Table 1

Mechanical dyssynchrony parameters

ParameterDescriptionCut-off value
LVFT/RR15Percentage left ventricular filling time (LVFT) in relation to cardiac cycle length (RR) as measured by transmitral pulsed-wave Doppler.LVFT/RR ≤40%
LPEI15Left ventricular pre-ejection interval (LPEI), defined as the time interval between the beginning of QRS and the beginning of left ventricular ejection (onset of aortic flow by Doppler).LPEI ≥140 ms
LLWC15Intraventricular dyssynchrony left lateral wall contraction (LLWC), defined as the presence of overlap between the end of lateral wall contraction (M-Mode) and onset of LV filling (transmitral pulsed-wave Doppler).Any overlap
SPWMD16Septal to posterior wall motion delay (SPWMD) in parasternal M-mode.SPWMD ≥130 ms
TS-SD17 18Standard deviation of time from QRS to peak systolic velocity for 12 segments (6 basal+6 middle), as measured by tissue Doppler imaging.TS-SD ≥32 ms
TS-(lateral – septal)19Delay between time to peak systolic velocity of basal septal and basal lateral segments, as measured by tissue Doppler imaging.TS-(lateral–septal) ≥60 ms
DLC20 21Delayed longitudinal contraction (DLC) measured in the 6 basal left ventricular segments with a systolic contraction component in early diastole by tissue Doppler imaging≥2 basal segments