(6)
Badke et al., explained the mechanism of a reduced rate of change of LV pressure (dP/dt) and the asynchronous pattern of contraction that occur with apical pacing. (7)
The early contraction of paced area occurs at the time of low load, but then later in systole it is stretched as the final contraction occurs in lateral wall. (7) Moreover, the stroke volume reduced significantly as the myocardium contracts in asynchronous pattern and this leads to right shift of the LV end-systolic pressure - volume curve. Discrepancy between the relaxation of early- and late stimulated areas shortens the filling time of LV. Thus, apical of RV apex causes ventricular dyssynchrony, impairment of both systolic and diastolic ventricular functions, elevated wall stress and energetic inefficiency. (8) In this study we aimed to assess LV regional and global systolic longitudinal strain by 2D STE in different pacing modes in patients with dual chamber pacemaker.