RT Journal T1 THe serial electrocardiogram—discussion JF Archives of Internal Medicine JO Archives of Internal Medicine YR 2011 FD April 11 VO 171 IS 7 SP 616 OP 618 DO 10.1001/archinternmed.2011.100 UL http://dx.doi.org/10.1001/archinternmed.2011.100 AB