Abstract 712: Recruitment, A New Index for the Assessment of Left Ventricular Dyssynchrony Using Two-Dimensional Speckle Tracking Echocardiography
Background: Echocardiographic assessment of left ventricular dyssycnhrony (LVD) may be unreliable in patients with severely depressed LV systolic function due to the flat profile of strain/velocity curves that makes accurate determination of waveform peaks difficult. Recruitment is a new LVD index that accounts for both the timing and degree of strain using 2D speckle tracking echocardiography.
Methods: To determine its potential, we acquired mid-papillary LV short axis and apical 4-chamber views in 40 normal subjects, 26 patients with dilated cardiomyopathy (DCMP) and 12 patients with left bundle branch block (LBBB). Regional radial (RS), circumferential (CS) and longitudinal strain (LS) waveforms were created using 2D speckle tracking software (Philips, QLAB). Recruitment waveforms were derived from calculations of strain within a region of interest, and from which two parameters were obtained: recruitment height and recruitment duration. Recruitment height reflects % of segments that surpasses a pre-determined threshold of 2D strain at a milestone. Recruitment duration calculates time differences between the earliest and most delayed segments that surpass this threshold from segments meeting the strain criterion.
Results: 6 LBBB and 4 DCMP in the short axis view and 2 DCMP in the apical 4-chamber view were excluded for the analysis due to poor tracking. 10% criterion and 100% milestone were used. Results are shown in figure⇓. Recruitment height and duration successfully discriminated among three groups especially using LS.
Conclusions: Recruitment may become a useful index for the assessment of LVD as it accounts for both the timing and degree of strain.