some studies describe that subjects with low cardiorespiratory fitness are more likely to have carviovascular disease, including sudden death. In this way, idf the subject have a higher fitness level this problem should be lower. However, it is frequently described sudden cardiac death in high trained athletes. because sometimes the development of the heart (mechanical and electrical) do are not harmonious.
No, it shouldn't in sports. Sudden death is a genetic, morphological and electrophysiological predisposition. It happens in athletes with perfect cardiorespiratory fitness.
However cardiovascular fitness is not associated with sudden death, but it can be occur in professional athletes because of : chance, arrhythmia, electrolyte imbalance, morphological disorder in heart and congenital problems!