I'm experiencing breathlessness when I exert myself and my heart rate seems really high. The recent echo shows mild TR, mild PAHRVSP at 45 mmHg, and a mild MR jet area of 2.5 sqcm, with tachycardia at 121 bpm. My hemoglobin and thyroid levels are normal, but I'm a bit concerned about the mild PAH. Should I be worried about this and check in with a doctor?

Yes, mild pulmonary arterial hypertension (PAH) should be followed up by a doctor, especially since you are experiencing breathlessness on exertion and have a high heart rate. Treatment for PAH may include medications such as sildenafil (Revatio) or tadalafil (Adcirca) to help lower the blood pressure in the lungs. It is important to monitor and manage PAH to prevent further complications.