8. Any cardiac pre-excitation syndromes, e.g. Wolff-Parkinson- White syndrome. 9. Active drug or alcohol use or dependence that, in the opinion of the investigator, would interfere with adherence to study requirements. 10. Prisoners or subjects who are compulsorily detained (involuntarily incarcerated) for treatment of either a psychiatric or physical (i.e. infectious disease) illness must not be enrolled into this study. 11. Any illness or condition that in the opinion of the investigator may affect the safety of the subject or the evaluation of any study endpoint. 12.