Cavo-tricuspid isthmus

Cavo-tricuspid isthmus (CTI) is a part of the anatomy of the heart, specifically located in the right atrium. It is a critical area in the pathophysiology of certain types of cardiac arrhythmias, particularly atrial flutter.

Anatomy

The cavo-tricuspid isthmus is a narrow, fibrous band of tissue in the lower part of the right atrium, between the inferior vena cava (IVC) and the tricuspid valve. It forms the lower border of the triangle of Koch, an important anatomical landmark in the heart.

Clinical significance

The cavo-tricuspid isthmus is a common site of re-entry for atrial flutter. This is a type of supraventricular tachycardia where the electrical signal circulates rapidly around the right atrium, causing the heart to beat faster than normal.

Catheter ablation of the cavo-tricuspid isthmus is a common treatment for atrial flutter. This procedure uses a catheter to deliver energy (usually radiofrequency) to the CTI, creating a line of scar tissue that blocks the re-entry circuit.

See also

• Cardiac electrophysiology
• Electrocardiography
• Cardiac arrhythmia