Selecting patients for cardiac resynchronization therapy: the fallacy of echocardiographic dyssynchrony

Area of Science:

• Cardiology
• Medical Devices
• Clinical Trials

Background:

• Cardiac resynchronization therapy (CRT) is established to reduce heart failure morbidity and mortality.
• International guidelines recommend QRS duration from electrocardiograms for CRT candidate selection based on large trials.
• Echocardiographic parameters have been proposed as superior but lack robust validation.

Purpose of the Study:

• To evaluate the clinical utility and validation status of echocardiographic parameters versus QRS duration for CRT patient selection.
• To address concerns regarding the use of unvalidated echocardiographic methods in clinical practice.
• To reaffirm the role of validated parameters in patient selection for life-saving therapies.

Main Methods:

• Review of international guidelines and landmark randomized trials for CRT patient selection.
• Analysis of proposed echocardiographic dyssynchrony parameters and their validation status.
• Assessment of reproducibility and predictive power of echocardiographic parameters in core laboratory settings.

Main Results:

• Over 30 echocardiographic dyssynchrony parameters have been proposed, most lacking validation.
• Prospective multicenter trials reveal significant variability, poor reproducibility, and limited predictive power of echocardiographic parameters.
• The electrocardiogram's QRS duration is the only parameter prospectively validated in landmark trials for CRT patient selection.

Conclusions:

• Echocardiographic parameters currently lack the necessary validation for routine CRT patient selection.
• Unvalidated echocardiographic methods should not be used to deny or select patients for CRT, avoiding risks and resource waste.
• The QRS duration, validated in landmark trials, remains the standard for identifying patients who will benefit from CRT.