Posterior Electrical Axis Deviation Is Associated With Future Development of Left Bundle Branch Block

doi:10.1016/j.jacadv.2026.102842

Arrhythmias & electrophysiologyCohort study

Posterior Electrical Axis Deviation Is Associated With Future Development of Left Bundle Branch Block

JACC AdvPublication date not resolved

Retrospective data from 35,749 UK Biobank participants
excluding those with overt cardiovascular disease
Kaplan-Meier analysis and Cox proportional hazards models adjusted for age, sex, hypertension, left ventricular ejection fraction and QRS duration (QRSd)

Authors' conclusion

Posterior deviation of the transverse electrical axis complements QRSd in identifying individuals at risk of developing LBBB. These findings suggest that the electrical axis is capturing early conduction disease and may contribute to risk stratification of future development of LBBB.

Study context

Population: UK Biobank participants without overt cardiovascular diseaseUK Biobank participants analyzed, median follow-up 6 years · developed left bundle branch block (LBBB) 41 · event-free population 35,688
Participants: 35,749 participants

Exposure: Associations with axis metrics and LBBB development
developed LBBBn = 41
event-free populationn = 35,688
Outcome: LBBB development
Follow-up: Median of 6 years

Main finding

As reported in the abstract

Hazard ratio (95% CI)P value

lower φElectricalmultivariable analysis; significantly associated with incident LBBB

0.73(0.56–0.94)

P = 0.014

both high QRSd and low φElectricalfour-fold increased risk

4.09(1.84–8.99)

P < 0.001

Observational data: associations, not effects.

Further findings

Age · older

P < 0.001

developed LBBB69.2 years

event-free population64.0 years

Hypertension · more likely to have hypertension

P < 0.001

developed LBBB31.7%

event-free population11.6%

°

Outcome	developed LBBB	event-free population	P value
φElectrical · significantly lower (more posterior) electrical axis	69.1	80.3	P = 0.01

Cohort characteristics

age: 63.4 ± 7.6 years
male: 45%
QRSd: 87.4 ± 12.8 ms
median follow-up: 6 years

Original publication

Posterior Electrical Axis Deviation Is Associated With Future Development of Left Bundle Branch Block. JACC Adv. doi:10.1016/j.jacadv.2026.102842

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Summarised from the published abstract; every number is checked against it