Page 173 - YORAM RUDY BOOK FINAL

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Examples of reentrantVT

Figure 5.31 and Movie 9 (https://youtu.be/qY7jdBXjoR8) show an example of reentrant VT
related to a ventricular scar . This patient had an extensive inferoseptal scar from a previous
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inferior wall myocardial infarction (see single-photon emission computed tomography (SPECT)

image in Figure 5.31C) He had a slow, hemodynamically tolerated VT, occasionally interrupted
by sinus capture (SC) beats (see ECG lead V2 in inset to Figure 5.31B; [B] is a VT beat, [A] is an SC
beat). Earliest activation of the VT beat (Figure 5.31B) is near the scar border in the inferior basal
septum (scar is depicted in red in the LV and inferior views). The main reentrant wave front

propagates clockwise with a high curvature (white arrows) and completes the beat by reentering
the area of earliest activation. Immediately before the VT beat, presystolic activation is detected
near the inferior scar border where the VT beat begins (the “exit site”; see Movie 9, https://youtu.
be/qY7jdBXjoR8). A second wave front (pink arrows) propagates toward the base, where it turns

slowly counterclockwise into the RV. It then propagates to the inferior base, back toward the scar.
In the inferobasal septal region, ECGI-reconstructed EGMs were low in amplitude and highly
fractionated, consistent with scar substrate. Invasive catheter mapping confirmed the ECGI
findings. EP study during VT confirmed inferior septal origin and reentrant mechanism. Ablation

in this region terminated the VT.

Figure 5.32 shows ECGI during a monomorphic VT from an infiltrative cardiomyopathy in
the lateral LV 329 . The figure shows activation patterns for three consecutive VT beats (T1, T2, and

T3) in three views. ECGI identified two distinct areas of early epicardial activation (white asterisks)
which varied slightly from beat to beat. The propagation pattern varied depending on the relative
contribution of the two sources, but for all beats, the wave front turned clockwise and propagated
toward the LV lateral base with a high degree of curvature, where it reached a line of block in the

inferolateral base.

Figure 5.33 top panels present an anterior scar-related VT with a double loop reentry
pattern . We also applied ECGI in sinus rhythm to map the scar-substrate with high resolution
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(Figure 5.33, bottom). The activation wave front exited the scar region in two directions, forming
a clockwise apical loop (white arrows) and a counterclockwise anterior loop (black arrows). The
two wave fronts merged in the anterior RV, and the merged wave front slowly traversed the
anterior scar border (zigzag arrow) and reentered the region of earliest activation. The VT common

pathway aligned with a region of relatively preserved voltage (green flanked by red in B) and late
potentials (LPs; red in C) within the scar.