Successful Catheter Ablation of Focal Left Atrial Tachycardia Originating From the Mitral Annulus Aorta Junction

Abstract

SUMMARYFocal left atrial tachycardias (AT) originating from the mitral annulus-aorta (MA-Ao) junction are rare and their mechanisms are unclear. We report a 35-year-old male with successful ablation of an exercise-induced focal AT due to triggered activity originating from the MA-Ao junction. The AT occurred spontaneously during treadmill exercise testing and was easily induced by an atrial extrastimulus and atrial burst pacing after intravenous administration of isoproterenol. The AT was terminated by an atrial extrastimulus as well as a bolus of 5 mg of adenosine 5'-triphosphate. The coupling intervals of the extrastimuli that induced the AT were positively correlated with the interval between the extrastimuli and the first beat of the AT, suggesting the triggered activity as a tachycardia mechanism. The AT was successfully eliminated by a focal ablation at the MA-Ao junction with the earliest atrial activation where fractionated atrial potentials were recorded. The MA-Ao junction should be recognized as an important arrhythmogenic region. (Int Heart J 2006; 47: 461-468)

Focal Atrial Tachycardia Surrounding the Anterior Septum

“…Furthermore, mapping of the left side of the interatrial septum after a trans-septal puncture is sometimes necessary to identify the optimal ablation site. 9,11,16–18 After the successful ablation of AAS-AT from the NCC was first reported in 2004, 12 more case series of ATs successfully eliminated from the NCC without complications were reported. 4–10,12 Subsequently, ATs from the AAS ablated from the RCC, LCC, and AMJ were described.…”

“…1–10 The close proximity to the atrioventricular (AV) node and the complex anatomy of this region continue to pose challenges during catheter ablation, and although successful ablation sites include the right anterior atrial septum (RAS), 1–3,10 left AAS, 11 noncoronary cusp (NCC), 4–10,12 left coronary cusp (LCC), 13,14 right coronary cusp (RCC), 15 and aortic mitral junction (AMJ), 16–18 the protocol for mapping and ablation, including choice ablation site, of AAS-ATs has thus far not been well defined, which is the subject of this study.…”

Electrophysiologic Characteristics of Ventricular Arrhythmias Arising From the Aortic Mitral Continuity – Potential Role of the Conduction System

“…Although successful ablation of arrhythmias at the AMC has been described, [1][2][3][4][5][6][7][8][9][10][11][12] the exact nature of the arrhythmogenic substrate remains unknown. 4,[13][14][15][16][17] While no myocardium has been found in this region, animal studies have shown that cells with electrophysiological properties similar to that of the atrioventricular (AV) junctional cells are present near the mitral annulus.…”

“…Although successful ablations of arrhythmias at the AMC have been reported in the literature, [1][2][3][4][5][6][7][8][9][10][11][12] knowledge of the clinical, electrocardiographic (ECG), and electrophysiological characteristics of idiopathic ventricular arrhythmias (VAs) arising from this region remains limited. Furthermore, being a fibrous structure, the exact nature of the arrhythmogenic substrate remains unclear.…”

The Cardiac Pacemaker and Conduction System Develops From Embryonic Myocardium that Retains Its Primitive Phenotype

“…Clinically, arrhythmias originating from the mitral and tricuspid annulus region have been reported. [46][47][48] …”