To verify concealed entrainment during typical flutter, the PPI must be within ___ of TCL?

To verify concealed entrainment during typical flutter, the PPI must be within ___ of TCL?

• A. 10 ms
• B. 20 ms
• C. 30 ms
• D. 60 ms

Answer: (C)

When assessing entrainment during typical flutter, the key idea is that the post-pacing interval (PPI) should almost match the flutter cycle length if your pacing site is within or very close to the flutter circuit. This is called concealed entrainment because pacing doesn’t produce overt changes in the tachycardia appearance, yet the timing shows the circuit is engaged. If the PPI is within about 30 milliseconds of the flutter cycle length, it strongly suggests the pacing site lies inside or right at the circuit and the paced impulse re-enters the circuit with minimal extra delay. This small margin accounts for inevitable conduction from the pacing site to the circuit and back, plus measurement variability. Larger differences imply the pacing site is outside or not part of the circuit, so entrainment isn’t concealed. So, the PPI must be within 30 milliseconds of the tachycardia cycle length.

When assessing entrainment during typical flutter, the key idea is that the post-pacing interval (PPI) should almost match the flutter cycle length if your pacing site is within or very close to the flutter circuit. This is called concealed entrainment because pacing doesn’t produce overt changes in the tachycardia appearance, yet the timing shows the circuit is engaged.

If the PPI is within about 30 milliseconds of the flutter cycle length, it strongly suggests the pacing site lies inside or right at the circuit and the paced impulse re-enters the circuit with minimal extra delay. This small margin accounts for inevitable conduction from the pacing site to the circuit and back, plus measurement variability. Larger differences imply the pacing site is outside or not part of the circuit, so entrainment isn’t concealed.

So, the PPI must be within 30 milliseconds of the tachycardia cycle length.