Quantitative analysis of intraventricular dyssynchrony using wall thickness by multidetector computed tomography.

Area of Science:

• Cardiovascular Imaging
• Medical Diagnostics
• Heart Failure Research

Background:

• Mechanical dyssynchrony predicts response to cardiac resynchronization therapy.
• Cardiac computed tomography (CT) has not been previously used for dyssynchrony assessment.

Purpose of the Study:

• To assess the feasibility of cardiac CT for detecting left ventricular dyssynchrony.
• To compare dyssynchrony in heart failure (HF) patients with wide QRS, narrow QRS, and controls.

Main Methods:

• Electrocardiogram-gated contrast-enhanced 64-slice multidetector CT was performed on 38 subjects.
• Left ventricular boundaries were delineated to assess global and segmental dyssynchrony metrics.
• A novel dyssynchrony index (DI) was defined using changes in wall thickness over time.

Main Results:

• The CT-derived DI demonstrated high reproducibility (inter- and intraobserver ICC >/=0.94).
• Significant differences in DI were found between HF patients (wide QRS: 152 +/- 44 ms; narrow QRS: 121 +/- 58 ms) and controls (65 +/- 12 ms; p < 0.0001).
• DI correlated well with echocardiographic measures of dyssynchrony (2D: r=0.65, 3D: r=0.68).

Conclusions:

• Quantitative CT-derived DI is a highly reproducible metric for assessing global left ventricular dyssynchrony.
• CT-based DI effectively differentiates patients with dyssynchrony from age-matched controls.
• This method shows promise for evaluating patients with heart failure and wide QRS.