Abstract: A method for assessing if a subject has or is at risk of developing cardiac arrhythmia is described. The method includes determining the activity of Rap1A protein in a bodily sample of the subject and comparing the activity of Rap1A protein from the bodily sample of the subject to at least one Rap1A control. A decreased level of Rap1A activity in the bodily sample of the subject as compared to the at least one Rap1A control indicates that the subject is at risk of developing or has cardiac arrhythmia. Methods for evaluating the efficacy of treatment of a subject having decreased Rap1A activity with an antiarrhythmic agent are also described.

Abstract: Pharmaceutical compositions in topical or parenteral form containing organic nitrites are effective in treating male impotence and erectile dysfunction through topical or intracavernosal administration to the penis. Methods of treatment utilizing the nitrite-containing compositions are also disclosed, as are certain novel organic nitrite compounds.