A 50-year-old man presents with palpitations. ECG shows a regular tachycardia at 150 bpm with sawtooth flutter waves visible in leads II, III, and aVF, with positive flutter waves in V1. What is the most likely atrial flutter circuit?
- A Typical clockwise cavotricuspid isthmus-dependent flutter
- B Typical counterclockwise cavotricuspid isthmus-dependent flutter ✓
- C Atypical left atrial flutter
- D Atrial tachycardia from the right atrial appendage
Correct answer: B. Typical counterclockwise cavotricuspid isthmus-dependent flutter
Explanation
Typical counterclockwise flutter shows negative sawtooth waves in inferior leads (II, III, aVF) and positive flutter waves in V1, with atrial rate around 300 bpm. Clockwise flutter shows positive waves in inferior leads and negative in V1. The ventricular rate of 150 bpm indicates 2:1 AV conduction (300/2 = 150), which is characteristic of atrial flutter.
Reference: Clinical Electrocardiography, 9th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.