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Reentrant tachycardia that often appears as a 'sawtooth' pattern on EKG. This pattern is best seen in leads II, III, AVF, and V1. The usual atrial rate is about 300 beats per minute with the ventricular response at 150 bpm, 75 bpm, or less in a 2:1, 3:1, 4:1 ratio. The flutter wave is sometimes referred to as the 'F' wave
Measurement of Successful Ablation
- Corridor of Widely split double potentials 90-110 ms
- Transisthmus Conduction Intervals
- Counter Clockwise defined as interval between stimulus on lateral wall and proximal coronary sinus electrode.
- Clockwise defined as interval between stimulus in proximal CS and electrodes lateral to line of block.
- Interval measured at 500, 400, and 300 ms. If this value increased by 50% or more this was defined as successs or 150ms
- Pacing at multiple sites. AD>BD and DA>CA
- Bipolar electrgrams lateral to line and pace from Proximal CS. Transition of polarity from positive to negative
- 3 pacing site protocol: Pace at two sites lateral (L1R and L2R) to the line on block and on the septal site (S) of the line. Measure the conduction delay from the pacing site to the R wave on the QRS (L1 to R, L2 to R and S to R). If (L1R-L2R) > 0 and (L1R-SR) > 94 then there is a 100% sensitivity and 98% specificity. See Figure
- Pace at 20 ms shorter than tachycardia cycle length from the CS in CW flutter and from the low right atrium in CCW flutter
1. Use SR0, SL1 or ramp sheath if you have difficulty or change to a larger curve catheter