**Core Concept**
Infective endocarditis is a serious infection of the heart valves, typically caused by bacteria, which can lead to various complications. The commonest complication of infective endocarditis is related to the formation of vegetations on the heart valves, which can embolize to other parts of the body.

**Why the Correct Answer is Right**
The correct answer is embolic events, which occur when the vegetations break loose from the heart valves and travel through the bloodstream, potentially causing damage to organs such as the brain, kidneys, or spleen. This is due to the formation of a sterile abscess within the vegetation, which eventually leads to its detachment and embolization. The embolic events are often caused by the presence of septic emboli, which are clumps of bacteria and platelets that form within the vegetation.

**Why Each Wrong Option is Incorrect**
**Option A:** Heart failure is a potential complication of infective endocarditis, but it is not the most common one. Heart failure occurs when the heart valves are severely damaged, leading to decreased cardiac output and increased pressure in the heart chambers.

**Option B:** Constrictive pericarditis is a rare complication of infective endocarditis, caused by the formation of adhesions on the pericardium, which can lead to impaired diastolic filling of the heart. While it is a potential complication, it is not the most common one.

**Option C:** Myocardial infarction is not a direct complication of infective endocarditis. However, embolic events can cause myocardial infarction by occluding the coronary arteries.

**Clinical Pearl / High-Yield Fact**
The embolic events in infective endocarditis can be remembered using the "MOF" acronym, which stands for Myocardial Infarction, Osteomyelitis, and **F**ocal neurological deficits (such as stroke). This mnemonic helps to recall the various potential complications of embolic events in infective endocarditis.

**Correct Answer:** C.