Background: Electrical dyssynchrony is one of the main criteria for determining eligibility for cardiac resynchronization therapy (CRT). However, recent data support the use of mechanical rather than electrical dyssynchrony as the major criterion for receiving CRT.
Methods and results: Tissue Doppler imaging (TDI) is emerging as an indispensable tool for measuring and quantifying mechanical dyssynchrony in patients with advanced heart failure. TDI techniques for quantifying dyssynchrony include: tissue tracking, tissue velocity imaging, tissue synchronization imaging, and strain analysis. This review details the different techniques and discusses advantages and disadvantages of each. As TDI is incorporated into clinical practice, the ability to select patients who are most likely to improve after CRT should increase. TDI may also prove to be a useful tool for optimizing pacemaker settings in patients who do not improve after CRT.
Conclusion: Ongoing research trials will further define the role of TDI in the clinical management of patients with heart failure.