Recurrence of Typical Counter-clockwise Atrial Flutter in a Postsurgical Patient: an Unexpected Trap

Abstract

This is a 49-year-old male patient with prior surgery for mitral valve replacement at the ages of 33 and 47. The surgical interventions comprised right atrial atriotomy and direct suture of an atrial septal defect. After the second intervention, the patient began complaining of palpitations. Initially, the episodes were short-lasting and self-terminating, but they later became persistent, were documented in all cases as typical common atrial flutter (Fig. 1a) and invariably recurred after DC-shock cardioversion in spite of therapy with oral amiodarone. During the year before undergoing the procedure described here, the patient developed left bundle branch block, initially rate-dependent and subsequently permanent. Echocardiogram showed enlarged right and left atria, normal functioning of the prosthetic mechanical mitral valve and preserved left ventricular function. While experiencing counter-clockwise typical atrial flutter at 250 ms cycle length, the patient was admitted to our institution. Cavotricuspid isthmus ablation terminated the arrhythmia and produced bidirectional conduction block, restoring stable sinus rhythm. However, two weeks later, the patient had recurrence of palpitations. Surface ECG showed recurrence of what appeared to be the same arrhythmia (Fig. 1b), but with a longer cycle length (305 ms), most likely due to conduction resumption over the cavotricuspid isthmus, delayed by previous ablation. For the recurrent arrhythmia, the patient was re-admitted for a second electrophysiologic procedure.