Two-dimensional echocardiographic features of the inferior right atrial isthmus: the role of vestibular thickness in catheter ablation of atrial flutter

• Published in: European heart journal cardiovascular imaging 2014-01, Vol.15 (1), p.32-40
• Main Authors: Marcos-Alberca, Pedro, Sánchez-Quintana, Damián, Cabrera, José A, Farré, Jerónimo, Rubio, José M, de Agustín, Jose A, Almería, Carlos, Pérez-Isla, Leopoldo, Macaya, Carlos
• Format: Article
• Language: English
• Subjects: Aged; Atrial Flutter - diagnostic imaging; Atrial Flutter - pathology; Atrial Flutter - surgery; Cadaver; Catheter Ablation - methods; Coronary Angiography; Echocardiography; Electrophysiologic Techniques, Cardiac; Feasibility Studies; Female; Humans; Male; Middle Aged; Predictive Value of Tests; Sensitivity and Specificity; Tachycardia, Supraventricular - diagnostic imaging; Treatment Outcome; Tricuspid Valve - diagnostic imaging; Tricuspid Valve - pathology; Tricuspid Valve - surgery
• ISSN: 2047-2404; 2047-2412
• DOI: 10.1093/ehjci/jet112

The aim of this study was to examine the feasibility of transthoracic two-dimensional (2D)-echocardiography in defining the cavo-tricuspid isthmus (CTI) anatomy and its value concerning the ease of catheter ablation of isthmic atrial flutter (AF). CTI analysis was accomplished in 39 cases: 16 necropsy specimens and 23 patients. Sixteen were patients with isthmus-dependent AF and seven controls with other supraventricular re-entrant tachycardias. Two-dimensional transthoracic echocardiography and a right atrium angiogram were performed before radiofrequency catheter ablation (RFCA). The measurements of the CTI with angiography were compared with those taken with echocardiography and correlation was excellent (r= 0.91; P < 0.0001). In normal patients, the dimension of the vestibular thickness was successfully compared and validated with the histological examination of the necropsy specimens: histology median 6.8 mm, range 4.4-10.5 vs. echo median 6.2 mm, range 5.4-8.7; P: NS. Vestibular thickness was greater in complex than in simple RFCA (13.6 ± 1.9 mm vs. 10.0 ± 2.3 mm; P = 0.01). When vestibular thickness ≥11.5 mm, the ablation prone to be complex (sensitivity 83.3%, specificity 80%, positive predictive value 71.4%, and negative predictive value 88.9%). Two-dimensional transthoracic echocardiography clearly depicts the inferior isthmus and, displaying the thickness of the tricuspid vestibule, it was related with complexity of the ablation procedure in isthmus-dependent AF.