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Table 1 Echocardiographic parameters of myocardial asynchrony used to determine the presence of relevant asynchrony.

From: Implementation of seven echocardiographic parameters of myocardial asynchrony to improve the long-term response rate of cardiac resynchronization therapy (CRT)

Parameter Definition Cut-off Ref. Example
Interventricular electromechanical delay (IMD) Interventricular electromechanical delay between pulmonary and aortic outflow. Measured as the time between the onset of the QRS to onset of aortic flow vs. QRS to onset of pulmonary flow ≥ 40 ms 6 1
Septal-to-posterior wall motion delay (SPWMD) M-mode: the interval between the maximum contraction of the septum and the maximum contraction of the left ventricular posterior wall ≥ 130 ms 14, 15 2
Ts-12 Maximum difference in Ts between any 2 of 12 LV segments ≥ 104 ms 16 3
Ts-12-SD Standard deviation of the time to peak myocardial velocity (Ts) of the 12 LV segments ≥ 34.4 ms 16 4
Septal-to-lateral delay in peak systolic velocity (TDId) Delay between the basal septal and basal lateral Ts, assessed with color-coded TDI ≥ 60 ms 17 5
LVEMD aortic pre-ejection delay measured as the time between the onset of the QRS to beginning aortic flow > 140 ms 6 6
Delayed longitudinal contraction (DLC) Number of LV segments with DLC assessed by tissue tracking in the apical 4-chamber, 2-chamber and long-axis view ≥ 2 18 7