Associations between left bundle branch block with different PR intervals, QRS durations, heart rates and the risk of
Marc Meller Søndergaard1, Johannes Riis2, Karoline Willum Bodker2
1Department of Clinical Epidemiology, Aalborg University Hospital, Aalborg, Denmark marc-m-s12@hotmail.com.
Insights
Left bundle branch block (LBBB) increases heart failure (HF) risk. Prolonged QRS duration and higher heart rate significantly elevate this risk, with the highest risk observed when both parameters are elevated.
Area of Science:
- Cardiology
- Electrocardiography
- Heart Failure Research
Background:
- Left bundle branch block (LBBB) is a known risk factor for developing heart failure (HF).
- Understanding the specific electrocardiogram (ECG) parameters that modify this risk is crucial for risk stratification.
Purpose of the Study:
- To investigate the association between common ECG parameters (PR interval, QRS duration, heart rate) and the risk of new-onset heart failure (HF) in patients with LBBB.
- To identify specific ECG criteria that identify high-risk individuals within the LBBB population.
Main Methods:
- Utilized large-scale primary care ECG data from 2001-2011.
- Identified HF-naive patients with a first-time LBBB ECG.
- Employed Cox regression analysis to assess the association between PR interval, QRS duration, heart rate, and subsequent HF development over a 2-year follow-up.
Main Results:
- A significant interaction was observed between QRS duration and heart rate (p<0.01).
- Both prolonged QRS duration (≥150 ms) and higher heart rate (≥70 bpm) were independently associated with increased HF risk.
- Patients with both prolonged QRS duration and higher heart rate exhibited the highest risk (HR 3.17).
- No significant association was found between the PR interval and HF risk.
Conclusions:
- Prolonged QRS duration and elevated heart rate are significant predictors of HF development in patients with LBBB.
- The combination of prolonged QRS duration (≥150 ms) and higher heart rate (≥70 bpm) identifies individuals at substantially increased risk for HF.
- PR interval is not a significant predictor of HF in this LBBB cohort.
Aim:
Left bundle branch block (LBBB) is associated with an increased risk of heart failure (HF). We assessed the impact of common ECG parameters on this association using large-scale data.
Methods And Results:
Using ECGs recorded in a large primary care population from 2001 to 2011, we identified HF-naive patients with a first-time LBBB ECG. We obtained information on sex, age, emigration, medication, diseases and death from Danish registries. We investigated the association between the PR interval, QRS duration, and heart rate and the risk of HF over a 2-year follow-up period using Cox regression analysis.Of 2471 included patients with LBBB, 464 (18.8%) developed HF during follow-up. A significant interaction was found between QRS duration and heart rate (p<0.01), and the analyses were stratified on these parameters. Using a QRS duration <150 ms and a heart rate <70 beats per minute (bpm) as the reference, all groups were statistically significantly associated with the development of HF. Patients with a QRS duration ≥150 ms and heart rate ≥70 bpm had the highest risk of developing HF (HR 3.17 (95% CI 2.41 to 4.18, p<0.001). There was no association between the PR interval and HF after adjustment.
Conclusion:
Prolonged QRS duration and higher heart rate were associated with increased risk of HF among primary care patients with LBBB, while no association was observed with PR interval. Patients with LBBB with both a prolonged QRS duration (≥150 ms) and higher heart rate (≥70 bpm) have the highest risk of developing HF.
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