Pulmonary Vein Remodeling Between Atrial Fibrillation Subtypes: A Matched Comparison Cardiac Computed Tomography-Based Study Between Patients With Paroxysmal and Persistent Atrial Fibrillation

Although pulmonary vein (PV) isolation (PVI) is the cornerstone for atrial fibrillation (AF) ablation, no data exist comparing PV anatomy between AF subtypes directly. We aimed to compare PV anatomic characteristics between paroxysmal (PAF) and persistent AF (PeAF) in a matched population using cardiac computed tomography (CCT). Fifty-eight PeAF patients (with CCT prior first AF ablation procedure, absence of valvular disease/previous cardiac intervention), and 58 age-, sex-, body surface area-matched PAF patients were evaluated for left atrial (LA) and PV anatomy: ostial area, ovality index (OVI), transverse/frontal angles. In PeAF vs PAF group, beside higher LA volume index (LAVI), PVs' ostial areas were significantly larger (between 64 - 101 mm2, P < 0.001 for all PVs; remaining valid after LAVI adjustment for left superior [LS], left inferior [LI], and right inferior [RI]PV); left PVs were less oval (0.7 - 0.11 OVI decrease, P =0.039 for LSPV; P = 0.012 for LIPV); LSPV (P = 0.019), LIPV (P < 0.001), RIPV (P = 0.029) were more posteriorly directed; whereas LSPV (P = 0.002), and right superior PV (P = 0.043) were more superiorly directed. Incidence of anatomic variations or early branching was not different. This study showed significant anatomical PV differences between patients with PeAF and PAF, in terms of PV orientation, ostial size and ovality. Anticipating such anatomical differences may aid in choosing the adequate catheter design and technology for PeAF ablation.

Impact of pulmonary vein anatomy and left atrial size on postoperative atrial fibrillation after esophagectomy for esophageal cancer

BACKGROUND

This study aimed to investigate the relationship between postoperative atrial fibrillation (POAF) after esophagectomy and pre-existing cardiac substrate.

METHODS

We retrospectively analyzed 212 consecutive patients from between July 2010 and December 2022 who were scheduled to undergo esophagectomy for esophageal cancer without previous history of atrial fibrillation. All the patients underwent both echocardiography and contrast-enhanced multi-detector computed tomography (MDCT).

RESULTS

POAF occurred in 49 patients (23.1%). Multivariable logistic analysis demonstrated that independent predictors for POAF were age [OR; 1.06 (1.01-1.10), P < 0.01), three-field lymph node dissection [OR; 2.55 (1.25-5.23), P < 0.01), left atrial dilatation (> 35 mm) assessment by echocardiography [OR; 3.05 (1.49-6.25), P < 0.01) and common left pulmonary vein [OR; 3.03 (1.44-6.39), P < 0.01). The correlation coefficient was high for left atrial dimensions assessed by echocardiography and MDCT (r = 0.91, P < 0.01). Combination of left atrial dilatation by echocardiography and common left pulmonary vein had high odds ratio [OR; 8.10 (2.62-25.96), P < 0.01). Instead of echocardiographic assessment, combination of left atrial enlargement (> 35 mm) assessed by MDCT and common left pulmonary vein also showed high odds ratio for POAF [OR; 11.23 [2.19-57.63], P < 0.01).

CONCLUSION

Incidence of POAF after esophagectomy was related to both left atrial enlargement and common left pulmonary vein assessed by preoperative MDCT. Additional analysis of atrial size and pulmonary vein variation would facilitate preoperative assessment of the risk of POAF, but future studies must ascertain therapeutic strategy.

Impact of pulmonary veins anatomy on the outcomes of radiofrequency ablation for paroxysmal atrial fibrillation in the era of contact force-sensing ablation catheters

BACKGROUND

Pulmonary vein (PV) isolation (PVI) has become the cornerstone of atrial fibrillation (AF) ablation in patients with paroxysmal AF (PAF). PVI durability is influenced by many factors including PVs anatomy. Data regarding the influence of PVs anatomical variations on the outcomes of PAF ablation in the era of contact force-sensing ablation catheters are scarce and contradictory.

METHODS

Consecutive patients referred to our center for a first ablation of PAF using radiofrequency (RF) were included. PVs anatomy was classified into 3 groups: typical anatomy (4 distinct veins), left common ostium (LCO), and right accessory PV (RAPV). The primary outcome was recurrence of atrial arrhythmia episode during a 12-month follow-up after ablation.

RESULTS

Two hundred twenty-three patients were included (mean age 58.4 ± 10.8 years and 70.9% male). Among this cohort, 141 patients (63.2%) had typical PV anatomy, 53 (23.8%) had a LCO, and 29 (13.0%) had a RAPV. The existence of a RAPV was not associated with a higher rate of AF recurrences (22 (14.3%) vs. 7 (10.1%), p = 0.519). After multivariate analysis, the presence of an LCO did not appear to be associated with the AF recurrence rate at 12 months (OR = 1.69, 95%CI 0.95-2.49, p = 0.098). Maintenance of antiarrhythmic drugs after ablation was the only factor independently associated with a decreased risk of AF recurrence at 12 months (OR = 0.76, 95%CI 0.60-0.97, p = 0.046).

CONCLUSION

This study suggests that the presence of an LCO or a RAPV is not associated with a higher rate of AF recurrence at 12 months after radiofrequency PVI using contact force-sensing catheters in PAF patients.

Rule-based definition of muscle bundles in patient-specific models of the left atrium

Atrial fibrillation (AF) is the most common arrhythmia encountered clinically, and as the population ages, its prevalence is increasing. Although the CHA2DS2−VASc score is the most used risk-stratification system for stroke risk in AF, it lacks personalization. Patient-specific computer models of the atria can facilitate personalized risk assessment and treatment planning. However, a challenge faced in creating such models is the complexity of the atrial muscle arrangement and its influence on the atrial fiber architecture. This work proposes a semi-automated rule-based algorithm to generate the local fiber orientation in the left atrium (LA). We use the solutions of several harmonic equations to decompose the LA anatomy into subregions. Solution gradients define a two-layer fiber field in each subregion. The robustness of our approach is demonstrated by recreating the fiber orientation on nine models of the LA obtained from AF patients who underwent WATCHMAN device implantation. This cohort of patients encompasses a variety of morphology variants of the left atrium, both in terms of the left atrial appendages (LAAs) and the number of pulmonary veins (PVs). We test the fiber construction algorithm by performing electrophysiology (EP) simulations. Furthermore, this study is the first to compare its results with other rule-based algorithms for the LA fiber architecture definition available in the literature. This analysis suggests that a multi-layer fiber architecture is important to capture complex electrical activation patterns. A notable advantage of our approach is the ability to reconstruct the main LA fiber bundles in a variety of morphologies while solving for a small number of harmonic fields, leading to a comparatively straightforward and reproducible approach.

[What the ablationist should know about pulmonary vein anatomy]

The importance of anatomy in daily clinical practice of the interventional electrophysiologist is crucial, especially for pulmonary vein isolation which is a predominantly anatomy-based approach. Many anatomical and morphological studies focusing on this topic were published in last two decades. In this article we are refreshing the knowledge of anatomy and morphology of the pulmonary veins and present them from a clinical perspective.

Variations in human pulmonary vein ostia morphology: A systematic review with meta-analysis

This study aimed to establish the most accurate and up-to-date anatomical knowledge of pulmonary veins (PV), ostia variations, diameters and ostial area, to provide physicians, especially heart and thoracic surgeons with exact knowledge concerning this area. The main online medical databases, such as PubMed, Embase, Scopus, Web of Science, and Google Scholar, were searched to gather all studies in which the variations, maximal diameter, and ostial area of the PVs were investigated. During the study, the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines were followed. Additionally, the critical appraisal tool for anatomical meta-analysis (CATAM) was used to provide the highest quality findings. The most common ostia variation is the classical one, which contains the left superior pulmonary vein (LSPV), left inferior pulmonary vein (LIPV), right superior pulmonary vein (RSPV) and right inferior pulmonary vein (RIPV). The mean diameter and ostial area of each pulmonary vein were established in the general population and in multiple variations considering the method of collecting the data and geographical location. Significant variability in PV ostia is observed. Left-sided PVs have smaller ostia than the corresponding right-sided PVs, and the inferior PVs ostia are smaller than the superior. The LCPV ostium size is the largest among all veins analyzed, while the RMPV ostium is the smallest. The results of this meta-analysis are hoped to help clinicians in planning and performing procedures that involve the pulmonary and cardiac areas, especially catheter ablation for atrial fibrillation.

Orientation of the right superior pulmonary vein affects outcome after pulmonary vein isolation

AIMS

Controversial results have been published regarding the influence of pulmonary vein (PV) anatomical variations on outcomes after pulmonary vein isolation (PVI). However, no data are available on the impact of PV orientation on the long-term success rates of point-by-point PVI. We sought to determine the impact of PV anatomy and orientation on atrial fibrillation (AF)-free survival in patients undergoing PVI using the radiofrequency point-by-point technique.

METHODS AND RESULTS

We retrospectively included 448 patients who underwent initial point-by-point radiofrequency ablation for AF at our department. Left atrial computed tomography angiography was performed before each procedure. PV anatomical variations, ostial parameters (area, effective diameter, and eccentricity), orientation, and their associations with 24-month AF-free survival were analysed. PV anatomical variations and ostial parameters were not predictive for AF-free survival (all P > 0.05). Univariate analysis showed that female sex (P = 0.025) was associated with higher rates of AF recurrence, ventral-caudal (P = 0.002), dorsal-cranial (P = 0.034), and dorsal-caudal (P = 0.042) orientation of the right superior PV (RSPV), on the other hand, showed an association with lower rates of AF recurrence, when compared with the reference ventral-cranial orientation. On multivariate analysis, both female sex [odds ratio (OR) 1.83, 95% CI 1.15-2.93, P = 0.011] and ventral-caudal RSPV orientation, compared with ventral-cranial orientation, proved to be independent predictors of 24-month AF recurrence (OR 0.37, 95% CI 0.19-0.71, P = 0.003).

CONCLUSION

Female sex and ventral-caudal RSPV orientation have an impact on long-term arrhythmia-free survival. Assessment of PV orientation may be a useful tool in predicting AF-free survival and may contribute to a more personalized management of AF.

Impact of Left Common Pulmonary Veins in the Contact-Force vs. Cryoballoon Atrial Fibrillation Ablation (CIRCA-DOSE) Study

BACKGROUND

Concerns remain regarding the effectiveness of PVI using the fixed diameter non-compliant cryoballoon in the presence of a left common pulmonary vein (LCPV). We sought to evaluate the effectiveness of PVI performed by contact-force guided radiofrequency (CF-RF) versus second-generation cryoballoon-based ablation in patients with LCPV.

METHODS AND RESULTS

We enrolled 346 patients with paroxysmal AF and randomized them to CF-RF or cryoballoon ablation. PV anatomy was not assessed prior to enrolment, and there were no exclusions based on PV anatomy. All patients received an implantable cardiac monitor. LCPV was observed in 13.6% of patients (47/346). Left atrial time and fluoroscopy time did not differ between those with and without LCPV (P=0.58 and P=0.06, respectively). Freedom from any atrial tachyarrhythmia at one year was observed in 46.8% with LCPV and 54.5% without LCPV (P=0.06). In those with LCPV the freedom from any atrial tachyarrhythmia did not differ between those randomized to CF-RF or cryoballoon ablation (HR for recurrence 1.19, 95% CI 0.53-2.65, P=0.69). In those with LCPV the AF burden was reduced to a similar extent with CF-RF and cryoballoon ablation (99.7% vs. 99.5%, respectively; P=0.97).

CONCLUSIONS

In this randomized clinical trial, the presence of a LCPV was associated with a trend towards higher rates of arrhythmia recurrence following PVI. No significant difference in arrhythmia recurrence was observed between patients with LCPV randomized to cryoballoon ablation or contact-force guided RF ablation, suggesting that either ablation modality is suitable in this population. (Cryoballoon vs. Irrigated Radiofrequency Catheter Ablation [CIRCA-DOSE], NCT01913522) This article is protected by copyright. All rights reserved.

Pulmonary Vein Enlargement as an Independent Predictor for New-Onset Atrial Fibrillation

Pulmonary vein (PV) enlargement is associated with atrial fibrillation (AF). However, the predictive value of PV volume for new-onset AF has not been determined. We retrospectively assessed and enrolled non-AF subjects who underwent echocardiography and cardiac CT angiography (CCTA) around the same time and evaluated the development of AF longitudinally. PV volume was assessed by estimating the three-dimensional CCTA-derived mid-diastolic PV volume from the ostium to tertiary branches. Overall, 1105 subjects were enrolled. Among them, 29 developed AF during a mean follow-up of 4.28 ± 3.08 years after baseline CCTA and echocardiography. The AF group had a higher proportion of older aged subjects, a higher ratio of early mitral flow velocity (E) to early mitral annular tissue velocity (Em), higher Em, and larger left atrial (LAVI) and PV (PVVI) volume indices. PVVI was independently associated with male sex, left ventricular dimension, E/Em and LAVI. AF incidence increased markedly across each baseline PVVI tertile (2.2%, 5.1%, and 10.8%). In the multivariate Cox model, increased PVVI was independently associated with new-onset AF (hazard ratio (HR) = 5.401, 4.931–6.193, p = 0.007). Based on the analysis of multimodal cardiac imaging, our results provide mechanistic insights into PV remodeling and its potential role as a link between diastolic dysfunction and developing AF.

A meta-analysis of the relationship between anatomical variations of pulmonary veins and atrial fibrillation

Background: Our aim was to provide an evidence-based assessment of the relationship between pulmonary vein variants and atrial fibrillation (AF).Methods: A comprehensive systematic search was performed on the databases PubMed, EMBASE, Cochrane library and Science Direct. Following assessment of eligibility and methodologic quality, data on PV variants were extracted and pooled into a meta-analysis.Results: A total of 12 studies (1337 cases and 1250 controls) were included. Presence of a right middle pulmonary vein was significantly associated with AF (OR = 1.85, 95% CI 1.26-2.72, p = .002). No significant association was however noted between presence of a common pulmonary vein ostia and AF. In the analysis of ostial diameters, the strongest association was observed between increased left common ostia diameter and AF (OR = 2.71, 95% CI 0.99-4.44, p = .002), followed by right superior (OR = 2.39, 95% CI 1.76-3.02, p < .00001), left superior (OR = 2.30, 95% CI 1.48-3.13, p < .00001), right inferior (OR = 2.19, 95% CI 1.69-2.69, p < .00001) and left inferior (OR = 1.79, 95% CI 1.25-2.34, p < .00001) pulmonary veins.Conclusion: The findings of the current study support the hypothesis that pulmonary vein variations predispose to AF. Further studies into the role of structural abnormalities of the pulmonary veins variations in the genesis of AF are recommended.

The Impact of Pulmonary Vein Anatomy on the Outcomes of Catheter Ablation for Atrial Fibrillation

Background and Objectives: Prior studies have identified a number of predictors for Atrial fibrillation (AF) ablation success, including comorbidities, the type of AF, and left atrial (LA) size. Ectopic foci in the initiation of paroxysmal AF are frequently found in pulmonary veins. Our aim was to assess how pulmonary vein anatomy influences the recurrence of atrial fibrillation after radiofrequency catheter ablation. Materials and Methods: Eighty patients diagnosed with paroxysmal or persistent AF underwent radiofrequency catheter ablation (RFCA) between November 2016 and December 2017. All of these patients underwent computed tomography before AF ablation. PV anatomy was classified according to the presence of common PVs or accessory PVs. Several clinical and imagistic parameters were recorded. After hospital discharge, all patients were scheduled for check-up in an outpatient clinic at 3, 6, 9, and 12 months after RFCA to detect AF recurrence. Results: A total of 80 consecutive patients, aged 53.8 ± 9.6 years, 54 (67.5%) men and 26 (32.5%) women were enrolled. The majority of patients had paroxysmal AF 53 (66.3%). Regular PV anatomy (2 left PVs, 2 right PVs) was identified in 59 patients (73.7%), a left common trunk (LCT) was detected in 15 patients (18.7%), an accessory right middle pulmonary vein (RMPV) was found in 5 patients (6.25%) and one patient presented both an LCT and an RMPV. The median follow-up duration was 14 (12; 15) months. Sinus rhythm was maintained in 50 (62.5%) patients. Age, gender, antiarrhythmic drugs, and the presence of cardiac comorbidities were not predictive of AF recurrence. The diagnosis of persistent AF before RFCA was more closely associated with an increase in recurrent AF after RFCA than after paroxysmal AF (p = 0.01). Longer procedure times (>265 minutes) were associated with AF recurrence (p = 0.04). Patients with an LA volume index of over 48.5 (mL/m²) were more likely to present AF recurrence (p = 0.006). Multivariate analysis of recurrence risk showed that only the larger LA volume index and variant PV anatomy were independently associated with AF recurrence. Conclusion: The study demonstrated that an increased volume of the left atrium was the most important predictive factor for the risk of AF recurrence after catheter ablation. Variant anatomy of PV was the only other independent predictive factor associated with a higher rate of AF recurrence.

Use of Intracardiac Echocardiography in Interventional Cardiology: Working With the Anatomy Rather Than Fighting It

The indications for catheter-based structural and electrophysiological procedures have recently expanded to more complex scenarios, in which an accurate definition of the variable individual cardiac anatomy is key to obtain optimal results. Intracardiac echocardiography (ICE) is a unique imaging modality able to provide high-resolution real-time visualization of cardiac structures, continuous monitoring of catheter location within the heart, and early recognition of procedural complications, such as pericardial effusion or thrombus formation. Additional benefits are excellent patient tolerance, reduction of fluoroscopy time, and lack of need for general anesthesia or a second operator. For these reasons, ICE has largely replaced transesophageal echocardiography as ideal imaging modality for guiding certain procedures, such as atrial septal defect closure and catheter ablation of cardiac arrhythmias, and has an emerging role in others, including mitral valvuloplasty, transcatheter aortic valve replacement, and left atrial appendage closure. In electrophysiology procedures, ICE allows integration of real-time images with electroanatomic maps; it has a role in assessment of arrhythmogenic substrate, and it is particularly useful for mapping structures that are not visualized by fluoroscopy, such as the interatrial or interventricular septum, papillary muscles, and intracavitary muscular ridges. Most recently, a three-dimensional (3D) volumetric ICE system has also been developed, with potential for greater anatomic information and a promising role in structural interventions. In this state-of-the-art review, we provide guidance on how to conduct a comprehensive ICE survey and summarize the main applications of ICE in a variety of structural and electrophysiology procedures.

Pulmonary vein anatomy variants as a biomarker of atrial fibrillation - CT angiography evaluation

Background

It has been suggested that changes in pulmonary veins (PV) and left atrium (LA) anatomy may have an influence on initiating atrial fibrillation (AF) and the effectiveness of pulmonary vein isolation (PVI) in patients (pts) with atrial fibrillation.

The aim of the study was to assess anatomy abnormalities of the PV and LA in the patients with the history of AF and compare it with the control group(CG).

Methods

The multi-slice tomography (MSCT) scans were performed in 224 AF pts. before PVI (129 males, mean age 59 ± 9 yrs). The CG consisted of 40 pts. without AF (26 males, age 45 ± 9 yrs). LA and PV anatomy were evaluated. Diameters of PV ostia were measured in two directions: anterior-posterior (AP) and superior-inferior (SI) automatically using Vitrea 4.0.

Results

Pulmonary veins anatomy variants were observed more frequently in the atrial fibrillation group - 83 pts. (37%) vs 6 pts. (15%) in CG; 9% (21 pts) left common ostia (CO), 2% (5 pts) right CO, 19% (42 pts) additional right PV (APV), (1.8%) 4 pts. APV left, 8% right early branching (EB) and 3.5% left EB. The LA diameter differed significantly in AF vs CG group (41.2 ± 6 mm vs 35 ± 4.2 mm, p < 0.0001) respectively.

Conclusions

The anomalies of pulmonary vein anatomy occurred more often in pts. with AF. They can be defined as an image biomarkers of atrial fibrillation. Right additional (middle) pulmonary vein was the most important anomaly detected in AF patients as well as enlargered diameters of the LA and PV ostia.

Influence of Clinical Parameters and Anticoagulation on Intraprocedural Cerebral Microembolic Signals during Pulmonary Vein Isolation

Objective

We had the objective to determine the impact of clinical parameters and anticoagulation status on cerebral microembolic signals (MES) during pulmonary vein isolation (PVI) for atrial fibrillation (AF).

Background

Thromboembolism and stroke are the most feared complications of PVI. MES can help to evaluate embolic burden. It is unknown whether clinical parameters have an impact on embolic risk during PVI.

Methods

In this retrospective analysis we investigated the impact of clinical parameters, including the CHADS₂- and CHA₂DS₂-VASc-score, pulmonary vein variants and echocardiographic parameters on MES rates in patients that underwent PVI using three different ablation approaches (radiofrequency ablation (iRF), pulmonary vein ablation catheter (PVAC) with deactivated electrode pair 1 or 5 (PVAC-red) or PVAC without deactivation (PVAC-all).

Results

118 AF patients (61±12 years) were included between 2011 and 2013 (Median: 489 MES during PVI). Patients were more likely to have more MES (within 4^th quartile) with the PVAC-all approach (60.7% vs. 25.0% (iRF) vs. 14.3% (PVAC-red) respectively (p<0.001). Patients with oral anticoagulation (OAC) pre-ablation were more likely to have lower MES-counts (1^st-3^rd quartile); (65.6% vs. 35.7%; p = 0.005). Additionally, patients with lower MES counts (1^st-3^rd quartile) had significantly higher INR values than those in the 4^th quartile (1.78 vs. 1.09; p = 0.029). 2 patients developed a potentially thromboembolic event during the procedure.

Conclusion

Clinical predictors of cerebral emboli and stroke do not correlate with cerebral embolic burden during PVI. Pre-ablation OAC and increased INR values correlate with decreased MES-rates. Therefore, it might be beneficial to perform PVI with pre-ablation anticoagulation even in low risk patients.

The role of transcription factors in atrial fibrillation

Atrial fibrillation (AF) is a complex disease that results from genetic and environmental factors and their interactions. In recent years, genome-wide association studies (GWAS) and family-based linkage analysis have found amounts of genetic variants associated with AF. Some of them lie in coding sequences and thus mediate the encoded proteins, some in non-coding regions and influence the expression of adjacent genes. These variants exert influence on the development of cardiovascular system and normal cardiac electrical activity in different levels, and eventually contribute to the occurrence of AF. Among these affected genes, as a crucial means of transcriptional regulation, several transcription factors play important roles in the pathogenesis of AF. In this review, we will focus on the potential role of PITX2, PRRX1, ZHFX3, TBX5, and NKX2.5 in AF.

Characterization of Pulmonary Vein Dimensions Using High-Definition 64-Slice Computed Tomography prior to Radiofrequency Catheter Ablation for Atrial Fibrillation

Background. Contrast-enhanced computed tomography is commonly acquired before radiofrequency catheter ablation (RFCA) for atrial fibrillation (AFib) to guide the procedure. We analyzed pulmonary vein (PV) ostial diameter and volumes on a high-definition 64-slice CT (HDCT) scanner in patients with AFib prior to RFCA. Methods and Results. This retrospective study included 50 patients (mean age 60.2 ± 11.4 years, 30 males) undergoing cardiac HDCT scanning before RFCA for drug refractory AFib and 50 age-, BMI-, and sex-matched controls with normal sinus rhythm undergoing HDCT. PV ostial diameter and volume were measured and calculated using a semiautomatic calliper tool. Total ostial PV volume was significantly increased in patients with AFib as compared to controls (P < 0.005). Similarly, total ostial PV diameter was significantly increased in AFib compared to controls (P < 0.001). In AFib, the largest PV volume and diameters were measured in right superior PV (P < 0.05 versus controls). The difference in PV volume between patients and controls was most pronounced in right superior PVs (P = 0.015). Right middle PVs were found more often in patients with AFib (16/50; 32%) than in normal subjects (7/50; 14%). Conclusion. Enlargement of PV ostial area and enlargement of volume are frequent findings in patients with drug refractory AFib. These parameters may add to the risk stratification for AFib recurrence following RFCA.

Toward Standardized Mapping for Left Atrial Analysis and Cardiac Ablation Guidance

In catheter-based cardiac ablation, the pulmonary vein ostia are important landmarks for guiding the ablation procedure, and for this reason, have been the focus of many studies quantifying their size, structure, and variability. Analysis of pulmonary vein structure, however, has been limited by the lack of a standardized reference space for population based studies. Standardized maps are important tools for characterizing anatomic variability across subjects with the goal of separating normal inter-subject variability from abnormal variability associated with disease. In this work, we describe a novel technique for computing flat maps of left atrial anatomy in a standardized space. A flat map of left atrial anatomy is created by casting a single ray through the volume and systematically rotating the camera viewpoint to obtain the entire field of view. The technique is validated by assessing preservation of relative surface areas and distances between the original 3D geometry and the flat map geometry. The proposed methodology is demonstrated on 10 subjects which are subsequently combined to form a probabilistic map of anatomic location for each of the pulmonary vein ostia and the boundary of the left atrial appendage. The probabilistic map demonstrates that the location of the inferior ostia have higher variability than the superior ostia and the variability of the left atrial appendage is similar to the superior pulmonary veins. This technique could also have potential application in mapping electrophysiology data, radio-frequency ablation burns, or treatment planning in cardiac ablation therapy.

Prevalence and spectrum of Nkx2.5 mutations associated with idiopathic atrial fibrillation

OBJECTIVE

The aim of this study was to evaluate the prevalence and spectrum of Nkx2.5 mutations associated with idiopathic atrial fibrillation (AF).

METHODS

A cohort of 136 unrelated patients with idiopathic atrial fibrillation and 200 unrelated, ethnically matched healthy controls were enrolled. The coding exons and splice junctions of the Nkx2.5 gene were sequenced in 136 atrial fibrillation patients, and the available relatives of mutation carriers and 200 controls were subsequently genotyped for the identified mutations. The functional characteristics of the mutated Nkx2.5 gene were analyzed using a dual-luciferase reporter assay system.

RESULTS

Two novel heterozygous Nkx2.5 mutations (p.N19D and p.F186S) were identified in 2 of the 136 unrelated atrial fibrillation cases, with a mutational prevalence of approximately 1.47%. These missense mutations co-segregated with atrial fibrillation in the families and were absent in the 400 control chromosomes. Notably, 2 mutation carriers also had congenital atrial septal defects and atrioventricular block. Multiple alignments of the Nkx2.5 protein sequences across various species revealed that the altered amino acids were completely conserved evolutionarily. Functional analysis demonstrated that the mutant Nkx2.5 proteins were associated with significantly reduced transcriptional activity compared to their wild-type counterpart.

CONCLUSION

These findings associate the Nkx2.5 loss-of-function mutation with atrial fibrillation and atrioventricular block and provide novel insights into the molecular mechanism involved in the pathogenesis of atrial fibrillation. These results also have potential implications for early prophylaxis and allele-specific therapy of this common arrhythmia.

[Cardiac computed tomography and ablation of atrial fibrillation]

Both cardiac computed tomography (CT) and interventional electrophysiology (EP) have evolved considerably in recent years. Technical improvements in CT have significantly reduced the radiation dose in cardiac applications. This imaging technology plays an important role in preprocedural planning and guidance of the procedures in many EP centers worldwide. Furthermore, CT is the imaging modality of choice to diagnose relevant complications in ablation of atrial fibrillation, e.g. pulmonary vein stenosis or atrioesophageal fistula. In anatomically driven ablation procedures, such as balloon-based procedures in atrial fibrillation, detailed analysis of the relevant cardiac structures is absolutely crucial not only to reduce radiation exposure and procedure times but also to improve ablation success and to reduce the occurrence of complications. Current software applications enable 3-dimensional reconstruction of cardiac images and the integration into electroanatomical navigation systems. This article reviews the available evidence in this field and highlights recent developments in image guidance for ablation of atrial fibrillation.

Novel GATA5 loss-of-function mutations underlie familial atrial fibrillation

OBJECTIVE

This study aimed to identify novel GATA5 mutations that underlie familial atrial fibrillation.

METHODS

A total of 110 unrelated patients with familial atrial fibrillation and 200 unrelated, ethnically matched healthy controls were recruited. The entire coding region of the GATA5 gene was sequenced in 110 atrial fibrillation probands. The available relatives of the mutation carriers and 200 controls were subsequently genotyped for the identified mutations. The functional effect of the mutated GATA5 was characterized using a luciferase reporter assay system.

RESULTS

Two novel heterozygous GATA5 mutations (p.Y138F and p.C210G) were identified in two of the 110 unrelated atrial fibrillation families. These missense mutations cosegregated with AF in the families and were absent in the 400 control chromosomes. A cross-species alignment of GATA5 protein sequence showed that the altered amino acids were completely conserved evolutionarily. A functional analysis revealed that the mutant GATA5 proteins were associated with significantly decreased transcriptional activation when compared with their wild-type counterpart.

CONCLUSION

The findings expand the spectrum of GATA5 mutations linked to AF and provide novel insights into the molecular mechanism involved in the pathogenesis of atrial fibrillation, suggesting potential implications for the early prophylaxis and personalized treatment of this common arrhythmia.