Aims: Left ventricular (LV) asynchrony assessment is mostly based on delays between regional myocardial velocity peaks. Regional function is barely considered. We propose apical transverse motion (ATM) as a new parameter integrating both temporal and functional information, which was tested in different conduction delays.
Methods and results: We examined 67 patients, 11 patients with post-infarct ischaemic left bundle branch blocks (iLBBB) and 25 patients with non-ischaemic left bundle branch block (nLBBB), 12 patients with right bundle branch block (RBBB), and 19 normal healthy volunteers (NORM). Longitudinal colour tissue Doppler data were used to calculate the total transverse apex motion (ATM), the transverse motion in the four-chamber view plane alone (ATM(4CV)) as well as regional myocardial deformation and conventional LV asynchrony parameters. Median ATM was 1.8 mm in NORM, 1.5 mm in RBBB (P = 0.999), 2.4 mm in iLBBB (P = 0.183), and 4.3 mm in nLBBB (P < 0.001 vs. NORM and RSB). ATM(4CV) behaved similarly, showed a good correlation with regional deformation data, and distinguished well between NORM and LBBB (AUC = 0.87).
Conclusion: Apical transverse motion is a new and simple parameter integrating information on both regional and temporal function inhomogeneities of the LV. It has a potential role in assessing LV asynchrony in the clinical context.