Spatial variance in the 12-lead ECG and mechanical dyssynchrony

Area of Science:

• Cardiology
• Electrophysiology
• Biomedical Engineering

Background:

• Electrical transmission disorders impair cardiac function by causing disorganized ventricular contraction and reduced mechanical efficiency.
• Cardiac resynchronization therapy (CRT) can correct mechanical dyssynchrony, but patient response rates are limited.
• Current CRT selection criteria, based on QRS duration, fail to identify all patients who could benefit.

Purpose of the Study:

• To evaluate electrocardiogram spatial variance as a novel predictor of mechanical dyssynchrony.
• To compare the efficacy of spatial variance against QRS duration in identifying mechanical dyssynchrony.

Main Methods:

• Prospective collection of 47 simultaneous electrocardiograms and 2D speckle tracking echocardiograms.
• Measurement of left ventricular mechanical dispersion using strain echocardiography.
• Electrocardiographic analysis of variance, including QRS complex and repolarization phases, using digital superposition.

Main Results:

• Spatial variance markers, combining depolarization and repolarization, showed a high area under the curve (AUC = 0.97) for predicting mechanical dispersion.
• QRS duration demonstrated a significantly lower AUC (0.64) in predicting mechanical dispersion.
• Electrocardiogram spatial variance is a more accurate marker of mechanical dyssynchrony than QRS duration.

Conclusions:

• Electrocardiogram spatial variance, integrating depolarization and repolarization data, surpasses QRS duration as a predictor of left ventricular mechanical dispersion.
• This finding may lead to improved patient selection for cardiac resynchronization therapy.