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This is an EKG rhythm from a patient with a Medtronic model 8081 Premier single chamber pacemaker.

The patient is a 65 year old man who had a history of blackouts while sitting.
During the episodes his wife described him as becoming limp and white.

His electrocardiogram showed a left bundle branch block with a normal pr interval. This conduction abnormality had been present for at least 16 years.

An electrophsiology test was performed and a pacemaker inserted.

What is the native rhythm?

Is the pacer working well ( in particular what do you think of the spike on the second QRS)?