Background
Inspite of the fact that the life quality improved for most patients
with a cardiac pacemaker implant, the pacing induced left bundle branch
block pattern can result in changes of the structure, function and
hemodynamic of the heart.
Methods: This study was performed on 30 patients with history
of dual chamber pacemaker implantation more than 6 months duration and
30 healthy volunteers as controls. Conventional and 2-D speckle tracking
echocardiography were performed to evaluate the LV global and regional
systolic longitudinal strain in different pacing modes.
Results: Pacemaker programming from atrial sensed-ventricular
paced mode (AS-VP mode) to atrial paced-ventricular paced mode (AP-VP)
showed a significant decrease in global LV longitudinal systolic strain
(P value <0.05). Moreover, programming to asynchronous
ventricular pacing (VVI mode) demonstrated a further significant
reduction of global LV LSS when compared to other pacing modes (P value
<0.05).
Conclusion: Permanent RV apical pacing leads to marked changes
of LV systolic function. Moreover, atrial pacing and asynchronous
ventricular pacing may cause more deterioration of LV global and
regional systolic longitudinal strain detected by 2-D speckle tracking
echocardiography.
Key words: pacing, strain, speckle tracking echocardiography