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Data concerning the left anterior hemiblock (LAHB) are scarce, which suggested various results from different regions. We conducted a perspective study to investigate the prevalence, incidence and predictors of newly acquired, and the all-cause mortality of LAHB based on Chinese population.
A total of 101510 participants from Kailuan study examined 2006-2007 and performed health examinations biennially until Dec 31 2014. We identified the isolated LAHB by using a rest standard 12-leads ECG according to ECG features as Minnesota code 7-7. We integrated the detail diagnosis on ECG recording till the 4rd visit (2012-2013). Detailed information on vital status was collected during the whole period. The all-cause of death was acquired from medical insurance database and death certificate, with further confirmation by their family members or local community health center. Logistic regression was used to estimate the risk factors of LAHB. Cox regression and Kaplan-Meier survival analyses were used to calculate multivariable-adjusted hazard ratios for outcome associated with presence of LAHB.
The baseline prevalence of LAHB is 0.7% (n=661) and significantly higher among men and aging participants (P<0.01). Obesity (9.7% vs 7.9%), history of myocardial infarction (3.9% vs 1.3%) were more prevalent in LAHB group (P<0.05). Prevalence and incidence of LAHB increased with age (gender adjusted P value<0.001). The prevalence of LAHB was higher in men (0.79% in men vs.0.15% in women, age adjusted P value<0.001), Likewise, the incidence of LAHB was significantly higher in men (1.05 per 1000 person-year in men vs. 0.25 per 1000 person-year in women, age adjusted P value<0.001). During a median of 6.3 years follow-up, among 97049 participants those free of bundle branch block at baseline, 417 (0.43%) participants developed to LAHB. In full-adjusted analysis, significant predictors of newly acquired LAHB include increased age (OR 1.045, 95%CI 1.036-1.054), male gender (OR 4.033 95%CI 2.726-5.966) and hypertension (OR 1.285, 95%CI 1.051-1.571). During a median of 7.9 years follow-up, no correlation was detected between the presence of LAHB and all-cause mortality in general population, no significant showed in the age/sex stratified analysis.
In this cohort study, the advancing age, male gender and hypertension were independent predictors of LAHB. The isolated LAHB might not have a poor prognostic value in Chinese population.