Single Catheter Technique Research Articles

Patients on the ledge; ablation of incessant tachycardia. A single centre registry

Abstract Background Incessant tachycardia was first described by Cassidy (1). in 1924, it is strongly associated with tachycardia induced cardiomyopathy. There is no data about its true incidence however, it seems to be more common during infancy and childhood. Objectives To present 5-year single centre experience in ablating incessant tachycardia in a cohort of pediatric and adult patients. Methods From 2018 to 2023, We reviewed patients presented to our centre with incessant tachycardia, their clinical data, ECGs, imaging modalities, procedures details & outcomes were examined thoroughly. Results Over 5 years, 900 patients were referred to our centre for ablation, among them 25 patients (2.7%) presented with incessant tachycardia. Of them: 10 patients were pediatrics (40%), the youngest was 40 days old, 3.4 Kg, 6 patients were haemdynamically unstable necessitating ventilation& IV supports, 14 patients had impaired EF, with the lowest EF of 20%.(A) Regarding the diagnosis, 14 patients had AT (4 CS ostium, 3 LAA, 2 parahisian, 2 Crista, 1 LSPV, 1 TA, 1RAA), 4 AVRT (2 concealed parahisian accessory pathways & 2 PJRT), 3 VT (2 scar related VT, 1 anterior papillary muscle), 4 AFL (3 CTI flutter & 1 mitral isthmus flutter). All patients were ablated using 3D mapping system except 4 pediatric patients (2 AT from CS, 2 concealed parahisian accessory pathways) due to accesses limitations or unavailability of 3D mapping, single catheter technique was used in one patient weighing 3.4kg with AT from CS (only one venous access accommodating 5F catheter could be obtained)(B), Rt & Lt jugular accesses were used for ablation of RAA AT in a pediatric patient with bilaterally occluded femoral veins.(C) NCC was used as a safe access for ablating parahsisan AT & accessory pathways in our cohort.(D) All patients had successful ablation with full recovery for those with impaired function except 2 patients of scar related VT as their EF was impaired previously. Regarding the complications, one patient had DVT and another patient had retroperitoneal hematoma, both were managed conservatively. Conclusion Incessant tachycardia ablation is quite challenging but carries good results. Careful planning, experienced team & selection of the appropriate approach are the keys for successful safe procedures.

Is single-catheter technique for coronary angiography an optimal tool for beginners in interventional cardiology?-randomized controlled study TRACT 2: Transradial Coronary Angiography Trial 2.

Transradial coronary angiography can be performed using a dual-catheter technique (DCT) or single-catheter technique (SCT). The current study aimed to compare DxTerity SCT Ultra and the Trapease curve SCT catheters with DCT catheters in procedures performed by young, less experienced, interventional cardiologists. For this prospective, single-blinded, randomized study 107 were enrolled and assigned to 1 of 3 groups. They underwent planned coronary angiography at the Second Department of Cardiology Jagiellonian University in Kraków. In groups 1 (n=37) and 2 (n=35), DxTerity SCT Ultra catheters and the Trapease curve were used, respectively. In control group 3 (n=35), standard DCT Judkins catheters were applied. One patient was excluded from group 2, bringing the total number of cases analysed to 106. The study endpoints comprised the percentage of optimal stability, proper ostial artery engagement, a good quality angiogram, the duration of each procedure stage, the amount of contrast and the radiation dose. The highest percentage of optimal stability was observed in group 1 for the right coronary artery (RCA): 94%, and in group 3, for the left coronary artery (LCA): 85%. The necessity to change the catheter was most common in group 2. Group 1 was characterised by a shorter total procedural time. The contrast volume was higher in group 2, while there were no differences in radiation dose. SCT is at least as adequate as DCT for young cardiologists. SCT was associated with lower necessity of catheter exchange during RCA visualization. The DxTerity Ultra curve catheter allows shortening the total procedure time.

Left coronary cusp ablation for elimination of left ventricular summit premature ventricular complex.

We first reported that epicardial LAVA in the LV summit can be mapped and PVC was completely eliminated by RF ablation above the left coronary cusp using single catheter technique.

Comparing Left Internal Mammary Angiography via Right Radial or Femoral Access With a Single-Catheter Technique

BackgroundWe compared the safety and effectiveness of left internal mammary artery (LIMA) angiography through right radial (Rad) or femoral (Fem) artery access with a single-catheter technique. MethodsLIMA selective imaging was attempted through Rad access with a Bartorelli-Cozzi 5.2Fr catheter in 190 consecutive patients. They were compared with 190 consecutive patients in whom LIMA was imaged with a mammary catheter via Fem access. Successful LIMA imaging within 15 min and time needed for imaging were efficacy end-point. Safety metrics were cerebral ischemic events and access site complications. ResultsOverall success rate of Rad LIMA imaging was 62 %. The success rate of Fem LIMA imaging was 97 %. In Rad group, patient age emerged as the single independent correlate of success at multivariate analysis (OR 9.938, CI 0.902–0.977 p = 0.002), with 77 % success rate in the lowest age quartile (<67 years).Median time needed to obtain selective LIMA imaging was significantly longer in Rad than in Fem (5.5 min vs. 4.0 min, p < 0.001), but right radial access was not a significant predictor of time needed to image LIMA at multivariate analysis (K 0.726, CI [−0.130–1.581], p = 0.09). Access site complications (6 vs. 0 cases, p = 0.030), and clinically significant bleeding (4 vs. 0 cases, p = 0.1) occurred in Fem group only.No peri-procedural cerebrovascular events were seen in either Group. ConclusionsRight radial artery is a suboptimal, yet reasonable access for LIMA-graft selective imaging in younger patients. The technique is free from vascular complications and peri-procedural cerebrovascular events.

Safety and Efficacy of Four Different Diagnostic Catheter Curves Dedicated to One-Catheter Technique of Transradial Coronaro-Angiography-Prospective, Randomized Pilot Study. TRACT 1: Trans RAdial CoronaryAngiography Trial 1.

Transradial coronaro-angiography (TRA) can be performed with one catheter. We investigate the efficacy of four different DxTerity catheter curves dedicated to the single-catheter technique and compare this method to the standard two-catheter approach. For this prospective, single-blinded, randomized pilot study, we enrolled 100 patients. In groups 1, 2, 3, and 4, the DxTerity catheters Trapease, Ultra, Transformer and Tracker Curve, respectively, were used. In group 5 (control), standard Judkins catheters were used. The study endpoints were the percentage of optimal stability, proper ostial artery engagement and a good quality angiogram, the duration of each procedure stage, the amount of contrast, and the radiation dose. The highest rate of optimal stability was observed in groups 2 (90%) and 5 (95%). Suboptimal results with at least one episode of catheter fallout from the ostium were most frequent in group 1 (45%). The necessity of using another catheter was observed most frequently in group 4. The analysis of time frames directly depending on the catheter type revealed that the shortest time for catheter introduction and for searching coronary ostia was achieved in group 2 (Ultra). There were no differences in contrast volume and radiation dose between groups. DxTerity catheters are suitable tools to perform TRA coronary angiography. The Ultra Curve catheter demonstrated an advantage over other catheters in terms of its ostial stability rate and procedural time.

Single-Center Experiences of Preoperative Juvenile Nasal Angiofibroma Embolization With Gelfoam, Reducing Financial Burden on Patients in Developing Country.

IntroductionJuvenile nasal angiofibroma (JNA) is a highly vascular tumor of the nasopharynx. Endovascular embolization followed by surgery is the treatment of choice. This study aimed to determine that single catheter technique with Gelfoam is an effective and safe technique for embolization to reduce the financial burden on patients in a developing country.Materials and methodsWe retrospectively reviewed the imaging, surgical, and histopathological records of 108 patients who underwent preoperative endovascular tumor embolization followed by surgical resection between March 2017 and March 2021.ResultsAfter embolization no major complication was observed in any patient. Complete devascularization of tumor was done in 87.8%. Intraoperative blood loss resulting in transfusion was almost the same as with other embolization techniques.ConclusionSingle catheter with Gelfoam is a cost-effective and safe technique for JNA embolization.

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

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

Comparison of Treatment Results by Coil Embolization Procedures for Ruptured Cerebral Aneurysms.

In coil embolization of ruptured cerebral aneurysms, intraoperative cerebral aneurysm re-rupture and thromboembolism are of concern. A good embolic condition can be expected by adjunctive techniques, but there is an increased risk of complications. We investigated the treatment results by coil embolization procedures for ruptured cerebral aneurysms. Between January 2016 and December 2019, 75 ruptured saccular cerebral aneurysms were treated by coil embolization at our hospital. The background factors, results of aneurysm embolization, intraoperative re-rupture, symptomatic cerebral embolism, and other factors were investigated retrospectively. We compared and examined these factors based on the procedure. The mean age was 62.8 and there were 57 female patients (76.0%). The single catheter technique (SCT) was used in 44 cases (58.7%) and the adjunctive technique was used in 31 cases (41.3%). Complete obliteration (CO) was achieved in 24 cases (32.0%), there was a neck remnant (NR) in 23 (30.7%), body filling (BF) was observed in 28 (37.3%), intraoperative re-rupture occurred in 7 (9.3%), and symptomatic cerebral embolism developed in 6 (8.0%), but no postoperative re-rupture was observed. Retreatment was required in only three cases of SCT. On comparison by procedure, the incidence of symptomatic cerebral embolism was significantly lower in SCT group than in the adjunctive technique group (2.3% vs 16.1%, p = 0.04). Among the cases of coil embolization for ruptured cerebral aneurysms at our hospital, SCT resulted in a lower incidence of symptomatic cerebral embolism than adjunctive techniques. It is essential to select an appropriate procedure in each case by understanding the characteristics of each procedure.

Feasibility and efficacy of coil embolization for middle cerebral artery aneurysms.

BackgroundThe anatomy of middle cerebral artery (MCA) aneurysms has been noted to be unfavorable for endovascular treatment. The purpose of this study was to assess the feasibility and efficacy of coiling for MCA aneurysms.MethodsFrom January 2004 to December 2015, 72 MCA aneurysms (38 unruptured and 34 ruptured) in 67 patients were treated with coils. Treatment-related complications, clinical outcomes, and immediate and follow-up angiographic outcomes were retrospectively analyzed. ResultsAneurysms were located at the MCA bifurcation (n=60), 1st segment (M1, n=8), and 2nd segment (M2, n=4). Sixty-nine aneurysms (95.8%) were treated by neck remodeling techniques using multi-catheter (n=44), balloon (n=14), stent (n=8), or combination of these (n=3). Only 3 aneurysms were treated by single-catheter technique. Angiographic results were 66 (91.7%) complete, 5 (6.9%) remnant neck, and 1 (1.4%) incomplete occlusion. Procedural complications included aneurysm rupture (n=1), asymptomatic coil migration to the distal vessel (n=1), and acute thromboembolism (n=10) consisting of 8 asymptomatic and 2 symptomatic events. Treatment-related permanent morbidity and mortality rates were 4.5% and 3.0%, respectively. There was no bleeding on clinical follow-up (mean, 29 months; range, 6-108 months). Follow-up angiographic results (mean, 26 months; range, 6-96 months) in patients included 1 major and 3 minor recanalizations.ConclusionCoiling of MCA aneurysms could be a technically feasible and clinically effective treatment strategy with acceptable angiographic and clinical outcomes. However, the safety and efficacy of this technique as compared to surgical clipping remains to be ascertained.

Interventional Treatment of Acute Portal Vein Thrombosis.

Acute portal vein thrombosis is a potentially fatal condition. In symptomatic patients not responding to systemic anticoagulation, interventional procedures have emerged as an alternative to surgery. This study sought to retrospectively evaluate initial results of interventional treatment of acute portal vein thrombosis (aPVT) using a transjugular interventional approach. Between 2014 and 2016, 11 patients were treated because of aPVT (male: 7; female: 4; mean age: 41.06 years). All patients presented a rapid onset of symptoms without collateralization of portal flow as assessed by a CT scan at the time of admittance. The patients showed thrombotic occlusion of the main portal vein (11/11), the lienal vein (10/11) and the superior mesenteric vein (10/11). Different techniques for recanalization were employed: catheter thromboaspiration (1/9), AngioJet device (7/9), local-lysis-only (1/9) and TIPSS (7/9). Local lysis was administered using a dual (4/9) or single (5/9) catheter technique. The mean follow-up was 24.32 months. In 9 patients transhepatic access was successful. Initially reduction of thrombus load and recanalization were achieved in all 9 cases with residual thrombi in PV (n = 3), SMV (n = 7), and IL (n = 5). In the collective undergoing interventional procedures (n = 9) rethrombosis and continuous abdominal pain were seen in one patient, and thrombus progression after successful recanalization was seen in another. Freedom from symptoms could be achieved in 6 patients. One patient developed peritoneal and pleural effusion, respiratory insufficiency and portosystemic collaterals. Both patients who could not undergo an interventional procedure developed a cavernous transformation of the portal vein. One of them also had continuous intermittent abdominal pain. Interventional percutaneous approaches are able to improve patient outcome in patients with aPVT. It appears to be of utmost importance to not only remove/reduce the thrombotic material but to establish sufficient inflow and outflow by TIPS and simultaneous multi-catheter thrombolysis. · Pharmacomechanic thrombectomy in combination with local thrombolysis is a feasible approach. · The transjugular transhepatic approach seems to be a safe procedure. · TIPSS and dual catheter lysis may support flow management. · Wolter K, Decker G, Kuetting D et al. Interventional Treatment of Acute Portal Vein Thrombosis. Fortschr Röntgenstr 2018; 190: 740 - 746.

Contact-force guided single-catheter approach for pulmonary vein isolation: Feasibility, outcomes, and cost-effectiveness

For conventional ablation of paroxysmal atrial fibrillation (AF), an ablation catheter in conjunction with a circular mapping catheter (CMC) is typically used for pulmonary vein isolation (PVI). The purpose of this study was to evaluate an approach for PVI with a single contact-force (CF) ablation catheter in terms of procedural reliability, outcomes, and cost-effectiveness. One hundred consecutive patients with paroxysmal AF were included in the study. Fifty patients (study group) underwent a CF-guided single-catheter approach, whereby PVI was demonstrated when sequential pacing at 9 equidistant points within the lesion set (carina included) failed to capture the left atrium. For confirmation, PVI was verified with a CMC. In comparison, 50 patients (control group) underwent a conventional PVI ablation guided by a CMC. Procedure time (101 ± 17 minutes vs 107 ± 15 minutes, P = .11), ablation time (24.2 ± 7.1 minutes vs 22.6 ± 8.8 minutes, P = .37), fluoroscopy time (5.6 ± 2.2 minutes vs 8.3 ± 3.4 minutes, P = .09), and applied CF (17.8 ± 2.6 g vs 18 ± 2.8 g, P = .72) did not reach statistical difference between the study and control groups. CF-guided single-catheter ablation achieved successful PVI in 98% of the study group and a 31% reduction in cost. At 1-year follow-up, sinus rhythm maintenance rate was similar in both groups (86% vs 84%, P = .78). In paroxysmal AF, a CF-guided single-catheter technique is an effective method for PVI, yielding substantial cost savings and clinical results similar to a conventional approach.

APACHE II score predicts mortality in patients requiring prolonged ventilation in a weaning center.

In the past decade, the rate and utilization of veno-venous extracorporeal membrane oxygenation (VV-ECMO) has increased dramatically. A single catheter technique has recently come into favour for providing VV-ECMO. Although it has been shown that intensivists can safely place these catheters, the safety of decannulation by intensivists has not been reported in the literature. We describe a technique for safely decannulating the Avalon Elite VV-ECMO catheter at the bedside and assess the safety of this technique, as compared with the standard technique of decannulation in the operating room by a surgeon. This was a retrospective cohort design conducted at a tertiary care cardiovascular intensive care unit at an academic medical centre. All patients who underwent VV-ECMO from 2009 to 2014 were included in the study except for those who had been decannulated for withdrawal of care. Complication rates from decannulation were compared between patients who were decannulated by surgeons in the operating room and those decannulated by intensivists in the intensive care unit (ICU). Twenty-eight patients were included in this study, of whom twenty-three patients (82%) were decannulated by intensivists, board certified in Critical Care Medicine through the American Board of Anesthesiology, while five (18%) the patients were decannulated by a surgeon. There was no significant difference in the complications rates between the surgeons (0) and intensivists (1) (P = 1.00). There were no major complications requiring operative intervention associated with decannulation identified in this study. It is safe for intensivists to decannulate the Avalon Elite VV-ECMO cannula in the ICU using our purse-string suture technique. Performing these decannulations at the bedside compared to operating room may have positive clinical ramifications that include improved patient safety, timely patient care and reduced operating room costs.

Safety of intensivist-led bedside decannulation of internal jugular bi-caval dual-lumen veno-venous extracorporeal membrane oxygenation cannulas and report of technique.

In the past decade, the rate and utilization of veno-venous extracorporeal membrane oxygenation (VV-ECMO) has increased dramatically. A single catheter technique has recently come into favour for providing VV-ECMO. Although it has been shown that intensivists can safely place these catheters, the safety of decannulation by intensivists has not been reported in the literature. We describe a technique for safely decannulating the Avalon Elite VV-ECMO catheter at the bedside and assess the safety of this technique, as compared with the standard technique of decannulation in the operating room by a surgeon. This was a retrospective cohort design conducted at a tertiary care cardiovascular intensive care unit at an academic medical centre. All patients who underwent VV-ECMO from 2009 to 2014 were included in the study except for those who had been decannulated for withdrawal of care. Complication rates from decannulation were compared between patients who were decannulated by surgeons in the operating room and those decannulated by intensivists in the intensive care unit (ICU). Twenty-eight patients were included in this study, of whom twenty-three patients (82%) were decannulated by intensivists, board certified in Critical Care Medicine through the American Board of Anesthesiology, while five (18%) the patients were decannulated by a surgeon. There was no significant difference in the complications rates between the surgeons (0) and intensivists (1) (P = 1.00). There were no major complications requiring operative intervention associated with decannulation identified in this study. It is safe for intensivists to decannulate the Avalon Elite VV-ECMO cannula in the ICU using our purse-string suture technique. Performing these decannulations at the bedside compared to operating room may have positive clinical ramifications that include improved patient safety, timely patient care and reduced operating room costs.

16-17: Contact-force guided single catheter approach for pulmonary vein antrum isolation: procedural feasibility

Purpose: Wedging a circular mapping catheter (CMC) into pulmonary vein (PV) is recommended to validate their isolation during wide antral circumferential ablation (WACA). Since appropriate catheter contact has proved crucial for lesion quality, we hypothesize that a contact-force (CF) guided single catheter approach might be suitable and effective for PV isolation (PVI). Methods: With the use of a CF ablation catheter, WACA was performed for both sets of PVs in 50 patients with paroxysmal AF. Antral exit block was demonstrated by sequential pacing at 9 equidistant points within the circular WACA lesion set (including the carina), with a target force ≥ 10g. Sites displaying persistent left atrial capture underwent additional pacing maneuvers and electrogram analysis, in order to detect and close residual gaps. Once exit block was deemed achieved, PVI was validated by conventional CMC-based analysis. Results: The mean procedural duration, fluoroscopy exposure time, total ablation time and force applied per-procedure were respectively of 101 ± 17 min, 5.6 ± 2.2 min, 23.2 ± 7.1 min and 17.8 ± 2.6 grams. 84 of 100 PV antra were disconnected after an exclusive anatomical approach, while 16 displayed residual gaps. Of the latter, 14 were isolated with the sole CF catheter. The positive predictive value of antral exit block reached 100% for predicting PVI as assessed with CMC. Conclusions: CF-guided single catheter technique is a feasible method for PVI in patients with paroxysmal AF. This simplified approach proves as effective as the standard CMC-based approach for residual gaps identification and conduction block validation.

Endovascular treatment of A1 aneurysms of the anterior cerebral artery.

The aim of this study was to present the clinical and angiographic outcomes of A1 aneurysms treated by coil embolization. We retrospectively evaluated 38 consecutive patients with A1 aneurysm (20 ruptured and 18 unruptured; mean age, 53.8 ± 11.9 years) from 2011 to 2014 treated by an endovascular approach in our hospital. Follow-up angiography was obtained in 30 patients. Clinical outcomes were evaluated by modified Rankin Scale (mRS) over telephone. Among the 38 patients, 24 were treated with single-catheter technique, 8 with stent-assisted coiling (Enterprise 3; Solitaire 5), 5 with parent vessel obliteration, and 1 with balloon-assisted coiling. Initial angiographic results revealed that complete occlusion was achieved in 21 aneurysms (55.3%), near-complete occlusion in 16 (42.1%), and partial occlusion with contrast agent filling the aneurysm sac in 1 (2.6%). Procedure-related complications were observed in 6 patients (15.8%). Follow-up angiographic imaging evaluation after coil embolization was performed in 32 aneurysms (mean interval, 22.6 ± 6.7 months), which showed that 31 (96.9%) aneurysms remained stable or improved without regrowth, while minor recanalization was found in 1 aneurysm (3.1%), which was treated by parent vessel occlusion. Clinical follow-up evaluation was excellent in 37 of the 38 patients (mRS score 0 in 34, and mRS score 1 in 3) at a mean duration of 26.6 ± 7.7 months. Endovascular treatment is feasible and effective for A1 segment aneurysms. The current treatment selections, including single-catheter embolization, balloon-assisted coiling, stent-assisted coiling, and parent vessel occlusion, should be performed according to the characteristics and morphology of A1 aneurysms.

Zero-fluoroscopy Intracardiac Echocardiography-guided Ablation of Atrial Fibrillation Using a Single-catheter Technique

Zero-fluoroscopy Intracardiac Echocardiography-guided Ablation of Atrial Fibrillation Using a Single-catheter Technique

Tu1625 Endoscopic Ultrasound (EUS)-Guided Drainage of Pancreatic Pseudocysts Using a Single Catheter Technique

Tu1625 Endoscopic Ultrasound (EUS)-Guided Drainage of Pancreatic Pseudocysts Using a Single Catheter Technique

AMP-Activated Protein Kinase α1 Regulates Cardiac Gap Junction Protein Connexin 43 and Electrical Remodeling Following Pressure Overload

Background/Aims: Adenosine 5'-monophosphate (AMP)-activated protein kinase (Ampk) modulates a wide array of cellular functions and regulates various ion channels and transporters. In failing human hearts an increased Ampkα1 activity was observed. The present study aimed to uncover the impact of Ampkα1 on cardiac electrical remodeling. Methods: Gene-targeted mice lacking functional Ampkα1 (Ampkα1-/-) and corresponding wild-type mice were exposed to pressure overload by “transverse aortic constriction” (TAC). In vivo electrophysiology was performed with a single catheter technique, myocardial conduction velocities and conduction characteristics investigated in isolated hearts, transcript levels quantified by RT-PCR and protein abundance determined by Western blotting. Moreover, connexin 43 (Cx43) was expressed in Xenopus oocytes with or without coexpression of wild-type or mutant AMPK and Cx43 protein abundance quantified utilizing confocal microscopy. Results: TAC treatment increased Ampkα1 protein expression in cardiac tissue from wild-type mice. TAC further increased left ventricular conduction inhomogeneity and triggered conduction blocks, effects blunted in the Ampkα1^-/- mice. TAC treatment decreased Cx43 protein abundance in cardiac tissue, an effect significantly blunted in the Ampkα1^-/- mice. TAC treatment did not modify Cx43 mRNA levels but increased ubiquitination of Cx43 protein, an effect mitigated by Ampkα1 deficiency. As shown in Xenopus oocytes, Cx43 cell membrane protein abundance was significantly downregulated by wild-type AMPK^WT and constitutively active AMPK^γR70Q, but not by catalytically inactive AMPK^αK45R. Conclusion: Ampkα1 stimulates ubiquitination of the gap junction protein Cx43, thereby contributing to gap junction remodeling following pressure overload.

Myasthenia gravis: A challenge

Sir, Most reports of patients with myasthenia gravis undergoing surgery are for thymectomy which is a treatment option in patients unresponsive to medical management.[1] There are few reports of patients with myasthenia posted for incidental surgery. We would like to report one such case where the patient was scheduled to undergo a modified radical mastectomy for carcinoma of the breast. A 40-year-old female (50 kg) diagnosed as a case of myasthenia gravis Grade II B since 1 year was scheduled for a mastectomy procedure. She had developed symptoms of dysphagia and dysarthria one year before. On further evaluation, it was diagnosed as myasthenia. She was started on pyridostigmine and steroid (since she did not improve only with pyridostigmine), to which she responded. She was also diabetic (due to steroid therapy) controlled on insulin. Her blood and other investigations were within normal range. Her pulmonary function tests (PFT) showed a decrease in vital capacity (2 L). Other parameters were normal. Since she was at risk of post-operative respiratory complications[1], we decided to avoid general anaesthesia. Among the various options paravertebral block (PVB),[2] thoracic epidural[3] block, and tumescent anaesthesia[4] (block) were considered. Tumescent anaesthesia involves the use of large volumes of local anaesthetic drugs, and was hence avoided. Thoracic epidural block[3,5] with a higher concentration of local anaesthetic may produce motor blockade and decrease vital capacity, forced expiratory volume and total lung capacity which was potentially dangerous in our patient due to bulbar muscle involvement. Hence, a PVB was decided to be administered. After patient consent and premedication with midazolam (1 mg) and fentanyl (70 μg), PVB was performed between T1 to T6 levels. 4cc of 0.25% bupivacaine with adrenaline was injected at each space. Sensory block was assessed over the respective dermatomes, and the surgery was continued with top ups of sedation and opioid analgesia (fentanyl 30 μg and dexmedetomidine 20 μg). Propofol (50 mg) was administered during the axillary clearance. Surgery lasted 90 min. The patient remained comfortable during the procedure. Analgesia lasted for 6 h post-operatively. She was restarted on oral dose of pyridostigmine soon after the procedure. She was discharged on the 3rd post-operative day. In patients with myasthenia, the parameters which indicate the need for post-operative mechanical ventilation include disease duration[1,6] >6 years, associated lung disease, pyridostigmine dose requirement >750 mg/day and vital capacity <2.9 L. Hence, a pre-operative lung function assessment is of utmost importance. Since the patient had dysphagia, possibility of aspiration is higher. A previous meta-analysis performed showed that PVB combined with general anaesthesia provided better post-operative analgesia[3,5] during breast surgery. Lesser incidence of adverse effects was reported with the use of PVB.[2,5] Since acute post-operative pain is a risk factor for the development of post-operative chronic pain[2,5], use of PVB is useful. PVB has also been shown to provide better analgesia than wound infiltration. PVB also provides better post-operative dynamic analgesia. Single level and catheter technique have been described, but we used the multiple injection technique. We conclude that regional anaesthesia, especially PVB is a feasible alternative in patients with myasthenia gravis undergoing modified radical mastectomy.

Remote magnetic navigation for circumferential pulmonary vein ablation: single-catheter technique or additional use of a circular mapping catheter?

Remote magnetic navigation (RMN) is utilized for catheter guidance during pulmonary vein ablation (PVA). We aimed to determine whether the additional use of a circular mapping catheter (CMC) influences efficacy and outcome of RMN-guided PVA. A total of 80 consecutive subjects (65 % male, age 62 ± 9 years) underwent circumferential PVA with a 3D mapping system and an RMN-guided irrigated catheter. Procedural endpoint was complete PV isolation (PVI), total radiofrequency (RF) time >60 min, or procedure duration >5 h. PVI was defined as an entrance and/or exit block, diagnosed with a CMC within the PV ostium or by pacing via the roving RMN-guided catheter (single-catheter technique). Prolonged Holter monitoring after 3 and 6 months was used to detect atrial tachyarrhythmia (AT/AF) recurrences. Complete PVI was achieved in 56 % (45/80) of all subjects (isolated PVs per patient, 3.1 ± 1.2; RF time, 56.3 ± 17.2 min; procedure duration, 3.8 ± 0.8 h). Prospective validation of the single-catheter technique for diagnosing PVI demonstrated high concordance (94 %) with blinded CMC results. CMC use in first-time PVA was associated with similar total RF and procedure times but higher PV isolation rate. Upon multivariate analysis, CMC use, female gender, left PV, smaller PV ostium and repeat PVA predicted PVI during RMN-guided ablation. Persistent AF and mitral regurgitation at baseline and the number of non-isolated PVs predicted AT/AF recurrence during follow-up. Concomitant CMC use for first-time, RMN-guided PVA is associated with similar procedure duration but higher PV isolation rates as compared to a single-catheter approach. Since the number of isolated PVs predicts freedom from AT/AF, CMC utilization appears advisable for first-time, RMN-guided PVA.