Pacs can cause it sure... If the pac is nonconducted (doesnt cause a ventricular response).. However if youre symptomatic, and experiencing a 50% reduction in ventricular rate from baseline thats a problem.
What you need is a longer term monitor like a holter that can record your rhythm when you experience said symptoms.
Its possible either 1 of 4 things are occuring...
1. You're experiencing a 50% burden of pacs that occur so early they dont conduct properly.. Id expect this to be the least probable explanation.
2. You simply experience expisodes of sinus bradycardia.. I.e. your heart rate just falls. This can be neurological in origin. Most probable outcome.
3. Instead of pac's what you're actually experiencing is pvc's with each individual pulse you feel actually being 2 seperate pulses. These would only be really obvious to a trained individual such as a cardiologist when checking your pulse. Third most likely option.
4. You have sick sinus syndrome and experience periods of sinus arrest. This option is very probable if you're older (at least 50), but much less so if you're younger.
5. You have some sort of av node dysfunction, such as a heart block. Given its lack of appearence on recent ekg, id rate the highest probability of being a second degree type 1, or wenkebach heart block. This block would respond to changes in vagal tone (again... Neurologic problem..) And is more likely to be transient.
At any rate you need to see someone probably a bit more specialized in the field of cardiology to know for sure.
If you see your primary doctor and tell him/her you have symptoms and your pulse feels slow they should have no issue refferring you to see cardiology. If not you should probably get a second opinion. Symptomatic bradycardia isnt something you just ignore without seeing cardiology.