Left Bundle Branch Area Pacing in Dextrocardia: Navigating Complex Anatomy for Successful Conduction System Pacing

Interview With Mehrdad Golian, MD

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EP LAB DIGEST. 2026;26(6):7.

Interview by Jodie Elrod

In this interview, Mehrdad Golian, MD, discusses the challenges and lessons learned from a recent case involving left bundle branch area pacing (LBBAP) in a patient with dextrocardia and situs inversus. Dr Golian shares how meticulous preprocedural planning, a deep understanding of cardiac anatomy, and reliance on electrophysiologic principles enabled successful conduction system pacing despite mirrored cardiac structures. The discussion highlights practical strategies for navigating complex anatomy, maintaining procedural efficiency, and building confidence in lead placement as conduction system pacing continues to expand into increasingly challenging patient populations.

This case involved LBBAP in a patient with dextrocardia and situs inversus—anatomy that can completely change your usual orientation in the EP lab. How did you prepare for the case and approach lead placement to achieve stable positioning and successful pacing?
Dextrocardia with situs inversus is a genuinely humbling anatomical variant. It strips away the subconscious spatial fluency that experienced implanters rely on and forces a deliberately methodical approach to every step. In cases like this, muscle memory can actually work against you.

Our preparation centered on a thorough review of preprocedural imaging, including magnetic resonance imaging and prior chest x-rays, to internalize the mirror-image anatomy before entering the lab. This was not simply about recognizing that the heart was on the right side; it required mentally remapping fluoroscopic views, identifying the location of the septum, and anticipating how catheter curves and torque responses would behave in a mirrored orientation. In many ways, it meant relearning familiar procedural movements in real time.

Intraprocedurally, we made a conscious decision early on to forget the usual catheter movements. Fluoroscopic landmarks were interpreted according to their mirrored orientation, and we relied more heavily on anatomical reference points such as the tricuspid and mitral rings, along with electrogram characteristics, pacing morphology, and impedance behavior, to guide and confirm lead position rather than depending solely on visual landmarks. The tricuspid and mitral annuli proved particularly valuable for spatial orientation, providing reliable reference points that helped us triangulate our septal target.

The fundamental principles of LBBAP, however, remained unchanged: identifying the appropriate interventricular septal location, achieving sufficient lead depth for subendocardial engagement, and confirming conduction system capture through properly placed (reversed) electrodes, detection of LBB potential, transition in paced morphology, and acceptable pacing thresholds.

From a lead management perspective, what unique challenges does mirrored cardiac anatomy create for lead delivery, fixation, and long-term pacing considerations, and how did this case influence your thinking around procedural adaptability?
Mirrored cardiac anatomy affects virtually every step of lead delivery. Sheath manipulation that would normally feel intuitive becomes counterintuitive, and achieving the correct angle of approach to the interventricular septum often requires deliberate adjustments in technique and constant reminder of septal location. There is also a greater reliance on understanding 3-dimensional anatomy, as fluoroscopic projections may not provide the familiar visual cues operators are accustomed to using. 

From a lead management perspective, maintaining adequate support and stability during lead deployment is critical. The challenge is not only reaching the target but ensuring secure fixation and reliable long-term lead performance. In this case, right-sided lead placement provided improved support and allowed more effective pressure to be applied to the septum.

This case reinforced an important principle: successful device implantation is less about memorizing procedural movements and more about understanding anatomy and the fundamentals of pacing. When those fundamentals are well understood, operators can adapt to unusual anatomies without compromising outcomes. It also highlights the importance of flexibility, thoughtful procedural planning, and a willingness to modify one's approach in real time when confronted with unexpected anatomy.

As conduction system pacing becomes more widely adopted, what lessons from this case would you share with electrophysiologists about managing complex anatomy while maintaining procedural efficiency, fluoroscopic orientation, and confidence in lead placement?
This case offers several lessons worth carrying forward for cardiovascular implantable electronic device operators.

The first is about mindset. Unusual anatomy should prompt careful preparation, not avoidance. In complex cases, there can be a temptation to default to a familiar approach, even when it may not always be the most optimal one. Our obligation, however, is to identify the best option for the patient while remaining honest about the limits of what can be achieved safely. Dextrocardia serves as a useful reminder that conduction system pacing is, at its core, an anatomy-based discipline. When the underlying anatomy and the electrophysiologic principles of conduction system capture are truly understood, unusual anatomical variants become challenging rather than prohibitive.

The second lesson is that efficiency is earned through preparation. Reviewing imaging in advance, anticipating how fluoroscopic views will differ, and considering practical adaptations ahead of time—whether that means mirroring the fluoroscopic display, assessing sheath orientation outside the body, or reshaping tools before the case begins—can meaningfully reduce intraoperative uncertainty and procedure time. The time invested before the first incision pays dividends throughout the case.

The third lesson is about where confidence should come from. Fluoroscopic appearance is a guide, not an absolute truth. Electrical parameters, paced QRS morphology, and objective evidence of conduction system capture are what ultimately confirm success. Operators should anchor their decision-making in the electrocardiographic criteria, which remain reliable even when visual landmarks are unfamiliar or misleading, provided the ECG electrodes are positioned correctly.

As conduction system pacing continues to expand, we will encounter increasing numbers of patients with congenital abnormalities, prior cardiac surgery, and complex structural disease. This case demonstrates that with deliberate planning, a strong understanding of anatomy, and a systematic approach, conduction system pacing can remain feasible, effective, and reproducible, even in anatomies that initially appear daunting.

Anatomy may vary. The principles do not