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Published on: December 11, 2017
Strauss-Defined LBBB Identifies Patients With Improved Outcomes After CRT-D: A Comparative Cohort Study
Athanasios Saplaouras1,2, Konstantinos Pamporis2, Panagiotis Mililis1
1Department of Cardiology, Onassis Hospital, Athens, Greece.
Insights
Stricter electrocardiographic criteria for left bundle branch block (LBBB) better predict response to cardiac resynchronization therapy (CRT) and improve patient outcomes. These findings aid in refining patient selection for CRT.
Area of Science:
- Cardiology
- Electrophysiology
- Heart Failure Management
Background:
- Left bundle branch block (LBBB) is a key predictor for cardiac resynchronization therapy (CRT) success in heart failure with reduced ejection fraction.
- Current electrocardiographic (ECG) definitions of LBBB vary, leading to uncertainty regarding their comparative effectiveness in predicting CRT response.
Purpose of the Study:
- To evaluate the association between different electrocardiographic definitions of LBBB and patient response to CRT.
- To determine if stricter LBBB criteria improve echocardiographic response and clinical outcomes in patients receiving CRT.
Main Methods:
- Retrospective analysis of 109 patients who received CRT-defibrillator implantation.
- Classification of baseline ECGs using six common LBBB definitions.
- Assessment of primary endpoint (echocardiographic response) and secondary endpoints (heart failure hospitalization, mortality) over a median follow-up of 30 months.
Main Results:
- The Strauss definition of LBBB was independently linked to significantly higher echocardiographic response rates (adjusted OR, 7.47).
- Strauss-defined LBBB demonstrated superior discriminative performance (AUC, 0.728).
- Patients meeting Strauss criteria had reduced heart failure hospitalizations (adjusted IRR, 0.30) and mortality (adjusted HR, 0.14).
Conclusions:
- Different LBBB definitions yield varying predictions for CRT response and clinical outcomes.
- Stricter ECG criteria for LBBB, such as the Strauss definition, more accurately identify patients likely to benefit from CRT.
- These results support the use of refined LBBB definitions to optimize patient selection for CRT, potentially improving treatment efficacy and patient prognosis.
Background:
Left bundle branch block (LBBB) is a well-established predictor of response to cardiac resynchronization therapy (CRT) in heart failure with reduced ejection fraction. However, several electrocardiographic definitions are used, and their relative significance remains unclear.
Hypothesis:
Stricter electrocardiographic definitions of LBBB are associated with improved response to CRT and more favorable clinical outcomes.
Methods:
We conducted a retrospective single-center cohort study including 109 patients who underwent CRT-defibrillator implantation. Baseline electrocardiograms were classified according to six commonly used LBBB definitions. The primary endpoint was echocardiographic response at 6 months, defined as a ≥ 10% absolute increase in left ventricular ejection fraction or a ≥ 15% reduction in left ventricular end-systolic volume. Secondary endpoints included heart failure hospitalization and all-cause mortality. Multivariable logistic, Cox, and negative binomial regression models were used, with odds ratios (OR), hazard ratios (HR), incidence rate ratios (IRR), and 95% confidence intervals (CI).
Results:
Strauss-defined LBBB was independently associated with echocardiographic response (adjusted OR, 7.47; 95% CI, 2.52-25.0; p < 0.001) and showed the highest discriminative performance (area under the curve, 0.728; 95% CI, 0.643-0.814). Strauss was also associated with lower heart failure hospitalization rates (adjusted IRR, 0.30; 95% CI, 0.13-0.64; p = 0.002) and reduced mortality (adjusted HR, 0.14; 95% CI, 0.02-0.99; p = 0.049). Median follow-up was 30 months (IQR 14-60).
Conclusions:
Different LBBB definitions are associated with differences in CRT response and outcomes. Stricter criteria appear to better identify patients more likely to respond, with more favorable outcomes. These findings may help refine patient selection for CRT.
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