New approach for rotational dyssynchrony using three-dimensional speckle tracking echocardiography

Area of Science:

• Cardiology
• Medical Imaging
• Echocardiography

Background:

• Two-dimensional speckle tracking echocardiography (2DSTE) has limitations in assessing global rotational dyssynchrony due to its inability to evaluate mid-wall rotation.
• Three-dimensional speckle tracking echocardiography (3DSTE) offers a novel approach to investigate left ventricular (LV) global rotational dyssynchrony.

Purpose of the Study:

• To investigate the role of LV torsion in the long-term effects of cardiac resynchronization therapy (CRT) using 3DSTE.
• To evaluate the relationship between rotational dyssynchrony, measured by the torsion delay index, and CRT response.

Main Methods:

• 43 patients (12 CRT responders, 14 CRT nonresponders, 17 controls) were assessed using 3DSTE.
• Regional torsion and rotation were analyzed during CRT-off and CRT-on states.
• Key parameters calculated included global peak twist, Δ global peak twist, and the torsion delay index (a measure of rotational energy loss due to dyssynchrony).

Main Results:

• Global peak twist significantly improved in CRT responders compared to nonresponders after CRT-on (P=0.029).
• The torsion delay index during CRT-off was significantly higher in responders than in nonresponders and controls (P=0.010, P=0.004).
• The torsion delay index during CRT-off significantly correlated with the improvement in global peak twist (Δ global peak twist) (r=0.503, P=0.009).

Conclusions:

• 3DSTE can effectively assess LV global rotational dyssynchrony and its impact on CRT outcomes.
• The torsion delay index, calculable only by 3DSTE, is a valuable predictor of long-term CRT response.
• Improvement in LV global peak twist, a mechanism of CRT, is linked to the degree of native conduction rotational dyssynchrony.