Differences between cardiac arrhythmia,atherosclerosis,ang... infarction & hypertension?

I learning about cardiovascular diseases in class and seem to be confused...the symptoms and how they developed..they seem to be quite similar...how do i differenciate them?anwers which are simple to understand really appreciated.
Update: the question is not complete..is it?..i mean, the differences between cardiac arrhythmia,atherosclerosis,angina,myocar... infacrtion and hypertension.
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