Electroanatomic reconstruction of the left atrium, pulmonary veins, and esophagus compared with the "true anatomy" on multislice computed tomography in patients undergoing catheter ablation of atrial fibrillation

BACKGROUND: Current concepts of catheter ablation for atrial fibrillation (AF) commonly use three-dimensional (3D) reconstructions of the left atrium (LA) for orientation, catheter navigation, and ablation line placement. OBJECTIVES: The purpose of this study was to compare the 3D electroanatomic reconstruction (Carto) of the LA, pulmonary veins (PVs), and esophagus with the true anatomy displayed on multislice computed tomography (CT). METHODS: In this prospective study, 100 patients undergoing AF catheter ablation underwent contrast-enhanced spiral CT scan with barium swallow and subsequent multiplanar and 3D reconstructions. Using Carto, circumferential plus linear LA lesions were placed. The esophagus was tagged and integrated into the Carto map. RESULTS: Compared with the true anatomy on CT, the electroanatomic reconstruction accurately displayed the true distance between the lower PVs; the distances between left upper PV, left lower PV, right lower PV, and center of the esophagus; the longitudinal diameter of the encircling line around the funnel of the left PVs; and the length of the mitral isthmus line. Only the distances between the upper PVs, the distance between the right upper PV and esophagus, and the diameter of the right encircling line were significantly shorter on the electroanatomic reconstructions. Furthermore, electroanatomic tagging of the esophagus reliably visualized the true anatomic relationship to the LA. On multiple tagging and repeated CT scans, the LA and esophagus showed a stable anatomic relationship, without relevant sideward shifting of the esophagus. CONCLUSION: Electroanatomic reconstruction can display with high accuracy the true 3D anatomy of the LA and PVs in most of the regions of interest for AF catheter ablation. In addition, Carto was able to visualize the true anatomic relationship between the esophagus and LA. Both structures showed a stable anatomic relationship on Carto and CT without relevant sideward shifting of the esophagus.

Pulmonary veins to left atrium cycle length gradient predicts procedural and clinical outcomes of persistent atrial fibrillation ablation.

BACKGROUND Rapid pulmonary vein (PV) activity has been shown to maintain paroxysmal atrial fibrillation (AF). We evaluated in persistent AF the cycle length (CL) gradient between PVs and the left atrium (LA) in an attempt to identify the subset of patients where PVs play an important role. METHODS AND RESULTS Ninety-seven consecutive patients undergoing first ablation for persistent AF were studied. For each PV, the CL of the fastest activation was assessed over 1 minute (PVfast) using Lasso recordings. The PV to LA CL gradient was quantified by the ratio of PVfast to LA appendage (LAA) AF CL. Stepwise ablation terminated AF in 73 patients (75%). In the AF termination group, the PVfast CL was much shorter than the LAA CL resulting in lower PVfast/LAA ratios compared with the nontermination group (71±10% versus 92±7%; P<0.001). Within the termination group, PVfast/LAA ratios were notably lower if AF terminated after PV isolation or limited adjunctive substrate ablation compared with patients who required moderate or extensive ablation (63±6% versus 75±8%; P<0.001). PVfast/LAA ratio <69% predicted AF termination after PV isolation or limited substrate ablation with 74% positive predictive value and 95% negative predictive value. After a mean follow-up of 29±17 months, freedom from arrhythmia recurrence off-antiarrhythmic drugs was achieved in most patients with PVfast/LAA ratios <69% as opposed to the remaining population (80% versus 43%; P<0.001). CONCLUSIONS The PV to LA CL gradient may identify the subset of patients in whom persistent AF is likely to terminate after PV isolation or limited substrate ablation and better long-term outcomes are achieved.

Interventional management of recurrent paroxysmal atrial fibrillation despite isolated pulmonary veins: impact of an ablation strategy targeting inducible atrial tachyarrhythmias

AIMS Pulmonary vein isolation (PVI) is an effective treatment option for paroxysmal atrial fibrillation (PAF). Reconnection of pulmonary veins (PVs) is the predominant cause for recurrence of PAF. However, treatment of patients with recurrence of PAF despite isolated PV in the absence of extra-PV foci remains challenging. METHODS AND RESULTS Of 265 patients undergoing repeat catheter ablation (CA) for recurrence of PAF 21 (8%) patients (14 men, age 58 ± 14 years) showed no reconnection of PV. Therefore, inducibility of sustained atrial arrhythmias was tested. If sustained atrial fibrillation (AF) or sustained atrial tachycardia (AT) was induced, patients underwent CA. During follow-up (FU), Holter- and Tele-electrocardiogram were performed. In 19 (91%) of 21 patients, sustained atrial arrhythmias [16 (84%) AF; 3 (15%) patients AT] were induced. One patient showed PAF. Eighteen patients underwent CA aiming for termination of induced arrhythmia. In 14 (77%) patients, termination into sinus rhythm was achieved. Despite extensive CA, three (16%) patients were externally cardioverted. No periprocedural complications occurred. During 21.2 ± 6.8-month FU, 10 (53%) patients were free of any arrhythmia. Paroxysmal atrial fibrillation recurred in 4 (21%) and AT in 5 (26%) patients. One patient showed persistent AF. Repeat CA was scheduled and successfully performed for these patients. CONCLUSION In patients with recurrence of PAF despite isolated PV, termination of induced atrial arrhythmias can be achieved in most patients by defragmentation and AT ablation. Moreover, this ablation strategy results in favourable mid-term outcome results.

16q24.1 microdeletion in a premature newborn: Usefulness of array-based comparative genomic hybridization in persistent pulmonary hypertension of the newborn.

OBJECTIVE:: Report of a 16q24.1 deletion in a premature newborn, demonstrating the usefulness of array-based comparative genomic hybridization in persistent pulmonary hypertension of the newborn and multiple congenital malformations. DESIGN:: Descriptive case report. SETTING:: Genetic department and neonatal intensive care unit of a tertiary care children's hospital. INTERVENTIONS:: None. PATIENT:: We report the case of a preterm male infant, born at 26 wks of gestation. A cardiac malformation and bilateral hydronephrosis were diagnosed at 19 wks of gestation. Karyotype analysis was normal, and a 22q11.2 microdeletion was excluded by fluorescence in situ hybridization analysis. A cesarean section was performed due to fetal distress. The patient developed persistent pulmonary hypertension unresponsive to mechanical ventilation and nitric oxide treatment and expired at 16 hrs of life. MEASUREMENTS AND MAIN RESULTS:: An autopsy revealed partial atrioventricular canal malformation and showed bilateral dilation of the renal pelvocaliceal system with bilateral ureteral stenosis and annular pancreas. Array-based comparative genomic hybridization analysis (Agilent oligoNT 44K, Agilent Technologies, Santa Clara, CA) showed an interstitial microdeletion encompassing the forkhead box gene cluster in 16q24.1. Review of the pulmonary microscopic examination showed the characteristic features of alveolar capillary dysplasia with misalignment of pulmonary veins. Some features were less prominent due to the gestational age. CONCLUSIONS:: Our review of the literature shows that alveolar capillary dysplasia with misalignment of pulmonary veins is rare but probably underreported. Prematurity is not a usual presentation, and histologic features are difficult to interpret. In our case, array-based comparative genomic hybridization revealed a 16q24.1 deletion, leading to the final diagnosis of alveolar capillary dysplasia with misalignment of pulmonary veins. It emphasizes the usefulness of array-based comparative genomic hybridization analysis as a diagnostic tool with implications for both prognosis and management decisions in newborns with refractory persistent pulmonary hypertension and multiple congenital malformations.

Endovascular treatment of pulmonary arteriovenous malformations in hereditary haemorrhagic telangiectasia.

PRINCIPLES: To assess the efficiency and complication rates of vaso-occlusion of pulmonary arteriovenous malformations (PAVMs) in Rendu-Osler-Weber disease (hereditary haemorrhagic telangectasia; HHT). METHODS: Seventy-two patients were investigated in our institution for HHT between March 2000 and November 2011. Sixteen presented PAVMs (22.2%), and 11 (68.8%) were treated with vaso-occlusion for a total of 18 procedures. Procedures included coils, plugs and combined approaches. Immediate success and recurrence rate, complication were recorded, as well as persistent and new PAVMs during clinical and computed tomography (CT) follow-up. RESULTS: Eighteen procedures were performed and a total of 37 PAVMs were treated, 19 with coils, 16 with plugs and 2 with combined treatment. Mean CT follow-up time was 41 months (1‒164). No major complication was observed. One distal translocation was treated during the same intervention. Two PAVMs persisted after treatment (5.7%), both treated by means of plug embolisation. One new PAVM was observed during follow-up CT. PAVMs with an afferent artery of less than 3mm or asymptomatic PAVMs were not treated. CONCLUSION: Recent studies have demonstrated that vaso-occlusion has become the gold standard treatment for PAVM. This study is in accordance with previous results and shows a minimal complication rate and little recurrence, whether by coils, plugs, or combined treatments.

Loss of pace capture on the ablation line: a new marker for complete radiofrequency lesions to achieve pulmonary vein isolation

Catheter ablation procedures for atrial fibrillation (AF) often involve circumferential antral isolation of pulmonary veins (PV). Inability to reliably identify conduction gaps on the ablation line necessitates placing additional lesions within the intended lesion set.

Pulmonary venous flow velocity patterns in 404 individuals without cardiovascular disease

OBJECTIVE To determine the pulmonary venous flow velocity (PVFV) values in a large normal population. DESIGN Prospective study in consecutive individuals. SETTING University hospital. METHODS Among 404 normal individuals, the flow velocity pattern in the right upper pulmonary vein was recorded in 315 subjects using transthoracic echocardiography, and in both upper pulmonary veins in 100 subjects using transoesophageal echocardiography. Subjects were divided into five age groups. The PVFV values were compared between transthoracic and transoesophageal echocardiography within the age groups, and intraindividually between the right and left upper pulmonary veins in transoesophageal echocardiography. RESULTS Normal PVFV values for the right upper pulmonary vein in transthoracic and transoesophageal echocardiography are presented. The duration of flow reversal at atrial contraction was overestimated using transthoracic echocardiography (mean (SD): 96 (21) ms in transoesophageal echocardiography, 120 (28) ms in transthoracic echocardiography, p < 0.0001). Systolic to diastolic peak flow velocity ratio (S:D) increased earlier with advancing age with transoesophageal echocardiography than with transthoracic echocardiography. Similar results were found for the corresponding time-velocity integrals. Data from the left and right upper pulmonary veins differed with respect to onset and deceleration of flow velocities, but not for flow durations or peak velocities. CONCLUSIONS Normal PVFV values generally show a wide range. The data presented will be of value in assessing left ventricular diastolic function and mitral regurgitation using the PVFV pattern.

Trigger activity more than three years after left atrial linear ablation without pulmonary vein isolation in patients with atrial fibrillation.

OBJECTIVES The aim of this study was to analyze trigger activity in the long-term follow-up after left atrial (LA) linear ablation. BACKGROUND Interventional strategies for curative treatment of atrial fibrillation (AF) are targeted at the triggers and/or the maintaining substrate. After substrate modification using nonisolating linear lesions, the activity of triggers is unknown. METHODS With the LA linear lesion concept, 129 patients were treated using intraoperative ablation with minimal invasive surgical techniques. Contiguous radiofrequency energy-induced lesion lines involving the mitral annulus and the orifices of the pulmonary veins without isolation were placed under direct vision. RESULTS After a mean follow-up of 3.6 +/- 0.4 years, atrial ectopy, atrial runs, and reoccurrence of AF episodes were analyzed by digital 7-day electrocardiograms in 30 patients. Atrial ectopy was present in all patients. Atrial runs were present in 25 of 30 patients (83%), with a median number of 9 runs per patient/week (range 1 to 321) and a median duration of 1.2 s/run (range 0.7 to 25), without a significant difference in atrial ectopy and atrial runs between patients with former paroxysmal (n = 17) or persistent AF (n = 13). Overall, 87% of all patients were completely free from AF without antiarrhythmic drugs. CONCLUSIONS A detailed rhythm analysis late after specific LA linear lesion ablation shows that trigger activity remains relatively frequent but short and does not induce AF episodes in most patients. The long-term success rate of this concept is high in patients with paroxysmal or persistent AF.

Thoracic Duct Decompression for Protein-Losing Enteropathy in Failing Fontan Circulation

An infrequent but devastating late complication of Fontan circulation is protein-losing enteropathy (PLE), which results from unbalanced lymphatic homeostasis. Surgical decompression of the thoracic duct by redirecting its drainage to the pulmonary venous atrium has been introduced recently as a possible treatment. This report describes a single-institution experience with this innovative procedure in 2 patients with failing Fontan circulation with PLE refractory to optimized medical therapy.

Extracorporeal membrane oxygenation support after heart explantation: a proposal on how to deal with hyperacute rejection of heart transplant

Purpose: In extreme situations, such as hyperacute rejection of heart transplant or major bleeding per-operating complications, an urgent heart explantation might be the only means of survival. The aim of this experimental study was to improve the surgical technique and the hemodynamics of an Extracorporeal Membrane Oxygenation (ECMO) support through a peripheral vascular access in an acardia model. Methods: An ECMO support was established in 7 bovine experiments (59±6.1 kg) by the transjugular insertion to the caval axis of a self-expanded cannula, with return through a carotid artery. After baseline measurements of pump flow and arterial and central venous pressure, ventricular fibrillation was induced (B), the great arteries were clamped, the heart was excised and right and left atria remnants, containing the pulmonary veins, were sutured together leaving an atrial septal defect (ASD) over the cannula in the caval axis. Measurements were taken with the pulmonary artery (PA) clamped (C) and anastomosed with the caval axis (D). Regular arterial and central venous blood gases tests were performed. The ANOVA test for repeated measures was used to test the null hypothesis and a Bonferroni t method for assessing the significance in the between groups pairwise comparison of mean pump flow. Results: Initial pump flow (A) was 4.3±0.6 L/min dropping to 2.8±0.7 L/min (P B-A= 0.003) 10 minutes after induction of ventricular fibrillation (B). After cardiectomy, with the pulmonary artery clamped (C) it augmented not significantly to 3.5±0.8 L/min (P C-B= 0.33, P C-A= 0.029). Finally, PA anastomosis to the caval axis was followed by an almost to baseline pump flow augmentation (4.1±0.7 L/min, P D-B= 0.009, P D-C= 0.006, P D-A= 0.597), permitting a full ECMO support in acardia by a peripheral vascular access. Conclusions: ECMO support in acardia is feasible, providing new opportunities in situations where heart must urgently be explanted, as in hyperacute rejection of heart transplant. Adequate drainage of pulmonary circulation is pivotal in order to avoid pulmonary congestion and loss of volume from the normal right to left shunt of bronchial vessels. Furthermore, the PA anastomosis to the caval axis not only improves pump flow but it also permits an ECMO support by a peripheral vascular access and the closure of the chest.

Caracterización de las variantes anatómicas de las venas pulmonares en pacientes candidatos a aislamiento de venas pulmonares en Colombia

Introducción y objetivos: El conocimiento de la anatomía de las venas pulmonares y de la aurícula izquierda es fundamental para la planeación y prevención de posibles complicaciones durante la ablación de las venas pulmonares, procedimiento realizado para el manejo de la fibrilación auricular. Este estudio pretende caracterizar la anatomía (tamaño y forma) de las venas pulmonares y determinar las variantes anatómicas más comunes de las mismas. Métodos: Se analizaron 277 estudios de angioresonancia tridimensional y tomografía computarizada realizados previo al procedimiento de aislamiento de venas pulmonares. Se evaluaron los diámetros de la aurícula izquierda, de los ostia de las venas pulmonares y se determinaron la presencia de venas pulmonares comunes, accesorias y ramificaciones tempranas. Resultados: 75% de nuestros pacientes presentaron la anatomía normal de dos venas pulmonares derechas y dos izquierdas. En un 10,1% de los casos se encontraron venas supernumerarias y en un 11,2% se encontró un tronco común. En un 61% de los pacientes se encontraron ramas ostiales, las cuales en un 39,4% de los casos se presentaron en la vena pulmonar inferior derecha. Conclusiones: La evaluación de la morfología de la aurícula derecha y las venas pulmonares por medio de angioresonancia o tomografía computarizada, es necesaria para la realización de ablación por radiofrecuencia dada la alta frecuencia de variantes anatómicas y presencia de ramas ostiales.

Descrição anátomo-topográfica do coração da paca (Agouti paca)

Background: The domestic animals heart is a conical hollow viscera, surrounded by pericardium, laterally compressed, accompanying the thorax shape. Atriums constituted the heart basis and their auricles partially bound the initial portion of the aorta and pulmonary trunk. In mammals, heart is kept suspended in the thoracic cavity and the pericardic sac is fixed dorsally by great veins and arteries roots, and ventrally fixed to the sternum, although its fixation to the diaphragm varies among species. This paper aimed to describe morphological aspects of the heart of the paca, the second biggest Brazilian rodent.Materials, Methods & Results: There were used 12 hearts of adult pacas for this study, obtained from the UNESP, Jaboticabal, SP, which died due fights or anesthesia during bandages or radiograph exams. The thoracic aorta was filled with colored latex and the animal was set in a 10% formaldehyde solution for at least 72 hours. The thoracic cavity was dissected and hearts individualized and measured with a paquimeter, lateromedially, craniocaudally and dorsoventrally. The paca heart is placed between the first and fifth intercostal space (ICS), in a craniocaudal oblique position; its basis is craniodorsally positioned, on the middle third between the first and second ICS and its apex is located near the sternodiaphragmatic joint, on the fifth ICS, tilted to the left antimere. The heart is surrounded by pericardium, which from ventrocaudally is originated the sternopericardic ligament, that continues as phrenopericardic ligament. At the heart basis, the rising of the pulmonary trunk was observed and the conus arteriosus formed a typical projection. The aorta also rised from the heart basis and its arch, which was caudally curved, crossed dorsally the pulmonary trunk; the right cranial and caudal cava veins drained to the right atrium. There is a left cranial cava vein, which surrounded the left atrium and joined the right caudal cava vein on the right atrium. The azygos vein joins the right cranial cava vein and four pulmonary veins drained to the left atrium. At palpation, a hard structure on the rising of the aorta was observed, similarly to a cartilaginous tissue, which would be part of the cardiac skeleton. The left and right coronary arteries were observed in all hearts.Discussion: The paca heart is anatomica and topographically similar to those of domestic mammals, differing from them for being placed one intercostal space more cranial and due to the presence of two cranial cava veins, the left and the right ones, besides the presence of the caudal cava vein. This vascular description is similar to that of small rodents, as rats and mice. In paca heart, the sinus venous, the terminal crest, the oval fossa, the atrioventricular valvae, the papillary muscles and tendinous cords, besides smooth atriums and auricles covered by pectinate muscles, were observed. The sternopericardic ligament, which is dorsally elongated as phrenopericardic ligament, is similar to the one present in humans, pigs, castors, and different from the one observed in carnivorous, that presents the phrenopericardic ligament and from the one of horses and ruminants, which present the sternopericardic ligament.

Fístula arteriovenosa pulmonar maciça. Causa rara, potencialmente curável de hipóxia neonatal.

The case of a six-day-old neonate admitted in an emergency situation because of dyspnea and increasing cyanosis is reported. Despite abnormal opacification on the chest X-ray and left ventricular overload on the electrocardiogram and echocardiogram, features compatible with the disease, the diagnosis of massive pulmonary arteriovenous fistula affecting the whole left superior lobe, was made possible only after necroscopic examination.