Concerns about the long-term outcome of transseptal cardiac resynchronization therapy: what we have learned from surgical experience

We read with a great interest the report of Nuta et al.1 in which, an alternative technique is described for cardiac resynchronization therapy (CRT). Indeed, this method becomes more and more utilized for pacing of the free-wall of the left ventricle (LV) in patients when epicardial approach failed. 2 , 3 After standard transseptal puncture and septal dilatation via the femoral route, the left atrium is cannulated with a combination of catheters and guide wires from the left or right subclavian vein. After advancement of this guiding catheter into the LV, a standard bipolar screw-in lead could be implanted in the posterolateral wall. Obviously, these patients require life-long oral anticoagulation after such a procedure. 1–3 It is not a big surprise that with a significant failure rate reported using the coronary sinus tributaries, alternative pacing techniques are being searched for CRT. However, the above-described technique has more possible limitations that mentioned by the authors. First, a foreign body enters from the right atrium into the left side of the heart through a continuously open connection. More importantly, there is a close and permanent contact with the mitral valve apparatus. This definitely increases the risk of infected endocarditis, involving the mitral valve itself. Moreover, when it happens the outcome is presumably even more deleterious than the potentially lethal right-sided pacemaker endocarditis. Although reports are not available on this subject, conclusions can be drawn from previous surgical experience. Interestingly enough, more and more reports confirm that the number of device related infections show instantaneous increment in the past two decades. 4 , 5 Pacing system related endocarditis and its consequences are well described. 6 Essential step of the treatment on the right side is complete removal of the pacing system, which requires sometimes high-tech technology. 7 , 8 After removal of the foreign body, the disease can be treated with acceptable results by antibiotics, as in any other aetiology of right-sided endocarditis. We must emphasize the fact on the other hand, that significantly worse outcome is expected, when endocarditis involves the valves of the left side. This location of the disease remains with high mortality and morbidity against the novel treatment options, as showed by the most recent studies. 9 , 10 On top of that, the consequence of septic embolization into the systemic circulation (brain vessels, coronaries, supplying arteries of parenchymal intra- and retroabdominal organs, and gastrointestinal territory) can be fatal. Abscess formations in the target tissues and organs such as in the brain, myocardium, liver, lien, kidneys, etc. are all very severe conditions, which simply not comparable with right-sided pathologies. The obligatory anticoagulation therapy decreases the healing possibilities of these secondary infected, abscessed tissues. 11 The infected mitral valve very often needs surgery itself. This is somewhat of a paradox, since most of these indications are based on inoperability of the patient. 1–3 Beyond this, under these special conditions mitral valve surgery carries a higher risk for mortality and morbidity. 12 We note that most of the above mentioned implantations were performed as last remaining option for the patients. With this present correspondence, we would like to draw attention to the possible drawbacks of this otherwise elegant technique. We do believe that more liberal utilization of this method requires more data on safety and should probably done under strict research protocols.