Tissue Doppler derived mechanical dyssynchrony does not change after cardiac resynchronization therapy.

Area of Science:

• Cardiology
• Biomedical Engineering
• Echocardiography

Background:

• Mechanical dyssynchrony assessed by tissue Doppler imaging (TDI) predicts cardiac resynchronization therapy (CRT) response.
• Limited research exists on TDI mechanical dyssynchrony changes post-CRT implantation.

Purpose of the Study:

• To evaluate changes in the extent and location of TDI mechanical dyssynchrony before and after CRT.
• To explore the relationship between dyssynchrony changes and CRT response.

Main Methods:

• 37 heart failure patients undergoing CRT implantation had TDI analysis pre- and post-CRT (up to 12 months).
• Regional dyssynchrony was defined as a >105 msec difference in time to peak systolic velocity between opposing LV walls.

Main Results:

• Pre-CRT, 76% of patients had significant mechanical dyssynchrony (18% septal, 10% LV free wall delay).
• Post-CRT, 78% still had significant dyssynchrony (17% septal, 12% LV free wall delay).
• No significant difference in dyssynchrony amount or location was observed pre- vs. post-CRT, despite 76% being responders.

Conclusions:

• TDI-derived mechanical dyssynchrony remains unchanged post-CRT, even with symptomatic and functional improvements.
• TDI appears to be of limited value for monitoring CRT response in heart failure patients.