Cavotricuspid isthmus ablation for atrial flutter: Anatomic challenges and troubleshooting

Figure 1. Patient’s electrocardiogram revealing typical atrial flutter.

Figure 2. Intracardiac echocardiography from the redo cavotricuspid isthmus ablation procedure.

Figure 3. In patients with a prominent sub-Eustachian pouch, the catheter can be positioned more laterally to allow better tissue contact and avoid rapid temperature and impedance rises. CS = coronary sinus; CT = crista terminalis; EP = Eustachian pouch; ER = Eustachian ridge; FO = foramen ovale; IVC = inferior vena cava; P = pectinate muscles; TV = tricuspid valve.

Figure 4. In patients with prominent pectinate muscles ablation can be preferably performed more medially to avoid the pectinates. See Figure 3 for abbreviations.

Figure 5. A: Normal anatomy. B: Prominent Eustachian ridge can act as a fulcrum that results in paradoxical lateral movement of the ablation catheter with clockwise torque. C: Arching the catheter over the Eustachian ridge can enable free clockwise or counterclockwise rotation while maintaining contact of the catheter tip with the isthmus. D: Using a guiding sheath over the Eustachian ridge can provide catheter support off of the Eustachian ridge so that clockwise rotation results in catheter movement toward the septum.

Figure 6. A: The right coronary artery (RCA) and the small cardiac vein (SCV) run on the epicardial aspect of the cavotricuspid isthmus (CTI) and can cause a “heat sink” effect when ablating the CTI. B: The problem can be addressed by ablation power uptitration guided by temperature and impedance monitoring. C, D: Alternatively, epicardial ablation of the CTI can be performed by advancing the ablation catheter into the SCV. CS = coronary sinus; IVC = inferior vena cava; LA = left atrium; LV = left ventricle; RA = right atrium; RV = right ventricle; SVC = superior vena cava.

Figure 7. A: Preprocedure cardiac computed tomography identified the small cardiac vein (black arrow) in a patient with tricuspid annuloplasty ring and cavotricuspid isthmus (CTI)-dependent atrial flutter. B: Intracardiac echocardiography (ICE) imaging shows the tip of the ablation catheter in the small cardiac vein (yellow arrow). Ablation in the small cardiac vein (SCV) was necessary for CTI block since a portion of the CTI tissue was inaccessible from the endocardium owing to the presence of the annuloplasty ring. MCV = middle cardiac vein. Reproduced with permission from Kella and colleagues.10