Peculiar repolarization in African descendant elite athlete

We report the case of an asymptomatic professional basketball player, 24 year-old African -Caribbean male, with curious early repolarization pattern in the anterolateral wall (V1-V6, I and aVL). The ECG was performed during periodic evaluation. Detailed examination was normal.
The ECG performed one year before was similar.

Personal antecedents were irrelevant. Deny use of drugs licit or illicit.
Negative familial background for sudden death or syncope in young first degree relatives.
Physical: Weight: 86 kg; Height: 2.02 m; Biotype: Asthenic; BP: 120/70 mmHg; HR: 51 bpm; normal height of the waveforms of jugular venous pulse (< 4 cm) with the patient reclined at a 45° angle; absence of cardiac manifestation of genetic disorder, such as Marfan’s syndrome or facial signs associated with cardiac conditions. Normal peripheral pulses. Normal apex beat. Absence of thrill. Normal heart sound with physiological splitting of the second heart sound. A third heart sound was heard after the second heart sound, interpreted as rapid, high-volume filling of the left ventricle. Absence of murmurs.
Normal vesicular breath sounds over the most of the both lung surface without adventitious sounds (crackles). They have an inspiration/expiratory ratio of 3 to 1 (normal).
Normal chest X-rays and echocardiogram.

Questions:

1) Which is the ECG diagnosis?

2) Is it necessary other complementary study?