Substrate associated with atypical flutter is:

Substrate associated with atypical flutter is:

• A. Scar tissue
• B. Normal atrial tissue
• C. Inflammation
• D. Hypertrophy

Answer: (A)

Atypical flutter relies on a fixed obstacle in the atrial tissue that creates a reentrant circuit. Scar tissue provides that obstacle because fibrosis produces patchy conduction with slow paths and blocks, forming a loop that the impulse can continuously travel around. This scar-related substrate is common after surgery, ablation, infarction, or chronic atrial disease, and it creates the necessary nonuniform conduction for a macro-reentrant tachycardia to sustain. Normal atrial tissue lacks the defined block needed for a stable reentrant circuit, inflammation tends to be transient and variable rather than a permanent substrate, and hypertrophy, while it enlarges tissue, does not by itself establish the conduction barriers required for this type of flutter.

Atypical flutter relies on a fixed obstacle in the atrial tissue that creates a reentrant circuit. Scar tissue provides that obstacle because fibrosis produces patchy conduction with slow paths and blocks, forming a loop that the impulse can continuously travel around. This scar-related substrate is common after surgery, ablation, infarction, or chronic atrial disease, and it creates the necessary nonuniform conduction for a macro-reentrant tachycardia to sustain. Normal atrial tissue lacks the defined block needed for a stable reentrant circuit, inflammation tends to be transient and variable rather than a permanent substrate, and hypertrophy, while it enlarges tissue, does not by itself establish the conduction barriers required for this type of flutter.