64yo male, with a history of HTN, DMII, and hyperlipidemia, is brought in by EMS to the ED with a 2 hour history of lightheadedness and palpitations. He states both these symptoms seem to fluctuate and nothing seems to make them better or worse when they occur. He has never had anything like this before. He denies syncope, chest pain, dyspnea, nausea, vomiting, diaphoresis, or vision changes.
General – NAD, A&Ox3
HEENT – no diaphoresis, no gaze deviation, no facial palsies
CV – irregular, no M/G/R
Pulm – CTA bilaterally
MSK – 5/5 strength throughout
Neuro – CN II-XII grossly intact, MAE
While getting set up for a formal 12 lead EKG, the paramedic hands you the rhythm strips from transport:
What is the most likely diagnosis?