Passing out and exhaustion are not specific symptoms that relates to heart illness. However in presence of previous rhythm disturbance and heart ablations, it should not be ignored. I insist you see your cardiologist who performed the procedures. He/she will have a baseline heart check up followed by EKG, echo and rhythm monitoring (such as holter) to know about current heart status.
Other common conditions that can mimic your symptoms include anemia
disturbances. I am sure the treating doctor will consider these differentials during evaluation.
Hope this helps. Let me know if you need clarifications.