Electrocardiographic imaging
Noninvasive cardiac mapping was obtained from 14 patients in whom recent
(<3 months) cardiac computed tomography or magnetic resonance
images were available. Two patients were excluded (one due to atrial
fibrillation during mapping and one because of insufficient image
quality). As expected, LV activation was delayed in comparison to RV
activation at intrinsic rhythm, while CRT activation led to a more
synchronous activation pattern in the LV (Figure 4 ). At
intrinsic rhythm, the biventricular activation time was 90±17 ms. Both
FOI configurations achieved the shortest biventricular activation times
(72±14 ms and 77±18 ms for SPP-FOI and MPP-FOI, respectively), and they
were significantly shorter than the activation times during intrinsic
rhythm (P=0.005 and P=0.04, respectively). No differences were observed
between the activation times during intrinsic rhythm and the MPP
strategy alone (83±19 ms, P=0.30) (Figure 5 ). The biventricular
activation times according to ECGI showed a good correlation with the
QRS durations determined via ECG (r = 0.58; Figure 6 ).