Dysplasia of the tricuspid valve leading to recurrent atrial flutter and fibrillation: a case report.

Background: Atrial flutter (AFL) is usually effectively treated by cavotricuspid isthmus (CTI) ablation. If AFL recurs despite ablation, there is risk of progression to atrial fibrillation (AF) and clinicians should consider underlying structural heart diseases. This consideration becomes especially critical when right-heart-chambers are dilated.

Case summary: A 50-year-old man presented with palpitations due to AFL. Fifteen years earlier, after polytrauma, mild tricuspid regurgitation (TR) and pericardial effusion had been diagnosed on transthoracic echocardiography (TTE). At present, TTE showed dilated right-heart-chambers and moderate TR. Despite two CTI-ablations, he developed AF for which he underwent pulmonary vein isolation (PVI). A further ablation was performed because of right-sided AFL due to transcrista conduction. Atrial fibrillation recurred, accompanied by heart failure. Tricuspid regurgitation severity and right-heart-chamber dilatation worsened. Finally, 3D-transoesophageal echocardiography (3D-TEE), performed 20 years after the first TTE, revealed that TR was due to restriction of the septal leaflet. The patient underwent surgery. The tricuspid valve was repaired by ring annuloplasty and a cleft between the anterior and septal leaflets was closed. Three years post-operatively, he is asymptomatic with chronic AF but no recurrent AFL. Transthoracic echocardiography shows only mild TR, though the right-heart-chambers remain dilated, likely due to long-standing TR.

Discussion: Tricuspid regurgitation and AFL/AF have a bidirectional relationship. Tricuspid regurgitation can both cause and result from AFL/AF. Structural heart diseases, including post-traumatic valve damage, should be considered in patients with recurrent AFL despite CTI-ablation and progression to AF. In cases with TR and right-heart-chamber enlargement, 3D-TEE is essential for accurate diagnosis and should be performed without delay.