Quantification of Radial Mechanical Dyssynchrony in Patients with Left Bundle Branch Block and Idiopathic Dilated Cardiomyopathy Without Conduction Delay by Tissue Displacement Imaging

Cardiac resynchronization therapy has made assessment of cardiac dyssynchrony clinically important. To test the hypothesis that echocardiographic displacement imaging can quantify dyssynchrony, 22 patients with left bundle branch block (LBBB), 14 with idiopathic dilated cardiomyopathy (IDC) without electrical conduction delay, and 22 normal controls were studied using radial angle-corrected displacement imaging. Control subjects had coordinated wall movement, whereas patients with LBBB had dyssynchrony characterized by early inward anteroseptal movement and markedly delayed posterior, lateral, or inferior regions (157 +/- 99 ms; p <0.001 vs normal). An interesting subset of patients with IDC without conduction delay (36%) had dyssynchrony with anteroseptal to posterior wall delays of 169 +/- 56 ms (p <0.001 vs normal), similar to patients with LBBB.