Table 1. Summary of in vivo parameters.

Age	1 month		2 months		3 months
	WT	DCM	WT	DCM	WT	DCM
BW (g)	12.8±0.9	13.3±0.6	21.4±0.6	21.7±0.8	23.2±1.0	22.7±0.7
N	8	8	18	13	11	16
ECG recording (anesthetized)
HR (bpm)	355±27	430±25* , a	392±18	394±37	ND	ND
PR (ms)	35±1	33±1	38±2	38±2	ND	ND
QRS (ms)	9.6±0.3	10.3±0.3	11.0±0.3	16.7±0.6*	ND	ND
QT (ms)	34±1	42±2*	36±1	53±1*	ND	ND
N	6	6	6	6	-	-
ECG recording (conscious)
HR (bpm)	740±16	773±15	721±10	700±6	726±9	698±17
PR (ms)	29.1±0.9	29.6±0.8	33.6±0.7	33.0±1.1	34.7±0.8	33.8±1.6
QRS (ms)	9.9±0.4	12.3±0.4	10.1±0.4	15.9±0.9**	10.1±0.1	16.9±1.4**
QT (ms)	17.1±0.4	23.3±0.9**	17.0±0.5	33.8±1.9**	18.5±0.6	37.9±2.2**
N	5	6	5	6	5	5

Data are means ± SEM.

^*P<0.05,

^**P<0.01 vs. WT. BW: body weight. ND: not determined.

^a: The significant difference from WT mice is probably due to a difference in depth of anesthesia.