Interpretation:
Rate: 114/minute
Rhythm: the overall rhythm is irregularly irregular – either atrial fibrillation…or, the other irregularly irregular rhythm. Multifocal Atrial Tachycardia (MAT).
Intervals: PR seems to vary where it can be easily measured
Chamber enlargement: none
Ischemia and infarct patterns: none

The rhythm is multifocal atrial tachycardia (MAT) as there are definite P waves discernible in front of some QRS complexes, of varying morphology and PR interval.

The wide-complex beat seen slightly after the middle of this tracing is most likely an aberrantly conducted supraventricular beat based on Ashman’s prediction. Notice the long R-R interval followed by a short R-R interval resulting in a RBBB morphology wide-complex (notice the tall R-wave in V1).

See also: EKG of the Week #42, and
EKG Discussion of Ashman beats