Real time three-dimensional echocardiography in assessment of left ventricular dyssynchrony and cardiac resynchronization therapy

Left ventricular (LV) mechanical dyssynchrony is an important prognostic marker for higher morbidity and mortality in patients with symptomatic heart failure. However, the response rate to resynchronization varies among patients meeting current guidelines for Cardiac resynchronization therapy (CRT). Two-dimensional echocardiography and Doppler-based techniques have shown variable results in the assessment of LV dyssynchrony. There is an obvious need for a noninvasive tool that can reliably measure LV dyssynchrony. Accurate prediction of response to CRT will improve patient selection for such therapy. Real time three-dimensional echocardiography (RT3DE) is a novel noninvasive imaging modality that has been recently used in quantitative evaluation of global and regional LV function. A number of published studies have described the use of RT3DE in the measurement of LV dyssynchrony in patients with normal or reduced LV function. The systolic dyssynchrony index derived from RT3DE has been used to quantify LV dysynchrony and to evaluate and predict the response to CRT. This review will discuss the recently published data regarding the role of RT3DE in CRT.