Figure 1.

Importance of L-type VGCCs in cardiac automaticity. (A) Representative recordings of consecutive action potentials recorded in pacemaker cells from wild-type (top left panel) and Ca_v1.3^−/− mice (top right panel). Cellular arrhythmia is evident as irregular cycle length duration in Ca_v1.3^−/− cells (bottom right panel) compared with wild-type cells (bottom left panel). Dotted lines indicate the zero voltage level (Data from Mangoni et al., 2003). (B) Telemetric ECGs showing prolongation of RR interval PQ interval in Ca_v1.3^−/− mice (top right panel) with respect to wild type littermates (top left panel). (C) Dot plot of beat to beat variability in wild-type (left panel) and Ca_v1.3^−/− mice (right panel) observed during 10 min recordings. Note the dispersion of the RR intervals in Ca_v1.3 knockout mice, revealing strong sinus arrhythmia. The dotted lines indicate the average heart rate as the number of beats per minutes (bpm) (reprinted from Mangoni et al., 2006a, with permission from Elsevier).