Presented at 2nd LARHS Scientific Sessions, Guadalajara, September 2019

1. #LAHRS2019
Sergio L. Pinski, MD, FHRS
Cleveland Clinic Florida
Weston, Florida, USA
@SergioPinski
Nomenclature:
Selective and nonselective His bundle
capture

2. Anatomical Variation of the Bundle of His
Kawashima et al. Surg Radiol Anat 2005;27:205

3. Physiology of His bundle pacing
• It is crucial to understand selective His bundle capture
(ie, only the conduction system) and nonselective His
bundle capture (ie, the conduction system and also the
the ventricular myocardium surrounding the electrode)
• Therefore one will likely find different thresholds (His,
myocardium, correction of bundle branch block, even
atrium at times)
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3

4. Selective His bundle capture

5. Non selective His bundle capture

6. Saini et al. Circ Arrh Electrophysiol 2019; 12:e006808

7. Saini et al. Circ Arrh Electrophysiol 2019; 12:e006808

8. Key concept
• The hallmark of His bundle pacing is the presence of changes
in QRS morphology as the pacing voltage is reduced.
• It is very useful to monitor several ECG leads (if possible 12).
QRS changes may not be very evident when monitoring only
1 or 2 leads.

9. Possible responses during threshold testing
• Customary to use 1 ms during implant
• No change, always narrow: All or none selective His bundle capture
• Non-selective capture➡️ Selective capture ➡️Loss of capture
• His threshold lower than myocardial threshold
• Non-selective capture ➡️ Myocardial capture ➡️ Loss of capture
• His threshold higher than myocardial threshold
• No change, always wide: Non-selective His bundle capture with identical
myocardial thresholds (hope) vs. only myocardial capture (likely reality)
• Bundle branch block normalization is also output dependent
• So you may end up with 1, 2 or 3 capture “thresholds”

10. • Diagnosis of selective His bundle capture is easy (especially when
QRS is narrow)
• Diagnosis of non-selective His bundle capture can be tricky.
• IT IS A RETROSPECTIVE DIAGNOSIS! One can only affirm it when
one sees a change
• Why is it important to make a positive diagnosis of non-selective
His bundle capture?
• To avoid self-deception (“Not sure if I capture the His but I narrowed
the QRS quite a bit”)
• To disarm detractors (“Everybody throws a lead in the septum and
calls it His bundle pacing”)

11. @SergioPinski
Non-selective to selective His capture during threshold testing
Non selective HBP Selective HBP

12. Non selective His capture to myocardial capture during threshold testing
Non selective HBP Myocardial capture

13. Non-selective His bundle pacing does not produce LV
dysynchrony & is not worse clinically
Vijayaraman et al. JACC 2018; 72:927 Beer et al. JACC Clin Electrophysiol 2019; 5:766

16. Lustgarten et al. Heart Rhythm 2015;12:1548

17. Keene et al. J Cardiovasc Electrophysiol 2019; (in press)

18. How to differentiate NS-HBP from pure RV
myocardial capture
• Sudden change in QRS, which becomes wider and notched
• Cannot use near-field EGM, it does not change. Far field EGM gets
wider
• Try at different pulse width to separate His bundle from myocardial
threshold
• Observe for changes in morphology at faster cycle length or with
extrastimulus, QRS gets wider
• Prolongation of the VA interval as the output is decreased generally
indicates loss of His bundle capture (requires VA conduction, cannot
be done in atrial fibrillation)

19. Saini et al. Circ Arrh Electrophysiol 2019; 12:e006808

22. 2V 1.25V
RV EGM
Lead I
Courtesy Dr. Pugal Vijayaraman

23. Jastrzbeski et al. Heart Rhythm 2019; (in press)

24. Liang et al. Heart Rhythm 2019; (in press)

25. Jastrzebski et al. Circ Arrh Electrophysiol 2019; 12:e007052

26. @SergioPinski

27. Jastrzebski et al. Circ Arrh Electrophysiol 2019; 12:e007052

28. 1.0V @ 1ms
RB capture only
Selective HBP
1.5V @ 1ms
RV and His capture
NonSelective-HBP
Baseline RBBB
1.25V @ 1ms
His capture only
Selective HBP

29. 1.75 V 1.50 V 1.25 V 1 V
NS-HBP with
LBBB correction
NS-HBP without
LBBB correction
S-HBP without
LBBB correction NSR with LBBB
Myocardial?

30. Starr et al. Heart Rhythm 2019; (in press)

31. His, RV and atrial capture
2.5V 2.0V
Atrial capture Loss of Atrial capture
3.5V 3.0V
Courtesy Dr. Pugal Vijayaraman

32. Atrial capture at site of His bundle
capture

33. @SergioPinski

34. Correction of RBBB
Sharma et al. Circ Arrh Electrophysiol 2018; 11:e006103