Isolated Potentials During Sinus Rhythm and Pace-Mapping Within Scars as Guides for Ablation of Post-Infarction Ventricular Tachycardia
Frank Bogun, MD, FACC*,
Eric Good, DO,
Stephen Reich, MD,
Darryl Elmouchi, MD,
Petar Igic, MD,
Kristina Lemola, MD,
David Tschopp, MD,
Krit Jongnarangsin, MD,
Hakan Oral, MD, FACC,
Aman Chugh, MD,
Frank Pelosi, MD, FACC and
Fred Morady, MD, FACC
University of Michigan Medical Center, Ann Arbor, Michigan
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Figure 1 Example of an isolated potential recorded within a posterior left ventricular scar. The isolated potential (arrow) is separated from the ventricular electrogram by an isoelectric segment of 120 ms. The amplitude of the isolated potential is 0.035 mV. The electrogram width is 260 ms. In this patient there were 11 different inducible ventricular tachycardias (VTs); after the ablation procedure and the displayed lesions (Fig. 2; 20 radiofrequency lesions of  60 s were delivered), these VTs were no longer inducible. Map dist = distal electrode pair of the mapping catheter.
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Figure 2 Voltage map of the posterior aspect of the left ventricle in the same patient as in Figure 1. Radiofrequency energy was delivered at points marked in red and at the pace-map sites illustrated in Figures 3 and 4. Sites with an isolated potential during sinus rhythm are marked in blue and sites where there was non-capture are marked in grey.
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Figure 3 Example of a perfect pace-map. The targeted ventricular tachycardia (VT) is shown in the left panel and the pace-map obtained at the site displayed in Figure 1 is shown in the right panel. The QRS complexes during VT and pacing are identical in all 12 leads.
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Figure 4 Example of a good pace-map, in which the QRS complexes during ventricular tachycardia (VT) (left) and pacing (right) are identical in 10 of 12 leads. Leads II, III, and aVF display some minor differences in the morphology of the paced QRS complexes as compared with the targeted VT.
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Figure 5 The voltage map shown in Figure 2, indicating where the pace-maps in Figures 3 and 4 were obtained.
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Figure 6 Number of appropriate implantable cardioverter-defibrillator (ICD) therapies delivered during the three months before and at three months and six months after ventricular tachycardia ablation. The mean ± 1 standard deviation is shown at each time point. RF = radiofrequency catheter ablation.
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