Pursuit of physiologic pacing
Letter to the Editor

Pursuit of physiologic pacing

Pugazhendhi Vijayaraman1, Daniel Gellan2

1Geisinger Heart Institute, Wilkes Barre, PA, USA; 2Department of Medicine, Geisinger Wyoming Valley Medical Center, Wilkes Barre, PA, USA

Correspondence to: Pugazhendhi Vijayaraman, MD. Geisinger Heart Institute, MC 36-10, 1000 E Mountain Blvd, Wilkes Barre, PA 18711, USA. Email: pvijayaraman1@geisinger.edu; pvijayaraman@gmail.com.

Provenance: This is an invited article commissioned by the Section Editor Fang-Zhou Liu (Guangdong Cardiovascular Institute, Guangzhou, China).

Response to: Zungsontiporn N, Wu R. Can His bundle pacing prevent right ventricular pacing-induced cardiomyopathy, heart failure, or death? J Thorac Dis 2018;10:S3192-4.


Submitted Sep 15, 2018. Accepted for publication Sep 26, 2018.

doi: 10.21037/jtd.2018.09.123


We thank Drs. Zungsontiporn and Wu for their insightful comments on our study (1). Since the first wearable and later implantable pacemaker invention in late 1950s to early 1960s, pacemaker has undergone revolutionary changes and still continuing to evolve. It is now well understood that the conventional right ventricular pacing is associated with deleterious effects of right ventricular pacing induced cardiomyopathy (PICM), heart failure and increased mortality. Cardiac resynchronization therapy in the form of biventricular pacing (BVP) has been proven to be effective in patients with pre-existing left bundle branch block and severe left ventricular (LV) systolic dysfunction, improving ventricular function, heart failure outcomes and reduced mortality. In patients with normal His-Purkinje conduction and ventricular synchrony as in those with atrioventricular (AV) block or long PR intervals, BVP still results in prolonged ventricular activation time, ventricular dyssynchrony and may worsen cardiac function and clinical outcomes. The role of BVP in this group of patients with preserved LV systolic function remains unsettled. The Biventricular Pacing for Atrioventricular Block to Prevent Cardiac Desynchronization (BioPace) trial compared right ventricular pacing to BVP in more than 1,800 patients and reported no difference in the rate of the composite endpoint that included time-to-death or first hospitalization due to heart failure (2).

Even though the physiologic advantage of His bundle pacing (HBP) was demonstrated in an experimental study by Kosowsky et al. (3), about 5 decades ago and the clinical feasibility by Deshmukh et al. 20 years ago (4), only in recent years HBP has reached mainstream (5). We agree with Drs. Zungsontiporn and Wu regarding the limitations of HBP observed in our study (1). Nonetheless, the higher pacing thresholds and lead revisions observed in our study are comparable to LV pacing in BVP studies. More importantly, we believe that the radiation exposure, procedural duration and the cost of HBP will prove to be favorable compared to BVP.

Despite high right ventricular pacing burden many patients do not develop PICM. Only about 12–20% of patients develop PICM during medium-term follow-up. Identifying patients at increased risk for developing PICM and heart failure may provide a subset of patients most likely to benefit from physiologic pacing. Additionally, HBP has also been shown to correct chronic bundle branch blocks in patients with cardiomyopathy and heart failure (6). HBP provides an alternative option for providing cardiac resynchronization therapy in these patients.

HBP is an emerging technology and is likely to gain momentum in the coming years with further research and investment in improved tools and technology. There are already ongoing randomized controlled trials on HBP, which will add to the evidence base for HBP (7). With improvements in leads and delivery systems, and positive results from randomized clinical trials, HBP is likely to become the optimal pacing site of choice.


Acknowledgements

None.


Footnote

Conflicts of Interest: PV, Speaker, Consultant, Research (Medtronic), Consultant (Boston Scientific, Abbott, Merritt Medical), Patent pending for His delivery tool. The other author has no conflicts of interest to declare.


References

  1. Abdelrahman M, Subzposh FA, Beer D, et al. Clinical outcomes of His bundle pacing compared to right ventricular pacing. J Am Coll Cardiol 2018;71:2319-30. [Crossref] [PubMed]
  2. Blanc JJ et al. Biopace trial preliminary results. Available online: clinicaltrialresults.org/Slides/TCT%202014/Blanc_Biopace.pdf
  3. Kosowsky BD, Scherlag BJ, Damato AN. Re-evaluation of the atrial contribution to ventricular function: study using His bundle pacing. Am J Cardiol 1968;21:518-24. [Crossref] [PubMed]
  4. Deshmukh P, Casavant DA, Romanyshyn M, et al. Permanent, direct His-bundle pacing: a novel approach to cardiac pacing in patients with normal His-Purkinje activation. Circulation 2000;101:869-77. [Crossref] [PubMed]
  5. Vijayaraman P, Chung MK, Dandamudi G, et al. His bundle pacing. J Am Coll Cardiol 2018;72:927-47. [Crossref] [PubMed]
  6. Sharma PS, Dandamudi G, Herweg B, et al. Permanent His bundle pacing as an alternative to biventricular pacing for cardiac resynchronization therapy: A multicenter experience. Heart Rhythm 2018;15:413-20. [Crossref] [PubMed]
  7. Saini H, Ellenbogen KA, Koneru JN. Future Developments in His Bundle Pacing. Card Electrophysiol Clin 2018;10:543-8. [Crossref] [PubMed]
Cite this article as: Vijayaraman P, Gellan D. Pursuit of physiologic pacing. J Thorac Dis 2018;10(10):E766-E767. doi: 10.21037/jtd.2018.09.123