Coronary Sinus Research Articles

Background: Persistent left superior vena cava (PLSVC) is a rare congenital venous anomaly that can complicate the anatomy of the right atrium and coronary sinus, posing technical challenges during catheter ablation of atrioventricular nodal reentrant tachycardia (AVNRT). Optimal ablation strategies in this subset remain poorly defined. Methods: We retrospectively analysed 11 patients with PLSVC who underwent typical AVNRT ablation at our centre between 2015 and 2024, identified from a cohort of 2,030 ablations (0.54%). PLSVC was suspected by dilated coronary sinus on transthoracic echocardiogram and confirmed by coronary sinus catheter manipulation or coronary sinus venography. All procedures were performed using the Claris EP Workmate system with right femoral vein access. Due to unstable His catheter positioning from distorted anatomy, fluoroscopic landmarks in the left anterior oblique (LAO 30°) view were used in review screen during radiofrequency ablation. Radiofrequency ablation (RFA) was delivered using a 4-mm non-irrigated Blazer™ catheter (max 40W, 60°C) targeting the slow pathway, guided either by low-amplitude electrograms or anatomical landmarks—primarily the anterior lip of the mid coronary sinus ostium (CSOS). A long sheath (SR0) was used in 5 patients for better catheter stability. Results: The mean age was 38 ± 11 years; 8 were female. Typical AVNRT was inducible in all 11 patients. Immediate procedural success was achieved in 100%, defined by non-inducibility of AVNRT post-ablation with and without isoproterenol. Junctional ectopy during energy delivery was used as a surrogate marker when slow pathway potentials were absent (8/11 patients). Long-term success at 24-month follow-up was 91%, with one recurrence. There were no major complications. In 3 patients, the slow pathway was localized to the posteroinferior septum; in the remainder, ablation was successful within the coronary sinus ostium. Conclusion: In patients with PLSVC, right-sided ablation of typical AVNRT remains effective, despite anatomical distortion. Atypical anterior ablation targets mostly within the Coronary sinus ostium, fluoroscopic guidance, and long sheath support facilitate successful outcomes. Awareness of these adaptations may reduce recurrence and procedural risk in this challenging subset.

Background: Coronary artery (CA) injury from catheter ablation is an uncommon complication, but the risk is under recognized. In pediatrics, CA imaging to assess for CA proximity is not commonly performed prior to ablation. The risk for CA injury significantly increases when a CA is within 3 mm of the site of ablation. Research Question: How often is there a CA within 3 mm of a potential ablation site in pediatric patients? Methods: A retrospective review of all coronary computed tomography angiograms (CTAs) in pediatric patients <18 years of age at Mayo Clinic from 2017 through 2023 was conducted. The proximity of CAs to potential ablation sites in the coronary sinus and the appendage bases were measured. Results: Seventy-two CTAs in 67 patients >15 kg and <18 years old were included. Median age was 12 years and median weight was 41 kg. In right dominant CA circulation, 23/36 (64%) had a CA within 3 mm of the coronary sinus. For those within 3 mm, the mean distance from the coronary sinus was 1.4 mm +/- 0.2 mm for a length of 10 mm +/- 2 mm (Figure 1A). In left and co-dominant CA circulation, 26/26 (100%) had a CA within 3 mm of the coronary sinus with a mean distance of 1.1 mm +/- 0.2 mm for a length of 27 mm +/- 2 mm (Figure 1B). The right CA was within 3 mm of the appendage base in 49/69 (71%). For those within 3 mm, the mean distance was 1.9 mm +/- 0.2 mm for a length of 17 mm +/- 2 mm. The circumflex CA was within 3 mm of the appendage base in 50/68 (74%). Of the 50 within 3 mm, the mean distance was 2.1 mm +/- 0.2 mm for a length of 9 mm +/- 2 mm. Conclusion: Most pediatric patients have a CA ≤ 3 mm from potential ablation sites in the coronary sinus and base of the appendages. Before performing catheter ablation in these areas, precautions should be taken to avoid CA damage.

Background: The incidence of persistent left superior vena cava (PLSVC) in the general population is estimated to be between 0.3% and 0.5%, which equates to approximately 1 in every 200 to 325 healthy individuals. Aims: To highlight the technical challenges posed by this congenital venous anomaly during cardiac pacing procedures, particularly in venous access and lead positioning. To raise awareness of the need for a multidisciplinary approach, involving cardiology, cardiovascular imaging, and cardiothoracic surgery, to ensure safe and effective management of such patients. Case Presentation: A 67-year-old male with a history of symptomatic bradycardia presented with episodes of severe sinus bradycardia at 40 bpm, sinus pauses lasting up to 2.9 seconds, and isolated ventricular extrasystoles, as documented on a two-month Holter monitor. He was admitted to hospital following a nocturnal syncopal episode and an electrocardiogram (ECG) showing a heart rate of 20 bpm. During initial management, there was difficulty obtaining venous access and advancing a temporary pacemaker lead via the jugular vein. As a result, a temporary pacemaker was implanted via the right femoral vein, and the patient was evaluated for permanent pacemaker implantation. Decision-Making: During the procedure in the cardiac catheterisation laboratory, difficulties were encountered in advancing the guidewire towards the subclavian vein. Consequently, bilateral subclavian vein angiography was performed, which revealed a persistent left superior vena cava with anomalous drainage into the coronary sinus. The procedure was therefore deferred. A cardiac CT angiogram confirmed the diagnosis. The cardiothoracic surgery team was subsequently consulted, and an epicardial pacemaker was successfully implanted via a subxiphoid approach in DDDR mode. Conclusion: Persistent left superior vena cava is a rare venous anomaly that can pose significant technical challenges during pacemaker implantation, particularly in patients with atrioventricular block. A thorough pre-procedural assessment of venous anatomy is essential for selecting the most appropriate implantation strategy and minimising procedural risks.

Introduction: Arterio-venous (AV) gradients across tissue beds provide insights into the metabolic activity by measuring the net uptake or release of lipids and metabolites. In the heart, these gradients can reflect real-time changes in myocardial substrate utilization in disease states like atrial fibrillation (AF). Aims: We aimed to explore the lipidomic and metabolic alterations due to acute rhythm changes in AF patients. Methods: Blood samples were collected from the left atrium (LA), coronary sinus (CS), and the vein of Marshall (VOM) during AF ablation procedures, representing the arterial and venous sides of the whole myocardial and atrial tissue, respectively. Samples were collected in the presenting rhythm (SR or AF), after which patients were either cardioverted or underwent AF induction before any ablation delivery. Sampling was repeated 5 minutes after the onset of the new rhythm (Panel A). Blood samples were analyzed for lipid species and metabolites using the Sciex Lipidyzer system and LC-MS metabolite analysis, respectively. Results: We analyzed 16 arterio-venous blood samples (8 in AF, 8 in SR) to measure 1,561 lipid species across 18 lipid classes and 29 metabolites, including those specific to the heart and atria. Oxygen saturation in the VOM was lower in AF (median 53%, IQR 40–58%) compared to SR (58%, IQR 46–68%; P=0.021), indicating greater oxygen extraction in AF by the atria (Panel B). However, there was no significant difference in oxygen saturation in the CS samples: AF (median 56%, IQR 44–63%) and SR (median 57%, 42– 62%; P=0.1). Differences in AV gradients between AF and SR were assessed in both whole-heart and atrial-specific samples. In whole-heart samples, there was a general balance between lipid import and export. However, atrial-specific samples showed a clear shift toward net lipid import in AF (Panel C). For metabolites, we found a mismatch between atrial and ventricular metabolism in AF. Specifically, glucose, valine, and isoleucine showed net export from the whole heart, but net import at the atrial level (Panel D). Conclusion: Atrial-specific metabolic alterations, characterized by increased lipid and amino acid uptake, altered glucose utilization, and increased oxygen extraction were observed with AF compared to SR. These findings point to an acute metabolic shift, with increased energetic demand in atrial tissue, and potential atrial–ventricular metabolic desynchrony during AF.

Introduction: Elevated circulating levels of solubilised urokinase plasminogen activator receptor (uPAR) predict adverse cardiovascular outcomes; however, its role in cardiac pathophysiology is unclear. uPAR is a cell-surface receptor involved in extracellular matrix remodelling, fibrinolysis, and integrin-mediated signalling in non-cardiac systems. This study examined (i) myocardial uptake of circulating soluble uPAR, (ii) the expression of uPAR in failing human heart tissue, and (iii) its capacity to interact with integrin subunits. Methods: suPAR concentrations across organ sites were measured using suPARnostic ELISA (ViroGates) in patients undergoing clinically indicated cardiac catheterization (n=45) to evaluate organ-specific extraction. uPAR protein expression was analyzed by Western blotting in paired atrial and ventricular tissues from explanted failing human hearts (n=12) (Uvitec Nine-alliance). In-house polyclonal antibodies targeting distinct uPAR domains enabled the detection of full-length and cleaved isoforms. In vitro co-incubation of recombinant uPAR with candidate integrin heterodimers was performed at 37°C for 4 h and analyzed by SDS-PAGE. Results: Regional blood sampling revealed reduced suPAR concentrations in the coronary sinus (p=0.01) and renal vein (p<0.0001) compared to their respective femoral arteries, suggesting renal and cardiac clearance/uptake of circulating uPAR. Immunoblotting confirmed uPAR expression in both atrial and ventricular tissues, with bands between ~35–55 kDa corresponding to full-length and truncated isoforms. In vitro binding assays demonstrated a direct interaction between uPAR and αVβ3 integrin, implicating a defined epitope of uPAR in integrin binding. In-house antibodies against this uPAR integrin-binding epitope confirmed its expression in human cardiac tissue, supporting its in situ expression. Conclusion: We provide novel evidence that uPAR is expressed in failing human myocardium and contains integrin-binding domains in situ. The observed myocardial uptake of circulating suPAR, combined with the presence of integrin-binding isoforms, suggests that uPAR may participate in signal transduction pathways involved in cardiac regulation. Further investigations into uPAR expression in normal and diseased hearts, as well as the functionality of uPAR-integrin pathways, may reveal its role in heart failure.

Persistent left superior vena cava (PLSVC) is a rare congenital anomaly, present in <1% of the population, typically draining into the coronary sinus and right atrium. When an anomalous drainage occurs into the left atrium—directly or via an unroofed coronary sinus—a right-to-left shunt may result, detected by an agitated saline (“bubble”) study from a left-sided vein. We present a rare case mimicking such a shunt. A 33-year-old man with ESRD on hemodialysis was admitted with subacute cough and weight loss, diagnosed with necrotizing MSSA pneumonia. His hospitalization was complicated by respiratory failure, septic shock, and transient effusive-constrictive pericarditis. TTE revealed an EF of 50–55%, normal RV function, small pericardial effusion, mild aneurysmal interatrial septum, and an unexpected bubble study finding: agitated saline injected via a left-arm IV resulted in bubbles first appearing in the left atrium via pulmonary veins (Figure 1), with robust left-sided opacification and delayed right-sided filling. No interatrial transit of bubbles was observed. CT angiography revealed chronic right SVC occlusion with extensive venous collaterals draining into the pulmonary veins (Figure 2), mimicking a PLSVC with unroofed coronary sinus. The SVC occlusion likely resulted from years of central venous catheterizations for dialysis. Thus, common sequelae of chronic illness produced a pattern resembling rare congenital anomalies. This case highlights the importance of careful interpretation of bubble studies, awareness of PLSVC mimickers, and the diagnostic value of multimodality imaging to avoid misdiagnosis, unnecessary testing, and patient burden. A high index of suspicion, combined with correlation across imaging modalities, is critical for accurate diagnosis and optimal patient care.

Description of Case: A 21-year-old G5P1 woman at 38.2 weeks gestation presented with worsening exertional chest pain, dyspnea, dizziness, and recurrent syncope. These symptoms have been present since adolescence and intensified during late pregnancy. Previous evaluations included a positive tilt table test, normal ECGs, ambulatory monitoring, and neurology consultation suggesting non-epileptic events. On presentation, vital signs were stable, and the acute coronary syndrome workup was negative. CT pulmonary angiography ruled out pulmonary embolism but revealed an anomalous left main coronary artery (LMCA) originating from the right coronary sinus and coursing between the aorta and pulmonary artery. She experienced intermittent chest pain and episodes of tachycardia up to 170 bpm, which were controlled with diltiazem. Following an uncomplicated cesarean delivery at 39 weeks, coronary CTA and left heart catheterization were performed. These confirmed a malignant interarterial LMCA arising from a shared ostium with the right coronary artery. The artery had no obstructive lesions but demonstrated high-risk features, including an acute-angle takeoff and a possible slit-like ostium, prone to dynamic compression during exertion. Discussion: Anomalous aortic origin of the LMCA from the right sinus of Valsalva is rare (0.1 to 0.3 percent) and significantly increases the risk of myocardial ischemia and sudden cardiac death, especially with an interarterial course and high-risk morphology. Physiological changes during the peripartum period—including elevated cardiac output, aortic root and pulmonary trunk dilation, and hormonal shifts—may exacerbate dynamic compression and reduce coronary flow. Coronary CTA is the preferred imaging modality for delineating coronary origin, course, and morphology. While Echo is widely used, its spatial resolution is limited. Cardiac MRI, traditional angiography, and intravascular ultrasound offer complementary data but may be limited by availability or invasiveness. Given the malignant anatomy and symptomatic presentation, surgical correction via coronary artery bypass grafting (CABG) was planned after three months postpartum. This case highlights the importance of considering structural heart disease in young women with unexplained exertional chest pain or syncope, particularly in the peripartum period. It also highlights the benefit of Coronary CTA in diagnosing and risk-stratifying anomalous coronaries for surgical intervention.

Introduction: Atrial fibrillation (AF) is associated with decreased cardiac output through loss of atrial contribution to ventricular filling and irregular and often rapid ventricular activation with shorter diastolic filling time. These hemodynamic changes may contribute to the variable symptoms and impaired quality of life (QoL) seen in AF. Myocardial oxygen extraction provides a novel mean of assessing the physiological basis behind the QoL in an AF population. Hypothesis: Myocardial oxygen extraction correlates with the general well-being, AF burden, and AF symptoms score. Methods: Myocardial arterial (left atrium) blood and venous (coronary sinus) blood were collected from patients undergoing AF ablation. Oxygen extraction was derived from the arterio-venous oxygen content of blood samples (Panel A). Pre-procedural hemoglobin levels were noted. The Atrial Fibrillation Severity Scale (AFSS) was used to assess pre-procedural quality of life measures, which include global well-being (GWB), AF burden, and AF symptoms score. GWB is assessed based on a Likert scale of a maximum of 10. AF burden and symptoms scores are based on a linear scale. AF burden is the sum of AF frequency, duration, and severity, while AF symptoms score is based on the sum of 6 major AF related symptoms which include: palpitations, shortness of breath at rest and during physical activity, fatigue at rest and during physical activity, lightheadedness, and chest pain. Results: Thirty AF patients were recruited (age was 65 ± 11 years). Fourteen patients (55%) were females, 6 (21%) were in persistent AF, and 8 (28%) had a diagnosis of heart failure. Myocardial oxygen extraction was 9.5 ± 1.9 mL of O2 extracted/dL of blood. The median GWB in patients with oxygen extraction ≤9.5 mL of O2 extracted/dL of blood was 8 (7-9) vs. 5(4-7) ( P = 0.005), AF burden was 13(5-20) vs. 21(17-27) ( P =0.017), and the AF symptom score was 7(1-12) vs. 13 (6-21) ( P = 0.043) (Panel B). There was a negative correlation between oxygen extraction and GWB (r=-0.51; P = 0.005) and a positive correlation with AF burden (r=0.44; P = 0.017) and AF symptom score (r= 0.42; P = 0.024) (Panel C). Conclusion: In AF patients, greater myocardial oxygen extraction correlates with lower self-reported well-being and higher AF burden and symptom scores. This relationship suggests that increased myocardial oxygen demand may reflect underlying physiological stress contributing to patients’ symptom perception and disease experience.

Atrial fibrillation occurs in a growing number of adults with congenital heart disease (ACHD); however, recommendations for procedural considerations are lacking. A 43-year-old woman with surgical repair of sinus venosus ASD and partial anomalous pulmonary venous return and history of atrial arrhythmias and sinus node disease presents for repeat ablation procedure for persistent atrial fibrillation. Echocardiogram two days prior to ablation procedure demonstrated no SVC stenosis, known left SVC with dilated coronary sinus (CS), and moderate LV systolic dysfunction, presumed due to persistent atrial fibrillation with tachycardia. The AF ablation was performed with intracardiac echo guidance of trans-septal puncture. All four pulmonary veins were confirmed to be isolated from prior ablation. Right and left atria were mapped during atrial fibrillation using Volta Medical to identify dispersion areas, which identified areas of spatial dispersion in the posterior wall and coronary sinus, for which posterior wall isolation was performed with CS ablation set. AF was converted to AFL with ablation and patient was cardioverted to junctional rhythm, her known baseline rhythm. At conclusion of the study no pericardial effusion was noted by ICE. Post-procedure, the patient continued to have junctional rhythm and hypotension requiring vasoactive support; limited bedside echo demonstrated no effusion. Due to persistent hypotension, additional echo imaging was performed which demonstrated no pericardial effusion, normal LV systolic function; however, an echo lucency posterior to aorta with compression of left atria was seen. CT scan confirmed a hematoma surrounding LA, 7.2 x 3.3 cm, with compression on left superior vena cava. No surgical intervention was performed due to contained hematoma and clinical stability, as surgical evacuation of the hematoma would increase the risk of bleeding. Repeat CT at 7 days demonstrated stable mediastinal hematoma of 7.2 x 3.3 cm. The patient continues to be monitored clinically with serial imaging. In ACHD patients, ablation complicated by perforation may be underrecognized due to prior surgical scarring, which may contain bleeding and obscure findings on limited imaging due to lack of circumferential effusion. Heightened vigilance and tailored procedural and post-procedural imaging strategies are necessary for ablation procedure in ACHD patients, considering their unique anatomy and surgical history

Background: Restrictive cardiomyopathy (RCM) is a rare cardiac condition characterized by stiff and noncompliant ventricular walls, leading to impaired diastolic filling and normal or near-normal systolic function. This condition often presents with subtle symptoms of heart failure. We present a compelling case of longstanding atrial fibrillation (Afib) and atrial flutter (AFL) culminating in refractory cardiogenic shock, ultimately revealing an undiagnosed restrictive cardiomyopathy. Case: A 40-year-old male with a history of persistent Afib and AFL, unremarkable cardiac MRI on first occurrence for atrial arrhythmias, presented with dyspnea, dizziness, fatigue, and palpitations while on dofetilide. He was found to have atypical AFL with a rapid ventricular response, refractory to pharmacological and electrical cardioversion. His arrhythmia history included multiple catheter ablations for recurrent atrial fibrillation: pulmonary vein and posterior box isolation, anterior wall homogenization, mitral annulus flutter ablation as well as focal atrial tachycardia ablation in the coronary sinus. His family history revealed a sister with refractory Afib at age 30, later diagnosed with restrictive cardiomyopathy, who underwent orthotopic heart transplantation (OHT) at age 44. On admission, echocardiography revealed severe right atrial enlargement and grade III diastolic dysfunction. Attempts at rate and rhythm control with multiple agents were unsuccessful. On day 2 of admission, he developed cardiogenic shock (CI 1.5, RA 20, PCWP 40, PA 50/30 [mPA 40], PVR 3, CPO 0.53, PAPI 1.0), necessitating V-A extracorporeal membrane oxygenation and Impella CP for circulatory support. Discussion: RCM often eludes early detection due to its presentation with preserved ejection fraction and relatively subtle heart failure symptoms. However, Afib or AFL refractory to ablation or cardioversion may serve as an early indication, especially in the context of a strong family history. We suspect progression of cardiomyopathy in this patient who, years ago, had a normal cardiac MRI. Identifying RCM through advanced imaging or genetic screening is crucial, as it enables early consideration of interventions, such as evaluation for OHT, which may prevent catastrophic outcomes. Proactive screening and repeat imaging, such as cardiac MRI, in patients with incessant atrial arrhythmias who also have a significant familial burden, can mitigate delays in treatment and improve prognosis.

Introduction: Conduction system pacing (CSP) is a more physiological pacing strategy with fewer deleterious effects compared to conventional myocardial pacing. However, data on outcomes beyond 1 year remain scarce. We aimed to evaluate electrocardiographic (ECG), echocardiographic (echo), and New York Heart Association (NYHA) functional class (FC) outcomes over a 2-year follow-up. Methods: Consecutive patients undergoing CSP between January 2020 and April 2025 were prospectively enrolled at 3 Brazilian centers. Patients underwent clinical assessment, standardized transthoracic echo at baseline and follow-up (3–6 months, 2 years), and digital ECG pre- and post-procedure. Variables of interest included QRS duration (ms), NYHA FC, and left ventricular ejection fraction (LVEF). Pre/post comparisons were assessed using the Wilcoxon test, and temporal parameter variation was compared between patients with reduced (<50%) vs. preserved LVEF using the Mann-Whitney test. Results: A total of 205 patients (mean age 77±14 years, 62% male) were enrolled; 63% were in NYHA FC III or IV and 24 (12%) had Chagas chronic cardiomyopathy. Left bundle branch pacing was performed in 151 (74%), His bundle pacing in 46 (22%), and 8 (4%) underwent additional cardiac resynchronization therapy via the coronary sinus. CSP significantly narrowed QRS duration from 140 (IQR 100–160) to 110 (95–120) ms (p<0.001); 130 patients (63%) demonstrated numerical QRS narrowing. Clinical and echo early follow-up was available for 152 (74%) and 117 (57%) patients, respectively. LVEF increased from 58% (43–64) to 62% (56–65) (p<0.001), and NYHA FC improved from 2.9 (2.0–3.0) to 1.4 (1.0–2.0) (p<0.001); only 7 patients remained in FC III or IV. Patients with baseline LVEF <50% (N=55, 32%) had greater QRS narrowing (-40 vs. -19 ms, p<0.001) and greater LVEF improvement (+11.0% vs. +0.1%, p<0.001) than those with preserved LVEF, while NYHA FC improvement was similar between groups. Among 39 patients with complete 2-year follow-up, LVEF gains persisted (+9.45%, p=0.02) ( Image 1 ), as did FC improvement (-51.2%, p<0.001). Conclusions: CSP resulted in significant QRS narrowing, LVEF improvement, and sustained NYHA FC improvement, with greater early benefits in patients with LV dysfunction. Improvements were maintained through 2 years of follow-up.

Background: Acute coronary obstruction (ACO) is a rare but potentially fatal complication of transcatheter aortic valve replacement (TAVR), particularly in patients with high-risk anatomy such as low coronary ostial height and narrow sinuses of Valsalva. Prophylactic coronary protection and real-time imaging are essential tools in safely managing these cases. Case: A 62-year-old woman with severe aortic stenosis and multiple comorbidities—including prior stroke, COPD, and peripheral vascular disease—was referred for transfemoral TAVR. Preprocedural CT angiography demonstrated a systolic LM coronary height of 8.36 mm, placing her at high risk for ACO. A 23 mm Edwards SAPIEN 3 Resilia valve was successfully deployed under rapid ventricular pacing. Prophylactic left main protection was achieved by positioning a coronary guidewire via a 6 French guiding catheter from left femoral arterial access. After deployment, this coronary guidewire was jailed at the upper end of the sapient valve. Post-deployment angiography raised suspicion for left main compromise by the displaced left coronary cusp, visualized as a hazy filling defect. Balloon angioplasty was performed using a 3.0 x 12 mm catheter, which resulted in partial improvement of angiographic appearance but did not fully resolve the haziness. IVUS catheter delivery initially failed but succeeded after introducing a second guidewire through the upper frame cell of the transcatheter valve. IVUS imaging revealed a preserved LM luminal area of >20 mm with no evidence of ostial narrowing or leaflet impingement. The jailed guidewire was safely removed without further intervention. Decision-making: Despite equivocal angiography, IVUS provided definitive confirmation of LM patency and ruled out true obstruction. This guided the clinical decision to defer coronary stenting and pursue a conservative strategy. In contrast to cases requiring chimney stenting or BASILICA, this approach avoided permanent hardware and minimized procedural risk. This case illustrates the critical role of IVUS in clarifying ambiguous findings and enabling individualized management in anatomically high-risk TAVR. Conclusion: Prophylactic LM protection, when paired with intravascular imaging, enables safe and tailored management of suspected ACO during TAVR. IVUS is essential in confirming patency and preventing unnecessary interventions in high-risk patients with ambiguous angiographic findings.

Background: Catheter ablation of typical atrial flutter (AFL) typically relies on femoral venous access. Inferior vena cava (IVC) interruption is a congenital anomaly that complicates right heart access. Alternative approaches, including jugular or axillary access have been described, but catheter stability and limited intraprocedural imaging are challenges. We present a novel case of AFL ablation using superior venous access for mapping and ablation paired with femoral access for intracardiac echocardiography (ICE) from the azygous vein. Description of Case: A 66-year-old woman with paroxysmal AFL and dual-chamber pacemaker presented with symptomatic AFL and variable AV block. A prior ablation attempt was aborted after bilateral femoral access attempts revealed interrupted IVC with anomalous SVC return via a dilated azygous vein. CT scan confirmed IVC interruption and azygous continuation coursing posterior to the left atrium. A second ablation attempt succeeded using superior access via the right internal jugular (RIJ) and left axillary vein (LAV) to advance ablation and coronary sinus catheters. An ICE catheter was introduced via femoral vein and navigated to the thoracic azygous vein imaging directly behind the heart. This gave excellent imaging of the right atrium and cavotricuspid isthmus (CTI). Ablation with a contact-force irrigated catheter via the LAV improved catheter stability compared to the RIJ approach. Discussion: This is the first report using ICE from the azygous vein via the femoral route for intraprocedural imaging of CTI ablation. The posterior trajectory of the azygous vein enabled ICE imaging in planes similar to transesophageal echocardiography. Superior access from RIJ and LAV allowed mapping and ablation despite the absence of IVC continuity. Ablation on the CTI with a superior approach is challenging. Reduced catheter contact and stability can result in breakthrough of the lesion set and recurrence of AFL. ICE provides visual feedback to ensure catheter contact and stability. This approach overcomes several limitations in patients with interrupted IVC. Conclusion: In patients with IVC interruption, superior venous access for catheter manipulation combined with transfemoral ICE catheter placement in the azygous vein is a novel, effective strategy for AFL ablation. This technique enables high-resolution imaging and improved catheter stability, expanding options for successful AFL ablation in patients with complex venous anatomy.

Background: Transvenous lead extraction (TLE) is a well-established procedure with expanding indications in contemporary practice. However, sex-specific outcomes remain understudied, and women are typically underrepresented in TLE cohorts. Most available data emphasize overall procedural safety and efficacy, without stratifying by sex. Hypothesis: We hypothesized that TLE outcomes are comparable between female and male patients. Methods: All patients who underwent TLE between August 1996 and September 2022 at a high-volume US tertiary center were included in a prospectively maintained registry and stratified by sex. Baseline characteristics, procedural parameters, and outcomes were compared. Multivariable logistic regression models were computed with sex as the independent variable, adjusting for age, infection indication, ICD presence, hypertension, diabetes mellitus, ischemic cardiomyopathy, coronary artery disease, NYHA class ≥ III, number of extracted leads, dwell time of the oldest lead, and coronary sinus lead position. Results: Among 5,090 patients (1,617 women; 3,473 men), women were younger (62 vs. 67.7 years) and had higher LVEF (50% vs. 38%), both p<0.001. They had lower rates of hypertension, diabetes mellitus, ischemic cardiomyopathy, and coronary artery disease (all p<0.001). Malfunction was the leading indication in women (40.4% vs. 31.2%), while infection predominated in men (43.7% vs. 32.3%), both p<0.001. The number of extracted leads (p=0.7), dwell time of the oldest lead (p=0.4) and fluoroscopy time (p=0.5) were similar between sexes. Use of advanced extraction tools, including mechanical sheaths (p=0.5), laser sheaths (p=0.2) and femoral workstations (p=0.4) were similar. Complete extraction (94.5% vs. 94.9%, p=0.2) and clinical success (97.1% vs. 97.2%, p=0.6) were high and comparable. With the exception of pocket infection or bleeding, which was more common in men (1.5% vs. 0.6%, p=0.008), complication rates did not significantly differ. Major complications occurred in 3.1% of women and 2.3% of men (p=0.1), and minor complications occurred in 2.3% and 3.2%, respectively (p=0.09). On multivariable analysis, sex was not an independent predictor of any complication. Conclusion: In one of the largest single-center TLE cohorts to date, sex was not an independent predictor of procedural risk. Despite differing baseline characteristics and extraction indications, women experienced equivalent safety and efficacy outcomes compared to men.

Introduction: In cases of cardiogenic shock, the transaortic micro-axial flow pump (Impella) improves systemic circulation and increases coronary perfusion pressure (CPP) while reducing myocardial oxygen consumption (MVO 2 ) via its left ventricular (LV) unloading effect. The Impella 5.5, in particular, enables stronger LV unloading due to its higher flow capacity. Physiologically, coronary blood flow (CBF) increases with CPP, while reduced MVO 2 may activate autoregulatory mechanisms that limit CBF. Hypothesis: We hypothesized that a marked reduction in MVO 2 by the Impella 5.5 may attenuate CBF. This study evaluates the impact of Impella 5.5 support on CBF in normal and post-reperfusion coronary arteries using a goat model of ischemia-reperfusion. Methods: Saanen goats (N=8, BW: 61.6±4.5 kg) were used under general anesthesia. The Impella 5.5 was inserted via the carotid artery into the LV. We measured blood pressure, LV pressure, pulmonary artery flow, arterial and coronary sinus oxygen saturation, and CBF in the left anterior descending artery (LAD) and left circumflex artery (LCX). We occluded the proximal LAD with a 3 mm balloon for 90 minutes, then deflated for reperfusion (Fig. A). At 30-min after reperfusion, Impella support was set at three stages: Control (P1), Partial support with residual native cardiac output (P3-7), and Total support (P6-9). Results: Increasing Impella support augmented CPP (37.8 ± 10.6 vs. 47.1 ± 8.5 vs. 75.2 ± 12.7 mmHg, P < 0.05) and reduced MVO 2 (298.3 ± 161.0 vs. 257.9 ± 122.2 vs. 161.0 ± 121.6, P < 0.05) (Fig. B). Total support with the Impella 5.5 suppressed MVO 2 by 53.0 ± 18.8% compared to the Control condition. LCX flow decreased with increasing Impella support (46.9 ± 26.6 vs. 45.0 ± 28.5 vs. 37.8 ± 31.0 mL/min, P < 0.05). Similarly, LAD flow was significantly reduced under Total support (30.9 ± 11.4 vs. 28.5 ± 11.7 vs. 23.7 ± 12.2 mL/min, P < 0.05) (Fig. C). Conclusion: In a goat model of ischemia–reperfusion, total support with the Impella 5.5 reduced CBF in both the normal LCX and the injured LAD. These results may be influenced by factors such as the severity of coronary injury, the timing of measurement, and the specific animal model used. Nevertheless, the findings suggest that autoregulatory mechanisms triggered by suppressed MVO 2 play a critical role in determining CBF, even in post-reperfusion setting, and should be carefully considered when evaluating the effects of Impella5.5 support on coronary circulation.

Background: Large (>2 cm) vegetations related to cardiac implantable electronic device (CIED) infections carry a high risk of pulmonary embolism during transvenous lead extraction. Open surgery may not be feasible in high-risk patients. Vacuum-assisted aspiration offers a less invasive alternative, but published data is limited to a few case reports with little emphasis on concomitant lead extraction or follow-up outcomes. Objective: To evaluate the safety, efficacy, and outcomes of vacuum-assisted removal of large CIED-related infective vegetations with concomitant lead extraction in the largest single-center cohort to date. Methods and Results: This retrospective series included 22 patients (mean age 60 ± 16 years; 11 females) between 2015 and 2025. Mean vegetation size was 2.5 x 1.4 cm. All patients underwent vacuum-assisted debulking under general anesthesia with fluoroscopic and transesophageal echocardiography guidance, utilizing femoral-femoral veno-venous bypass circuit with a large-bore suction cannula for vegetations aspiration. After adequate debulking, the circuit was discontinued, and transvenous lead extraction was performed using locking stylets and extraction sheaths as needed. Temporary pacing was required perioperatively in four pacemaker-dependent patients. Procedural success, defined as complete or >90% mass removal (n=10) or partial 50%:90% (n=11), was achieved in 21 (95%) cases. One patient required a sternotomy due to a coronary sinus tear during extraction in the setting of atypical anatomy. Another developed septic shock following debulking, and a third experienced transient worsening of tricuspid regurgitation. For successful cases, all leads were successfully extracted in the same procedure with no embolic events perioperatively in any patient. Ten patients underwent successful CIED reimplantation within less than 30 days from the procedure. Within the first 12 post-operative months, four patients died, including one from cardiac arrest despite ICD reimplantation. Conclusion: Vacuum-assisted removal of large CIED-related vegetations with concomitant lead extraction is a safe, effective surgical alternative, showing improved efficiency and fewer complications with operator experience.

Background: The coronary sinus reducer (CSR) has placebo-controlled evidence of angina benefit from two randomised placebo-controlled trials. The characteristics of patients with most to gain from this therapy remain unknown. Research Question: What is the relationship between endocardial to epicardial blood flow ratio at stress and the placebo-controlled angina response to the CSR? Methods: The Coronary Sinus Reducer Objective Impact on Symptoms, MRI Ischaemia and Microvascular Resistance (ORBITA-COSMIC) trial was a randomised, double-blind, placebo-controlled trial of the CSR in patients with angina on the maximum tolerated antianginal medication, myocardial ischaemia, epicardial coronary artery disease and no further options for revascularisation. Patients underwent a quantitative adenosine-stress perfusion cardiac magnetic resonance (CMR) scan and started daily angina reporting on a smartphone application (ORBITA-app) on enrolment to the trial. At the enrolment CMR, myocardial blood flow (MBF) in all 16 myocardial segments was quantified using an automated perfusion quantification sequence, with further stratification into endocardial and epicardial layers. Patients were randomised in the cardiac catheterisation laboratory to CSR or placebo and entered a 6-month period of blinded follow-up prior to a repeat stress CMR and scheduled unblinding. Results: Enrolment quantified perfusion CMR data were available for 48/51 (94.1%) patients randomised in ORBITA-COSMIC, 22 CSR and 26 placebo (median age 67 (IQR 60 to 73), 42/48 (87.5%) male). The median endocardial to epicardial perfusion ratio (EN:EP) of stress MBF in ischaemic myocardial segments was 0.76 (IQR 0.72 to 0.87). The lower the EN:EP stress MBF, the greater the placebo-controlled improvement with CSR. There was strong evidence that a patient with EN:EP stress MBF in the lower quartile at baseline would have greater placebo-controlled benefit in angina episodes with the CSR than a patient in the upper quartile (EN:EP stress MBF 0.72 versus 0.87, OR 1.26, 95% CrI 1.13 to 1.41, probability of interaction>99.9%). Conclusion: EN:EP stress MBF is the first biological variable which has been shown to predict placebo-controlled benefit with the CSR. This may have a role in the selection of patients for treatment.

Background: In catheter ablation for atrial fibrillation (AF), the efficacy of adjunctive ablation strategies beyond pulmonary vein isolation remains uncertain. Although complex atrial electrograms have been proposed as potential targets, conventional identification methods of these electrograms are subjective and lack reproducibility. A novel tool, Complex Signal Identification (CSI), has recently become available to automatically detect and annotate complex atrial electrograms. Hypothesis: We hypothesized that the CSI algorithm can objectively identify electrograms associated with atrial remodeling and is associated with post-ablation outcomes in patients with AF. Methods: We analyzed 47 consecutive patients (mean age: 66 years; 71% male) who underwent first-time AF ablation using the CARTO3 ® system between October 2024 and January 2025. All patients underwent pulmonary vein isolation by radiofrequency ablation, followed by high-resolution mapping of the entire left atrium using an OCTARAY ® catheter under coronary sinus pacing. CSI-positive areas were quantified across the entire left atrium and within six predefined anatomical regions ( Figure 1 ). A CSI-positive area was defined as any region containing at least one CSI-positive point. Structural remodeling was assessed by identifying low-voltage areas (< 0.5 mV) and evaluating their overlap with CSI-positive regions. Electrical remodeling was assessed by calculating conduction velocity based on activation time and the distance between earliest and latest sites of the left atrium. Results: A total of 103 CSI-positive areas were identified across all patients, within the anterior and septum being the most frequently involved regions ( Figure 2 ). Twelve low-voltage areas were found, and all of these areas overlapped with CSI-positive regions. The total number of CSI-positive points per patients inversely correlated with conduction velocity (R = –0.448, P = 0.001) (Figure 3) . When patients were stratified based on the presence or absence of CSI-positive area, the early recurrence rate of atrial fibrillation was significantly higher in the CSI-positive group (n = 28) than in the CSI-negative group (n =19) (21% vs. 0%, P < 0.05). Conclusion: CSI identified abnormal electrograms associated with impaired conduction and early AF recurrence. CSI-positive regions extended beyond low-voltage areas, suggesting that CSI may provide a more comprehensive assessment of electrical remodeling than voltage mapping.

Y-incision aortic annular enlargement (Y-AAE) is increasingly utilized to facilitate valve upsizing. Its application in patients with an anomalous left circumflex artery (LCx) introduces additional complexity. We present a case of a Y-AAE with aortic valve replacement in a patient with an anomalous LCx originating from the right coronary sinus. The annulus was enlarged from 25 mm to accommodate a size 29 prosthesis. The anomalous LCx was carefully dissected from the aortic root and preserved, with no postoperative myocardial ischaemia. We reviewed 4 institutional cases of Y-AAE with upsizing by 3 valve sizes or to the largest size (size 29). One patient required primary repair of an LCx injury. During follow-up of up to 3 years, no patient developed myocardial ischaemia. These findings suggest that Y-AAE can be safely performed in the presence of an anomalous LCx, enabling optimal valve upsizing.

Changes in syndecan-1 concentration in the coronary sinus immediately after cardiac reperfusion reflect postoperative myocardial injury.