Table 1.

Patient Demographic and QTc Intervals (ms) during EST.

	LQT1 (n=29)	LQT2 (n=21)	Control (n=108)
Mean age±SD	10.4±4.2	11.7±4.7	11.8±3.6
Female sex, n (%)	19(61)	11(52)	45(42)
Beta-blocker usage, n (%)	17(59)	11(52)
Rest (QTc ms±SD)	452±33†	475±35†*	407±21
Peak exercise	488±35†	439±32†*	406±25
1 min recovery	481±35†	434±27†*	401±22
3 min recovery	491±38†	460±34†*	408±22
5 min recovery	487±32†	468±22†*	427±19
7 min recovery	484±29†	478±20†	431±18
9 min recovery	486±32†	473±23†	432±18

^†P-value <0.001 LQT1 and LQT2 vs controls

^*P-value <0.001 LQT1 vs LQT2