Block of the mitral-pulmonary isthmus during ablation of a single left-sided accessory pathway causing different patterns of retrograde atrial activation.
The case of a 16-year-old patient with atrioventricular tachycardia caused by a single left anterolateral accessory pathway is reported. When the patient underwent radiofrequency ablation, a lesion on the mitral annulus lateral wall produced changes in the retrograde atrial activation pattern determined by that pathway; changes ranged from a delay in depolarization of the annulus posterior portions to full left atrium counterclockwise activation. Such phenomena were probably caused by a block in the isthmus between the annulus and the lower left pulmonary vein ostium. This case illustrates the importance of the mitral-pulmonary isthmus in the process of left atrium activation, an alert to changes induced by its unintentional block during accessory pathway ablation.
de Vasconcelos
José Tarcísio Medeiros
JT
Clínica de Ritmologia Cardíaca, Hospital Beneficência Portuguesa de São Paulo.
Costa
Eduardo Rodrigues Bento
ER
dos Santos Galvão Filho
Silas
S
Barcellos
Cecília Monteiro Boya
CM
Maldonado
Jaime Giovany Arnez
JG
D000293:Adolescent; D016279:Atrial Function, Left / Q000502:physiology*; D017115:Catheter Ablation / Q000009:adverse effects*; D004562:Electrocardiography; D005260:Female; D006327:Heart Block / Q000209:etiology*; D006329:Heart Conduction System / Q000002:abnormalities; D006801:Humans; D008943:Mitral Valve / Q000503:physiopathology*; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000601:surgery*