Normal Variant: T wave inversion in lead V1 can be a normal variant, especially in younger individuals or those with a low body mass index. This is often seen without any other signs of cardiac pathology.

Benign Early Repolarization: This condition can cause T wave inversion in the anterior leads, including V1, and is generally considered benign.
Anxiety or Stress: Transient T wave inversions can be seen in individuals under stress or experiencing anxiety, likely due to the effects of catecholamines on the heart.
Hyperventilation: Hyperventilation can lead to T wave changes, including inversion, due to the effects of respiratory alkalosis on cardiac repolarization.

Acute Coronary Syndrome (ACS): Although less common in a 35-year-old male without risk factors, ACS, including myocardial infarction, must be considered, especially if accompanied by chest pain or other symptoms.
Pulmonary Embolism: T wave inversion in the anterior leads can be a sign of pulmonary embolism, which is a life-threatening condition requiring immediate diagnosis and treatment.
Cardiac Tamponade: While rare, cardiac tamponade can cause T wave inversion among other ECG changes and is a medical emergency.

Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC): This condition can cause T wave inversion in the right precordial leads (V1-V3) and is associated with an increased risk of ventricular arrhythmias.
Brugada Syndrome: Characterized by ST elevation in leads V1-V3, but can also present with T wave inversion in these leads, and is associated with an increased risk of sudden cardiac death.
Myocarditis: Inflammation of the heart muscle can cause various ECG abnormalities, including T wave inversion, and can be a serious condition if not recognized and treated appropriately.