HPI:
90 y/o woman h/o sick sinus syndrome, AF, and a pacemaker presents with atypical CP.  Troponins are negative, CTPA is negative for PE.  She denies palpitations, shock-like sensations, or chest wall contractions. Palpated HR corresponds with QRS complexes on the monitor.

EKG:

Question:
What's going on with this pacemaker? Is the malfunction the cause of her symptoms?

HPI: 50 y/o male with hx of COPD, heroin use, and recently diagnosed cor pulmonale presents with 3 weeks of lower extremity edema. No chest pain, shortness of breath, or palpitations. An EKG is obtained in the emergency department.

HPI: 57 y/o woman with remote hx of CABG/PCI presents with 2 hrs of 6-10/10 substernal chest tightness and SOB. No recent cardiac events/complaints. Initial troponin is 1.48.

Question:  Is this patient experiencing a STEMI despite the lack of ST elevations ≥1mm?  How would you diagnose this and explain to your cardiology consultants?