His Bundle Pacing Versus Cardiac Resynchronization This document discusses His bundle pacing as an alternative to cardiac resynchronization therapy (CRT) for treating heart failure. Right ventricular pacing can cause left ventricular dyssynchrony, while CRT has limited success due to non-physiological biventricular pacing. His bundle pacing aims to restore normal conduction by capturing the native conduction system. Studies show His bundle pacing improves left ventricular function and reduces dimensions more than CRT. A randomized trial found His bundle pacing had superior electrical resynchronization compared to CRT. However, potential issues with His bundle pacing include lead dislodgement and increased capture thresholds over time. More research is still needed but His bundle pacing

1. His Bundle Pacing
Versus
Cardiac Resynchronization
Alireza Ghorbani Sharif, MD
Electrophysiologist
Tehran arrhythmia Center
August 2019

2. Outline
Background
What’s wrong with what we have done before?
Clinical results
Conclusion

3. His Bundle Pacing

4. Published Articles on His Bundle Pacing

5. Bundle of His
Discovered in 1893 by Wilhelm His

6. Cardiology Journal 2010, Vol. 17, No. 4, pp. 428–433 ,Copyright © 2010 Via Medica ISSN 1897–5593

7. © 2014 Wiley Periodicals, Inc.PACE, Vol. 00

8. Circulation, Volume XXXIX, January 1969

9. CIRCULATION VOL 57, No 3, MARCH 1978

10. CIRCULATION VOL 57, No 3, MARCH 1978

11. (Circulation. 2000;101:869-877)
• Total of 18 patients aged 69±10 years who had a history of
chronic AF, DCM, and normal activation (QRS≤120 ms) were
screened for permanent DHBP using an electrophysiology
catheter.
• In 14 patients, the His bundle could be reliably stimulated. Of
these 14, permanent DHBP using a fixed screw-in lead was
successful in 12 patients.

12. (Circulation. 2000;101:869-877)

13. • Permanent HBP is feasible in select patients who have chronic AF and DCM.
• Long-term, HBP results in a reduction of left ventricular dimensions and
improved cardiac function.
Conclusions
(Circulation. 2000;101:869-877)

14. Why do we need something new?
Prevent Pacing induced CMP
A solution for CRT non-responder
Improve on BIV pacing

15. Deleterious Effects of RV Pacing
Altered left ventricular electrical and mechanical activation:
• Pacing-induced LV dyssynchrony secondary to the
abnormal activation sequence, ventricular dyssynchrony
may be present in up to 50% of the patients after long
term RV apical pacing.
• Less work produced for given LVEDV.
• Delayed papillary muscle activation  Valvular
insufficiency thus causing MR.
ANTONIO DE SISTI, M.D., ePACE 2012; 35:1035–1043

16. Prevent Pacing Induced CMP

17. Cardiac Resynchronization Therapy
• CRT has an established role in the treatment of
patients with heart failure and electromechanical
dyssynchrony with wide QRS duration.
• CRT has been consistently shown to improve quality of
life, NYHA status, and left ventricular (LV) remodeling
with improvements in LV ejection fraction (LVEF) and
reduction in LV dimensions and volumes.
• Mortality reduction was demonstrated in the CARE HF
trial (2005) with CRT pacing alone.
FLA 5.6.0 DTD HRTHM8021 proof 17 June 2019

18. Non-Responder to CRT
• Despite these benefits, non-response to CRT remains
high, estimated between 30% and 40%.
• A possible limitation to conventional CRT is that
electrical synchronization via BiV is achieved through
non-physiological means, via fusion of an epicardial LV
wavefront with an endocardial wavefront from the RV
apex.
FLA 5.6.0 DTD HRTHM8021 proof 17 June 2019

19. Non-Physiological Wave

20. Received 23 September 2013; accepted after revision 9 December 2013

21. Received 23 September 2013; accepted after revision 9 December 2013
• BiV endocardial LV pacing
from the optimal endocardial
site appears to be superior
overall to conventional CRT.
The two forms of MSP tested
(via multiple leads or a single-
quadripolar lead) were not
significantly superior to
conventional.

22. How Can His Bundle Pacing Correct LBBB?
• Recent data suggest that the underlying pathophysiology of
LBBB patterns is attributable to focal disease located
proximally in the left conduction system, which provides a
mechanistic explanation for QRS correction with pacing of
distal conduction block with a sufficient pacing stimulus.
FLA 5.6.0 DTD HRTHM8021 proof 17 June 2019
Why should We do His bundle
Pacing?

23. His Bundle Pacing
Ali et al. Arrhythm Electrophysiol Rev 2018;7:103

24. His Bundle Pacing (HBP)
• HBP has been to shown to be a viable bailout option for
CRT and more recently has been valuated for feasibility
as a first-line strategy.
• Capture of the native conduction system can achieve
complete restoration of normal physiologic His-Purkinje
conduction, which may more favorably promote
remodeling compared to BiV.
FLA 5.6.0 DTD HRTHM8021 proof 17 June 2019

25. CS
T
V
R
A HBP
RV
Correa de Sa et al. Circ Arrhythm Electrophysiol 2012;5;244
TV
M
SV
His lead generally does not cross the TV

26. • 4.1 FR lead body diameter
• Bipolar
• Fixed screw helix
• Steroid eluting
• Polyurethane outer insulation
• Cable inner conductor
How to deliver a lead

27. Direct His Bundle Pacing
S1547-5271(17)31207-9 10.1016/j.hrthm.2017.10.014

28. Selective His Bundle Pacing
Ajijola et al. Heart Rhythm 2017;14:1353

29. Non-Selective His Bundle Pacing
Ajijola et al. Heart Rhythm 2017;14:1353

30. • A total of 106 patients underwent an attempt at HBP for CRT
at 5 centers (Geisinger Heart Institute , Rush University Medical Center , Indiana University ,
University of South Florida, Virginia common wealth University ).
• HBP was successful in 95 patients with an overall success
rate of 90%.
• Patients were followed for an average duration of 14.4±15
months.
(Heart Rhythm 2018;15:413–420)

31. • Patients were classified into two groups based on their
indication for CRT:
Group I (rescue HBP) included 30 patients:
1. Patients with unsuccessful LV lead implantation
2. Non-responders to BVP
(Heart Rhythm 2018;15:413–420)

32. (Heart Rhythm 2018;15:413–420)
• Group II (primary HBP) included, patients in whom HBP was
attempted as the first option:
1. AV block with QRS duration <120 ms or post AV junction ablation
2. Primary His bundle pacing, BBB (QRS duration >120ms)
3. Upgrade to CRT due to >40% RV pacing

33. (Heart Rhythm 2018;15:413–420)

34. • HBP was associated with significant narrowing of QRS and
improvement in LV function.
• HBP can be an excellent alternative to BVP in patients who fail
LV pacing or as primary option in select populations.
(Heart Rhythm 2018;15:413–420)
Conclusion

35. • Indications for BiV were based on standard clinical
criteria ; inclusion criteria for the study were LBBB
with QRSd >130 ms ejection fraction <35%, and
NYHA class II to IV.
J A C C V O L . 7 2 , NO . 2 4 , 2 0 1 8

36. • In this prospective study compared the
electromechanical effects of His resynchronization
against conventional BiV, using high-precision
hemodynamic assessment and noninvasive epicardial
ventricular activation mapping.
J A C C V O L . 7 2 , NO . 2 4 , 2 0 1 8

37. • 23 patients were recruited. In 4 patients, temporary HBP did not
shorten LVAT-95 by at least 10 ms, and were excluded.
• In 1 patient, a technical fault prevented acquisition of ECGI
(electrocardiographic imaging) data, therefore excluded
• 18 patients therefore demonstrated the 10ms LVAT-95 shortening
J A C C V O L . 7 2 , NO . 2 4 , 2 0 1 8

38. J A C C V O L . 7 2 , NO . 2 4 , 2 0 1 8

39. J A C C V O L . 7 2 , NO . 2 4 , 2 0 1 8

40. J A C C V O L . 7 2 , NO . 2 4 , 2 0 1 8

41. J A C C V O L . 7 2 , NO . 2 4 , 2 0 1 8
Noninvasive ECGI (electrocardiographic imaging)
epicardial of LV and RV activation mapping

42. Conclusion
• HBP appears to be a very promising alternative to BiV in
patients with LBBB and heart failure.
• It can deliver larger reductions in ventricular activation time,
which leads to significantly greater improvements in acute
hemodynamic function.
• His resynchronization therapy has the potential to produce
better clinical outcomes than BiV.
J A C C V O L . 7 2 , NO . 2 4 , 2 0 1 8

43. • His-SYNC pilot trial was an prospective, randomized,
controlled clinical trial that aimed to assess the feasibility and
efficacy of His-CRT as a first-line strategy for CRT
compared to BiV-CRT with regard to both ECG and Echo
responses.
(Heart Rhythm 2019;-:1–11)

44. • A total of 41 patients were enrolled; 21 were initially randomized
to His-CRT and 20 to BiV, 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.
(Heart Rhythm 2019;1–11)

45. • Crossover was mandated in patients randomized to His-
CRT if the paced QRS width did not narrow by at least 20%
or to a QRS width of ≤ 130 ms or if fixation of the HBP lead
could not be performed with adequate stability or pacing
output (≤5 V @ 1.0 ms).
(Heart Rhythm 2019;-:1–11)

46. (Heart Rhythm 2019;1–11)

47. • The primary endpoints included measures of
electrocardiographic (ie, change in QRS width) and
echocardiographic (ie, change in LVEF) parameters at 6
months.
• Time to first cardiovascular (CV) hospitalization or all-cause
mortality at 12 months was also examined.
(Heart Rhythm 2019;1–11)

48. (Heart Rhythm 2019;1–11)

49. (Heart Rhythm 2019;1–11)

50. (Heart Rhythm 2019;1–11)

51. (Heart Rhythm 2019;1–11)

52. 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
(Heart Rhythm 2019;1–11)

53. Conclusion
• It was the 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.
(Heart Rhythm 2019;1–11)

54. His Bundle Pacing for CRT
in Patients With Heart Failure and RBBB
• Benefits of biventricular pacing may be limited in patients with
RBBB
• The aim of the study was to assess the feasibility and outcomes of
HBP in patients with RBBB and heart failure.
• Methods HBP was attempted as a primary or rescue (failed LV lead
implant) strategy in patients with reduced LV ejection fraction,
RBBB, QRS duration ≥120 ms, NYHA class II to IV heart failure.
Sharma et al. Circ Arrhyhm Electrophysiol 2018;11:e006613

55. • NYHA class, and echo data were assessed in follow-up. Results Mean
age was 72±10 years, female 15%, with an average LV ejection fraction
of 31±10%.
• HBP was successful in 37 of 39 patients (95%) with narrowing of RBBB
in 78% cases.
• During a mean follow-up of 15±23 months:
• there was a significant narrowing of QRS from 158±24 to 127±17 ms ( P=0.0001)
• increase in LV ejection fraction from 31±10% to 39±13% ( P=0.004)
• improvement in NYHA class from 2.8±0.6 to 2±0.7 ( P=0.0001)
• Increase in capture threshold occurred in 3 patients.
Sharma et al. Circ Arrhyhm Electrophysiol 2018;11:e006613
His Bundle Pacing for CRT
in Patients With Heart Failure and RBBB

56. Normalization of RBBB
Sharma et al. Circ Arrhyhm Electrophysiol 2018;11:e006613

57. Conclusions
• Permanent HBP was associated with significant narrowing of
QRS duration and improvement in LV function in patients
with RBBB and reduced LV ejection fraction.
• Permanent HBP is a promising option for cardiac
resynchronization therapy in patients with RBBB and
reduced LV ejection fraction.
Sharma et al. Circ Arrhyhm Electrophysiol 2018;11:e006613

58. Potential pitfalls/Concerns
• Dislodgments
• Capture threshold/battery longevity
• Extraction
• Damage to conduction system
• Decrease in RV sensing

59. Take Home Message
• His resynchronization therapy has the potential to produce
better clinical outcomes than BiV
• As first line therapy in LBBB and RBBB
• In non-responder and in patient with failed implantation of CRT
• We should consider the potential pitfalls of His bundle
pacing; dislodgments, higher capture threshold , less
battery longevity, difficult in extraction, damage to
conduction system and decrease in RV sensing.
• More randomized clinical trial are essential.

60. Tehran Arrhythmia Center
www.IranEP.org
info@IranEP.org