In contrast regular excercise and a healthy life style may increase HDL and significantly reduce the risk. The immediate treatment of angina is to relieve the metabolic strain on the heart. This may be achieved by slowing the heart rate by the use of beta-adrenergic blocking drugs, or by the use of calcium antagonists, or by causing vasodilation of coronary arteries by the use nitrates, such as nitroglycerin. These however offer only temporary relief, and the disease will progress towards heart attack and infarction if the cause is not addressed. If cells are deprived of oxygen for more than a few minutes they die.
Myocardial infarction is ischaemia which has progressed to irreversibility.
It is often a sudden event, recognised as a 'heart attack', and may be caused by a thrombosis forming at a constriction, plaque rupture, or a sudden arterial constriction. Generally however, interruption of the circulation leads to cell death and the development of scar tissue in the dead region of the heart. Two consequences follow - the contractile power of the heart is reduced, and the excitatory pathways through the heart may be interrupted, leading to irregular beating, arrhythmias. Treatment Loss of part of the muscle of the heart may lead to decreased contractile power and result in complications such as reduced cardiac output, falling blood pressure, or congestive heart failure. The last may be treated with diuretics, but otherwise there is little to be done but relieve symptoms.