This is a double blind placebo controlled study of one hundred and four subjects which will be randomized for treatment with Sentra PM alone, Sentra PM with trazadone, trazadone alone and placebo alone. Twenty -six subjects will be randomly placed in one of the four groups. Each of the one hundred and four subjects will undergo baseline examination to include a sleep study questionnaires and 24- hour electrocardiographic recording. The one hundred and four subjects will then be randomly placed in one of the four groups.