Question

identify this rhythm

sinus tachycardia with st segment depression
atrial fibrillation
junctional tachycardia
idioventricular rhythm
atrial flutter

Explanation:

Analyze atrial activity and baseline characteristics

The baseline shows rapid, regular, saw-tooth shaped waves (F-waves) instead of normal P waves. These flutter waves are especially prominent between the QRS complexes, demonstrating a classic atrial flutter pattern.

Determine ventricular rate and conduction ratio

The QRS complexes are narrow and occur at regular intervals. Counting the flutter waves between each R wave reveals a constant conduction ratio (typically 4:1 or 3:1 conduction), which is highly characteristic of stable atrial flutter.

Rule out alternative diagnoses

• Sinus tachycardia with ST segment depression: No normal sinus P waves are present.
• Atrial fibrillation: The rhythm is regular, and distinct saw-tooth waves are visible rather than irregular fibrillatory waves.
• Junctional tachycardia / Idioventricular rhythm: The presence of rapid, organized atrial flutter waves rules these out.

Answer:

• (A) Sinus tachycardia with ST segment depression
• (B) Atrial fibrillation
• (C) Junctional tachycardia
• (D) Idioventricular rhythm
• (E) Atrial flutter (Correct answer)