All subjects will receive single doses of GSK2140944 1000 mg, GSK2140944 1800 mg, moxifloxacin 400 mg, and placebo in a randomized sequence. A double-dummy approach will be used to maintain blinding. Thus, on each dosing day, moxifloxacin or moxifloxacin placebo and GSK2140944 or placebo will be administered.