Disclosed are novel heterocyclic compounds having the structure
##STR00001## which are useful for the treatment of various disease
states, in particular cardiovascular diseases such as atrial and
ventricular arrhythmias, intermittent claudication, Prinzmetal's
(variant) angina, stable and unstable angina, exercise induced angina,
congestive heart disease, and myocardial infarction. The compounds are
also useful in the treatment of diabetes.