(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.