His bundle pacing can lead to complications that depend on lead positioning and hardware. Possible issues include high capture thresholds that may worsen over time, disease progression distal to the pacing site, atrial oversensing, and poor ventricular sensing. Careful evaluation at implant and thoughtful programming can prevent many complications, though some patients still experience issues like increased thresholds. Most patients do well long-term with His bundle pacing when complications are managed appropriately.

1. His Bundle Pacing: Which are
the Reported Complications &
How to Avoid Them
Sergio L. Pinski, MD, FHRS
Cleveland Clinic Florida
Weston, FL, USA
@SergioPinski

2. Complications of His Bundle Pacing
• Dependent on the hardware used (ie, Medtronic 3830 lead)
• Dependent on the lead position in the annulus (e.g, large A signal and
small V signal)

3. B
TV
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 Tricuspid Valve

4. • 4.1 FR lead body diameter
• Bipolar
• Fixed screw helix
• Steroid eluting
• Polyurethane outer insulation
• Cable inner conductor

5. Zanon et al. Europace 2018 (in press)

8. Bhatt et al. JACC Clin Electrophysiol 2018;4:1397

9. Possible Complications
• Higher capture threshold, trade-off between safety margin and
battery longevity
• Possible progression of disease distal to the site of pacing resulting in
block
• Atrial oversensing
• Poor ventricular sensing
• Atrial capture
• No specific devices or algorithms, need to adapt.

10. @SergioPinski
Non-selective to selective His capture during threshold testing

11. Non selective His capture to myocardial capture during threshold testing

12. 2V 1.25V
RV EGM
Lead I
Courtesy Dr. Pugal Vijayaraman

13. @SergioPinski

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

15. Higher capture thresholds
Huang et al. Heart 2018; (in press) Vijayaraman et al. Heart Rhythm 2018; 15:696

16. High threshold
• A high threshold at implant > a higher threshold at follow-up. Do not
accept a threshold at implant > 2.5 V at 1 ms
• Exception is His current injury. Threshold may be initially high, but drops
during the case. Predicts excellent long-term outcome
• Red flags during implant:
• Large difference between unipolar and bipolar threshold
• Lead that is too positional, threshold changes a lot with more or less slack
• Too low impedance
• Loss of 1:1 His bundle pacing with rapid pacing
• Even so, some patients with good implant thresholds develop high
threshold in follow up. Fibrosis, microdislodgment, excessive slack

17. His current of injury – Recorded in ~ 35%
of pts

18. His current of injury
Vijayaraman et al. PACE 2015;38:540

19. @SergioPinski

20. @SergioPinski

21. Rate-dependent His block
@Marek_Jastrz_EP

22. High Threshold
• > 2.5 V at 1 ms 20-35% at follow-up
• Lead revision in 5-10 %

23. Management of High Threshold
• Minimize V pacing
• Turn off, use back up lead
• Accept high output and accelerated battery drain
• Accept septal pacing (high His, low myocardial threshold)
• Lead revision

26. Back up RV lead
• At initial implant: more likely to use in infranodal block, selective HBP,
simultaneous AV nodal ablation, higher threshold, early on in experience.
Use a CRT device, His in LV channel.
• During upgrade from conventional dual-chamber pacing. Better to keep the
lead, but you don’t have to
• Always with defibrillator. If His lead to atrial channel (ie, permanent atrial
fibrillation with complete heart block) you can only pace bipolar.
• Connecting the His lead in the LV port of a CRTD allows tip-to-coil pacing
which has lower threshold
• No need to worry about sensing in the His lead, which will occur via RV
lead

27. Programming with back-up RV lead
• If 3 leads, His lead in LV channel. Program DDD(R) LV 80 ms ahead, the
back-up RV pulse will fall in refractory. With current MDT RV pacing
cannot be turned off. Chronically, output can be minimized to save
battery.
• If 2 leads (i.e., permanent atrial fibrillation with complete heart
block), His lead in atrial channel. Program DVI(R) (or DDI(R) with low
atrial sensitivity). Program AV delay long enough to allow inhibition
and disable safety pacing.

32. Progression of Disease
• Septal inflammation/scarring (e.g, sarcoidosis)
• Future TAVR or SAVR
• Future AV nodal ablation (+++ if needed from the left side)

33. @SergioPinski

35. Vijayaraman et al. Europace 2017;19:iv10

36. @SergioPinski

37. @SergioPinski

38. Sensing (applies to DDD or VVI
pacemaker)
• Best assessed at the time of implant
• Unipolar or bipolar configuration
• Acceptable R wave amplitude 1 - 3mV
• More important is size of A signal in relationship to the V signa;
• May vary with patient position. Enough slack minimizes changes in
thresholds with position
• Different conducted beat vs. ectopic
• Use pacemakers with high sensitivity/autogain

39. Sugrue et al. Card Electrophysiol Clin 2018;10;461

40. Oversensing of P waves
@SergioPinski

41. Oversensing of P waves
@SergioPinski

42. Spurious VT due to Oversensing of P waves

43. A
H
V
A
H
V
BIPOLAR Sensitivity 0.5 mV
H
V
H
V
UNIPOLAR Sensitivity 1.0 mV
Far-field Atrial Oversensing in Sinus Rhythm
Courtesy Dr. Pugal Vijayaraman

44. Unipolar and Bipolar EGMs
Courtesy Dr. Pugal Vijayaraman

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

51. Atrial capture at site of His bundle capture

53. Conclusions
• His bundle pacing creates unique challenges due to the lead location at
the AV annulus
• Complications are still more common than with standard RV pacing.
Most can be prevented by careful evaluation at implant.
• Complications not expected at implant can often be circumvented by
thoughtful programming
• Majority of patients with permanent HBP do well with no significant
issues
• Understanding the nuances and limitations associated with HBP is
crucial for long term success

54. •Slides will be available for download at
www.slideshare.net/sergiopinski
•I recommend following the Twitter hashtag
#dontdisthehis to learn, present, comment
about His bundle pacing