Elsevier

Heart Rhythm

Volume 16, Issue 12, December 2019, Pages 1797-1807
Heart Rhythm

His Bundle Branch Pacing
On-treatment comparison between corrective His bundle pacing and biventricular pacing for cardiac resynchronization: A secondary analysis of the His-SYNC Pilot Trial

https://doi.org/10.1016/j.hrthm.2019.05.009Get rights and content

Background

The His-SYNC pilot trial was the first randomized comparison between His bundle pacing in lieu of a left ventricular lead for cardiac resynchronization therapy (His-CRT) and biventricular pacing (BiV-CRT), but was limited by high rates of crossover.

Objective

To evaluate the results of the His-SYNC pilot trial utilizing treatment-received (TR) and per-protocol (PP) analyses.

Methods

The His-SYNC pilot was a multicenter, prospective, single-blinded, randomized, controlled trial comparing His-CRT vs BiV-CRT in patients meeting standard indications for CRT (eg, NYHA II–IV patients with QRS >120 ms). Crossovers were required based on prespecified criteria. The primary endpoints analyzed included improvement in QRS duration, left ventricular ejection fraction (LVEF), and freedom from cardiovascular (CV) hospitalization and mortality.

Results

Among 41 patients enrolled (aged 64 ± 13 years, 38% female, LVEF 28%, QRS 168 ± 18 ms), 21 were randomized to His-CRT and 20 to BiV-CRT. Crossover occurred in 48% of His-CRT and 26% of BiV-CRT. The most common reason for crossover from His-CRT was inability to correct QRS owing to nonspecific intraventricular conduction delay (n = 5). Patients treated with His-CRT demonstrated greater QRS narrowing compared to BiV (125 ± 22 ms vs 164 ± 25 ms [TR], P < .001;124 ± 19 ms vs 162 ± 24 ms [PP], P < .001). A trend toward higher echocardiographic response was also observed (80 vs 57% [TR], P = .14; 91% vs 54% [PP], P = .078). No significant differences in CV hospitalization or mortality were observed.

Conclusions

Patients receiving His-CRT on-treatment demonstrated superior electrical resynchronization and a trend toward higher echocardiographic response than BiV-CRT. Larger prospective studies may be justifiable with refinements in patient selection and implantation techniques to minimize crossovers.

Section snippets

Methods

The study was conducted at 7 centers and the University of Chicago (UChicago) served as the Study Coordinating Site (NCT0270045). Approval by the local institutional review board was obtained at each participating center prior to enrollment, and all patients provided written informed consent. Patients were blinded to their treatment allocation (His-CRT or BiV-CRT) in this 2-parallel-arm study. Enrollment began in May 2016 and ended in June 2018. All data were sent to the core laboratory

Study population

A total of 41 patients were enrolled; 21 were initially randomized to His-CRT and 20 to BiV-CRT, with 1 patient withdrawal prior to device implantation in the BiV arm. The average duration of follow-up was 12.2 months, with 1 patient lost to follow-up during the study period. Overall, the mean age was 64.6 ± 12.6 years, 38% were female, 63% were white, 65% demonstrated a history of coronary artery disease, 33% had a history of paroxysmal or persistent atrial fibrillation, and 48% had a history

Discussion

The major findings of this secondary analysis of His-SYNC are as follows: (1) His-CRT was superior to BiV-CRT for electrical resynchronization, as measured by QRS narrowing; (2) echocardiographic response was numerically but not statistically higher in patients receiving His-CRT vs BiV-CRT; and (3) inclusion of IVCD accounted for the majority of crossovers in patients allocated to His-CRT.

The His-SYNC pilot trial represents an investigator-initiated collaboration to prospectively assess the

Conclusion

In this first randomized pilot trial of His-CRT vs BiV for CRT in clinical practice, His-CRT demonstrated superior electrical resynchronization than BiV-CRT in on-treatment analysis, with a trend toward greater echocardiographic improvement, which did not reach significance. These secondary analyses should be interpreted as hypothesis-generating, and larger prospective studies with refinements in patient selection and implantation techniques may be justifiable to test for differential clinical

Acknowledgments

We would like to thank Dr Pratik Patel, Rush University Medical Center, Chicago, Illinois, and Dr Susan Kim, Northwestern University, Chicago, Illinois for their collaboration and assistance with enrollment.

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    Funding: None.

    Conflicts of Interest: Dr Gaurav Upadhyay has been a speaker for Abbott, Biotronik and Medtronic, and has been a consultant to Abbott, Biotronik, and Medtronic. Dr Pugazhendhi Vijayaraman has been consultant to Abbott, Biotronik, Boston Scientific, and Medtronic; he also has a patent pending for a His delivery tool. Dr Hemal Nayak has been a speaker for Medtronic, Biotronik, and Boston Scientific. Dr Nishant Verma has been a speaker for Biotronik and Medtronic. Dr Gopi Dandamudi has been a speaker and consultant for Medtronic and serves on the advisory board for Biotronik. Dr Parikshit Sharma has been a speaker for Medtronic and has been a consultant for Abbott and Biotronik. Dr Moeen Saleem has been a speaker for Abbott, Medtronic, and Boston Scientific. Dr Faiz Subzposh has been a consultant to Medtronic. Dr Zaid Aziz has been a speaker for Biotronik. Dr Richard Trohman has been a speaker for Abbott, AltaThera Pharmaceuticals, Boston Scientific, Daiichi Sankyo, and Medtronic; he has been an advisor to Boston Scientific; he has received research grants from Abbott, Boston Scientific, Medtronic, Vitatron, and Wyeth-Ayerst/Wyeth Pharmaceuticals; and he is a consultant for Abbott, AltaThera Pharmaceuticals, and Biosense Webster. Dr Knight has been a speaker or consultant for Abbott, Biosense Webster, Biotronik, Boston Scientific, Medtronic, and Philips. Dr Roderick Tung has been a speaker for Abbott and Boston Scientific. Dr John Mandrola, Dr Andrew Beaser, Dr Davide Genovese, Dr Jess Oren, Dr Roberto Lang, Dalise Shatz, and Stephanie Besser report no relevant disclosures. Northwestern University receives institutional support for the training of fellows from Abbott, Biosense Webster, Biotronik, Boston Scientific, and Medtronic. The University of Chicago Medicine receives institutional support for the training of fellows from Abbott, Biotronik, Boston Scientific, and Medtronic.

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