Circulation Journal REVIEW Official Journal of the Japanese Circulation Society http://www.j-circ.or.jp Catheter Ablation of Tachyarrhythmias From the Aortic Sinuses of Valsalva – When and How? – Hiroshi Tada, MD, PhD The aortic root is at the center of the heart. Each of the aortic sinuses of Valsalva, positioned at the base of the aortic root, is in contact with the atrial myocardium and/or ventricular myocardium at their bases, which enables mapping and ablating of some ventricular arrhythmias with an outflow tract origin and supraventricular tachycardias (ie, atrial tachycardia, accessory pathways) from the aortic sinuses of Valsalva. These arrhythmias have character- istic electrocardiographic findings associated with their origins, and almost all are difficult to ablate from an atrial or ventricular endocardial site. Site-specific and potential complications, such as a coronary artery occlusion or atrio- ventricular block, can occur with catheter ablation at the aortic sinuses of Valsalva. Therefore, accurate diagnosis and proper ablation at the aortic sinuses of Valsalva are required for a cure. This review describes the anatomic features of the aortic sinuses of Valsalva and focuses on the diagnosis and radiofrequency catheter ablation of ar- rhythmias that can be ablated from this site. (Circ J 2012; 76: 791 – 800) Key Words: Aortic sinus of Valsalva; Catheter ablation; Supraventricular tachycardia; Ventricular arrhythmia adiofrequency (RF) catheter ablation has been estab- left coronary sinus of Valsalva (LSV) are connected with the lished as an effective and curative therapy for ven- ventricular musculature at their bases (Figures 1,2A). Al- R tricular tachycardias (VTs) or symptomatic premature though ventricular arrhythmias can be ablated either within ventricular contractions (PVCs) originating from the outflow or below the RSV or LSV, it is the myocardium of the LV tract (VT/PVCs).1–3 Although most of these arrhythmias have ostium that is the target for ablation.16,17 The remaining pos- their origin in the right ventricular outflow tract (RVOT),1–3 it terior part of the LSV and the entire non-coronary sinus of has become clear that some could be ablated from the aortic Valsalva (NSV) do not come in direct contact with the LV sinuses of Valsalva.1–6 Furthermore, recent studies have dem- myocardium, and the NSV is exclusively composed of fibrous onstrated that some supraventricular tachycardias are also abol- walls (Figures 1,2).12,15 The RVOT is usually situated slightly ished by RF catheter ablation within the aortic sinuses of Val- anterior and superior to the RSV and is adjacent to the supe- salva.7–11 rior area of the RVOT (Figure 2). The right atrial appendage and superior vena cava/right atrial junction may overlie por- tions of the RSV. The NSV is the most posterior of the 3 si- Anatomy of the Aortic Root nuses, and is located between the right and left atria, immedi- The aortic root, which is the portion of the aortic valve from ately anterior to the interatrial septum (Figure 2). In some its position at the left ventricular (LV) outlet to its junction patients, the posterior portion of the RSV can be related to the with the ascending portion of the aorta (sinotubular junction), interatrial septum or to the anteroseptal portion of the annular, forms the center of the heart.12–16 It is adjacent but to the anteroseptal portion of the right atrium. The LSV is typically right and posterior of the subpulmonary infundibulum, with not anatomically related to either the right or left atrium. Im- its posterior margin wedged between the orifice of the mitral portantly, the commissure between the NSV and RSV is lo- valve and the muscular ventricular septum (Figure 1A). The cated immediately adjacent to the commissure of the anterior basal portion of the aortic root consists of the sinus of Valsal- and septal leaflets of the tricuspid valve. The joining of these va, fibrous interleaflet triangles, and the valvular leaflets them- commissures forms the membranous portion of the interven- selves (Figure 1B). The aortic root is connected to the muscu- tricular septum and is the location of the penetrating bundle lar ventricular septum, with the remaining one-third in fibrous of His and, more distally, the origin of the left bundle branch. continuity with the aortic leaflet of the mitral valve. The right The compact atrioventricular (AV) node itself is located more coronary sinus of Valsalva (RSV) and the anterior part of the posteriorly and inferiorly to this commissure. The fast pathway Received January 17, 2012; accepted February 20, 2012; released online March 6, 2012 Cardiovascular Division, Institute of Clinical Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan Mailing address: Hiroshi Tada, MD, PhD, Cardiovascular Division, Institute of Clinical Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan. E-mail: [email protected] ISSN-1346-9843 doi: 10.1253/circj.CJ-11-1554 All rights are reserved to the Japanese Circulation Society. For permissions, please e-mail: [email protected] Circulation Journal Vol.76, April 2012 792 TADA H Figure 1. (A) Diagram of the aortoventricular membrane that covers the left ventricular (LV) ostium. The red arrows indicate the zone where the left and right aortic sinuses of Valsalva come in contact with the ventricular myocardium of the LV ostium. (B) Relationship between the aortic valve and mitral valve. The basal portion of the aortic root consists of the sinuses of Valsalva, fi- brous interleaflet triangles, and the valvular leaflets themselves. The aortic root is connected to the muscular ventricular septum, with the remaining one-third in fibrous continuity with the aortic leaflet of the mitral valve (light pink areas below the left and non- coronary aortic sinuses of Valsalva). A-M, aortic-mitral; AML, anterior mitral leaflet; L, left aortic sinus of Valsalva; LA, left atrial; LFT, left fibrous trigone; N, non-coronary sinus of Valsalva; PML, posterior mitral leaflet; R, right sinus of Valsalva. input to the AV node, however, is located directly posterior to V1 or V2, and R/S-wave amplitude ratio in lead V1 or V22,4 are this commissure and is thus related to the anterior portion of useful. Early precordial R-wave transition and the presence of the NSV. The triangle between the right- and non-coronary an S-wave in lead I favor LSV-VT/PVCs rather than ROVT- leaflets adjoins the interventricular part of the membranous VT/PVCs (Figure 3B-a,b).2 Some patients with LSV-VT/ septum, which together with the right fibrous trigone, forms PVCs have a late R-wave transition (after V3), which may be the central fibrous body Figure( 1B). This anatomical relation- explained by preferential conduction to the RVOT.22 An R/S- ship is important because energy application in the NSV and wave amplitude index (calculated from the greater percentage RSV is potentially associated with a substantial risk for AV of the R/S-wave amplitude ratio in lead V1 or V2) ≥0.3 and an nodal block.18 R-wave duration index (calculated percentage by dividing the QRS complex duration by the longer R-wave duration in lead V1 or V2) ≥50% are both useful for differentiating LSV-VT/ Ventricular Arrhythmias PVCs from RVOT-VT/PVCs (Figure 3B-c,d).2,4 A high R/S- The connection of the myocardium of the LV ostium to the wave amplitude ratio in lead V1 or V2 may reflect a more pos- RSV and anterior part of the LSV enables abolition of VT/ terior location of the LSV compared with an endocardial area PVCs arising from this portion by application of RF energy of the RVOT. Although an S-wave (≥0.1 mV) in lead V6 is within these 2 aortic sinuses. Recently, 2 cases of successful present in VT/PVCs of an LV endocardial origin, it is absent elimination of VT/PVCs by catheter ablation from the NSV in VT/PVCs arising from the LSV or LVOT just beneath the have been reported.19,20 However, it is very rare because the LSV.2,5 Recently, the V2 transition ratio for differentiating be- ventricular myocardium is not adjacent to the NSV. Outflow tween VT/PVCs arising from the left side and those from the tract VT/PVCs, including those with origins in these 2 aortic right side23 and the transition zone (TZ) index for distinguish- sinus, usually demonstrate a single bundle branch block QRS ing aortic sinus VT/PVCs from RVOT-VT/PVCs24 were re- morphology with an inferior axis, and triggered activity is ported. The use of these novel ECG criteria may increase the considered as their mechanism.21 The VT/PVCs arising from accuracy of diagnosis. the LSV and RSV should be differentiated from those arising Even if the earliest ventricular activation of a VT/PVC is at from the RVOT (RVOT-VT/PVCs) in order to obtain a cure the LSV, some VT/PVCs cannot be ablated from the LSV be- and avoid futile RF energy applications and ensuing complica- cause of the distance from the LSV. These OT-VTs (Epi-VT/ tions (Figures 3A,4A). PVCs) are thought to originate from the LV epicardial portion around the transitional area from the great cardiac vein to the Ventricular Arrhythmias Arising From the LSV anterior interventricular vein or LV summit.6,25 Neither the R/S- (LSV-VT/PVCs) wave amplitude index nor the R-wave duration index is helpful To differentiate VT/PVCs arising from the left side (LVOT, for differentiating LVEpi-VT/PVC from LSV-VT/PVC because LSV or LV epicardium remote from the LSV) and those from most LVEpi-VT/PVCs fulfill the criteria of LSV-VT.2 The the right side (RVOT-VT/PVCs), the precordial R-wave transi- LVEPi-VT/PVCs are often associated with S-waves in lead I, tion,1,2 QRS morphology in lead I,1,2 R-wave duration in lead an early R-wave transition (≤lead V3), and a degree of slurring Circulation Journal Vol.76, April 2012 Ablation From the Aortic Sinuses of Valsalva 793 Figure 2.