A 30-year-old male presents with fatigue and dizziness. He has a heart rate of 45 beats/min and blood pressure of 110/70 mmHg. On examination, his heart sounds are regular, and there are no other significant findings. What could be the potential diagnosis, and what are the next steps?
This patient's bradycardia could be due to a variety of causes, including high vagal tone (common in athletes), hypothyroidism, or a heart block. Given his age and absence of other symptoms, a high vagal tone might be the most likely cause, but further investigations are required. Lab tests should include thyroid function tests, electrolyte levels, and an ECG to assess the rhythm and look for any conduction abnormalities.