Complex sentence: There are a number of cases in which patients feel the effect of myocardial ischaemia, which is associated with referred pain, classically to the front of the chest, the left arm and the jaw.
Split into simpler sentences: There are a number of cases in which patients feel the effect of myocardial ischaemia. Myocardial ischaemia is associated with referred pain, classically to the front of the chest, the left arm and the jaw.