History, current illness and physical examination
A 79-year-old woman under follow-up for frequent palpitations without associated structural heart disease, who was referred for an electrophysiological study and possible ablation of atrial tachycardia. She had a history of hypertension and dyslipidaemia.
Physical examination was normal. The echocardiogram showed a non-dilated left ventricle with preserved LVEF and no significant valvular abnormalities. In a Holter study, there were episodes of non-sustained atrial tachycardia. The usual laboratory tests were normal and the chest X-ray showed no evidence of pleuropulmonary disease or significant alterations in the cardiopericardial silhouette. He was on antiarrhythmic treatment with atenolol 50 mg/12h. Other cardiological treatment: eprosartan, hydrochlorothiazide, amlodipine, furosemide, pitavastatin, ezetimibe.

Complementary tests
Baseline electrocardiogram: sinus rhythm at 101 bpm. PR 173 ms, QRS: 99 ms. Left ventricular systolic overload. Non-sustained atrial tachycardia.

Clinical course
Electrocatheters were introduced via femoral approach for electrophysiological studies in the RA, RV and His, in the coronary sinus, as well as an ablation catheter. Basically, non-sustained atrial tachycardia was observed with a negative P wave in the inferior face, positive in D1 and aVL. Under isoproterenol administration it becomes sustained. AH: 120 ms and HV: 48 ms. Electroanatomical mapping of the RA was performed, with greater precocity in the perihisian region. Patent foramen ovale. Retrograde aortic mapping was performed, with greater precocity in the posterior aortic sinus in the vicinity of the right aortic sinus. In this area a precocity of 39 ms is obtained with respect to the P wave. RF energy is applied with interruption of the tachycardia in the first second. Then 3 minutes of safety is applied around the area, first with 20 watts and then with 30 watts. At the end of the procedure, sinus rhythm of 75 bpm and HRBBB of mechanical aetiology was observed. There were no significant complications and the patient was discharged the day after the procedure.

Diagnosis
Atrial tachycardia originating in the posterior aortic sinus region. Radiofrequency ablation of the tachycardia via retrograde aortic route with efficacy criteria.
