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Evaluation of mortality in bundle branch block patients from an electronic cohort: Clinical Outcomes in Digital
Gabriela M M Paixão1, Emilly M Lima1, Paulo R Gomes1
1Telehealth Network of Minas Gerais, Hospital das Clínicas and Faculdade de Medicina, Universidade Federal de Minas Gerais, Avenida Professor Alfredo Balena 110, Belo Horizonte, Minas Gerais 30130-100, Brazil.
Insights
Right bundle branch block (RBBB) and left bundle branch block (LBBB) increase overall mortality risk. LBBB is linked to higher cardiovascular mortality, and women with RBBB face greater all-cause death risk.
Area of Science:
- Cardiology
- Public Health
- Epidemiology
Background:
- Left bundle branch block (LBBB) is a known risk factor for mortality.
- The prognostic significance of right bundle branch block (RBBB) in the general population remains debated.
- This study investigates the mortality risks associated with RBBB and LBBB in a large Brazilian cohort.
Purpose of the Study:
- To evaluate the association between RBBB and LBBB and overall mortality.
- To assess the link between RBBB and LBBB and cardiovascular mortality.
- To explore potential sex differences in mortality risk for RBBB.
Main Methods:
- Retrospective analysis of a large electronic cohort of primary care patients in Brazil (2010-2017).
- Data linkage between digital ECGs and national mortality information systems.
- Cox regression analysis was used to estimate hazard ratios for mortality, adjusting for covariates.
Main Results:
- In a cohort of over 1.5 million patients, both RBBB (HR 1.32) and LBBB (HR 1.69) were associated with increased overall mortality.
- LBBB was significantly associated with higher cardiovascular mortality (HR 1.77).
- Women with RBBB exhibited a higher risk of all-cause death compared to men.
Conclusions:
- Both RBBB and LBBB are associated with an elevated risk of overall mortality.
- LBBB is a significant predictor of cardiovascular mortality.
- RBBB poses a greater all-cause mortality risk for women than for men.
Background:
Left bundle branch block is recognized as a marker of higher risk of death, but the prognostic value of the right bundle branch block in the general population is still controversial. Our aim is to evaluate the risk of overall and cardiovascular mortality in patients with right (RBBB) and left bundle branch block (LBBB) in a large electronic cohort of Brazilian patients.
Methods:
This observational retrospective study was developed with the database of digital ECGs from Telehealth Network of Minas Gerais, Brazil (TNMG). All ECGs performed from 2010 to 2017 in primary care patients over 16 years old were assessed. The electronic cohort was obtained by linking data from ECG exams (name, sex, date of birth, city of residence) and those from national mortality information system, using standard probabilistic linkage methods (FRIL: Fine-grained record linkage software, v.2.1.5, Atlanta, GA). Only the first ECG of each patient was considered. Clinical data were self-reported, and ECGs were interpreted manually by cardiologists and automatically by the Glasgow University Interpreter software. Hazard ratio (HR) for mortality was estimated using Cox regression.
Results:
From a dataset of 1,773,689 patients, 1,558,421 primary care patients over 16 years old underwent a valid ECG recording during 2010 to 2017. We excluded 17,359 patients that didn't have a valid QRS measure from the Glasgow program and 11,091 patients from the control group that had QRS equal or above 120 ms and were not RBBB or LBBB. Therefore, 1,529,971 were included (median age 52 [Q1:38; Q3:65] years; 40.2% were male). In a mean follow-up of 3.7 years, the overall mortality rate was 3.34%. RBBB was more frequent (2.42%) than LBBB (1.32%). In multivariate analysis, adjusting for sex, age and comorbidities, both patients with RBBB (HR 1.32; CI 95% 1.27-1.37) and LBBB (HR 1.69; CI 95% 1.62-1.76) had higher risk of overall mortality. Women with RBBB had an increased risk of all-cause death compared to men (p < 0.001). Cardiovascular mortality was higher in patients with LBBB (HR 1.77; CI 95% 1.55-2.01), but not for RBBB.
Conclusions:
Patients with RBBB and LBBB had higher risk of overall mortality. Women with RBBB had more risk of all-cause death than men. LBBB was associated with higher risk of cardiovascular mortality.
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