Functional mapping to reveal slow conduction and substrate progression in atrial fibrillation.

AIMS: The aim of our study was to analyse the response to short-coupled atrial extrastimuli to identify areas of hidden slow conduction (HSC) and their relationship with the atrial fibrillation (AF) phenotype. METHODS AND RESULTS: Twenty consecutive patients with paroxysmal AF and persistent AF (10:10) underwent the first pulmonary vein isolation procedure. Triple short-coupled extrastimuli were delivered in sinus rhythm (SR), and the evoked response was analysed: sites exhibiting double or highly fragmented electrograms (EGM) were defined as positive for HSC (HSC+). The delta of the duration of the bipolar EGM was analysed, and bipolar EGM duration maps were built. High-density maps were acquired using a multipolar catheter during AF, SR, and paced rhythm. Spatial co-localization of HSC+ and complex fractionated atrial EGMs (CFAE) during AF was evaluated. Persistent AF showed a higher number and percentage of HSC+ than paroxysmal AF (13.9% vs. 3.3%, P < 0.001). The delta of EGM duration was 53 ± 22 ms for HSC+ compared with 13 ± 11 (10) ms in sites with negative HSC (HSC-) (P < 0.001). The number and density of HSC+ were lower than CFAE during AF (19 vs. 56 per map, P < 0.001). The reproducibility and distribution of HSC+ in repeated maps were superior to CFAE (P = 0.19 vs. P < 0.001). Sites with negative and positive responses showed a similar bipolar voltage in the preceding sinus beat (1.65 ± 1.34 and 1.48 ± 1.47 mV, P = 0.12). CONCLUSION: Functional mapping identifies more discrete and reproducible abnormal substrates than mapping during AF. The HSC+ sites in response to triple extrastimuli are more frequent in persistent AF than in paroxysmal AF.

Tromboembolismo pulmonar masivo en paciente previamente anticoagulado y con antecedente de intervención de Fontan / Massive pulmonary thromboembolism in patient treaty with anticoagulant previously and with intervention of Fontan

Presentamos el caso de un varón de 18 años sometido a los tres años de vida a la intervención de Fontan por atresia tricuspídea, que ingresó en nuestro servicio de Cardiología por descompensación de insuficiencia cardíaca. Tras estudio exhaustivo se diagnosticó de tromboembolismo pulmonar masivo pese a estar anticoagulado. Hemos realizado una búsqueda bibliográfica de casos similares y aportamos nuestra opinión sobre las recomendaciones sobre anticoagulación en estos pacientes

We present the case of a 18 years-old male subjected to at the age of three years old to the Fontan operation for tricuspid atresia, that entered in our Cardiology Unit for descompensated heart failure. After exhaustive study, a massive pulmonary thromboembolism was diagnosed in spite of the patient was treated with anticoagulant drugs previously. We have carried out a bibliographical search of similar cases and we contribute our opinion on the recommendations about anticoagulation in these patients