Animal fats and hydrogenated vegetable margarine contain saturated triglycerides. Saturated triglycerides are those that are made of saturated fatty acids. These saturated fatty acids are capable of forming atheroma (/plaques) along arterial walls, causing atherosclerosis or arteriosclerosis. These could both result in coronary thrombosis (blocking of a coronary artery by a clot of blood), and hence a myocardial infarction (heart attack).
