Premature Atrial Complex - Atrial Rhythms

Intro to PACs

• PACs can occur for a number of different reasons i.e., diet, fatigue, stress, disease, ischemia to name a few.
• Premature complexes frequently occur in bradycardic rhythms, but may occur almost any time.
• PACs occur when an early electrical impulse occurs from a location in the atria other than the SA node.

Intro to PACs 2

• This early impulse causes an early cardiac complex which disrupts the underlying rhythm.
• The locus of stimulation being different, results in a change in the morphology of the P wave.
• PACs can occur occasionally or frequently.
• PACs ECG can be observed with or without a pattern
• The P wave with PAC's will always be upright

EKG Analysis

Notice the following: the R to R interval is irregular, the fifth complex is early and the P wave on the early complex is a different shape.

EKG Practice Strip

Analyze this tracing using the five steps of rhythm analysis.