Which of the following is an effect of coronary thrombosis?

Coronary thrombosis refers to the formation of a blood clot within one of the coronary arteries, which supply blood to the heart muscle. When this clot obstructs blood flow, it can lead to myocardial infarction, commonly known as a heart attack. During a myocardial infarction, the heart muscle suffers from a lack of oxygenated blood, leading to tissue damage and, if not promptly treated, can result in severe complications, including heart failure or death.

This effect ties directly to how coronary thrombosis impacts the body's cardiovascular system by preventing crucial blood flow. Other conditions listed, such as stroke, pulmonary embolism, and cardiac arrest, have different underlying causes and mechanisms.

A stroke typically occurs due to a blockage in a blood vessel supplying the brain or due to bleeding within the brain, not primarily from issues related to coronary thrombosis. Pulmonary embolism is caused by a blood clot that travels to the lungs, often originating from deep vein thrombosis in the legs, while cardiac arrest can result from a variety of heart diseases, including those related to coronary artery disease, but it does not directly stem from coronary thrombosis alone.

Thus, the most direct and immediate effect of coronary thrombosis is myocardial infarction, making it the correct answer