PMC1253517_01
PMC1253517_02
ECG morphology at different AV intervals. Different ECG morphology corresponding to each programmed AV interval, including the basal ECG of the patient without ventricular pacing. With the progressive shortening of the programmed AV interval, QRS morphology (mainly in V1 lead) changes from LBBB to a RBBB-like trace at the shortest AV interval, corresponding to a complete capture of both ventricles by LV pacing. Different degrees of ventricular fusion between RV spontaneous activation and LV pacing can be seen for AV intervals programmed in the range 200-120 ms.
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PMC1253517_02_1476-7120-3-29-1.jpg
F1
PMC1253517_03
Echocardiographic parameters at each step of AV interval. Ejection fraction (EF%), diastolic filling time (DFT), E wave deceleration time (DT), Aortic Velocity Time Integral (Aortic VTI), Myocardial performance index (MPI).
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F2
Within an AV interval of 200 and 120 ms we choose to program the AV interval at an intermediate value of 160 ms (figure 2).