and percutaneous transhepatic vein approach.11
Trans-septal puncture via internal jugular/subclavian vein and SVC was described by Masumoto et al.9 PVs isolation was effectively performed under 3D navigation system. However, the procedure was reported as extremely long despite authors simplified the procedure by omitting electrophysiological mapping of the LA (over 360 minutes of procedural time with more than 60 minutes of PVI time). Major concerns raised mainly while performing the trans-septal puncture with a procedure generally defined as “not smooth”. Of note, authors avoided to approaching the IVC because of the tortuosity.9
An intriguing trans-aortic solution was reported by Okajima and colleagues 10 in this specific subset of patients. Via the left femoral artery authors gained access to the LA in a retrograde fashion and under magnetic navigation system. However, authors were unable to perform a complete isolation of the four PVs: the right inferior PV isolation was aborted since the ablation catheter repeatedly dropped into the left ventricle because of an unfavourable angle and short distance between mitral annulus and PV orifice. Moreover, in order to simplify a such complex procedure, authors avoided to evaluate entrance/exit block as well as the electro-anatomical mapping. 9,10
A percutaneous trans-hepatic vein approach was described by Tandon et al.11 in a patient with dextrocardia and IVC continuation in the azygos vein. LA access was gained via hepatic vein puncture under ultrasound guidance and fluoroscopy. The procedure was reported as safe, however, only addressed the LAA. 11
Non-invasive percutaneous solutions provided a stable restoration of the sinus rhythm, however they were reported as particularly challenging. In most instances, the major drawbacks were the necessity to use different types of catheters, the complex catheter guidance and manoeuvrability, thus leading to exceedingly long and often incomplete procedures.
Surgical thoracoscopic AF ablation had the advantage of a direct vision of the complex anatomy of the patient, allowing the surgeons to promptly recognize cardiac structures despite the complete SID. Effective lesions were safely performed and confirmed by testing the presence of the exit block, thus without affecting the completeness of the ablation lesion set and the procedural time. Moreover, the LAA was successfully excluded by epicardial access with no additional risk.
CONCLUSION In conclusion, patients with complex anatomy should be carefully evaluated with a multidisciplinary approach in specialistic facilities with a wide expertise in minimally invasive arrhythmia surgery. A patient-tailored approach was guaranteed once risks and benefits of the surgical procedure over percutaneous strategy were wisely balanced, thus providing the best option in terms of safety, efficacy and patient satisfaction.