Hello and welcome to the forum. My apologies if you've received no response. Unfortunately, I am unable to maintain a regular presence on the forum and it can be several days or more before I may be able to personally respond.

Supraventricular ectopics and paroxysmal atrial contractions (PACs) are one in the same. It's important not to begin characterizing your heart rythym in terms of the report from the monitor, which is largely generated by the onboard computer. This equipment only provides what is programmed into it in terms of algorithms which technically compares the patient's recording intervals with pre-stored data.

People tend to begin characterizing their evaluation by stating "I have PACs, PVCs, PSVT and so on. This is actually inaccurate. Those definitions are intended to reference arrhythmias originating within the heart.

The palpitation events you and others here are experiencing are extra-cardial in nature, or originate from outside the heart. They are merely events subsequent to stumulation of the heart by the vagus nerve as a consequence of stress and/or anxiety.  

Mild valve regurgitation is purely an incidental finding and since your ejection fraction is normal, this would not in any way represent a causal factor relating to premature fatigue. Failure of patency within the heart produces physical weakness on exertion, not lethargy and drowsiness.

If you are pre-loading with carbohydrates or energy drinks prior to exercising then it explains the onset of drowsiness. While carbohydrate loading provides a quick burst of energy, it also causes the body to most rapidly produce insulin in response. The result is overwhelming lethargy and sleepiness.

I'm uncertain of your age or general health, but if no carbohydrate loading is evident, then you should undergo a fasting glucose following exercise to determine whether it could represent the causal factor.

Best regards,

Rutheford Rane, MD (ret.)