As the cardisc arteries which feed blood to the heart muscles develop fatty plaques the heart becomes starved for oxygen. This causes serious pain (angina pectoralis). Nitroglycerin, in minute doses, strongly dilates your arteries and restores blood flow. The image of an old man clutching his chest and asking for his pills comes from folks needing their nitroglycerin pills. Angina is a chronic condition.
As MacGyver attempts to enter the Hospital, he tries to blend into the staff carrying cartons. These cartons are marked, "lazarsky zasoby" which loosely translates to medical supplies or medicines which is a bit odd it is so non-descript.