Question

identify this rhythm

sinus rhythm with 1st degree heart block
2nd degree type i heart block
sinus arrhythmia
2nd degree type ii heart block
3rd degree heart block

Explanation:

Analyze the PR intervals and QRS complexes

• First cycle: PR interval is approximately 6 small boxes (0.24 s).
• Second cycle: PR interval lengthens to approximately 9 small boxes (0.36 s).
• Third cycle: PR interval lengthens further to approximately 12 small boxes (0.48 s).
• Fourth cycle: A P wave occurs but is not followed by a QRS complex (non-conducted P wave / dropped beat).

Identify the pattern of AV block

• The PR interval progressively prolongs with each successive beat until a QRS complex is completely dropped.
• This progressive prolongation followed by a dropped beat is the hallmark of Wenckebach block.

Match with the correct diagnosis

• This pattern corresponds to Second-Degree AV Block, Mobitz Type I (also known as Wenckebach).
• The matching option is "2nd Degree Type I Heart Block".

Answer:

• (A) Sinus Rhythm with 1st degree Heart Block
• (B) 2nd Degree Type I Heart Block (Correct answer)
• (C) Sinus Arrhythmia
• (D) 2nd Degree Type II Heart Block
• (E) 3rd Degree Heart Block