Are beta blockers alone effective in vasodilation around the heart or is combination therapy neccessary, i.e. ace-inhibitors, calcium blockers, etc?

Not always ...: Beta Blockers are interesting drugs. Their use in treating coronary artery disease, high blood pressure and myocardial disease fills volumes. I would love to get into that because it's interesting .... however .... to answer your question quite simply. Most patients require more than one medication because they also have high blood pressure. But some can get away with Beta Blockers alone.

BB not vasodilators: The medicines you mention act in three different ways and depending in what you are trying to achieve they can be used separately or together for a variety of conditions, from hypertension to even heart failure (although cal antagonists not recommended for the latter). But beta blockers are not vasodilators