This patient presented with general malaise. Can you interpret the EKG?  Specifically, what is the underlying rhythm? (Answer at the bottom)

When this patient presented, an old EKG was available from approximately 6 1/2 months prior. (Click for interpretation)

Subsequent EKG's are posted here.  Remember, these were not available when the patient presented to the ED.  (Click on a date to have the EKG open in a separate window)

1 day after presentation	pdf	Interpretation	Sinus rhythm @ 74 bpm with LAD Poor R-wave progression QRS 144 -> LBBB QTc 468 No ST or T-wave changes
4 days after presentation	pdf	Interpretation	Sinus rhythm at 77 with LAD Q-waves in III, aVF Poor R-wave progression QRS 140 -> LBBB QTc 479 No ST or T-wave changes
5 days after presentation	pdf	Interpretation	Sinus rhythm at 77 with LAD Q waves in III, aVF Poor R-wave progression QRS 142 -> LBBB QTc 482 -> No ST or T-wave changes

Ventricular bigeminy @ 55 bpm rate with related LBBB