Which of the following laboratory results should a medical assistant recognize is indicative of a patient having a history of myocardial infarction?

High-density lipoprotein (HDL) is known as "good cholesterol," and while it plays a role in cardiovascular health, its levels do not directly indicate a history of myocardial infarction. Instead, higher HDL levels are generally associated with a lower risk of heart disease, rather than serving as a marker for past cardiac events.

Low-density lipoprotein (LDL) is often referred to as "bad cholesterol" and is linked to an increased risk of atherosclerosis and heart disease. However, like HDL, LDL levels are not specific indicators of a history of myocardial infarction. They reflect cholesterol metabolism and risk factors rather than direct evidence of prior heart damage.

Triglycerides are a type of fat found in the blood, and while high levels can indicate an increased risk for heart disease, they do not specifically indicate a history of myocardial infarction. Triglycerides are more of a general risk factor rather than a definitive marker of past heart attacks.