Fig.6a.6a. Along each spline read more of the basket, the interelectrode distance is 4�C5mm, while the distance between the splines can be estimated as<1cm at the equator of the basket and<4mm near its poles. Thus, this technique produces activation maps on an 8 �� 8 grid with a spatial resolution between 0.4 and 1cm. Figure 6 (A) Schematic depiction of the data acquisition in patients. The atria are presented in an anterior (frontal) view (see torso) with the left atrium shown in red and the right atrium in gray. Some of the contact electrodes, inserted into the atria to record ... Multisite electrograms are recorded with a temporal resolution of 1ms (filtered at 0.05�C500Hz at the source recording). From the resolution estimates above, we anticipated that this temporal and spatial resolution should distinguish activation events between neighboring electrodes.
AF data are exported digitally over a period of >30min. Multipolar AF signals are then analyzed by filtering electrograms to exclude noise and far-field signals, followed by determination of the activation times at each electrode over successive cycles to map electrical propagation in AF.21 Data from multiple institutions have used this system to show that human AF is perpetuated by a small number of rotors or focal sources.20, 38 Unexpectedly, these sources were found to be stable over a prolonged period of time (hours to months). Empirically, the mechanistic relevance of these sources to sustaining AF was recently demonstrated by brief targeted ablation only at sources (Focal Impulse and Rotor Modulation, FIRM), which acutely terminated AF with subsequent inability to induce AF (“non-reinducibility”) in a majority of patients.
20 Importantly, the long-term results of this novel ablation approach have recently been shown to be substantially better than conventional ablation of empirical anatomic targets without knowledge of the propagation patterns in any given individual.20 We will now examine the clinical data using isochronal maps as described above. As in our previous work, activation is visualized in panels where the RA is opened vertically through the tricuspid valve such that the left edge of each panel indicates the lateral tricuspid annulus and the right edge indicates the septal tricuspid annulus.12, 20, 39 A schematic illustration of the anatomical position of the electrode grid in the patients is shown in Fig.
Fig.6b.6b. In Figs. Figs.6c,6c, ,6d,6d, ,6e,6e, ,6f,6f, ,6g,6g, ,6h,6h, we plot a sequence of isochronal maps at ��I=55ms isochrone intervals Cilengitide in the right atrium of a patient with persistent AF. The activation map is visualized on an 8 �� 8 grid in (c) and has been bi-linearly interpolated in ((d)-(h)). The maps reveal a spatially localized rotor in the low RA (white line in (h)) with a coherent domain that is larger than the visualization domain. Thus, similar to rotor shown in Figs. Figs.