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. 2015 Oct 1;37(18):1469–1475. doi: 10.1093/eurheartj/ehv449

Figure 1.

Figure 1

Arrhythmia development in Irx3−/− and Irx3+/− mice. (A) Representative ambulatory telemetric electrocardiogram recordings in homozygous Irx3−/− mice. Upper panel shows transient atrio-ventricular block. Arrows indicate P waves without following ventricular excitations. Lower panel shows spontaneous non-sustained ventricular tachycardias. Solid lines indicate the timing with non-sustained ventricular tachycardias. Reverse triangles show ventricular premature contractions. (B) Comparison of frequency of atrio-ventricular block, ventricular tachyarrhytmias, and ventricular tachycardias in ambulatory telemetric electrocardiography in WT (n = 10) and Irx3−/− (n = 9) mice. Ventricular tachyarrhytmias was defined as consecutive ventricular premature contractions more than couplets, and ventricular tachycardias as consecutive ventricular premature contractions more than triplets. Statistical analysis was done with Fisher's exact test. (C) Representative ambulatory telemetric electrocardiogram recordings in heterozygous Irx3+/−. Upper panel shows transient atrio-ventricular block. Arrows indicate P waves without following ventricular excitations. Lower panel shows spontaneous non-sustained ventricular tachycardias. Solid lines indicate the timing with non-sustained ventricular tachycardias. Reverse triangles show ventricular premature contractions. (D) Transient atrio-ventricular block induced by isoproterenol infusion in Irx3−/− mice. Arrows represent P waves without following ventricular excitation. (E) Comparison of frequency of atrio-ventricular block, ventricular tachyarrhytmias, and ventricular tachycardias after isoproterenol infusion in WT (n = 10) and Irx3−/− (n = 9) mice. Statistical analysis was done with by Fisher's exact test. (F) Non-sustained ventricular tachycardias induced by isoproterenol infusion in Irx3+/− mice. Solid lines indicate the timing with non-sustained ventricular tachycardias. (G) Representative electrocardiogram recordings during swimming in Irx3−/− mice. Reverse triangles show ventricular premature contractions. (H) Comparison of frequency of atrio-ventricular block, ventricular tachyarrhytmias, and ventricular tachycardias during swimming in wild-type (n = 10) and Irx3−/− (n = 9) mice. Statistical analysis was done with Fisher's exact test. (I) Representative electrocardiogram recordings within 24 h after surgical creation of myocardial infarction in Irx3−/− mice. Dotted lines indicate the timing with bigeminy, and solid lines indicate the timing with ventricular tachycardias. (J) Comparison of frequency of atrio-ventricular block, ventricular tachyarrhytmias, and ventricular tachycardias within 24 h after myocardial infarction in wild-type (n = 6) and Irx3−/− (n = 6) mice. Statistical analysis was done with Fisher's exact test. (K) Incidence of ventricular premature contractions within 24 h after surgical creation of myocardial infarction in wild-type (n = 6) and Irx3−/− (n = 6) mice. Statistical analysis was done with Mann–Whitney U test.