Core distinction
- Typical flutter
- Cavotricuspid isthmus (CTI) dependent
- Circuit around tricuspid annulus (RA)
- Atypical flutter
- Not CTI dependent
- Often scar-related (RA or LA)
- Common after AF ablation or cardiac surgery
EKG clues
Typical (counterclockwise)
- Negative flutter waves in II, III, aVF
- Positive in V1
- Classic sawtooth pattern
- Atrial rate ~240–300
Reverse Typical (clockwise)
- Less common
- Often positive flutter waves in inferior leads
- Still CTI dependent
Atypical
- No classic sawtooth
- Variable or unusual flutter wave morphology
- Changing patterns across EKGs
- Often in patients with:
- Prior AF ablation
- Prior cardiac surgery
- Structural heart disease
Ablation implications
Typical flutter
- Target CTI line (RA)
- Standardized procedure
- High success
- Low recurrence
- Relatively quick
Atypical flutter
- Target depends on circuit
- Requires detailed mapping
- Often LA or scar-related
- Longer, more complex
- Lower success, higher recurrence
