Coxsackievirus and adenovirus receptor (CAR) mediates atrioventricular-node function and connexin 45 localization in the murine heart
J. Clin. Invest. Byung-Kwan Lim, et al. 118:2758 doi:10.1172/JCI34777 [Go to this article.]

Figure 2
AV–node block in CAR-cKO mice (A) Electrocardiograms obtained from lightly anesthetized WT and CAR-cKO 4- to 5-week-old mice demonstrated complete AV dissociation in CAR-cKO mice. P (arrow) indicates atrial depolarizations (P-wave). Right panel shows representative signal averages of 100 beats obtained using high-resolution ECG recording in WT and CAR-cKO mice. P-wave (arrow) and QRS complex (arrowhead) are shown in a WT mouse. The P-wave is not present in the CAR-cKO tracing because it was not associated with the QRS complex and was lost in the signal averaging. (B) Telemetric ECG analysis in conscious mice. All WT mice had normal AV conduction. CAR-cKO mice had either complete AV block (top 2 tracings) or first degree AV block (bottom 2 tracings). None of the CAR-cKO mice had normal AV conduction. (C and D) Optical mapping studies in CAR-cKO mice. The activation maps showed the pattern of intrinsic anterior or posterior activation of isolated atria (C) and epicardial intrinsic activation of isolated heart ventricles (D). There was no significant difference in the activation propagation pattern or averaged action potentials over several beats in the atria or ventricles of WT versus CAR-cKO mice. LA, left atrium; SAN, sinoatrial node; RA, right atrium. (E) Ventricular activation times from the anterior view with an intrinsic depolarization and LV epicardial pacing is shown (left panel).The conduction velocity was not different between WT and CAR-cKO mice (middle panel). APD from LV epicardial pacing was also not different (APD20, APD50, and APD80) (right panel). P = NS between all groups; WT (n = 7) vs. CAR-cKO (n = 6); mean ± SD. BCL, basal cycle length.