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Updated: Jun 12, 2026
Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing
Published on: December 11, 2017
Longer Baseline Left Ventricular Activation Time Is Associated With Lower Mortality and Lower Risk of Heart Failure
Sofia Marinko1, Pyotr G Platonov1,2, Rasmus Borgquist1
1Department of Cardiology, Clinical Sciences, Lund University, Lund, Sweden.
Insights
A longer baseline left ventricular activation time (LVAT) measured by electrocardiogram (ECG) is linked to better outcomes for cardiac resynchronization therapy (CRT). This finding may improve patient selection for CRT.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Devices
Background:
- Cardiac resynchronization therapy (CRT) effectiveness varies among patients.
- Current selection criteria for CRT may not identify all suitable candidates.
- Left ventricular activation time (LVAT) is a potential marker for CRT response.
Purpose of the Study:
- To investigate the association between pre-implant LVAT and clinical outcomes in patients receiving CRT.
- To determine if LVAT measured by standard 12-lead ECG can predict CRT response.
Main Methods:
- Retrospective analysis of 415 patients who underwent CRT implantation.
- Measurement of LVAT from pre- and post-implant digital ECGs.
- Primary endpoint: heart failure hospitalization or all-cause mortality.
Main Results:
- A longer pre-implant LVAT was associated with a reduced risk of the primary endpoint in patients with left bundle branch block (LBBB).
- Post-implant LVAT did not show a significant association with clinical outcomes.
- The study included patients with a median age of 72.8 years and LVEF of 27.5%.
Conclusions:
- Baseline LVAT may serve as a predictor of CRT response.
- A longer pre-implant LVAT is associated with lower heart failure hospitalization and mortality risk.
- Further prospective studies are warranted to validate LVAT in CRT patient selection.
Introduction:
Many patients do not benefit from cardiac resynchronization therapy (CRT) with current guideline parameters. The objective of this study was to examine the relationship between left ventricular activation time (LVAT) from the standard 12-lead surface electrocardiogram (ECG) and clinical outcome from CRT.
Methods:
A retrospective study was performed on patients receiving CRT implants at a large-volume tertiary care center. Digital ECGs were collected pre- and post-implant. LVAT was defined as the time from QRS onset to maximum deflection in lead V6. The primary combined endpoint was heart failure hospitalization or all-cause mortality.
Results:
The study group comprised 415 patients (median age [Q1-Q3] of 72.8 years [65.1-78.7], 77.3% male, median baseline LVEF 27.5% [22-30], and 43.1% with ischemic heart failure etiology) who were followed for up to 7.6 years (median 2.8). LVAT was measured pre-implant (median 78 ms [66-98]) and post-implant (median 88 ms [74-106]). In Kaplan-Meier analysis, a longer pre-implant LVAT was associated with a reduced risk of reaching the primary endpoint in patients with LBBB (log-rank p = 0.046). Post-implant LVAT was not associated with clinical outcome.
Conclusion:
Our results show that a longer baseline LVAT is associated with a lower risk of heart failure hospitalization and all-cause mortality. This relationship was of borderline significance in multivariable analysis. Prospective trials would be useful to further explore the potential role of pre-implant LVAT in patient selection for CRT.
