Cavotricuspid Isthmus: A Key Structure in Cardiac Electrophysiology

Introduction

The cavotricuspid isthmus (CTI) is an important region in the right atrium of the heart, located between the tricuspid valve and the inferior vena cava. It plays a critical role in certain types of heart arrhythmias, especially atrial flutter.

Anatomy and Function

• The CTI is part of the right atrial anatomy and is a pathway for electrical signals in the heart.
• This region is particularly relevant in typical atrial flutter, where abnormal electrical circuits use the CTI as a conduction pathway.

Clinical Significance

Atrial Flutter and CTI

• Typical atrial flutter involves a circular electrical wave that moves through the right atrium.
• The CTI is a critical part of this reentrant circuit, meaning that blocking conduction in this area can effectively terminate the arrhythmia.

CTI Ablation Procedure

• A catheter ablation procedure is often used to treat CTI-dependent atrial flutter.
• In this procedure, radiofrequency energy is applied to the CTI to interrupt abnormal electrical activity.
• This is a highly successful treatment, with success rates often exceeding 90%.

Associated Conditions

While treating CTI-dependent atrial flutter, doctors must also consider associated conditions: - Atrial fibrillation (AFib) – Many patients with atrial flutter also have episodes of AFib. - Structural heart disease – Conditions like valve disease or previous heart surgery may influence treatment strategies. - Clot formation (thromboembolic risk) – Patients with atrial flutter often need anticoagulation therapy to prevent stroke.

Conclusion

Understanding the cavotricuspid isthmus is essential for diagnosing and treating typical atrial flutter. Catheter ablation is an effective and widely used therapeutic option for patients experiencing this condition.

Source recommendations

1. American Heart Association Guidelines on Atrial Flutter

1. https://www.heart.org/en/health-topics/atrial-fibrillation/what-is-atrial-fibrillation-afib-or-af/atrial-flutter
2. https://www.ahajournals.org/doi/10.1161/CIR.0000000000001193
3. https://www.heart.org/en/health-topics/atrial-fibrillation
4. https://professional.heart.org/en/science-news/2023-acc-aha-accp-hrs-guideline-for-the-diagnosis-and-management-of-atrial-fibrillation
5. https://newsroom.heart.org/news/sweetened-drinks-linked-to-atrial-fibrillation-risk

2. European Society of Cardiology Guidelines on Supraventricular Tachycardia

1. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Supraventricular-Tachycardia
2. https://academic.oup.com/eurheartj/article/41/5/655/5556821
3. https://pubmed.ncbi.nlm.nih.gov/31504425/
4. https://www.acc.org/Latest-in-Cardiology/ten-points-to-remember/2019/09/10/12/36/2019-ESC-Guidelines-for-Supraventricular-Tachycardia
5. https://www.ahajournals.org/doi/10.1161/cir.0000000000000311