Wegener's Granulomatosis is a rare systemic vasculitis. Lesions commonly occur in the upper airways, lungs, kidneys, and can also affect the skin, eyes, joints, peripheral nervous system, and the heart. Cardiac involvement is rare and can affect the endocardium, myocardium, or pericardium. Pulmonary arterial hypertension (PAH) has been rarely reported. We report the case of D.R., a 17-year-old without significant personal medical history, referred for the evaluation of new-onset exertional dyspnea. The clinical examination was normal except for an irregular heart rhythm with a pronounced pulmonary B2 sound. The ECG revealed atrial fibrillation (AF) with incomplete right bundle branch block (iRBBB). A chest X-ray showed cardiomegaly primarily affecting the atria without signs of pulmonary congestion. Precapillary PAH was suggested by echocardiography and confirmed through right heart catheterization. Routine blood tests were normal. Contrast-enhanced chest CT showed no evidence of pulmonary embolism or signs of pulmonary parenchymal involvement. Given the patient's young age, a specific vasculitis work-up was conducted, leading to a diagnosis of Wegener's Granulomatosis. Through this case report, we will present the cardiac and extracardiac manifestations of this vasculitis, as well as therapeutic management strategies.