Key result
Left axis deviation in patients with left bundle branch block was associated with a higher rate of major adverse cardiac events compared to a normal axis (5.5% vs. 1.3%), although this prognostic value was attenuated in multivariable analysis (HR 4.117, p=0.058).
Why the study?
Does left axis deviation predict major adverse cardiovascular events in asymptomatic patients with left bundle branch block?
Cohort (n=314)
No
Does left axis deviation predict major adverse cardiovascular events in asymptomatic patients with left bundle branch block?
Hazard Ratio: 4.117 (95% CI 0.955–17.743)
Absolute Event Rate: 5.5% vs 1.3%
p-value: p=0.058
Concomitant left axis deviation in asymptomatic patients with left bundle branch block is associated with greater myocardial scarring and may indicate a poorer prognosis for major adverse cardiovascular events.
Should not yet guide risk stratification in asymptomatic LBBB; leaves open independent prognostic value after multivariable adjustment.
BACKGROUND AND OBJECTIVES: Left bundle branch block (LBBB) with left axis deviation (LAD) has a worse prognosis than LBBB with a normal axis, and myocardial dysfunction has been suggested as a cause of left axis deviation. This study investigated the prognostic significance of the QRS axis in patients with LBBB and analyzed its relationship with the amount of myocardial scarring. SUBJECTS AND METHODS: A total of 829 patients were diagnosed with LBBB at Seoul National University Hospital from October 2004 to June 2014. Of these, 314 who were asymptomatic and had no previous history of cardiac disease were included in the present study. Myocardial scarring was calculated using the Selvester QRS scoring system, and LAD was defined as a QRS axis between -180° and -30°. RESULTS: Of the total patients, 91 (29%) had LAD, and patients were followed for a median of 30 months. During follow-up, two patients were hospitalized for de novo heart failure, four had pacemaker implants, and 10 died. There was a significant inverse correlation between myocardial scar score and the QRS axis (r=-0.356, p<0.001). Patients with concomitant LAD had a higher rate of major cardiac adverse events compared with patients with a normal axis (5.5% vs. 1.3%, log-rank p=0.010); the prognostic value was attenuated in multivariable analysis (hazard ratio 4.117; 95% confidence interval 0.955-17.743; p=0.058). CONCLUSION: Concomitant LAD is an indicator of poor prognosis for patients with LBBB and may be associated with greater myocardial scarring.
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Park et al. (2016) conducted a cohort in Left bundle branch block (n=314). Left axis deviation vs. Normal QRS axis was evaluated on Major adverse cardiovascular event (MACE) (HR 4.117, 95% CI 0.955-17.743, p=0.058). Left axis deviation in patients with left bundle branch block was associated with a higher rate of major adverse cardiac events compared to a normal axis (5.5% vs. 1.3%), although this prognostic value was attenuated in multivariable analysis (HR 4.117, p=0.058).
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