Discussion
In this report, we presented successful Micra implantation through BTV in a patient with repaired congenital heart disease. The procedure was straightforward without any complications. During follow-up, the patient was asymptomatic and the Micra interrogation showed proper functioning.
Tricuspid valve surgery carries a significant risk of conduction disorders requiring PPM implantation. The implantation rate decreased over time from 13-22% before 200013 to 5-11% in the recent years.14 The PPM implantation after TV surgery involves technical challenges that must be acknowledged by the implanters to select the best technical option in each patient.
Several approaches have been reported: epicardial leads, standard transvenous leads, his-bundle pacing, leadless pacing, or coronary sinus leads.15
1) Although epicardial PPMs are proven to provide adequate pacing, the reliability of endocardial leads has been shown to be superior to the epicardial systems.16 This is especially true if patients already had multiple cardiac surgeries with resultant pericardial adhesion, since surgeons may have a tough time to find a ventricular site with acceptable pacing thresholds.
2) Transvenous leads can interfere with the function of tricuspid valves, leading to a significant morbidity and mortality through hemodynamic impairment. The presence of transvenous lead was an independent predictor of tricuspid regurgitation (TR) during follow-up.17 Although there is no clear evidence of increased TR after transvenous lead implantation in the presence of BTV, most operators prefer to avoid transvenous lead in these patients.
3) His-bundle pacing (HBP) is a more physiologic form of pacing compared to ventricular pacing. This could be an interesting alternative for treating AVBs after TV surgeries, especially as the block site is nodal in most cases. HBP has been described to be feasible in small series (n=10) of patients after TV repair but none with TV replacement.18 In these settings, the TV ring may act as a radiographic marker of the his-bundle and facilitate the implantation.
4) Since cardiac resynchronization therapy emerged as a cornerstone treatment for advanced heart failure patients, rare data have been published in the literature regarding CS pacing after TV surgery. Only one small series of 17 patients (11 TV repairs and 6 TV replacements) was published.19 Due to the right atrial dilatation and resulting malposition of the CS ostium, CS catheterization and lead placement may be more challenging in this specific situation compared to typical CRT patients.
5) There are currently no large data about the safety and efficacy of leadless pacemakers in patients after TV surgery. To date, there is a few reports on Micra implantation after TV repair and BTV surgery.10-12, 20, 21 The procedures were performed successfully with no complications and patients did not have any valvular dysfunction after the procedure.
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LLP implantation is an emerging technology validated in clinical studies and real-world setting with the potential advantage of overcoming some of the limits of the traditional transvenous pacing lead such as need for extraction after battery depletion. LLPs overcome this limit and don’t need extraction after battery depletion; because LLP is endothelialized into ventricle and according to the existing studies, up to 3 LLP (with battery longevity of 10-12 years) can be placed inside the RV. Therefore, there is no need to remove the previous LLP and a new one can be implanted in the RV22.so it prevents further open surgeries and the risk of post operation complications .LLP implantation after BTV might represent an ideal option in this setting by eliminating the risks connected with the presence of the lead across the bioprosthetic valve, including valve dysfunction and valvular endocarditis, 8,23,24. In conclusion, our case demonstrates that a leadless pacemaker is an ideal option in patients developing persistent conduction disorders after BTV.