Biventricular pacing significantly shortened the native QT interval compared with right ventricular pacing or sham operation in normal rabbit hearts (P=0.004).
Does biventricular pacing alter electrical remodeling compared to right ventricular pacing in normal hearts?
Biventricular pacing, unlike right ventricular pacing, directly shortens the native and paced QT intervals in a normal rabbit heart model, suggesting a direct effect on electrical remodeling.
p-value: p=0.004
BACKGROUND: Biventricular (BIV) pacing can improve cardiac function in heart failure by altering the mechanical and electric substrates. We investigated the effect of BIV versus right ventricular (RV) pacing on the normal heart. METHODS AND RESULTS: Male New Zealand White rabbits (n=33) were divided into 3 groups: sham-operated (control), RV pacing, and BIV pacing groups. Four weeks after surgery, the native QT (P=0.004) interval was significantly shorter in the BIV group compared with the RV or sham-operated groups. Also, compared with rabbits in the RV group, rabbits in the BIV group had shorter RV effective refractory period at all cycle lengths and shorter LV paced QT interval during the drive train of stimuli and close to refractoriness (P<0.001 for all comparisons). Protein expression of the KVLQT1 was significantly increased in the BIV group compared with the RV and control groups, whereas protein expression of SCN5A and connexin43 was significantly decreased in the RV compared with the other study groups. Erg protein expression was significantly increased in both pacing groups compared with the controls. CONCLUSIONS: In this rabbit model, we demonstrate a direct effect of BIV but not RV pacing on shortening the native QT interval as well as the paced QT interval during burst pacing and close to the ventricular effective refractory period. These findings underscore the fact that the effect of BIV pacing is partially mediated through direct electric remodeling and may have implications as to the effect of BIV pacing on arrhythmia incidence and burden.
Saba et al. (Thu,) conducted a other in Normal heart (n=33). Biventricular (BIV) pacing vs. Right ventricular (RV) pacing and sham-operated (control) was evaluated on Native QT interval (p=0.004). Biventricular pacing significantly shortened the native QT interval compared with right ventricular pacing or sham operation in normal rabbit hearts (P=0.004).