Two distinct stages and mechanisms of ST-elevation during cryothermal cavotricuspid isthmus ablation guided by intracardiac echocardiography: A case report.

Radiofrequency (RF) catheter ablation is the primary treatment for cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL), with cryothermal energy as an alternative. While cryoablation offers comparable effectiveness and safety to RF ablation, it poses a risk of coronary artery spasm leading to ST-elevation. This case report presents a 65-year-old man with drug-refractory atrial fibrillation (AF) and AFL undergoing cryothermal CTI ablation guided by intracardiac echocardiography (ICE). During the procedure, two distinct ST-elevation episodes were observed. The first episode coincided with the pull-down of the cryoablation catheter, potentially resulting in coronary compression, as indicated by ICE, and was rapidly resolved by discontinuing the freezing process. The second episode, occurring without active freezing, was attributed to coronary artery spasm and resolved with intracoronary nitroglycerin administration. During the second episode, emergent right coronary angiography confirmed total occlusion in the segment 4 AV adjacent to the region where cryoablation was performed, which fully resolved post-nitroglycerin. This report underscores the dual mechanisms of ST-elevation-coronary artery compression and spasm-during cryothermal CTI ablation, highlighting the critical role of ICE in enhancing procedural safety.

Wire ThRoUgh Snare Twice (Wire TRUST) technique: A novel method to grasp a lead with inaccessible ends as a supportive femoral approach for transvenous lead extraction.

INTRODUCTION: Transvenous lead extraction (TLE) is a crucial procedure for managing cardiac implantable electronic devices. The use of a combined superior and femoral approach has been found to enhance the success rate of TLE. This report introduces a novel technique, named "Wire ThRoUgh Snare Twice" (Wire TRUST), for effectively grasping a lead without a free end during TLE. METHOD: The Wire TRUST technique was applied in a case involving a 49-year-old male patient requiring TLE due to electrical artifact on the right ventricular (RV) lead, replacement of the RV lead, and pacemaker generator exchange. The Wire TRUST technique involved the insertion of a 4-Fr pigtail catheter and a 6-Fr snare catheter through the 14-Fr sheath inserted from the right common femoral vein. The 4-Fr pigtail catheter was hooked to the RV lead under multidirectional fluoroscopic guidance in the right atrium. The 0.014-in. guidewire was advanced through the pigtail catheter, crossing the RV lead until reaching the inferior vena cava. Subsequently, the distal end of the 0.014-in. guidewire was captured using a snare and pulled, facilitating externalization of the guidewire. After externalization, both ends of the 0.014-in. guidewire were passed through the snare outside the body and reinserted into the 14-Fr sheath. By simultaneously advancing and closing the snare while applying tension to the 0.014-in. guidewire, a secure grip on the lead without free ends was achieved. RESULTS: The Wire TRUST technique enabled successful lead extraction and replacement without any complications. The technique facilitated the co-axial alignment of the powered sheath with the RV lead, ensuring safe and efficient extraction. CONCLUSION: The Wire TRUST technique presents a novel and effective approach for grasping leads with inaccessible ends during TLE.

Predictors of Pacing Capture Threshold Exacerbation After Leadless Pacemaker Implantation.

The predictors of pacing capture threshold (PCT) exacerbation after leadless pacemaker implantation remain unknown. We analyzed the predictors of poor PCT by identifying risk factors using multivariate logistic regression analysis for 211 patients with leadless pacemaker implantation. Twenty patients met the criteria for elevated PCT levels and were categorized in the poor PCT group. Multivariate analyses revealed that PCT (P < 0.0001) and pacing impedance (P = 0.03) were independent predictors of PCT exacerbation. Elevated PCT levels and low pacing impedance during leadless pacemaker implantation were potential risk factors for the replacement of leadless pacemakers after the procedure.

Occurrence of Torsade de Pointes prior to complete lead connection during pacemaker implantation.

Torsade de Pointes (TdP) can be triggered by a pacing spike on the T-wave, due to pacemaker undersensing. However, it is not widely known that this phenomenon can occur even during pacemaker implantation. An 84-year-old woman underwent pacemaker implantation for the treatment of a complete atrioventricular block with dyspnea. During the procedure, immediately following ventricular lead insertion and before torque wrench tightening, TdP was observed. Ventricular pacing was initiated by inserting the lead into the header of the generator; however, sensing remained unstable. T-waves associated with undersensed PVCs and ventricular pacing occurred simultaneously, resulting in a spike on the T-wave and TdP.

Retrieval of a Micra transcatheter pacing system in a heart with a preexisting lead.

We report the case of a 74-year-old man with a previously implanted pacemaker lead. He had undergone Medtronic™ Micra Transcatheter Pacing System (TPS, Medtronic plc, MN, USA) implantation because of lead fracture. We implanted a new TPS and retrieved the dislodged one. We used a multiple-loop snare (EN snare®) and an 8.5F steerable sheath (Agilis NXT; St. Jude Medical, St Paul, MN, USA). The TPS was obstructed by the chordae tendineae of the tricuspid valve and the pacemaker lead. We pushed the TPS to the apex site; this enabled us to move the TPS away from the chordae tendineae and pacemaker lead. The TPS body was caught in the inferior vena cava and was successfully retrieved. To our knowledge, this is the first case reporting TPS retrieval in a heart with preexisting lead.

Substrate recognition of N,N'-diacetylchitobiose deacetylase from Pyrococcus horikoshii.

Enzymes of carbohydrate esterase (CE) family 14 catalyze hydrolysis of N-acetyl groups at the non-reducing end of the N-acetylglucosamine (GlcNAc) residue of chitooligosaccharides or related compounds. N,N'-diacetylchitobiose deacetylase (Dac) belongs to the CE-14 family and plays a role in the chitinolytic pathway in archaea by deacetylating N,N'-diacetylchitobiose (GlcNAc2), which is the end product of chitinase. In this study, we revealed the structural basis of reaction specificity in CE-14 deacetylases by solving a crystal structure of Dac from Pyrococcus horikoshii (Ph-Dac) in complex with a novel reaction intermediate analog. We developed 2-deoxy-2-methylphosphoramido-d-glucose (MPG) as the analog of the tetrahedral oxyanion intermediate of the monosaccharide substrate GlcNAc. The crystal structure of Ph-Dac in complex with MPG demonstrated that Arg92, Asp115, and His152 side chains interact with hydroxyl groups of the glucose moiety of the non-reducing-end GlcNAc residue. The amino acid residues responsible for recognition of the MPG glucose moiety are spatially conserved in other CE-14 deacetylases. Molecular dynamics simulation of the structure of the Ph-Dac-GlcNAc2 complex indicated that the reducing GlcNAc residue is placed in a large intermolecular cleft and is not involved with specific interactions with the enzyme. This observation was consistent with results indicating that Ph-Dac displayed similar kinetic parameters for both GlcNAc and GlcNAc2. This study provides the structural basis of reaction-site specificity of Dac and related CE-14 enzymes.

Improvement in respiratory function and exercise tolerance following video-assisted thoracoscopic diaphragm plication for symptomatic iatrogenic persistent diaphragm paralysis after radiofrequency catheter ablation.

Hemidiaphragm paralysis, a complication of catheter ablation for atrial fibrillation, can severely affect respiratory function and can lead to paradoxical breathing and dyspnea on exertion. A 75-year-old woman with iatrogenic diaphragm paralysis showed improved symptoms, respiratory function, and exercise tolerance after video-assisted thoracoscopic diaphragm plication.

Successful transvenous retrieval of an electrode ring dislodged from a novel visualized steerable sheath by inflation of a balloon inside the ring.

The VIZIGO sheath (Biosense Webster, Irvine, CA, USA) is used for catheter ablation (CA) of atrial arrhythmia. In this case report, we describe a complication associated with the VIZIGO sheath and present a successful bailout method. An 82-year-old woman with paroxysmal atrial fibrillation (AF) and atrial tachycardia (AT) was referred to our hospital after experiencing palpitations for 6 months. She underwent CA using the VIZIGO sheath and a fixed Swartz sheath (St. Jude Inc., St. Paul, MN, USA). Pulmonary vein isolation and left atrial posterior wall isolation were performed to address AF and AT. Following ablation, the Swartz sheath was removed; however, the VIZIGO sheath showed resistance to removal. A wire was inserted into the VIZIGO sheath for removal, but the distal electrode ring detached in the vessel. To retrieve the electrode ring, a Mustang over-the-wire angioplasty balloon was dilated inside the ring and withdrawn with the ring. After venography and confirmation of a hemostatic seal, the ablation procedure was completed. The patient experienced postoperative anemia, which was resolved by erythrocyte transfusion. No further paroxysmal AF or AT occurred during the 1-year follow-up. In conclusion, the VIZIGO sheath's distal electrode ring may become detached during CA, and the detached ring can be successfully retrieved using our original bailout technique. Learning objective: This case report highlights the unique complication of electrode ring detachment associated with the novel visualized steerable sheath (VIZIGO; Biosense Webster, Irvine, CA, USA) during catheter ablation procedures and presents the successful technique as a bailout method for retrieving the dislodged ring. The technique involves dilating a non-compliant over-the-wire angioplasty balloon inside the ring and withdrawing it along with the detached ring.

Successful coronary sinus left ventricular lead extraction 9 years postimplantation using the wire ThRoUgh Snare Twice (wire TRUST) technique.

The newly-proposed tandem approach, Wire ThRoUgh Snare Twice (Wire TRUST) is effective for grasping a lead with inaccessible ends. This case report shows that Wire TRUST can also enable successful extraction of a left ventricular lead by iteratively grasping and repositioning to the distal portion of the lead.

Cryoballoon ablation using the sheath-in-sheath technique in a patient with a tortuous common iliac vein.

The sheath-in-sheath technique, utilizing a 15Fr cryoballoon delivery sheath inserted into a 25 cm 16Fr sheath, effectively navigates tortuous iliac veins during cryoballoon ablation for atrial fibrillation, ensuring safe delivery and maintaining essential device performance without complications.

Structure of peroxiredoxin from the anaerobic hyperthermophilic archaeon Pyrococcus horikoshii.

The crystal structure of peroxiredoxin from the anaerobic hyperthermophilic archaeon Pyrococcus horikoshii (PhPrx) was determined at a resolution of 2.25 Å. The overall structure was a ring-type decamer consisting of five homodimers. Citrate, which was included in the crystallization conditions, was bound to the peroxidatic cysteine of the active site, with two O atoms of the carboxyl group mimicking those of the substrate hydrogen peroxide. PhPrx lacked the C-terminal tail that forms a 32-residue extension of the protein in the homologous peroxiredoxin from Aeropyrum pernix (ApPrx).

Rocket-shape crossing technique: A combination of lead extraction and modified venoplasty for device upgrade with venous occlusion.

This case discusses an upgrade method to cardiac resynchronization therapy defibrillator for a 54 year old man with superior vena cava occlusion. Right ventricular lead extraction with modified venoplasty, Rocket shape Crossing Technique (RCT), was performed. In RCT the integration of the inflated balloon, halfway inside the laser sheath, and the laser sheath are advanced through the occlusion like a rocket shape crossing.

Oversensing caused by trapped air in the header of subcutaneous cardioverter-defibrillator generator.

In this study, we report two cases with oversensing due to air accumulation in the subcutaneous implantable cardioverter-defibrillator (S-ICD) device generator header. If trapped air in the header of the device is suspected, the re-connection procedure should be considered or the primary vector must be used, which might prevent oversensing.

Retrieval of an infectious leadless pacemaker with vegetation.

This case discusses the retrieval of a pacemaker with vegetation from a 78-year-old man. It suggests that grasping side of Micra body and pulling Micra into Agilis sheath is a possible technique for retrieval.

Lock and dock: Two-step transvenous retrieval of a fractured femoral sheath with a vascular snare via the right internal jugular vein.

An 86-year-old male with progressive palpitations and dyspnea was referred to our hospital for heart failure treatment. Catheter ablation was performed for atrial flutter as we suspected tachycardia-induced cardiomyopathy as the cause of the patient's heart failure. Due to difficulty securing a peripheral venous route, a 6-Fr sheath was inserted via the right common femoral vein prior to administering general anesthesia. While attempting to insert a mapping catheter, the 6-Fr sheath became lodged and subsequently fractured during removal. Percutaneous transvenous retrieval using an 8-Fr sheath was unsuccessful, and a switch to a right internal jugular vein approach with a 16-Fr sheath was necessary for successful retrieval. The following two-step retrieval ("lock and dock") was then performed: 1) lock: a vascular snare was used to catch the remaining wire crossing into the fractured sheath lumen to prevent the risk of sheath migration to the right ventricle or the pulmonary artery, and 2) dock: the same snare was subsequently used to catch the fractured sheath. The planned catheter ablation was then successfully performed, without any complications. Learning objective: Our case presents, "lock and dock," a novel approach for percutaneous transvenous retrieval that involves two steps: a vascular snare is used to catch the wire and subsequently the fractured sheath. This use of a vascular snare and a large-diameter sheath through the right internal jugular vein effectively reduces the possibility of fractured sheath migration.

Predictors of lead break during transvenous lead extraction.

BACKGROUND: The incidence, predictors, and clinical impact of lead break during transvenous lead extraction (TLE) were previously unknown. METHODS: We included consecutive patients who underwent TLE between September 2013 and July 2019 at our institute. Lead break during removal was defined as lead stretching and becoming misshapen, as assessed by fluoroscopy. RESULTS: A total of 246 patients underwent TLE for 501 leads. At a patient level, complete success was achieved in 226 patients (91.9%). At a lead level, 481 leads (96.0%) were completely removed and 101 leads (20.1%) were broken during the procedure. Of 392 identified pacemaker leads, 71 (18.3%) were broken during the TLE procedure. A multivariable analysis confirmed high lead age (odds ratio [OR] 1.12, 95% confidence interval (CI) 1.07-1.17; P < .001), passive leads (OR 2.29 95% CI 1.09-4.80; P = .028), coradial leads (OR 3.45 95% CI 1.72-6.92; P < .001), and insulators made of nonpolyurethane (OR 2.38 95% CI 1.03-5.26; P = .04) as predictors of lead break. Broken leads needed longer procedure times and were associated with a higher rate of cardiac tamponade. CONCLUSIONS: Lead age, coradial bipolar leads, passive leads, and leads without polyurethane insulation were predictors of lead break and could increase the difficulty of lead extraction.