Macroreentrant Atrial Tachycardia in a Left Atrium With a Prosthetic Mitral Valve (Example 2): the Problem of Minimal Amplitude Potentials
This is a 43-year-old male patient who had rheumatic disease during childhood and developed mitral stenosis associated with regurgitation. At the age of 39, he underwent mitral valve replacement with a mechanical prosthesis. Since he suffered from episodes of atrial fibrillation before surgical intervention, intraoperative ablation of the pulmonary vein was carried out as well, but a detailed description of the procedure was missing. At the age of 41, 2 years prior to our observation, he had recurrent typical atrial flutter, for which he underwent ablation of the cavotricuspid isthmus conduction at another centre. Subsequently, he suffered from very frequently recurring episodes of atrial tachycardia, which usually showed a long cycle length (570 ms) with positive P waves in the inferior leads and in the precordial leads V1-V5, flat in I and V6 and negative in aVL (Fig. 1). The arrhythmia recurred in spite of antiarrhythmic drug therapy with flecainide, sotalol and amiodarone, which was withdrawn 9 months prior to our observation for thyroid dysfunction. Then, the patient was referred for catheter ablation. Transthoracic echocardiogram showed an enlarged left atrium with preserved left ventricular function; the transesophageal echocardiogram showed no intracavitary thrombus. The procedure was performed 1 week after withdrawal of the last antiarrhythmic drug therapy (combination of flecainide and sotalol).
KeywordsPulmonary Vein Left Atrium Cycle Length Coronary Sinus Antiarrhythmic Drug Therapy
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