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Updated: Jul 19, 2026

Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing

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

Left ventricular lead electrical delay predicts response to cardiac resynchronization therapy.

Jagmeet P Singh¹, Dali Fan, E Kevin Heist

¹Cardiac Arrhythmia Service, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA. jsingh@partners.org

|November 1, 2006

Summary

Measuring left ventricular (LV) lead electrical delay during cardiac resynchronization therapy (CRT) implantation helps predict patient response. Shorter delays indicate worse outcomes, guiding better lead placement for improved CRT effectiveness.

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Last Updated: Jul 19, 2026

Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing

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Published on: December 11, 2017

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Area of Science:

Cardiology
Biomedical Engineering
Electrophysiology

Background:

Intracardiac electrograms guide left ventricular (LV) lead placement in cardiac resynchronization therapy (CRT).
Predicting acute hemodynamic response and long-term outcomes using LV lead electrical delay is not well-established.

Purpose of the Study:

To assess intracardiac electrogram measurements during LV lead placement for predicting CRT response.
To evaluate the utility of LV lead electrical delay in forecasting acute and long-term CRT outcomes.

Main Methods:

Seventy-one patients undergoing CRT had electrogram and echocardiogram measurements.
LV lead electrical delay was measured intraoperatively as a percentage of QRS interval.
Hemodynamic response (dP/dt) and 12-month clinical outcomes (hospitalization/mortality) were assessed.

Main Results:

LV lead electrical delay weakly correlated with acute hemodynamic response (dP/dt) overall, but strongly in nonischemic cardiomyopathy.
Longer electrical delay was observed in acute responders with nonischemic cardiomyopathy.
Reduced LV lead electrical delay (<50% QRS duration) predicted worse long-term clinical outcomes across all patients.

Conclusions:

Intracardiac electrogram measurements of LV lead electrical delay are valuable during CRT implantation.
This measurement aids in predicting both hemodynamic response and long-term clinical outcomes.
Optimizing LV lead placement based on electrical delay may improve CRT efficacy.