What mechanism is Atrial Flutter?

What mechanism is Atrial Flutter?

• A. Macro-reentrant
• B. Micro-reentrant
• C. Focal atrial tachycardia
• D. Atrial fibrillation

Answer: (A)

The mechanism is macro-reentrant. Atrial flutter arises from a large reentrant circuit that travels through the atria, creating a rapid, organized spiral of activation. In the typical flutter, this circuit often runs around the tricuspid annulus and through the cavo-tricuspid isthmus, producing a consistent and regular atrial rhythm. That large, fixed loop distinguishes it from other mechanisms: micro-reentrant would involve a much smaller reentrant circuit, focal atrial tachycardia comes from a single ectopic focus rather than a loop, and atrial fibrillation is driven by multiple, disorganized reentrant wavelets with no stable circuit.

The mechanism is macro-reentrant. Atrial flutter arises from a large reentrant circuit that travels through the atria, creating a rapid, organized spiral of activation. In the typical flutter, this circuit often runs around the tricuspid annulus and through the cavo-tricuspid isthmus, producing a consistent and regular atrial rhythm. That large, fixed loop distinguishes it from other mechanisms: micro-reentrant would involve a much smaller reentrant circuit, focal atrial tachycardia comes from a single ectopic focus rather than a loop, and atrial fibrillation is driven by multiple, disorganized reentrant wavelets with no stable circuit.