Sympathetic toggled paroxysmal atrial fibrillation and recurrent premature atrial contractions in ambulatory patients

BACKGROUND

Autonomic nerve activity is important in the mechanisms of paroxysmal atrial fibrillation (PAF).

OBJECTIVE

To test the hypothesis that a single burst of skin sympathetic nerve activity (SKNA) can toggle on and off PAF or premature atrial contraction (PAC) clusters.

METHODS

We performed neuECG recording over 7 days in patients with PAF.

RESULTS

In Study 1, we found 8 patients (7 men, 1 woman, 62±8 years) had 124 episodes of PAF. An SKNA burst toggled both on and off PAF in 8 (6.5%) episodes (Type 1), toggled on but not off in 12 (9.7%) episodes (Type 2), and toggled on a PAC cluster, followed by PAF in 4 (3.2%) episodes (Type 3). The duration of these PAF episodes was < 10 min. The remaining 100 (80.6%) episodes were associated with active SKNA bursts throughout PAF (Type 4) and lasted longer than Type 1 (p=0.0185) and Type 2 (p=0.0027) PAF. There were 47 PAC clusters. Among them, 24 (51.1%) were toggled on and off, and 23 (48.9%) were toggled on but not off by an SKNA burst. In Study 2, we found 17 patients (9 men, 8 women, 58±12 years) with < 10 min PAF (4, 8, 0, and 31 of Types 1-4, respectively). There were significant circadian variations of all types of PAF.

CONCLUSIONS

A single SKNA burst can toggle short-duration PAF and PAC cluster episodes on and off. The absence of continued SKNA after the onset might have affected the maintenance of these arrhythmias.

Feasibility and image quality of bright-blood and black-blood phase-sensitive inversion recovery (BOOST) sequence in clinical practice using for left atrial visualization in patients with atrial fibrillation

OBJECTIVES

Visualizing left atrial anatomy including the pulmonary veins (PVs) is important for planning the procedure of pulmonary vein isolation with ablation in patients with atrial fibrillation (AF). The aims of our study are to investigate the feasibility of the 3D whole-heart bright-blood and black-blood phase-sensitive (BOOST) inversion recovery sequence in patients with AF scheduled for ablation or electro-cardioversion, and to analyze the correlation between image quality and heart rate and rhythm of patients.

METHODS

BOOST was performed for assessing PVs both with T2 preparation pre-pulse (T2prep) and magnetization transfer preparation (MTC) in 45 patients with paroxysmal or permanent AF scheduled for ablation or electro-cardioversion. Image quality analyses were performed by two independent observers. Qualitative assessment was made using the Likert scale; for quantitative analysis, signal to noise ratios (SNR) and contrast to noise ratios (CNR) were calculated for each PV. Heart rate and rhythm were analyzed based on standard 12-lead ECGs.

RESULTS

All MTC-BOOST acquisitions achieved diagnostic quality in the PVs, while a significant proportion of T2prep-BOOST images were not suitable for assessing PVs. SNR and CNR values of the MTC-BOOST bright-blood images were higher if patients had sinus rhythm. We found a significant or nearly significant negative correlation between heart rate and the SNR and CNR values of MTC-BOOST bright-blood images.

CONCLUSION

3D whole-heart MTC-BOOST bright-blood imaging is suitable for visualizing the PVs in patients with AF, producing diagnostic image quality in 100% of cases. However, image quality was influenced by heart rate and rhythm.

CLINICAL RELEVANCE STATEMENT

The novel 3D whole-heart BOOST CMR sequence needs no contrast administration and is performed during free-breathing; therefore, it is easy to use for a wide range of patients and is suitable for visualizing the PVs in patients with AF.

KEY POINTS

• The applicability of the novel 3D whole-heart bright-blood and black-blood phase-sensitive sequence to pulmonary vein imaging in clinical practice is unknown. • Magnetization transfer-bright-blood and black-blood phase-sensitive imaging is suitable for visualizing the pulmonary veins in patients with atrial fibrillation with excellent or good image quality. • Bright-blood and black-blood phase-sensitive cardiac magnetic resonance sequence is easy to use for a wide range of patients as it needs no contrast administration and is performed during free-breathing.

[Catheter ablation of atrial fibrillation : Evidence and current techniques]

Atrial fibrillation (AF) is the most frequent cardiac arrhythmia with increasing clinical and healthcare economic relevance. A timely treatment prevents or slows the remodelling process of the atrial and ventricular myocardium initiated by AF, emphasizing its relevance especially in heart failure patients. Catheter ablation for the treatment of AF is safe and effective. The three ablation techniques currently used are comparable in terms of success rates but differ in terms of risk profile and the type of lesion formation.

Can CT-Based Arterial and Venous Morphological Markers of Chronic Obstructive Pulmonary Disease Explain Pulmonary Vascular Remodeling?

RATIONALE AND OBJECTIVES

We analyzed changes in quantitative pulmonary artery and vein parameters to investigate pulmonary vascular remodeling characteristics in chronic obstructive pulmonary disease (COPD) patients.

MATERIALS AND METHODS

This retrospective study recruited healthy volunteers and COPD patients. Participants undergoing standard-of-care pulmonary function testing (PFT) and computed tomography (CT) evaluations were classified into five groups: normal and Global Initiative for Chronic Obstructive Lung Disease (GOLD) grades 1-4. Artery and vein analyses (volumes, numbers, densities, and fractions) were performed using artificial intelligence.

RESULTS

Among 139 subjects (136 men; mean age, 64years±8 [SD]) with GOLD grade 1 (n = 13), grade 2 (n = 49), grade 3 (n = 42), grade 4 (n = 17) and control subjects (n = 18) enrolled, differences in arterial volumes (BV5-10, BV10+, pulmonary arterial volume) and venous densities (BV5 density, BV10+ density, pulmonary venous density, pulmonary venous branch density) among control and GOLD grades 1-4 were statistically significant (P < .05). Higher pulmonary arterial volumes and lower number were observed with more advanced COPD. The number and volumes of pulmonary veins were lower in GOLD grades 2 and 3 than in GOLD grade 1 but higher in GOLD grade 4 than in GOLD grade 3. The numbers and volumes of pulmonary arteries and veins showed varying positive correlations (γ = 0.18-0.96, P < .05). Pulmonary vascular densities were mildly to moderately correlated with PFT results (γ = 0.236-0.495, P < .05) and were moderately negatively correlated with the emphysema percentage (γ = -0.591 to -0.315, P < .05).

CONCLUSION

Patients with COPD exhibited pulmonary vascular remodeling, which occurred in the arteries at the early grade of COPD and in the veins at the late grade. CT-based quantitative analysis of pulmonary vasculature may become an imaging marker for early diagnosis and assessment of COPD severity.

Morphological and morphometric study of pulmonary vein anatomy in relation to cardiac invasive and electrophysiological procedures

Pulmonary veins (PVs) and their myocardial sleeves play an important role in the development of atrial fibrillation. Hence, detailed knowledge of PV anatomy is required to improve the procedural success rate and prevent complications during cardiac procedures. The aim of this study was to evaluate the PV anatomy along with anatomical variations in the Indian population. Total 100 formalin fixed cadaveric hearts were examined. The number and pattern of the PVs were observed along with the measurement of their horizontal and vertical diameters. The ovality index for each PV was calculated. Classical PV pattern was observed in 62% cases. Variant pattern like additional right middle PV pattern and left common PV pattern were found in 20% and 10% cases respectively. A separate pattern with presence of both right middle PV and left common PV was observed in 6% cases. In the classical pattern right superior PV was the largest followed by right inferior, left superior and left inferior PV. The additional right middle PV had the smallest diameter whereas the left common PV had the largest diameter. Almost all the veins had greater vertical diameters in comparison to horizontal diameters. The variant PVs were oval and had greater ovality index compared to the normal PVs. In classical pattern 54.8% hearts whereas in variant pattern 79% hearts had one or more oval PV. The given data can help clinicians for planning and execution of various interventional and electrophysiological procedures involving PVs.

An analysis of the left top pulmonary vein and comparison with the right top pulmonary vein for lung resection by three-dimensional CT angiography and thin-section images

PURPOSE

The right top pulmonary vein (RTPV) is defined as an anomalous branch of the right superior PV (SPV) draining into the PV or left atrium (LA). Several previous reports have described the RTPV, but only a few have mentioned the left top PV (LTPV). The present study aimed to evaluate the branching patterns of the RTPV and LTPV using thin-section CT images and three-dimensional CT angiography (3D-CTA).

MATERIALS AND METHODS

This study included 1437 consecutive patients for evaluation of the right side and 1454 consecutive patients for the left side who were suspected of lung cancer and underwent CTA. We assessed the presence of each RTPV and LTPV and their branching patterns on the CTA images. When the RTPV or LTPV was identified, the maximum short-axis diameter was measured.

RESULTS

RTPV was found in 9.1% (131/1437), whereas LTPV was found in 2.9% (42/1454) of the patients. RTPV was also observed in 17.1% (7/41) of LTPV cases, except for one case in which the right side could not be evaluated. The most common RTPV inflow site was the right inferior PV (IPV) in 64.9% (85/131) of the patients, whereas that of the LTPV was the left IPV in 100.0% (42/42) of the patients. The mean diameter of the RTPV and LTPV was 3.3 mm (range, 1.3-7.5 mm) and 2.4 mm (range, 0.9-6.3 mm), respectively (P < 0.01).

CONCLUSION

The top PV branching pattern variations can be evaluated using thin-section CT and 3D-CTA images. RTPV is not a rare finding, and LTPV should also be identified in lung cancer cases scheduled for resection.

Pulmonary vein flow split effects in patient-specific simulations of left atrial flow

Disruptions to left atrial (LA) blood flow, such as those caused by atrial fibrillation (AF), can lead to thrombosis in the left atrial appendage (LAA) and an increased risk of systemic embolism. LA hemodynamics are influenced by various factors, including LA anatomy and function, and pulmonary vein (PV) inflow conditions. In particular, the PV flow split can vary significantly among and within patients depending on multiple factors. In this study, we investigated how changes in PV flow split affect LA flow transport, focusing for the first time on blood stasis in the LAA, using a high-fidelity patient-specific computational fluid dynamics (CFD) model. We use an Immersed Boundary Method, simulating the flow in a fixed, uniform Cartesian mesh and imposing the movement of the LA walls with a moving Lagrangian mesh generated from 4D Computerized Tomography images. We analyzed LA anatomies from eight patients with varying atrial function, including three with AF and either a LAA thrombus or a history of Transient Ischemic Attacks (TIAs). Using four different flow splits (60/40% and 55/45% through right and left PVs, even flow rate, and same velocity through each PV), we found that flow patterns are sensitive to PV flow split variations, particularly in planes parallel to the mitral valve. Changes in PV flow split also had a significant impact on blood stasis and could contribute to increased risk for thrombosis inside the LAA, particularly in patients with AF and previous LAA thrombus or a history of TIAs. Our study highlights the importance of considering patient-specific PV flow split variations when assessing LA hemodynamics and identifying patients at increased risk for thrombosis and stroke. This knowledge is relevant to planning clinical procedures such as AF ablation or the implementation of LAA occluders.

Neglected Partial Anomalous Pulmonary Venous Return during Atrial Septal Defect Device Closure

Partial anomalous pulmonary venous return (PAPVR) is a rare congenital heart malformation in which 1 or more pulmonary veins drain into the systemic venous circulation or directly into the right atrium instead of the left atrium. It may occur alongside other congenital heart defects, including atrial septal defect (ASD). All patients with newly diagnosed ASD must be evaluated thoroughly for the likelihood of PAPVR to select surgical or percutaneous procedures. Here, we describe a 10-year-old girl with PAPVR who underwent percutaneous device closure of her secundum ASD with her PAPVR neglected at 3 years of age. We had to correct the anomalous venous connection by removing the device during an intricate procedure. The typical connection of the pulmonary veins to the left atrium was reported on her postoperative echocardiography 1 day after surgery. The patient was discharged without complications, and her first follow-up visit 7 days after discharge was unremarkable. While the most accurate diagnostic tools for PAPVR are cardiovascular magnetic resonance imaging and computed tomographic angiography, a careful examination of the pulmonary veins during pulmonary angiography or transesophageal echocardiography in children helps identify PAPVR in patients with ASD.

A modified primary culture method of rat pulmonary vein smooth muscle cells

BACKGROUND

Although the pressure of pulmonary vein increases before pulmonary artery in pulmonary hypertension due to left heart disease (PH-LHD), only a few studies have assessed pulmonary vein smooth muscle cells (PVSMCs) because of the lack of a simple and feasible isolation method.

METHODS

In this study, we introduced a simple method to obtain PVSMCs. Primary pulmonary veins were removed by puncture needle cannula guidance. Then, PVSMCs were cultured by the tissue explant method and purified by the differential adhesion method. The cells were characterized by hematoxylin-eosin (HE) staining, immunohistochemistry, western blotting, and immunofluorescence to observe the morphology and verify the expression of alpha-smooth muscle actin (α-SMA).

RESULTS

The HE staining results showed that the pulmonary vein media was thinner than the pulmonary artery, the intima and adventitia of the pulmonary vein were removed by this method, and the obtained cells with good activity exhibited morphological characteristics of smooth muscle cells. In addition, higher α-SMA expression was observed in the cells obtained by our isolation method than in the traditional method.

CONCLUSION

This study established a simple and feasible method to isolate and culture PVSMCs that might facilitate the cytological experiments for PH-LHD.

Safety and efficacy of balloon angioplasty compared to stent-based-strategies with pulmonary vein stenosis: A systematic review and meta-analysis

BACKGROUND

Pulmonary vein stenosis (PVS) is an uncommon but known cause of morbidity and mortality in adults and children and can be managed with percutaneous re-vascularization strategies of pulmonary vein balloon angioplasty (PBA) or pulmonary vein stent implantation (PSI).

AIM

To study the safety and efficacy outcomes of PBA vs PSI in all patient categories with PVS.

METHODS

We performed a literature search of all studies comparing outcomes of patients evaluated by PBA vs PSI for PVS. We selected all published studies comparing PBA vs PSI for PVS with reported outcomes of restenosis and procedure-related complications in all patient categories. In adults, PVS following atrial fibrillation ablation and in children PVS related to congenital etiology or post-procedural PVS following total or partial anomalous pulmonary venous return repair were included. The patient-centered outcomes were risk of restenosis requiring re-intervention and procedural-related complications. The meta-analysis was performed by computing odds ratios (ORs) using the random effects model based on underlying statistical heterogeneity.

RESULTS

Eight observational studies treating 768 severe PVS in 487 patients met our inclusion criteria. The age range of patients was 6 months to 70 years and 67% were males. The primary outcome of the re-stenosis requiring re-intervention occurred in 196 of 325 veins in the PBA group and 111 of 443 veins in the PSI group. Compared to PSI, PBA was associated with a significantly increased risk of re-stenosis (OR 2.91, 95%CI: 1.15-7.37, P = 0.025, I² = 79.2%). Secondary outcomes of the procedure-related complications occurred in 7 of 122 patients in the PBA group and 6 of 69 in the PSI group. There were no statistically significant differences in the safety outcomes between the two groups (OR: 0.94, 95%CI: 0.23-3.76, P = 0.929), I² = 0.0%).

CONCLUSION

Across all patient categories with PVS, PSI is associated with reduced risk of re-intervention and is as safe as PBA and should be considered first-line therapy for PVS.

Computed tomography of pulmonary veins: review of congenital and acquired pathologies

Newer-generation CT scanners with ultrawide detectors or dual sources offer millisecond image acquisition times and significantly decreased radiation doses compared to historical cardiac CT and CT angiography. This technology is capable of nearly freezing cardiac and respiratory motion. As a result, CT is increasingly used for diagnosing and monitoring cardiac and vascular abnormalities in the pediatric population. CT is particularly useful in the setting of pulmonary vein evaluation because it offers evaluation of the entire pulmonary venous system and lung parenchyma. In this article we review a spectrum of congenital and acquired pulmonary venous abnormalities, including potential etiologies, CT imaging findings and important factors of preoperative planning. In addition, we discuss optimization of CT techniques for evaluating the pulmonary veins.

Surgical correction of partial anomalous left superior pulmonary venous connection to the innominate vein

Partial anomalous pulmonary venous connection is reported to occur in 0.4 to 0.7% of children. Only 3% of these cases involve an anomalous left-sided pulmonary venous connection to the innominate vein [1]. In this video tutorial, we present the technique of reimplantation of the partial anomalous left superior pulmonary venous connection to the left atrial appendage through a median sternotomy and with a cardioplegic heart. We debate the merits of our strategy with respect to our ultimate goal of achieving long-term patency.

Is creation of a fully circumferential lesion set necessary for laser balloon ablation-based pulmonary vein isolation?

BACKGROUND

Despite reports of remote pulmonary vein (PV) stenosis after visually guided laser balloon (VGLB) ablation, circumferential (360°) lesion sets are routinely performed. This study aimed to determine whether fully circumferential lesion creations are required for all PVs to achieve PV isolations (PVIs) and to determine PV's vulnerability to chronic-phase stenosis.

METHODS

Fifty-one patients with paroxysmal atrial fibrillation underwent mapping-guided PVIs using circular mapping catheters. VGLB ablation was performed circumferentially beginning at the 12 o'clock position and continued clockwise or counterclockwise. PVIs obtained within the bounds of the first half of the circumferential lesion (≤ 180°) were defined as "early PVIs."

RESULTS

"Early PVIs" were documented in real time for 39% (80/204) of the PVs and at a significantly greater frequency among lower PVs than upper PVs (60.1% vs. 17.6%; p < 0.0001). The PV sleeve length, PV diameter, and isolation of ipsilateral PVs within a semicircular lesion set were identified as predictors of an "early PVI" phenomenon. The amount of energy delivered to the lower PVs was significantly less than that to the upper PVs (5553 [5089-6188] vs. 3559 [2793-4380] J; p < 0.0001), but the incidence of narrowing of the lower PVs at 6 months was comparable to that of the upper PVs (p = 0.73).

CONCLUSION

Our study revealed electrical isolations of more than 60% of the lower PVs while creating the first half of the circumferential lesions. Crosstalk via the carina region was presumably involved due to the preceding upper PVI. Further study is needed to determine whether energy delivery adjustments are needed for lower PVs to avoid chronic narrowing.

A rare case of left dominant pulmonary edema in acute mitral regurgitation

Unilateral pulmonary edema (UPE) due to cardiac causes is an unusual clinical finding and typically emerges on the right side. UPE poses a diagnostic challenge due to difficulty distinguishing infiltrative pneumonia from cardiogenic edema on chest imaging. Consequently, corrective clinical management is significantly delayed in UPE compared to bilateral cardiogenic pulmonary edema. We present a very rare case of left-sided cardiogenic pulmonary edema due to acute severe MR wherein a prompt cardiac evaluation for UPE led to successful corrective surgery and favorable outcome.

Left atrial inflow propagation velocity derived by color M-mode Doppler in acute heart failure

Left atrial (LA) inflow propagation velocity from the pulmonary vein (LAIF-PV) has been proposed as a novel measure of LA reservoir function and is associated with pulmonary capillary wedge pressure in critically ill patients. However, data on LAIF-PV in acute heart failure (AHF) are lacking. We sought to examine the feasibility of measuring LAIF-PV and evaluate clinical and echocardiographic correlates of LAIF-PV in AHF. In a prospective cohort study of adults hospitalized for AHF, we used color M-mode Doppler of the pulmonary veins to obtain LAIF-PV in systole. Among 142 patients with appropriate images and no more than moderate mitral regurgitation, LAIF-PV measures were feasible in 76 patients (54%) aged 71 ± 14 years, including 68% men with left ventricular ejection fraction (LVEF) 38% ± 13. Mean LAIF-PV was 24.2 ± 5.9 cm/s. In multivariable regression analysis adjusted for age, sex, systolic blood pressure, heart rate, body mass index, New York Heart Association class, LA volume and LVEF, the only independent echocardiographic predictors of LAIF-PV were right ventricular (RV) S' [ß 0.46 cm/s per cm/s (95% CI 0.01-0.91), p = 0.045] and tricuspid annular plane systolic excursion (TAPSE) [ß 0.28 cm/s per mm (95% CI 0.02-0.54), p = 0.039]. Notably, LAIF-PV was not significantly correlated with measures of LV function, LA function or E/e'. In conclusion, LAIF-PV was measurable in 54% of patients with AHF, and lower values were associated with measures of impaired RV systolic function but not LV or LA function.

What we have learned: is pulmonary vein isolation still the cornerstone of atrial fibrillation ablation?

Ablation of atrial fibrillation (AF) is an established treatment option for symptomatic patients. The cornerstone of all ablation strategies is electrical isolation of the pulmonary veins (PVs). Ablation strategies going beyond PV isolation (PVI) might be considered in the setting of recurrent AF despite durably isolated PVs. The lack of persistent PVI, however, limits the opportunities to perceive the real impact of this endpoint on AF suppression and to fully understand the benefit of extended ablation strategies going beyond. To overcome this limitation, novel and innovative ablation systems have been developed to facilitate acute PVI and to increase its durability. These systems include balloon-based ablation devices incorporating different energy sources such as cryo energy, laser, or radiofrequency current, but also new energy sources such as pulsed field ablation as a non-thermal energy source. These technologies could advance catheter ablation of AF to an early stage of the disease and to the primary treatment tool. The current manuscript focuses on the past, the present, and the future value of PVI as the cornerstone for interventional treatment of AF and on how to achieve durable PVI during the first procedure and to further improve the clinical success rates of AF ablation. It also analyses extended ablation strategies going beyond PVI and their impact.

Prognostic Role of Circulating Tumor Cells in the Pulmonary Vein, Peripheral Blood, and Bone Marrow in Resectable Non-Small Cell Lung Cancer

Background

Studies of the prognostic role of circulating tumor cells (CTCs) in early-stage non-small cell lung cancer (NSCLC) are still limited. This study investigated the prognostic power of CTCs from the pulmonary vein (PV), peripheral blood (PB), and bone marrow (BM) for postoperative recurrence in patients who underwent curative resection for NSCLC.

Methods

Forty patients who underwent curative resection for NSCLC were enrolled. Before resection, 10-mL samples were obtained of PB from the radial artery, blood from the PV of the lobe containing the tumor, and BM aspirates from the rib. A microfabricated filter was used for CTC enrichment, and immunofluorescence staining was used to identify CTCs.

Results

The pathologic stage was stage I in 8 patients (20%), II in 15 (38%), III in 14 (35%), and IV in 3 (8%). The median number of PB-, PV-, and BM-CTCs was 4, 4, and 5, respectively. A time-dependent receiver operating characteristic curve analysis showed that PB-CTCs had excellent predictive value for recurrence-free survival (RFS), with the highest area under the curve at each time point (first, second, and third quartiles of RFS). In a multivariate Cox proportional hazard regression model, PB-CTCs were an independent risk factor for recurrence (hazard ratio, 10.580; 95% confidence interval, 1.637–68.388; p<0.013).

Conclusion

The presence of ≥4 PB-CTCs was an independent poor prognostic factor for RFS, and PV-CTCs and PB-CTCs had a positive linear correlation in patients with recurrence.

Left Partial Anomalous Pulmonary Venous Connection and Vertical Vein

The Article Abstract is not available.

Outcomes of the Warden Procedure for Anomalous Pulmonary Venous Return to the Superior Vena Cava: A 17-Year Experience

Background

Surgical repair of partial anomalous pulmonary venous return (PAPVR) to the superior vena cava (SVC) using the Warden procedure has favorable outcomes. However, there remain some concerns after the Warden procedure, such as sinoatrial nodal dysfunction and systemic or pulmonary venous stenosis. We investigated the outcomes of the Warden procedure for repair of PAPVR to the SVC.

Methods

This retrospective study included 22 consecutive patients who underwent the Warden procedure for PAPVR between 2002 and 2018. The median age and body weight at operation were 27.5 months (interquartile range [IQR], 5.0–56.8 months) and 13.2 kg (IQR, 6.5–16.0 kg), respectively. The median follow-up duration was 6.2 years (IQR, 3.5–11.6 years).

Results

There were no cases of early or late mortality. No patients had postoperative heart rhythm problems, except 1 patient who showed transient sinoatrial nodal dysfunction in the immediate postoperative period. Procedure-related complications requiring reintervention occurred in 5 patients, including 3 of 4 SVC stenosis cases and 2 pulmonary venous stenosis cases during follow-up. The rate of freedom from reintervention related to the Warden procedure was 75.9% at 10 years.

Conclusion

In cases requiring extension or creation of an atrial septal defect to achieve a sufficient venous pathway, or interposition of an entire circumferential conduit between the SVC and right atrium due to the shortness of the SVC in the Warden procedure, stenotic complications of the venous pathway occurred. Careful observation of changes in the pressure gradient or anatomical stenosis is required in such patients.

Cryptogenic, Embolic Stroke-Looking Backstage

Stroke is a common and devastating event and the majority of cases are caused by thromboembolism from the left atrium, left ventricle or left sided valves. This case report describes a case of embolic stroke with the origin of the thrombus from the left inferior pulmonary vein. The importance of this case is twofold. Firstly, it is the fourth case report of pulmonary venous thrombosis, a very rare condition, due to COVID-19 infection and secondly, it focuses attention on the fact that the left atrium is not the most proximal address of arterial thromboembolism-the pulmonary veins are. Thus, it is proposed that a thorough assessment of the pulmonary veins should be done in all cases of arterial thromboembolism.

Recent advances in the tools available for atrial fibrillation ablation

INTRODUCTION

Atrial fibrillation (AF) is the commonest arrhythmia in clinical practice with significant detrimental health impacts. Much effort has been spent in mapping AF, determine its triggers and drivers, and how to develop tools to eliminate these triggers.

AREAS COVERED

In this state of-the-art review article, we aim to highlight the recent techniques in catheter-based management of Atrial Fibrillation; including new advancements either in the catheter design or the software used. This includes a comprehensive summary of the most recent tools used in AF mapping and subsequent ablation.

EXPERT OPINION

Electrical isolation of the pulmonary veins has been developed and established as the cornerstone in AF ablation with good results in patients with paroxysmal AF (PAF) whilst new ablation tools are aimed at streamlining the procedure. However, the quest for persistent AF (PeAF) remains. The future of AF ablation, we believe, lies in identifying AF drivers by means of the new developing mapping tools and altering their electrical properties in a safe, reproducible, and effective manner.

Vascular endothelial growth factor modulates pulmonary vein arrhythmogenesis via vascular endothelial growth factor receptor 1/NOS pathway

Atrial fibrillation (AF) is a common form of arrhythmia with serious public health impacts, but its underlying mechanisms are not yet fully understood. Vascular endothelial growth factor (VEGF) is highly expressed in the atrium of patients with AF, but whether VEGF affects AF pathogenesis remains unclear. Pulmonary veins (PVs) are important sources for the genesis of atrial tachycardia or AF. Therefore, this study assessed the effects of VEGF on PV electrophysiological properties and evaluated its underlying mechanisms. Conventional microelectrodes and whole-cell patch clamps were performed using isolated rabbit PV preparations or single isolated PV cardiomyocytes before and after VEGF or VEGF receptor (VEGFR), Akt, NOS inhibitor administration. We found that VEGF (0.1, 1, and 10 ng/mL) reduced the PV beating rate in a dose-dependent manner. Furthermore, VEGF (10 ng/mL) reduced late diastolic depolarization and diastolic tension. Isoproterenol increased PV beating and burst firing, which was attenuated by VEGF (1 ng/mL). In the presence of VEGFR-1 inhibition (ZM306416 at 10 μM) and L-NAME (100 μM), VEGF (1 ng/mL) did not alter PV spontaneous activity. In isolated PV cardiomyocytes, VEGF (1 ng/mL) decreased L-type calcium, sodium/calcium exchanger, and late sodium currents. In conclusion, we found that VEGF reduces PV arrhythmogenesis by modulating sodium/calcium homeostasis through VEGFR-1/NOS signaling pathway.

Midline crossing pulmonary vein: right upper lobe dual venous drainage, with partial anomalous venous return of the right lung into a persistent left superior vena cava

Introduction

We present a case of dual drainage of the right upper lobe of the lung into the left atrium and via partial anomalous venous pulmonary return (PAPVR) into a persistent left superior vena cava (SVC).

Discussion

It is only in the minority of PAPVR cases where the anomalous pulmonary veins cross the midline. We provide a review of current literature on this topic and an explanatory embryological model. Knowledge of embryonic development and possible anatomic variations, including the concept of dual venous drainage of the lung, leads to better interpretation of imaging, with more accurate description of the morphology at hand. High-resolution multidetector computed tomography (MDCT) helps to delineate the exact vascular anatomy. This will enhance a better understanding of and anticipation on the patient’s disease status, with more accurate planning of intervention, and possibly less complications.

Anatomic characteristics of the left atrium in subjects undergoing radiofrequency ablation for atrial fibrillation

OBJECTIVE

To analyze the anatomic characteristics of the left atrium and pulmonary veins in individuals undergoing ablation for atrial fibrillation and to identify possible anatomic factors related with recurrence.

MATERIAL AND METHODS

We retrospectively reviewed the CT angiography studies done to plan radiofrequency ablation for atrial fibrillation in 95 patients (57 men; mean age, 65 ± 10 y). We reviewed the anatomy of the pulmonary veins and recorded the diameters of their ostia as well as the diameter and volume of the left atrium. We analyzed these parameters according to the type of arrhythmia and the response to treatment.

RESULTS

In 71 (74.7%) patients, the anatomy of the pulmonary veins was normal (i.e., two right pulmonary veins and two left pulmonary veins). Compared to patients with paroxysmal atrial fibrillation, patients with persistent atrial fibrillation had slightly larger diameter of the left pulmonary veins (left superior pulmonary vein 17.9 ± 2.6 mm vs. 16.7 ± 2.2 mm, p = 0.04; left inferior pulmonary vein 15.3 ± 2 mm vs. 13.8 ± 2.2 mm, p = 0.009) and larger left atrial volume (91.9 ± 24.9 cm³ vs. 70.7 ± 20.3 mm³, p = 0.001). After 22.1 ± 12.1 months' mean follow-up, 41 patients had sinus rhythm. Compared to patients in whom the sinus rhythm was restored, patients with recurrence had greater left atrial volume (81.4 ± 23.0 mm³ vs. 71.1 ± 23.2 mm³, p = 0.03). No significant differences in pulmonary vein diameters or clinical parameters were observed between patients with recurrence and those without.

CONCLUSION

The volume of the left atrium is greater in patients with persistent atrial fibrillation and in those who do not respond to ablation.

Targeting non-pulmonary vein triggers in persistent atrial fibrillation: results from a prospective, multicentre, observational registry

AIMS

We evaluated the efficacy of an ablation strategy empirically targeting pulmonary veins (PVs) and posterior wall (PW) and the prevalence and clinical impact of extrapulmonary trigger inducibility and ablation in a large cohort of patients with persistent atrial fibrillation (PerAF).

METHODS AND RESULTS

A total of 1803 PerAF patients were prospectively enrolled. All patients underwent pulmonary vein antrum isolation (PVAI) extended to the entire PW. A standardized protocol was performed to confirm persistent PVAI and elicit any triggers originating from non-PV sites. All non-PV triggers initiating sustained atrial tachyarrhythmias were ablated. Ablation of non-PV sites triggering non-sustained runs (<30 s) of atrial tachyarrhythmias or promoting frequent premature atrial complexes (≥10/min) was left to operator's discretion. Overall, 1319 (73.2%) patients had documented triggers from non-PV areas. After 17.4 ± 8.5 months of follow-up, the cumulative freedom from atrial tachyarrhythmias among patients without inducible non-PV triggers (n = 484) was 70.2%. Patients with ablation of induced non-PV triggers had a significantly higher arrhythmia control than those whose triggers were not ablated (67.9% vs. 39.4%, respectively; P < 0.001). After adjusting for clinically relevant variables, patients in whom non-PV triggers were documented but not ablated had an increased risk of arrhythmia relapse (hazard ratio: 2.39; 95% confidence interval: 2.01-2.83; P < 0.001).

CONCLUSION

Pulmonary vein antrum isolation extended to the entire PW might provide acceptable long-term arrhythmia-free survival in PerAF patients without inducible non-PV triggers. In our population of PerAF patients, non-PV triggers could be elicited in ∼70% of PerAF patients and their elimination significantly improved outcomes.

Durable pulmonary vein isolation but not complex substrate ablation determines the type of arrhythmia recurrence after persistent atrial fibrillation ablation

BACKGROUND

Complex ablation for persistent atrial fibrillation (AF) aims to modify the arrhythmogenic substrates to become incapable to perpetuate the arrhythmia. Ablation-associated determinants of atrial tachycardia (AT) rather than AF recurrences are unknown. The aim of the study was to evaluate the association between the type of arrhythmia recurrence and electrophysiological findings during redo procedures.

METHODS

A total number of 384 consecutive patients with persistent AF underwent complex ablation consisting of PV isolation (PVI), biatrial electrogram-guided ablation, and linear ablation with the desired procedural endpoint of AF termination. Electrophysiological findings during redo procedures and its relation to AR type are the subject of this study.

RESULTS

Overall, 177 (46%) patients underwent a second procedure. Patients with AT recurrences had significantly more often persistent PVI (47 vs. 25%; P = 0.002). Moreover, a higher number of recovered PVs were associated with AF recurrence (3 PVs recovered, AF = 16.1% vs. AT = 5.2%; P = 0.02; 4 PVs recovered, AF = 18.5% vs. AT = 6.3%; P = 0.01), regardless of the extent of substrate ablation during the first procedure.

CONCLUSIONS

Durable PV isolation but not the extent of atrial substrate ablation determines the type of arrhythmia recurrence. Thus, the PVs may represent dominant perpetuators (and not only triggers) of persistent AF even in the presence of a significantly modified atrial substrate.

Surgical repair of total anomalous pulmonary venous connection: Lateral approach

We describe the lateral approach to the surgical repair of a total anomalous pulmonary venous connection in this video tutorial. The goal of the operation is to create an unobstructed anastomosis between the pulmonary confluence and the left atrium, ligate the systemic venous connections, and close the atrial septal defect. After a median sternotomy and initial dissection of the structures surrounding the heart, cardiopulmonary bypass is initiated by aortobicaval cannulation. The patient is then cooled to attain mild hypothermia (30°C). The heart is arrested by a dose of antegrade cold cardioplegia. The right pleural cavity is opened widely. The heart is retracted and pushed into the right pleural cavity. The vertical vein is ligated near its connection with the innominate vein. An incision is made along the length of the confluence, stopping short of the individual pulmonary veins. The left atrial appendage is retracted, and the left atrium is opened in alignment with the opening in the confluence. The left atrium and the pulmonary confluence are anastomosed widely with 7-0 polypropylene suture material. The heart is put back into the mediastinum. Rewarming is started. The atrial septal defect is closed through the right atrium using a large untreated autologous pericardium patch. The patient is then weaned off cardiopulmonary bypass.

Mapping atrial fibrillation : An overview of potential mechanisms underlying atrial fibrillation

Mechanisms sustaining atrial fibrillation are yet to be clarified. This article focuses on milestones in the theory of atrial fibrillation and addresses the different leading hypotheses concerning atrial fibrillation mechanisms. We start off with electric potential originating from the pulmonary vein, which triggers atrial fibrillation, discuss classic activation mapping and phase mapping as well as computer models, which have contributed to the our understanding of atrial fibrillation, and end with new mapping methods and studies highlighting the advantages and disadvantages of current mechanistic hypotheses. The technical evolution of mapping atrial fibrillation has led to new insights into the potential mechanisms underlying atrial fibrillation. A comparison between methods is essential for understanding the advantages and disadvantages of each method when mapping atrial fibrillation. Ultimately, the combination of several methods might shed light on the underlying mechanisms of atrial fibrillation and lead to a better understanding of atrial fibrillation and subsequently improve treatment of this condition.

Computed tomographic angiography (CTA) diagnosis of a rare meandering right pulmonary vein (MRPV)

Meandering right pulmonary vein (MRPV) is an exceedingly rare congenital pulmonary vascular variant with less than 20 reported cases. MPVR is a tortuous aberrant venous drainage of the right pulmonary upper lobe anastomosing with the right lower pulmonary vein instead of directly joining the left atrium. The variant is benign with an orthotopic venous drainage without any kind of shunting. The differential diagnosis mostly comprises the scimitar syndrome but also primary varix, arteriovenous malformations, and pulmonary sequestration. We report a case of MRPV fortuitously diagnosed in a 70-year-old patient. Multi-detector computed tomographic angiography (CTA) with MPR, MIP, and 3D reconstructions allowed the diagnosis obviating the need for invasive procedures.

Repair of intracardiac total anomalous pulmonary venous return

Total anomalous pulmonary venous return is an uncommon congenital anomaly of the pulmonary venous system.  Excision of the common wall between the atrial septum and the coronary sinus and closure with a single patch is a popularly used technique to repair cardiac total anomalous pulmonary venous return. We have used the same approach in our patient: Our tutorial shows a simple method to divert pulmonary venous return into the mitral valve without causing damage to the internodal pathways.  Marking the coronary sinus is highlighted because using that landmark to locate the atrioventricular node is no longer possible after the common wall is cut.

Platelet-derived growth factor-BB induces pulmonary venous smooth muscle cells proliferation by upregulating calcium sensing receptor under hypoxic conditions

Pulmonary hypertension (PH) is characterized by pulmonary vascular remodeling, which exists in both pulmonary arteries and pulmonary veins. Pulmonary vascular remodeling stems from excessive proliferation of pulmonary vascular myocytes. Platelet-derived growth factor-BB (PDGF-BB) is a vital vascular regulator whose level increases in PH human lungs. Although the mechanisms by which pulmonary arterial smooth muscle cells respond to PDGF-BB have been studied extensively, the effects of PDGF-BB on pulmonary venous smooth muscle cells (PVSMCs) remain unknown. We herein examined the involvement of calcium sensing receptor (CaSR) in PDGF-BB-induced PVSMCs proliferation under hypoxic conditions. In PVSMCs isolated from rat intrapulmonary veins, PDGF-BB increased the cell number and DNA synthesis under normoxic and hypoxic conditions, which was accompanied by upregulated CaSR expression. The influences of PDGF-BB on proliferation and CaSR expression in hypoxic PVSMCs were greater than that in normoxic PVSMCs. In hypoxic PVSMCs superfused with Ca²⁺-free solution, restoration of extracellular Ca²⁺ induced an increase of [Ca²⁺]_i, which was significantly smaller than that in PDGF-BB-treated hypoxic PVSMCs. The positive CaSR modulator spermine enhanced, whereas the negative CaSR modulator NPS2143 attenuated, the extracellular Ca²⁺-induced [Ca²⁺]_i increase in PDGF-BB-treated hypoxic PVSMCs. Furthermore, the spermine enhanced, whereas the NPS2143 inhibited, PDGF-BB-induced proliferation in hypoxic PVSMCs. Silencing CaSR with siRNA attenuated the extracellular Ca²⁺-induced [Ca²⁺]_i increase in PDGF-BB-treated hypoxic PVSMCs and inhibited PDGF-BB-induced proliferation in hypoxic PVSMCs. In conclusion, these results demonstrated that CaSR mediating PDGF-BB-induced excessive PVSMCs proliferation is an important mechanism involved in the initiation and progression of PVSMCs proliferation under hypoxic conditions.

Initial experience of the High-Density Grid catheter in patients undergoing catheter ablation for atrial fibrillation

PURPOSE

A significant proportion of patients undergoing catheter ablation for atrial fibrillation (AF) experience arrhythmia recurrence. This is mostly due to pulmonary vein reconnection (PVR). Whether mapping using High-Density Wave (HDW) technology is superior to standard bipolar (SB) configuration at detecting PVR is unknown. We aimed to evaluate the efficacy of HDW technology compared to SB mapping in identifying PVR.

METHODS

High-Density (HD) multipolar Grid catheters were used to create left atrial geometries and voltage maps in 36 patients undergoing catheter ablation for AF (either due to recurrence of an atrial arrhythmia from previous AF ablation or de novo AF ablation). Nineteen SB maps were also created and compared. Ablation was performed until pulmonary vein isolation was achieved.

RESULTS

Median time of mapping with HDW was 22.3 [IQR: 8.2] min. The number of points collected with HDW (13299.6±1362.8 vs 6952.8±841.9, p<0.001) and used (2337.3±158.0 vs 1727.5±163.8, p<0.001) was significantly higher compared to SB. Moreover, HDW was able to identify more sleeves (16 for right and 8 for left veins), where these were confirmed electrically silent by SB, with significantly increased PVR sleeve size as identified by HDW (p<0.001 for both right and left veins). Importantly, with the use of HDW, the ablation strategy changed in 23 patients (64% of targeted veins) with a significantly increased number of lesions required as compared to SB for right (p=0.005) and left veins (p=0.003).

CONCLUSION

HDW technology is superior to SB in detecting pulmonary vein reconnections. This could potentially result into a significant change in ablation strategy and possibly to increased success rate following pulmonary vein isolation.

Latin-American experience in cryoablation of paroxysmal and persistent atrial fibrillation using second generation cryo-balloon. Acute success and 12 months of follow-up

Objective

Catheter ablation has become a usual technique to treat atrial fibrillation (AF). Medium-term results of prospective and multicenter data concerning pulmonary veins cryoablation in Latin America are limited. The objective is to assess the safety and efficacy of ablation by second generation cryoballoon in patients with paroxysmal atrial fibrillation (PAF) or persistent atrial fibrillation (PerAF) in Latin America.

Method

We evaluate the characteristics of the procedure and the acute and 12-month results. Inclusion criteria include patients over 18 years old with AF who have a planned procedure of pulmonary veins isolation with second generation cryoballoon. Treatment failure was defined as any episode of AF, atrial flutter or atrial tachycardia greater than 30 seconds outside the 90-day blinded period.

Results

A total of 218 patients (57 ± 11 years, 66.5% men, CHA2DS2-VASc 1.2 ± 1.1) were included in the study. Of these, 83.9% evidenced PAF, 12.8% PerAF, and 2.3% long-standing PerAF. Fifteen with history of atrial flutter. Most patients had failed at least one antiarrhythmic drug (89.4%). The acute success of the procedure was obtained in 211 patients (96.8%). The average procedure time was 73.2 ± 26.7 min, the fluoroscopy time was 21.4 ± 23.9 min, and the total lab occupancy time was 114.6 ± 41.3 min. During the 12-month follow-up, freedom from AF recurrence was 88.6% in PAF, and 73.1% in PerAF. Twenty-one patients experienced device or procedure-related complications (9.6%).

Conclusions

These results support pulmonary veins electrical isolation with cryoballoon as an effective treatment for AF in Latin America.

Radial-based acquisition strategies for pre-procedural non-contrast cardiovascular magnetic resonance angiography of the pulmonary veins

BACKGROUND

Computed tomography angiography (CTA) or contrast-enhanced (CE) cardiovascular magnetic resonance angiography (CMRA) is often obtained in patients with atrial fibrillation undergoing evaluation prior to pulmonary vein (PV) isolation. Drawbacks of CTA include radiation exposure and potential risks from iodinated contrast agent administration. Free-breathing 3D balanced steady-state free precession (bSSFP) Non-contrast CMRA is a potential imaging option, but vascular detail can be suboptimal due to ghost artifacts and blurring that tend to occur with a Cartesian k-space trajectory or, in some cases, inconsistent respiratory gating. We therefore explored the potential utility of both breath-holding and free-breathing non-contrast CMRA, using radial k-space trajectories that are known to be less sensitive to flow and motion artifacts than Cartesian.

MAIN BODY

Free-breathing 3D Cartesian and radial stack-of-stars acquisitions were compared in 6 healthy subjects. In addition, 27 patients underwent CTA and non-contrast CMRA for PV mapping. Three radial CMR acquisition strategies were tested: (1) breath-hold (BH) 2D radial bSSFP (BH-2D); (2) breath-hold, multiple thin-slab 3D stack-of-stars bSSFP (BH-SOS); and (3) navigator-gated free-breathing (FB) 3D stack-of-star bSSFP using a spatially non-selective RF excitation (FB-NS-SOS). A non-rigid registration algorithm was used to compensate for variations in breath-hold depth. In healthy subjects, image quality and vessel sharpness using a free-breathing 3D SOS acquisition was significantly better than free-breathing (FB) Cartesian 3D. In patients, diagnostic image quality was obtained using all three radial CMRA techniques, with BH-SOS and FB-NS-SOS outperforming BH-2D. There was overall good correlation for PV maximal diameter between BH-2D and CTA (ICC = 0.87/0.83 for the two readers), excellent correlation between BH-SOS and CTA (ICC = 0.90/0.91), and good to excellent correlation between FB-NS-SOS and CTA (ICC = 0.87/0.94). For PV area, there was overall good correlation between BH-2D and CTA (ICC = 0.79/0.83), good to excellent correlation between BH-SOS and CTA (ICC = 0.88/0.91) and excellent correlation between FB-NS-SOS and CTA (ICC = 0.90/0.95). CNR was significantly higher with BH-SOS (mean = 11.04) by comparison to BH-2D (mean = 6.02; P = 0.007) and FB-NS-SOS (mean = 5.29; P = 0.002).

CONCLUSION

Our results suggest that a free-breathing stack-of-stars bSSFP technique is advantageous in providing accurate depiction of PV anatomy and ostial measurements without significant degradation from off-resonance artifacts, and with better image quality than Cartesian 3D. For patients in whom respiratory gating is unsuccessful, a breath-hold thin-slab stack-of-stars technique with retrospective motion correction may be a useful alternative.

Pulmonary vein stenosis mimicking interstitial lung disease

Pulmonary vein stenosis (PVS) is a rare condition, often difficult to diagnose and associated with poor prognosis at advanced stages. Lung parenchymal abnormalities are indirect evidence of PVS and can manifest as multifocal opacities, nodular lesions, unilateral effusions, and interstitial septal thickening. These can lead to erroneous diagnoses of airway disease, pneumonia, malignancy or interstitial lung disease. This review summarizes the current literature about the approach, evaluation and management of these patients. Our case report demonstrates that PVS is an under-recognized complication of cardiovascular surgery and should be considered in all patients presenting with respiratory symptoms after a cardiac procedure.

Focal source and trigger mapping in atrial fibrillation: Randomized controlled trial evaluating a novel adjunctive ablation strategy

BACKGROUND

Intraoperative mapping has demonstrated focal activations during human atrial fibrillation (AF). These putative AF sources can manifest sustained periodic bipolar and unipolar QS electrograms (EGMs). We have automated the detection of these EGM features using our validated Focal Source and Trigger (FaST) computational algorithm.

OBJECTIVE

The purpose of this study was to conduct a randomized controlled pilot evaluating the feasibility and efficacy of FaST mapping/ablation as an adjunct to pulmonary vein isolation (PVI) in reducing AF recurrence.

METHODS

We randomized 80 patients with high-burden paroxysmal or persistent AF (age 61 ± 10 years; 75% male) to PVI alone (n = 41) or PVI+FaST mapping/ablation (n = 39). The primary endpoint was time to AF recurrence >30 seconds between 3 and 12 months after 1 procedure.

RESULTS

FaST sites were identified in all but 1 patient and were localized to pulmonary vein (PV) (2.1 ± 1.1 per patient) and extra-PV regions (2.8 ± 1.4 per patient). FaST mapping and ablation times were 27 ± 9 minutes and 8.5 ± 5 minutes, respectively. Patients with AF termination during ablation had greater AF cycle length prolongation with PVI+FaST than PVI (Δ20 ± 14 ms vs Δ5 ± 17 ms; P = .046). Freedom from AF recurrence at 12 months was higher in PVI+FaST vs PVI for patients off antiarrhythmic drugs (74% vs 51%; hazard ratio 0.48; 95% confidence interval 0.21-1.08; P = .064) but did not quite reach statistical significance. Major adverse events were similar between the 2 groups.

CONCLUSION

In this randomized controlled pilot, real-time FaST mapping provided an intuitive, automated approach for localizing focal AF sources. FaST ablation as an adjunct to PVI may reduce AF recurrence, which requires verification with a larger multicenter trial.

A novel function of calcium sensing receptor in chronic hypoxia-induced pulmonary venous smooth muscle cells proliferation

Chronic hypoxia (CH) causes remodeling not only in pulmonary arteries but also in pulmonary veins. Pulmonary vascular remodeling stems from increased pulmonary vascular myocyte proliferation. However, the pathogenesis of CH-induced proliferation of pulmonary venous smooth muscle cells (PVSMCs) remains unknown. The present study aimed to explore the mechanisms by which CH affects PVSMCs proliferation. PVSMCs were isolated from rat distal pulmonary veins and exposed to CH (4% O₂ for 60 h). The expression of calcium sensing receptor (CaSR) was determined by immunofluorescence, real-time quantitative PCR and Western blotting. Cell proliferation was assessed by cell counting, CCK-8 assay, and BrdU incorporation. Apoptosis analysis was examined by flow cytometry. In rat distal PVSMCs, CH increased the cell number and cell viability and enhanced DNA synthesis, which is accompanied by upregulated mRNA and protein expression levels of CaSR. Two negative CaSR modulators (NPS2143, NPS2390) not only attenuated CH-induced CaSR upregulation but also inhibited CH-induced increases in cell number, cell viability and the proliferation index of PVSMCs, whereas two positive modulators (spermine, R568) not only amplified CH-induced CaSR upregulation but also intensified CH-induced increases in cell number, cell viability and the proliferation index of PVSMCs. Silencing CaSR with siRNA similarly attenuated the CH-induced enhancement of cell number, cell viability and DNA synthesis in PVSMCs. Neither CH nor downregulation of CaSR with siRNA had an effect on apoptosis in PVSMCs. These results suggest that CaSR mediating excessive proliferation is a new pathogenic mechanism involved in the initiation and progression of distal PVSMCs proliferation under CH conditions.

The local repolarization heterogeneity in the murine pulmonary veins myocardium contributes to the spatial distribution of the adrenergically induced ectopic foci

An atrial tachyarrhythmias is predominantly triggered by a proarrhythmic activity originate from the pulmonary veins (PV) myocardial sleeves; sympathetic or adrenergic stimulation facilitates PV proarrhythmia. In the present study the electrophysiological inhomogeneity, spatiotemporal characteristics of the adrenergically induced ectopic firing and sympathetic nerves distribution have been investigated in a murine PV myocardium to clarify mechanisms of adrenergic PV ectopy. Electrically paced murine PV demonstrate atrial-like pattern of conduction and atrial-like action potentials (AP) with longest duration in the mouth of PV. The application of norepinephrine (NE), agonists of α- and β-adrenergic receptors (ARs) or intracardiac nerves stimulation induced spontaneous AP in a form of periodical bursts or continuous firing. NE- or ARs agonists-induced SAP originated from unifocal ectopic foci with predominant localization in the region surrounding PV mouth, but not in the distal portions of a murine PV myocardium. A higher level of catecholamine content and catecholamine fiber network density was revealed in the PV myocardial sleeves relative to LA appendage. However, no significant local variation of catecholamine content and fiber density was observed in the murine PV. In conclusion, PV mouth region appear to be a most susceptible to adrenergic proarrhythmia in mice. Intrinsic spatial heterogeneity of AP duration can be considered as a factor influencing localization of the ectopic foci in PV.

Multidetector computed tomography in planning the treatment of atrial fibrillation

OBJECTIVE

To know the anatomy of the pulmonary veins (PVs) by multidetector computed tomography (MDCT) in patients with atrial fibrillation (AF) prior to ablation.

MATERIALS AND METHODS

MDCT was performed in 89 patients with AF, analyzing the number of PVs, accessory variants and veins, diameter and ostial shape, distance to the first bifurcation and thrombus in the left atrial appendage.

RESULTS

The most frequent venous pattern was 4 PVs (two right and two. left) in 49 patients (55.1%). The superior veins had a statistically significant greater mean ostial diameter than the inferior veins (Right Superior Pulmonary Vein (RSPV)> Right Inferior Pulmonary Vein (RIPV); p=0.001 and Left Superior Pulmonary Vein (LSPV)> Left Inferior Pulmonary Vein (LIPV); p<0.001). The right pulmonary veins ostial diameters were significantly larger than the left pulmonary veins ostial diameters (RSPV> LSPV; p<0.001 and RIPV> LIPV; p<0.001). The most circular ostium was presented by the VPID (ratio: 0.885) compared to the LIPV (p<00.1) and LSPV (p<0.001). The superior veins had a statistically significant greater mean distance to first bifurcation than the inferior veins (RSPV> RIPV; p=0.008 and LSPV> LIPV; p=0.038). Mean distance to first bifurcation has been greater in left PVs respect to the right PVs (LSPV> RSPV; p<0.001and LIPV> RIPV; p<0.001). Other findings found in AI: diverticula (30), accessory auricular appendages (5), septal aneurysms (8), septal bags (6) and 1 thrombus in the left atrial appendage.

CONCLUSION

MDCT prior to ablation demonstrates the anatomy of the left atrium (LA) and pulmonary veins with significant differences between the diameters and morphology of the venous ostia.

Two autopsy cases of siblings with alveolar capillary dysplasia: clinical and post-mortem issues

Alveolar capillary dysplasia with misalignment of pulmonary veins (ACD/MPV) is a rare but fatal lung disorder, which causes persistent pulmonary hypertension of the newborn (PPHN) and which is unresponsive to treatment. We report the case of two siblings, both of whom died a few hours after birth because of severe pulmonary failure. Post-mortem histology confirmed ACD/MPV as the cause of death in both cases, and genetic analysis identified the same 16p13.3 deletion. ACD/MPV can occur suddenly in apparently healthy newborns after a regular pregnancy, and always leads to death. Nevertheless, an autopsy is not always performed after the death of an infant. For these reasons ACD/MPV represents a challenge for diagnosis and therapeutic management with medicolegal implications. Prenatal assessment of ACD/MPV is very difficult, and it should be suspected when irreversible and persistent fetal circulation occurs rapidly in newborns. An early diagnosis during pregnancy would facilitate adequate counselling regarding treatment and prognosis. When death occurs, a complete autopsy with histological and genetic investigations is recommended in order to define the exact cause of death, and potentially inform appropriate genetic counselling of family members who could be affected by hereditary disorders.

[Clinical analysis of scimitar syndrome in 6 pediatric patients]

Objective: To characterize the clinical features and outcomes of scimitar syndrome (SS) to aid the understanding of this syndrome. Methods: This retrospective study included 6 children who were diagnosed with SS at the pediatric cardiovascular center of Beijing Anzhen Hospital from January 2012 to September 2018. SS was diagnosed by echocardiography and confirmed by cardiac computed tomography angiography(CTA) or surgery. All data were collected to analyze the clinical and imaging characteristics and prognosis. Results: Among the 6 SS children (aged 2 months to 15 years; 5 males) weighed 5.6-17.1 kg. Three cases were infant type, the clinical manifestations were recurrent respiratory tract infection with growth retardation, including 2 cases with severe pulmonary hypertension, while 3 cases with adult type, were asymptomatic. Cardiac CTA imaging showed that the right single or all pulmonary veins descended through the diaphragm and converged into the inferior vena cava. One case was isolated infracardiac partial anomalous pulmonary venous connection (PAPVC) without other malformations. The remaining 5 cases complicated with atrial septal defect, different vascular and trachea malformations as well as spinal malformations. Vascular malformations included pulmonary veins stenosis, abnormal origin of pulmonary artery branches, collateral branches of systemic artery supplying local lung tissue, and persistent left superior vena cava. The treatment varied according to the specific location of anomalous pulmonary venous connection, the degree of pulmonary hypertension and the severity of clinical symptoms. Four cases underwent one-stage radical surgery, one case accepted intervention to occlude the collateral artery which was supplying the right lower lung and received stage Ⅱ radical surgery half a year later, and the remaining one case died from pulmonary hypertension crisis preoperation. Conclusions: Isolated SS can easily miss diagnosis due to mild clinical symptoms. Patients with complicated malformations can benefit from combination therapy. SS associated with severe pulmonary hypertension can lead to early death. Therefore, early diagnosis and appropriate treatment can improve the prognosis of patients.

Pulmonary vein reconnection following cryo-ablation: Mind the "Gap" in the carinae and the left atrial appendage ridge

Pulmonary vein (PV) isolation (PVI) remains cornerstone to ablation of atrial fibrillation (AF). For effective and durable PVI and thus fewer AF recurrences, lesion gaps in transmurality and contiguity responsible for PV reconnection (PVR) could only be addressed when one is cognizant of the potential location and sites where these lesion characteristics may be more prevalent and responsible for PVR. In the case of RF ablation, newer technologies incorporating contact force, time and power with automated monitoring of lesion formation, paying attention to difficult areas (carinae, left superior PV-LAA ridge, right inferior PV) and measuring inter-lesion distance may provide the tools to reduce PVR. On the other hand, the improved thermodynamic characteristics of the latest generation of cryoballloons and operator dexterity to achieve better PV occlusion, may be crucial determinants towards the direction of reduced PVR. Whether newer visualization tools, more vigilant testing during the index ablation procedure in these particular regions, prolonging or adding cryothermic applications, waiting longer to test for entrance and exit block, and/or use of provocative drug testing (isoproterenol/adenosine challenge) might help prevent future PVRs awaits further studies.

Morphology and morphometry of pulmonary veins and the left atrium in multi-slice computed tomography

Purpose

Pulmonary veins are involved in pathogenesis and treatment of atrial fibrillation and structures at risk during thoracic surgeries. There is lack of data regarding pulmonary vein morphology and morphometry in normal population.

Methods

The study was conducted using 135 chest computed tomography studies with intra-venous iodine contrast injection. The study population contained 86 females and 49 males, mean age was 60. 13 had atrial fibrillation.
The studies were analyzed using radiological workstation.

Results

Mean dimensions of the left atrium: transverse 52 mm, coronal 49 mm, and sagittal 35 mm. The mean volume of the left atrium was 93 cm³. The mean volume of the left atrium in patients with atrial fibrillation was 176 cm³. The sagittal dimension and the volume of the left atrium were correlated with age, r = 0.43 and r = 0.42, respectively. Surface area of the left inferior pulmonary vein ostium was 136 mm², significantly less than the surface area of other ostia of pulmonary veins. The mean distance between two pulmonary veins was 5.42 mm on the right and 4.02 mm on the left side. 13 types of pulmonary veins outflow patterns were described on the right side and 5 types on the left side. 66.7% of right pulmonary veins and 82% of the left pulmonary veins emptied into the left atrium with two venous trunks on each side (the typical pattern).

Conclusions

Morphological features of pulmonary veins and morphometry of the left atrium and pulmonary veins are important for clinical purposes and are in accordance with previous papers.

Catheter Ablation of Long-standing Persistent Atrial Fibrillation: a Reckless Challenge or a Way to Real Cure?

Long-standing persistent atrial fibrillation (L-PeAF) is a category in which rhythm control is attempted while atrial fibrillation (AF) is maintained for more than 1 year. Because AF is a progressive disease and L-PeAF accompanies significant electrical and structural remodeling of atria, it is difficult to restore and maintain sinus rhythm in patients with L-PeAF. Nonetheless, the rhythm outcome is being increasingly improved by the development of sophisticated mapping devices, highly efficient catheters, and evidence-based ablation strategies, and the rational choice of patient selection criteria. This review discusses the evolution of the rhythm control outcome of L-PeAF and its future direction of development.

Computed tomography pulmonary angiography and venography with a low dose of contrast medium

The authors developed a method to ensure sufficient opacification of pulmonary vasculature for separate depiction of arteries and veins in three-dimensional form with a small dose of contrast medium utilizing a test injection to determine optimal timing of computed tomography (CT) scanning. The dose was determined by a simulation based on a pharmacokinetic model. The contrast medium was administered at a rate of 5.0 mL/s for 3 s, followed by helical scanning at the timing determined by a dynamic CT scanning following the test injection. Images of 20 consecutive patients acquired with a 64-row CT scanner were evaluated. Quality of vessel depiction was assessed on the basis of the following: HU values at the main pulmonary artery (MPA) and left atrium (LA), distance between the pleural surface and the distal end of the pulmonary vessels on three-dimensional CT pulmonary arteriography and venography (3D-CTPAV), and subjective visual assessment of quality of the 3D-CTPAV images. Time to generate the 3D-CTPAV images was recorded. The mean ± standard deviation (SD) of the HU values at MPA/LA and the distances to the pleural surface for pulmonary arteries/veins were 448.0 ± 123.1/277.3 ± 60.85 HU and 9.21 ± 3.60/10.7 ± 5.45 mm, respectively. The image quality was visually rated as excellent for all of the patients. The mean time ± SD to generate 3D-CTPAV images was 13.6 ± 6.7 min. In conclusion, three-dimensional images of the pulmonary vasculature can be created using 21 mL (including 6 mL for the test injection) of contrast medium.

Pictorial review of the pulmonary vasculature: from arteries to veins

Pathology of the pulmonary vasculature involves an impressive array of both congenital and acquired conditions. While some of these disorders are benign, disruption of the pulmonary vasculature is often incompatible with life, making these conditions critical to identify on imaging. Many reviews of pulmonary vascular pathology approach the pulmonary arteries, pulmonary veins and bronchial arteries as individual topics. The goal of this review is to provide an integrated overview of the high-yield features of all major disorders of the pulmonary vasculature. This approach provides a more cohesive and comprehensive conceptualisation of respiratory pathology. In this review, we present both the salient clinical and imaging features of congenital and acquired disorders of the pulmonary vasculature, to assist the radiologist in identifying pathology and forming a robust differential diagnosis tailored to the presenting patient. TEACHING POINTS: • Abnormalities of the pulmonary vasculature are both congenital and acquired. • Pathology of a single pulmonary vascular territory often affects the entire pulmonary vasculature. • Anomalous pulmonary venous flow is named as a function of its location and severity. • Bronchial arteries often undergo dilatation secondary to cardio-respiratory pathology.