What is the most likely diagnosis for a young man who suddenly collapses while playing sports, considering a family history of similar incidents?

In this scenario, the most likely diagnosis is hypertrophic cardiomyopathy. This condition is characterized by the abnormal thickening of the heart muscle, particularly affecting the interventricular septum. It is a common cause of sudden cardiac arrest in young athletes, especially those participating in high-intensity sports.

The mention of a family history of similar incidents is particularly relevant because hypertrophic cardiomyopathy often has a genetic basis, with many cases inherited in an autosomal dominant pattern. This suggests that if there have been previous unexplained collapses or cardiac events in the family, hypertrophic cardiomyopathy could be a plausible underlying cause.

The acute nature of the collapse during sports further supports this diagnosis, as individuals with hypertrophic cardiomyopathy can experience life-threatening arrhythmias that may lead to sudden cardiac death during vigorous physical activity. Early recognition and screening for this condition in at-risk individuals can be critical, especially for young athletes and their families.