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. Author manuscript; available in PMC: 2021 Aug 2.
Published in final edited form as: Circ Res. 2020 Apr 15;127(3):e94–e106. doi: 10.1161/CIRCRESAHA.118.314460

Figure 4. Spontaneous ventricular tachycardia (VT) in VCS-specific Tbx5-deficient adult mice originates in the VCS and is caused by inappropriate automaticity within the VCS.

Figure 4.

(A). Electrocardiograms recorded from adult VCS-specificTbx5-deficient mice during Langendorff-perfusion showing sinus rhythm and ectopy (extra a-b). (B) Simultaneously recorded optical action potentials showed that ectopic beat originated in the ventricle. (C) Representative voltage activation maps from VCS-specific Tbx5–deficient mice have been reconstructed from sinus beat and two consecutive beats during ventricular ectopy. (D) ECG trace of episode of spontaneous VT (right) and reconstructed activation maps during two consecutive beats (left). Note, spontaneous VT was only detected in Tbx5-deficient mice, not in control mice. The activation patterns during sinus rhythm (SR) and VT are similar. (E) Graphic model of inappropriate activation pattern observed within the VCS of VCS-specific Tbx5 mutant mice that results in spontaneous VT. For (A-D), n=4 or 6 animals/ genotype.