Where is the cavotricuspid isthmus located?

Where is the cavotricuspid isthmus located?

• A. Between the tricuspid valve and the inferior vena cava
• B. Between the tricuspid valve and the right atrial appendage
• C. Between the mitral valve and the aorta
• D. Between the interatrial septum and the tricuspid valve

Answer: (A)

The cavotricuspid isthmus is a region on the right atrium that lies between the tricuspid valve annulus and the opening of the inferior vena cava. This area forms the inferior boundary of the right atrial chamber and is the classic corridor through which typical atrial flutter circuits travel, making it the main target for ablation to interrupt the flutter. The other options point to boundaries that are not this region: near the right atrial appendage, in the left-sided heart structures, or between the interatrial septum and the tricuspid valve.

The cavotricuspid isthmus is a region on the right atrium that lies between the tricuspid valve annulus and the opening of the inferior vena cava. This area forms the inferior boundary of the right atrial chamber and is the classic corridor through which typical atrial flutter circuits travel, making it the main target for ablation to interrupt the flutter. The other options point to boundaries that are not this region: near the right atrial appendage, in the left-sided heart structures, or between the interatrial septum and the tricuspid valve.