What defines atrial trigeminy?

What defines atrial trigeminy?

• A. A PAB after every normal cycle
• B. A PAB following two normal cycles
• C. Multiple premature beats in quick succession
• D. An absence of P waves after every third beat

Answer: (B)

Atrial trigeminy is characterized by the occurrence of a premature atrial beat (PAB) following two normal sinus beats. This pattern indicates that after every two normal rhythmic atrial contractions, a single aberrant contraction occurs due to the early depolarization of atrial tissue. This sequence gives the heart the rhythm characteristic of trigeminy, signifying that the premature beats are interspersed among the normal beats in a repeating pattern. Understanding this pattern helps in recognizing the abnormal beat's placement within the overall cardiac cycle, which can be critical for diagnosis and treatment of various arrhythmias.