Machine Learning of Cardiac Anatomy and the Risk of New-Onset Atrial Fibrillation After TAVR.

BACKGROUND: New-onset atrial fibrillation (NOAF) occurs in 5% to 15% of patients who undergo transfemoral transcatheter aortic valve replacement (TAVR). Cardiac imaging has been underutilized to predict NOAF following TAVR. OBJECTIVES: The objective of this analysis was to compare and assess standard, manual echocardiographic and cardiac computed tomography (cCT) measurements as well as machine learning-derived cCT measurements of left atrial volume index and epicardial adipose tissue as risk factors for NOAF following TAVR. METHODS: The study included 1,385 patients undergoing elective, transfemoral TAVR for severe, symptomatic aortic stenosis. Each patient had standard and machine learning-derived measurements of left atrial volume and epicardial adipose tissue from cardiac computed tomography. The outcome of interest was NOAF within 30 days following TAVR. We used a 2-step statistical model including random forest for variable importance ranking, followed by multivariable logistic regression for predictors of highest importance. Model discrimination was assessed by using the C-statistic to compare the performance of the models with and without imaging. RESULTS: Forty-seven (5.0%) of 935 patients without pre-existing atrial fibrillation (AF) experienced NOAF. Patients with pre-existing AF had the largest left atrial volume index at 76.3 ± 28.6 cm3/m2 followed by NOAF at 68.1 ± 26.6 cm3/m2 and then no AF at 57.0 ± 21.7 cm3/m2 (P < 0.001). Multivariable regression identified the following risk factors in association with NOAF: left atrial volume index ≥76 cm2 (OR: 2.538 [95% CI: 1.165-5.531]; P = 0.0191), body mass index <22 kg/m2 (OR: 4.064 [95% CI: 1.500-11.008]; P = 0.0058), EATv (OR: 1.007 [95% CI: 1.000-1.014]; P = 0.043), aortic annulus area ≥659 mm2 (OR: 6.621 [95% CI: 1.849-23.708]; P = 0.004), and sinotubular junction diameter ≥35 mm (OR: 3.891 [95% CI: 1.040-14.552]; P = 0.0435). The C-statistic of the model was 0.737, compared with 0.646 in a model that excluded imaging variables. CONCLUSIONS: Underlying cardiac structural differences derived from cardiac imaging may be useful in predicting NOAF following transfemoral TAVR, independent of other clinical risk factors.

Echocardiographic Measurements in Normal Chinese Adults (EMINCA) II focusing on left ventricular and left atrial size and function by three-dimensional echocardiography.

Current guidelines encourage large studies in a diverse population to establish normal reference ranges for three-dimensional (3D) echocardiography for different ethnic groups. This study was designed to establish the normal values of 3D-left ventricular (LV) and left atrial (LA) volume and function in a nationwide, population-based cohort of healthy Han Chinese adults. A total of 1117 healthy volunteers aged 18-89 years were enrolled from 28 collaborating laboratories in China. Two sets of 3D echocardiographic instruments were used, and full-volume echocardiographic images were recorded and transmitted to a core laboratory for image analysis with a vendor-independent off-line workstation. Finally, 866 volunteers (mean age of 48.4 years, 402 men) were qualified for final analysis. Most parameters exhibited substantial differences between different sex and age groups, even after indexation by body surface area. The normal ranges of 3D-LV and 3D-LA volume and function differed from those recommended by the American Society of Echocardiography and the European Association of Cardiovascular Imaging guidelines, presented by the World Alliance Societies of Echocardiography (WASE) study, and from the 2D values in the EMINCA study. The normal reference values of 3D echocardiography-derived LV and LA volume and function were established for the first time in healthy Han Chinese adults. Normal ranges of 3D-LV and 3D-LA echocardiographic measurements stratified with sex, age, and race should be recommended for clinical applications.

Vertebral heart size and vertebral left atrial size reference ranges in healthy Miniature Schnauzers.

OBJECTIVE: The inclusion of vertebral heart score (VHS) and, more recently, the inclusion of the vertebral left atrial size (VLAS) in radiographic evaluation have become important screening tools for identifying dogs with occult cardiac disease. Several recent papers have shown there are interbreed variations in the VHS reference range. Our hypothesis is that the Miniature Schnauzer would also have a higher reference range for its VHS. ANIMALS: The electronic medical records of IDEXX Telemedicine Consultants were searched for Miniature Schnauzers undergoing thoracic radiographs between March 1, 2022, and February 28, 2023. METHODS: Dogs were included if they had 3 view thoracic radiographs performed and no evidence of cardiopulmonary disease was detected. Dogs with incomplete radiographic studies or cardiac or extracardiac disease were excluded. The VHS and VLAS measurements were performed by 2 board-certified cardiologists independent of one another. RESULTS: A total of 1,000 radiographs were obtained of which 272 were included for the study. The overall range for the VHS in this cohort was 9.68 to 12.07 with a median of 10.9. For VLAS measurements, a range of 1.71 to 2.4 was documented with a median of 2.0. CLINICAL RELEVANCE: The VHS for Miniature Schnauzers without cardiac disease was confirmed to be higher than the canine reference range.

Reference intervals for various measurements of canine left atrial size and function obtained using two-dimensional and three-dimensional echocardiography.

BACKGROUND: Many canine cardiac diseases are associated with left atrial (LA) remodeling and decreased function. For accurate assessment of LA indices, large-scale and prospectively determined reference intervals are necessary. OBJECTIVES: To generate reference intervals of LA size and function using two-dimensional and three-dimensional echocardiography. ANIMALS: Two hundred and one healthy adult dogs. METHODS: Left atrial volume was assessed in right parasternal long-axis, left apical four-chamber and two-chamber views using monoplane Simpson's method, two-dimensional and three-dimensional speckle tracking. Additionally, LA diameter was measured in right parasternal short-axis and long-axis views. Furthermore, LA function was determined by measuring strain and calculating LA fractional shortening and ejection fraction. All variables were tested for correlation to heart rate, age, and body weight. For LA diameter and volume, scaling exponents and prediction intervals were generated using allometric scaling. Reference intervals for LA function parameters were calculated using nonparametric methods. RESULTS: Left atrial diameter and volume showed a strong correlation with body weight. The scaling exponent for LA diameter was approximately 1/3 (0.34-0.40) and approximately one for volume measurements (0.97-1.26). Parameters of LA function showed no clinically relevant correlation with body weight, except for two variables, which showed a mild negative correlation. No clinically relevant correlations with age or heart rate were found. CONCLUSIONS: Reference intervals for linear, two-dimensional and three-dimensional measurements of LA size and function were established. The wide range of measurement methods offers the opportunity to select the appropriate reference values for LA evaluation depending on the available technical possibilities.

The so-called absorption process of the pulmonary vein into the left atrium of the heart: a histological study using human embryos and fetuses.

BACKGROUND: Embryonic pulmonary veins (PVs) are believed to be absorbed into the left atrium (LA) to provide an adult morphology in which "four" veins drain separately into the atrium. MATERIALS AND METHODS: Serial histological sections were obtained from 27 human embryos and fetuses. RESULTS: Between 5 and 6 weeks, the four PVs joined together to form a trunk-like structure (initial spatium pulmonalis) that was larger than the initial LA (two-ostia pattern). The cardiac nerves ran inferiorly along the posterior aspect of the four veins, as well as the spatium. At and until 7 weeks, the cardiac nerves were concentrated to elongate the nerve fold, and the latter separated the left PV trunk from the expanding LA (left spatium). Similarly, the right PV opened to a thick and deep LA recess (right spatium). At 8-12 weeks, depending on the growth of the LA, the opening of the left and right PVs became distant, and the spatium was elongated transversely. The left spatium was enlarged to open widely to the proper left atrium in contrast to the right spatium pushed anteriorly by the right atrium. The three-ostia pattern was transiently observed because of the lost delimitation between the left spatium and proper atrium. The myocardium was thin in the left spatium behind the left atrial nerve fold, whereas the right spatium was tube-like with a thick myocardium. CONCLUSIONS: The four-ostia pattern seemed to be established at birth due to a drastically increased venous return from the lung, resulting in a flat smooth left atrial posterior wall.

Association of Echocardiographic Measures of Left Atrial Function and Size With Incident Dementia.

Importance: Atrial myopathy-characterized by alterations in left atrial (LA) function and size-is associated with ischemic stroke, independent of atrial fibrillation (AF). Electrocardiographic markers of atrial myopathy are associated with dementia, but it is unclear whether 2-dimensional echocardiographic (2DE)-defined LA function and size are associated with dementia. Objective: To examine the association of LA function and size with incident dementia. Design, Setting, and Participants: The Atherosclerosis Risk in Communities (ARIC) study is a community-based prospective cohort. An exploratory, retrospective analysis was conducted. ARIC centers are located in Forsyth County, North Carolina; Jackson, Mississippi; Washington County, Maryland; and suburban Minneapolis, Minnesota. For this analysis, visit 5 (2011-2013) served as the baseline. Participants without prevalent AF and stroke and who had 2DEs in 2011-2013 were included and surveilled through December 31, 2019. Exposures: LA function (reservoir strain, conduit strain, contractile strain, emptying fraction, passive emptying fraction, and active emptying fraction), and LA size (maximal and minimal volume index) as evaluated by 2DE. Main Outcomes and Measures: Dementia cases were identified using in-person and phone cognitive assessments, hospitalization codes, and death certificates. Cox proportional hazards models were used. Results: Among 4096 participants (mean [SD] age, 75 [5] years; 60% women; 22% Black individuals), 531 dementia cases were ascertained over a median follow-up of 6 years. Dementia incidence for the lowest LA quintile was 4.80 for reservoir strain, 3.94 for conduit strain, 3.29 for contractile strain, 4.20 for emptying fraction, 3.67 for passive emptying fraction, and 3.27 for active emptying fraction per 100 person-years. After full-model adjustments, there were statistically significant associations between measures of LA function and dementia; the hazard ratios (HRs) from the lowest vs highest quintile for reservoir strain were 1.98 (95% CI, 1.42-2.75); for conduit strain, 1.50 (95% CI, 1.09-2.06); for contractile strain, 1.57 (95% CI, 1.16-2.14); for emptying fraction, 1.87 (95% CI, 1.31-2.65); and for active emptying fraction, 1.43 (95% CI, 1.04-1.96). LA passive emptying fraction was not significantly associated with dementia (HR, 1.26 [95% CI, 0.93-1.71]). Dementia incidence for the highest LA maximal volume index quintile was 3.18 per 100 person-years (HR for highest vs lowest quintile, 0.77 [95% CI, 0.58-1.02]) and for the highest minimal volume index quintile was 3.50 per 100 person-years (HR for the highest vs lowest quintile, 0.95 [95% CI, 0.71-1.28]). Both measures were not significantly associated with dementia. These findings were robust to sensitivity analyses that excluded participants with incident AF or stroke. Conclusions and Relevance: In this exploratory analysis of a US community-based cohort, several echocardiographic measures of lower LA function were significantly associated with an increased risk of subsequent dementia. Measures of LA size were not significantly associated with dementia risk. These findings suggest that impaired LA function may be a risk factor associated with dementia.

Predicting Values of Neutrophil-to-Lymphocyte Ratio (NLR), High-Sensitivity C-Reactive Protein (hs-CRP), and Left Atrial Diameter (LAD) in Patients with Nonvalvular Atrial Fibrillation Recurrence After Radiofrequency Ablation.

BACKGROUND The purpose of this study was to evaluate the predictive values of lipid level, inflammatory biomarkers, and echocardiographic parameters in late NVAF (nonvalvular atrial fibrillation) recurrence after RFA (radiofrequency ablation). MATERIAL AND METHODS This retrospective single-center study enrolled 263 patients with paroxysmal or persistent NVAF who underwent initial RFA from Jan 2017 to Jan 2019. The patients were divided into a Recurrent group (n=70) and a Nonrecurrent group (n=193). Univariate and multivariate logistic regression analyses were used for evaluating the predictive factors of late NVAF recurrence. Receiver operating characteristic (ROC) curves were constructed to assess the predictive performance and the optimum cut-off level of variables. RESULTS Late NVAF recurrence occurred in 70 patients (26.6%) after initial RFA within 12-month follow-up. Patients in the Recurrent group had significant higher NLR (neutrophil-to-lymphocyte ratio), hs-CRP (high-sensitivity C-reactive protein), LVEDD (left ventricular end-diastolic dimension), LVESD (left ventricular end-systolic dimension), and LAD (left atrial diameter) than those in the Nonrecurrent group (P<0.05). In multivariate analysis, increased NLR (HR=1.438, 95% CI: 1.036-1.995, P<0.05), hs-CRP (HR=1.137, 95% CI: 1.029-1.257, P<0.05) and LAD (HR=1.089, 95% CI: 1.036-1.146, P<0.05) were independent predictors of NVAF recurrence. The area under the curve (AUC) of NLR and hs-CRP was 0.603 (95% CI 0.525-0.681) and 0.584 (95% CI 0.501-0.666), respectively. The combination of NLR, hs-CRP, and LAD revealed an AUC of 0.684 (95% CI 0.611-0.757), with cut-off values of 2.33, 2.025 ng/L, and 44.5 mm, respectively. CONCLUSIONS The combination of preoperative NLR, hs-CRP, and LAD can predict late NVAF recurrence.

Miniseries 1-Part III: 'Behind the scenes' in the triangle of Koch.

AIMS: To take full advantage of the knowledge of cardiac anatomy, structures should be considered in their correct attitudinal orientation. Our aim was to discuss the triangle of Koch in an attitudinally appropriate fashion. METHODS AND RESULTS: We reviewed our material prepared by histological sectioning, along with computed tomographic datasets of human hearts. The triangle of Koch is the right atrial surface of the inferior pyramidal space, being bordered by the tendon of Todaro and the hinge of the septal leaflet of the tricuspid valve, with its base at the inferior cavotricuspid isthmus. The fibro-adipose tissues of the inferior pyramidal space separate the atrial wall from the crest of the muscular interventricular septum, thus producing an atrioventricular muscular sandwich. The overall area is better approached as a pyramid rather than a triangle. The apex of the inferior pyramidal space overlaps the infero-septal recess of the subaortic outflow tract, permitting the atrioventricular conduction axis to transition directly to the crest of the muscular ventricular septum. The compact atrioventricular node is formed at the apex of the pyramid by union of its inferior extensions, which represent the slow pathway, with the septal components formed in the buttress of the atrial septum, thus providing the fast pathway. CONCLUSIONS: To understand its various implications in current cardiological catheter interventions, the triangle of Koch must be considered in conjunction with the inferior pyramidal space and the infero-septal recess. It is better to consider the overall region in terms of a pyramidal area of interest.

Revisiting left atrial volumetry by magnetic resonance imaging: the role of atrial shape and 3D angle between left ventricular and left atrial axis.

BACKGROUND: Accurate measurement of left atrial (LA) volumes is needed in cardiac diagnostics and the follow up of heart and valvular diseases. Geometrical assumptions with 2D methods for LA volume estimation contribute to volume misestimation. In this study, we test agreement of 3D and 2D methods of LA volume detection and explore contribution of 3D LA axis orientation and LA shape in introducing error in 2D methods by cardiovascular magnetic resonance imaging. METHODS: 30 patients with prior first-ever ischemic stroke and no known heart disease, and 30 healthy controls were enrolled (age 18-49) in a substudy of a prospective case-control study. All study subjects underwent cardiac magnetic resonance imaging and were pooled for this methodological study. LA volumes were calculated by biplane area-length method from both conventional long axis (LAVAL-LV) and LA long axis-oriented images (LAVAL-LA) and were compared to 3D segmented LA volume (LAVSAX) to assess accuracy of volume detection. 3D orientation of LA long axis to left ventricular (LV) long axis and to four-chamber plane were determined, and LA 3D sphericity indices were calculated to assess sources of error in LA volume calculation. Shapiro-Wilk test, Bland-Altman analysis, intraclass and Pearson correlation, and Spearman's rho were used for statistical analysis. RESULTS: Biases were - 9.9 mL (- 12.5 to - 7.2) for LAVAL-LV and 13.4 (10.0-16.9) for LAVAL-LA [mean difference to LAVSAX (95% confidence interval)]. End-diastolic LA long axis 3D deviation angle to LV long axis was 28.3 ± 6.2° [mean ± SD] and LA long axis 3D rotation angle to four-chamber plane 20.5 ± 18.0°. 3D orientation of LA axis or 3D sphericity were not correlated to error in LA volume calculation. CONCLUSIONS: Calculated LA volume accuracy did not improve by using LA long axis-oriented images for volume calculation in comparison to conventional method. We present novel data on LA axis orientation and a novel metric of LA sphericity and conclude that these measures cannot be utilized to assess error in LA volume calculation. TRIAL REGISTRATION: Main study Searching for Explanations for Cryptogenic Stroke in the Young: Revealing the Etiology, Triggers, and Outcome (SECRETO; NCT01934725) has been registered previously.

Right atrium size in the general population.

Echocardiography is the most common routine cardiac imaging method. Nevertheless, only few data about sex-specific reference limits for right atrium (RA) dimensions are available. Transthoracic echocardiographic RA measurements were studied in 9511 participants of the Gutenberg-Health-Study. A reference sample of 1942 cardiovascular healthy subjects without chronic obstructive pulmonary disease was defined. We assessed RA dimensions and sex-specific reference limits were defined using the 95th percentile of the reference sample. Results showed sex-specific differences with larger RA dimensions in men that were attenuated by standardization for body-height. RA-volume was 20.2 ml/m in women (5th-95th: 12.7-30.4 ml/m) and 26.1 ml/m in men (5th-95th: 16.0-40.5 ml/m). Multivariable regressions identified body-mass-index (BMI), coronary artery disease (CAD), chronic heart failure (CHF) and atrial fibrillation (AF) as independent key correlates of RA-volume in both sexes. All-cause mortality after median follow-up-period of 10.7 (9.81/11.6) years was higher in individuals who had RA volume/height outside the 95% reference limit (HR 1.70 [95%CI 1.29-2.23], P = 0.00014)). Based on a large community-based sample, we present sex-specific reference-values for RA dimensions normalized for height. RA-volume varies with BMI, CHF, CAD and AF in both sexes. Individuals with RA-volume outside the reference limit had a 1.7-fold higher mortality than those within reference limits.

Decreased estimated glomerular filtration rate predicts long-term recurrence after catheter ablation of atrial fibrillation in mild to moderate renal insufficiency.

BACKGROUND: Catheter ablation is an established therapy for atrial fibrillation (AF), but recurrence after ablation remains a great challenge. Additionally, little is known about the effect of renal function on the efficiency of AF ablation. This study aimed to evaluate the predictors of the prognosis of catheter ablation for AF, especially the effect of renal function. METHODS: A total of 306 drug-refractory symptomatic patients with AF who underwent first-time catheter ablation were enrolled in the present study. Individuals underwent circumferential pulmonary vein isolation for paroxysmal AF and stepwise ablation for persistent AF. RESULTS: The follow-up time was 27.2 ± 19.5 months, 202 patients (66.01%) were free of atrial tachyarrhythmia (non-recurrence group), and the other 104 patients experienced recurrence (recurrence group). The recurrence group had a larger left atrial diameter (LAD) and left atrial volume (LAV), a higher LAV index (LAVI) (both, p < 0.01), and a lower estimated glomerular filtration rate (eGFR) (53.5 ± 14.4 vs. 65.5 ± 13.3 ml/min/1.732, p < 0.001) and creatinine clearance rate (CCr) (85.2 ± 26.1 vs. 101.5 ± 29.4 ml/min, p < 0.05). Multivariate logistic regression indicated both eGFR (p = 0.002) and LAVI (p < 0.001) as independent associated factors for long-term recurrence after single catheter ablation; multivariate Cox proportional hazard regression with backward feature selection identified both eGFR (HR: 0.93, 95% CI: 0.91-0.95, p < 0.001) and LAVI (HR: 1.32, 95% CI: 1.25-1.40, p < 0.001) as independent prognostic factors for recurrence when adjusting other clinical variables. CONCLUSIONS: Decreased eGFR and elevated LAVI may facilitate the long-term recurrence of atrial tachyarrhythmia after catheter ablation for AF.

Anatomical Characteristics of the Left Atrium and Left Atrial Appendage in Relation to the Risk of Stroke in Patients With Versus Without Atrial Fibrillation.

[Figure: see text].

Relationship between hepatic venous anatomy and hepatic venous blood loss during hepatectomy.

PURPOSE: Predicting increased blood loss based on anatomical intervascular relationships is essential in major hepatectomy. METHODS: We assessed 63 consecutive patients undergoing anatomical hepatectomy exposing the hepatic vein (HV) trunk at two institutes. Correlations between anatomical alterations of the hepatic inferior vena cava (IVC), HV, hepatic IVC, or right atrium (RA) and the blood loss per standard weight (BLSW) or blood transfusion (n = 18) were analyzed. The results of IVC partial clamping (PC) were additionally examined. RESULTS: The BLSW in type V-up anatomical morphology was significantly higher than that in straight type (p < 0.05). The parameters associated with an increased BLSW (> 13.5 mL/kg) were tumor size (> 4 cm), prothrombin activity (< 87%), CVP (> 7 mmHg), area of suprahepatic IVC (< 360 mm2), IVC-RA gap (> 28 mm), longitudinal angle of IVC (< 160°), and axial angle of the MHV (< 55°). A multivariate analysis revealed that a high IVC-RA gap was a significant independent risk factor (odds ratio; 4.32, p < 0.05). Among 25 patients undergoing IVC-PC, only three showed a remarkable decrease in hepatic venous bleeding. No other statistically significant differences in the surgical records were observed in most cases. CONCLUSION: The IVC-RA gap might be a promising novel predictive parameter reflecting increased blood loss leading to blood transfusion in anatomical hepatectomy.

Atrial fibrillation and left atrial size and function: a Mendelian randomization study.

Atrial fibrillation (AF) patients have enlarged left atria (LA), but prior studies suggested enlarged atria as both cause and consequence of AF. The aim of this study is to investigate the causal association between AF and LA size and function. In the UK Biobank, all individuals with contoured cardiovascular magnetic resonance data were selected. LA maximal volume (LA max), LA minimal volume (LA min), LA stroke volume and LA ejection fraction were measured and indexed to body surface area (BSA). Two-sample Mendelian randomization analyses were performed using 84 of the known genetic variants associated with AF to assess the association with all LA size and function in individuals without prevalent AF. A total of 4274 individuals (mean age 62.0 ± 7.5 years, 53.2% women) were included. Mendelian randomization analyses estimated a causal effect between genetically determined AF and BSA-indexed LA max, LA min, and LA ejection fraction, but not between AF and LA stroke volume. Leave-one-out analyses showed that the causal associations were attenuated after exclusion of rs67249485, located near PITX2 gene. Our results suggest that AF causally increases LA size and decreases LA ejection fraction. The AF risk allele of rs67249485, located near the PITX2 gene, contributes strongly to these associations.

A new machine learning approach for predicting likelihood of recurrence following ablation for atrial fibrillation from CT.

OBJECTIVE: To investigate left atrial shape differences on CT scans of atrial fibrillation (AF) patients with (AF+) versus without (AF-) post-ablation recurrence and whether these shape differences predict AF recurrence. METHODS: This retrospective study included 68 AF patients who had pre-catheter ablation cardiac CT scans with contrast. AF recurrence was defined at 1 year, excluding a 3-month post-ablation blanking period. After creating atlases of atrial models from segmented AF+ and AF- CT images, an atlas-based implicit shape differentiation method was used to identify surface of interest (SOI). After registering the SOI to each patient model, statistics of the deformation on the SOI were used to create shape descriptors. The performance in predicting AF recurrence using shape features at and outside the SOI and eight clinical factors (age, sex, left atrial volume, left ventricular ejection fraction, body mass index, sinus rhythm, and AF type [persistent vs paroxysmal], catheter-ablation type [Cryoablation vs Irrigated RF]) were compared using 100 runs of fivefold cross validation. RESULTS: Differences in atrial shape were found surrounding the pulmonary vein ostia and the base of the left atrial appendage. In the prediction of AF recurrence, the area under the receiver-operating characteristics curve (AUC) was 0.67 for shape features from the SOI, 0.58 for shape features outside the SOI, 0.71 for the clinical parameters, and 0.78 combining shape and clinical features. CONCLUSION: Differences in left atrial shape were identified between AF recurrent and non-recurrent patients using pre-procedure CT scans. New radiomic features corresponding to the differences in shape were found to predict post-ablation AF recurrence.

Left atrial wall thickness of the pulmonary vein reconnection sites during atrial fibrillation redo procedures.

BACKGROUND: Left atrial wall thickness (LAWT) has been related to pulmonary vein (PV) reconnections after atrial fibrillation (AF) ablation. The aim was to integrate 3D-LAWT maps in the navigation system and analyze the relationship with local reconnection sites during AF-redo procedures. METHODS: Consecutive patients referred for AF-redo ablation were included. Procedure was performed using a single catheter technique. LAWT maps obtained from multidetector computerized tomography (MDCT) were imported into the navigation system. LAWT of the circumferential PV line, the reconnected segment and the reconnected point, were analyzed. RESULTS: Sixty patients [44 (73%) male, age 61 ± 10 years] were included. All reconnected veins were isolated using a single catheter technique with 55 min (IQR 47-67) procedure time and 75 s (IQR 50-120) fluoroscopy time. Mean LAWT of the circumferential PV line was 1.46 ± 0.22 mm. The reconnected segment was thicker than the rest of segments of the circumferential PV line (2.05 + 0.86 vs. 1.47 + 0.76, p < .001 for the LPVs; 1.55 + 0.57 vs. 1.27 + 0.57, p < .001 for the RPVs). Mean reconnection point wall thickness (WT) was at the 82nd percentile of the circumferential line in the LPVs and at the 82nd percentile in the RPVs. CONCLUSION: A single catheter technique is feasible and efficient for AF-redo procedures. Integrating the 3D-LAWT map into the navigation system allows a direct periprocedural estimation of the WT at any point of the LA. Reconnection points were more frequently present in thicker segments of the PV line. The use of 3D-LAWT maps can facilitate reconnection point identification during AF-redo ablation.

Atrio-aortic erosion caused by Amplatzer Atrial Septal Occluder - a case report.

BACKGROUND: In specialized centers, percutaneous closure using specific occluders is the first-choice treatment in atrial septal defects (ASD). Late complications after this intervention, such as erosion of the aorta or the atria, are rare and have not been sufficiently approached and dealt with in literature. In our clinic we have been faced with the problematic situation of diagnosing and treating such cases. That is why, we have decided to share our experience with other colleagues. CASE PRESENTATION: We present two cases of severe late complications after percutaneous closure of atrial septal defects (ASD). In both cases, the atrial septal occluder (Amplatzer™ Atrial Septal Occluder Device, Abbott, Chicago USA) caused the erosion between the left atrium and the aortic root. The atrio-aortic erosion led to acute cardiac tamponade with upper venous congestion and shock. As the bleeding source remained undetectable for any imaging tools, a diagnostical sternotomy remained the only solution. The cause of the acute bleeding was discovered to be the erosion between the left atrium and the aortic root. The treatment consisted in the removal of the occluder, direct suturing of the perforated areas and the surgical closure of the remaining ASD. The patients fully recovered within the nine to fourteen days' hospital stay. Six months after surgery both patients were well and able to recover their daily routine. CONCLUSIONS: The atrio-aortic erosion after percutaneous closure of atrial septal defects is a surgical emergency. The more so, since it can be complicated by the absence of specific symptoms. A key-element in the diagnosis of this rare pathology remains the medical history of the patient, which the surgeon has to consider thoroughly and launch the diagnostic sternotomy without delay.

Morphological variations of the conduction system in the atrioventricular zone and its clinical relationship in different species.

Atrioventricular node is responsible for delaying the passage of the electrical impulse to ventricles in order to protect them from fast depolarizations coming from the atria. The importance of this study is to identify the morphological variations of the components of atrioventricular zone that affect the conduction system and its clinical relationship in different species of mammals. We analyzed ten human hearts, nine from horses, eight from pigs, and five from dogs without a clinical history of cardiac pathologies. Histological section thickness of 5 µm were obtained with a microtome and stained with hematoxylin-eosin and Masson's trichrome. We observed both an increase in collagen fibers and a decrease in the size of P cells (nodal pacemaker cells) within the atrioventricular node in dogs, horses and pigs in cases that presented cartilage in fibrous body. The percentage of fundamental substance in atrioventricular node was significantly higher in dogs and the percentage of collagen fibers was higher in pigs, both than in humans. The presence of cartilaginous metaplasia in cardiac fibrous skeleton from different species decreases the size of atrioventricular node and its cells and increases the percentage of collagen fibers within the node, which can reduce the transmission of the electrical impulse to ventricles and therefore predispose to the presentation of ventricular arrhythmias. Morphometric analysis has allowed us to objectively quantify each of the components of AV node and compare them in the different species.

Constructing a Human Atrial Fibre Atlas.

Atrial anisotropy affects electrical propagation patterns, anchor locations of atrial reentrant drivers, and atrial mechanics. However, patient-specific atrial fibre fields and anisotropy measurements are not currently available, and consequently assigning fibre fields to atrial models is challenging. We aimed to construct an atrial fibre atlas from a high-resolution DTMRI dataset that optimally reproduces electrophysiology simulation predictions corresponding to patient-specific fibre fields, and to develop a methodology for automatically assigning fibres to patient-specific anatomies. We extended an atrial coordinate system to map the pulmonary veins, vena cava and appendages to standardised positions in the coordinate system corresponding to the average location across the anatomies. We then expressed each fibre field in this atrial coordinate system and calculated an average fibre field. To assess the effects of fibre field on patient-specific modelling predictions, we calculated paced activation time maps and electrical driver locations during AF. In total, 756 activation time maps were calculated (7 anatomies with 9 fibre maps and 2 pacing locations, for the endocardial, epicardial and bilayer surface models of the LA and RA). Patient-specific fibre fields had a relatively small effect on average paced activation maps (range of mean local activation time difference for LA fields: 2.67-3.60 ms, and for RA fields: 2.29-3.44 ms), but had a larger effect on maximum LAT differences (range for LA 12.7-16.6%; range for RA 11.9-15.0%). A total of 126 phase singularity density maps were calculated (7 anatomies with 9 fibre maps for the LA and RA bilayer models). The fibre field corresponding to anatomy 1 had the highest median PS density map correlation coefficient for LA bilayer simulations (0.44 compared to the other correlations, ranging from 0.14 to 0.39), while the average fibre field had the highest correlation for the RA bilayer simulations (0.61 compared to the other correlations, ranging from 0.37 to 0.56). For sinus rhythm simulations, average activation time is robust to fibre field direction; however, maximum differences can still be significant. Patient specific fibres are more important for arrhythmia simulations, particularly in the left atrium. We propose using the fibre field corresponding to DTMRI dataset 1 for LA simulations, and the average fibre field for RA simulations as these optimally predicted arrhythmia properties.