Ventricular electrical storm after Micra™ leadless pacemaker implant.

Peri- and post-procedural ventricular tachycardia (VT) is a rare complication after leadless pacemaker implantation and requires an individualized approach. In this case report we describe the management of VT in a patient with subendocardial scarring due to prior coronary artery disease who presented with monomorphic VT the day after implant. The etiology was found to be related to the novel ventricular activation wavefront by ventricular pacing which induced a reentrant circuit dependent on pre-existing myocardial substrate. Invasive electrophysiologic study and ablation is a safe and successful treatment strategy in selected patients with evidence of myocardial scarring.

Leadless cardiac pacemakers: present and the future.

PURPOSE OF REVIEW: Pacing technology for many decades has been composed of a generator attached to leads that are usually transvenous. Recently, leadless pacemakers have been studied in clinical settings and now available for use in many countries. This includes the single-component Nanostim Leadless Cardiac Pacemaker and Micra Transcatheter Pacing System, as well as the multicomponent Wireless Stimulation Endocardial system. RECENT FINDINGS: Clinical studies in single-component leadless pacing technology has shown that they can be successfully implanted with minimal complications. The follow-up studies also seem to confirm the findings from the initial clinical trials. These systems offer some advantages over a traditional pacing system comprised of a subcutaneous generator and transvenous leads. SUMMARY: In many ways, these leadless systems are disruptive technologies that are changing the traditional pacemaker concept and preferred for some patients. Ongoing research is needed to better assess their long-term function, safety, and end-of-life strategies. In the future, multichamber leadless pacing is expected to be developed and perhaps obviating the need for transvenous leads and their associated complications.

Valued Components of a Consultant Letter from Referring Physicians' Perspective: a Systematic Literature Synthesis.

BACKGROUND: Effective communication between the consultants and physicians form an integral foundation of effective and expert patient care. A broad review of the literature has not been undertaken to determine the components of a consultant's letter of most value to the referring physician. We aimed to identify the components of a consultant's letter preferred by referring physicians. METHODS: We searched Embase and MEDLINE (OVID) Medicine (EBM) Reviews and Cochrane Database of Systematic Reviews for English articles with no restriction on initial date to January 6, 2017. Articles containing letters from specialists to referring physicians regarding outpatient assessments with either an observational or experimental design were included. Studies were excluded if they pertained to communications from referring physicians to consultant specialists, or pertained to allied health professionals, inpatient documents, or opinion articles. We enumerated the frequencies with which three common themes were addressed, and the positive or negative nature of the comments. The three themes were the structure of consultant letters, their contents, and whether referring physicians and consultants shared a common opinion about the items. RESULTS: Eighteen articles were included in our synthesis. In 11 reports, 91% of respondents preferred structured formats. Other preferred structural features were problem lists and brevity (four reports each). The most preferred contents were oriented to insight: diagnosis, prognosis, and management plan (16/21 mentions in the top tertile). Data items such as history, physical examination, and medication lists were less important (1/23 mentions in the top tertile). Reports varied as to whether referring physicians and consultants shared common opinions about letter features. CONCLUSIONS: Referring physicians prefer brief, structured letters from consultants that feature diagnostic and prognostic opinions and management plans over unstructured letters that emphasize data elements such as detailed histories and medication lists. Whether these features improve outcomes is unknown.

Initial human feasibility of infusion needle catheter ablation for refractory ventricular tachycardia.

BACKGROUND: Ablation of ventricular tachycardia (VT) is sometimes unsuccessful when ablation lesions are of insufficient depth to reach arrhythmogenic substrate. We report the initial experience with the use of a catheter with an extendable/retractable irrigated needle at the tip capable of intramyocardial mapping and ablation. METHODS AND RESULTS: Sequential consenting patients with recurrent VT underwent ablation with the use of a needle-tipped catheter. At target sites, the needle was advanced 7 to 9 mm into the myocardium, permitting pacing and recording. Infusion of saline/iodinated contrast mixture excluded perforation and ensured intramyocardial deployment. Further infusion was delivered before and during temperature-controlled radiofrequency energy delivery through the needle. All 8 patients included (6 male; mean age, 54) with a mean left ventricular ejection fraction of 29% were refractory to multiple antiarrhythmic drugs, and 1 to 4 previous catheter ablation attempts (epicardial in 4) had failed. Patients had 1 to 7 (median, 2) VTs present or inducible; 2 were incessant. Some intramyocardial VT mapping was possible in 7 patients. A mean of 22 (limits, 3-48) needle ablation lesions were applied in 8 patients. All patients had at least 1 VT terminated or rendered noninducible. During a median of 12 months follow-up, 4 patients were free of recurrent VT, and 3 patients were improved, but had new VTs occur at some point during follow-up. Two died of the progression of preexisting heart failure without recurrent VT. Complications included tamponade in 1 patient and heart block in 2 patients. CONCLUSIONS: Intramyocardial infusion-needle catheter ablation is feasible and permits control of some VTs that have been refractory to conventional catheter ablation therapy, warranting further study.

High-density mapping improves detection of conduction gaps after pulmonary vein isolation ablation with a circular mapping catheter.

BACKGROUND: High-density (HD) mapping of the pulmonary vein (PVs) has been hypothesized to improve the detection of conduction gaps in the radiofrequency ablation lesions set after pulmonary vein isolation (PVI) for the treatment of atrial fibrillation (AF). We aimed to compare the incidence of gaps after PVI with a standard 20-pole circumferential mapping catheter (CMC-20) and an HD mapping catheter (HD Grid). METHODS: This prospective study included patients scheduled for high-power short-duration PVI. Acute PVI was defined as an entrance and exit block using the CMC-20 after ≥ 20 min waiting period. The left atrium was then remapped using the HD Grid high-density mapping catheter to identify residual conduction gaps in the PVI lines by voltage and activation criteria. The primary endpoint was the number of gaps identified per patient by the HD Grid catheter. RESULTS: A total of 20 patients were included (mean age 59.9 ± 10.8 years, 15% female, 70% paroxysmal AF). The new map with the HD Grid identified 6 gaps in 4 patients (20%) or 0.3 ± 0.7 gaps per patient (p = 0.055 when compared to CMC-20). Five gaps (83%) were located at the right PVs. There was no difference in mapping time (CMC-20 12.2 ± 2.6 min vs HD Grid 11.7 ± 3.4 min, p = 0.452); however, the number of points was significantly higher in the HD Grid map (1662.7 ± 366.1 vs 1171.6 ± 313.6, p < 0.001). CONCLUSIONS: HD mapping during AF ablation identified PVI gaps in 1 out of 5 patients. Therefore, HD mapping may have the potential to improve AF ablation success rates in the long term. TRIAL REGISTRATION: ClinicalTrials.gov NCT04850508 on April 20, 2021.

Acute hyperkalemia detected by alert from implantable cardioverter-defibrillator.

Two cases of implantable cardioverter-defibrillator lead impedance changes that corresponded with changes in serum potassium are described. In the first case, an audible lead alert was triggered due to a significant change in lead impedance caused by hyperkalemia. In the second case, a patient was admitted with hyperkalemia and renal failure. Device interrogation revealed a change in lead impedance corresponding to changes in serum potassium. As devices and leads become more sophisticated, their role for monitoring parameters and triggering alerts may expand to include electrolyte and other metabolic changes.

Experiences and Impacts of Harassment and Discrimination Among Women in Cardiac Medicine and Surgery: A Single-Center Qualitative Study.

Background: Gender- and sex-based harassment and discrimination are consistently reported by about 50% of women physicians, and the prevalence may be even greater among women in cardiology. An exploration of these experiences and their impacts on women in healthcare is necessary to design interventions, create supports, and facilitate empathy, support, and allyship among leadership. Methods: To understand and describe the experiences of harassment and discrimination among women working in cardiac sciences, to inform the design of interventions and supports, we performed one-on-one, semi-structured interviews with women in the Department of Cardiac Sciences in a single institute. Interviews were coded independently in parallel using thematic analysis and reconciled by trained qualitative researchers. Experiences were categorized as harassment using the Canadian Human Rights Act. Codes were grouped into themes by iterative discussion. Results: There were 15 participants, including trainees, physicians in a variety of cardiac subdisciplines, and nurse practitioners. All participants had experienced sex- or gender-based discrimination at work, though the impact and perception of these experiences varied. Whereas some participants felt that these experiences had little influence on their careers or personal lives, others changed practice specialties or locations due to harassment. Several participants had been sexually assaulted at work. Interviews revealed modifiable barriers to reporting harassment. Conclusions: This qualitative dataset enriches the prevalence data on sex- and gender-based harassment among women working in cardiology by describing the impacts and perceptions of this harassment. Organizations should address commonly described barriers to reporting harassment, including addressing retaliation, and create systems-level supports for those affected by harassment.

Introduction: Environ 50 % des femmes médecins signalent constamment la discrimination et le harcèlement fondés sur le genre et le sexe. Cette prévalence est encore plus grande chez les femmes en cardiologie. L'exploration de ces expériences et de leurs répercussions sur les femmes dans les soins de santé est nécessaire pour concevoir des interventions, créer du soutien, et faciliter l'empathie, le soutien et le concept d'allié chez les dirigeants. Méthodes: En vue de comprendre et de décrire les expériences de harcèlement et de discrimination chez les femmes qui travaillent en sciences cardiaques, d'orienter la conception d'interventions et de soutien, nous avons réalisé des entretiens individuels semi-structurés auprès de femmes du Service des sciences cardiaques d'un seul établissement. Les entrevues ont indépendamment été codifiées en parallèle par l'analyse thématique et rapprochées par des chercheurs formés aux méthodes qualitatives. Les expériences ont été catégorisées en harcèlement conformément à la Loi canadienne sur les droits de la personne. Des échanges itératifs ont permis de regrouper les codes par thèmes. Résultats: Les 15 participantes étaient des stagiaires, des médecins de diverses sous-disciplines de la cardiologie et des infirmières praticiennes. Toutes les participantes avaient subi de la discrimination fondée sur le sexe ou le genre au travail, même si les répercussions et la perception de ces expériences variaient. Alors que quelques participantes ont senti que ces expériences avaient eu peu d'influence sur leur carrière ou leur vie personnelle, d'autres ont changé de spécialité ou de lieu de pratique en raison du harcèlement. Plusieurs participantes ont subi des agressions sexuelles au travail. Les entretiens ont révélé des obstacles au signalement du harcèlement qui sont modifiables. Conclusions: Cet ensemble de données qualitatives enrichit les données sur la prévalence du harcèlement fondé sur le sexe et le genre chez les femmes qui travaillent en cardiologie en décrivant les répercussions et les perceptions de ce harcèlement. Les organisations devraient se pencher sur les obstacles au signalement du harcèlement fréquemment décrits, notamment les représailles, et créer du soutien à l'échelle du système pour les femmes qui sont touchées par le harcèlement.

Iatrogenic Arteriovenous Fistula: A Rare Complication of Pacemaker Implantation.

Severe vascular complications associated with pacemaker implantation are rare. Typically, they are overt, and require immediate resolution. We present 2 patients with insidious presentation of arteriovenous fistulae due to pacemaker implantation that were recognized early post-implantation. Both were repaired endovascularly and had good outcomes post-repair. (Level of Difficulty: Intermediate.).

Review of Stereotactic Arrhythmia Radioablation Therapy for Cardiac Tachydysrhythmias.

Cardiac tachyarrhythmias are a major cause of morbidity and mortality. Treatments for these tachyarrhythmias include antiarrhythmic drugs, catheter ablation, surgical ablation, cardiac implantable electronic devices, and cardiac transplantation. Each of these treatment approaches is effective in some patients but there is considerable room for improvement, particularly with respect to the most common of the tachydysrhythmias, atrial fibrillation, and the most dangerous of the tachydysrhythmias, ventricular tachycardia (VT) or ventricular fibrillation. Noninvasive stereotactic ablative radiation therapy is emerging as an effective treatment for refractory tachyarrhythmias. Animal models have shown successful ablation of arrhythmogenic myocardial substrates with minimal short-term complications. Studies of stereotactic radioablation involving patients with refractory VT have shown a reduction in VT recurrence and promising early safety data. In this review, we provide the background for the application of stereotactic arrhythmia radioablation therapy along with promising results from early applications of the technology.

Les tachyarythmies cardiaques sont une cause importante de morbidité et de mortalité. Les traitements employés comprennent des antiarythmiques, l'ablation par cathéter, l'ablation par chirurgie, l'implantation de dispositifs cardiaques électroniques et la transplantation cardiaque. Toutes ces démarches thérapeutiques sont efficaces dans certains cas, mais les traitements peuvent encore être largement améliorés, en particulier en ce qui concerne la fibrillation auriculaire, qui est la tachyarythmie la plus fréquente, et la tachycardie ventriculaire (TV, aussi appelée fibrillation ventriculaire), qui est la tachyarythmie la plus dangereuse. La radiochirurgie stéréotaxique non invasive se démarque de plus en plus comme traitement efficace des tachyarythmies réfractaires. Des substrats myocardiques arythmogènes ont pu être réséqués avec succès sur des modèles animaux, l'intervention n'ayant entraîné que des complications minimales de courte durée. Dans le cadre d'études menées auprès de patients présentant une TV réfractaire, la radiochirurgie stéréotaxique a permis de réduire le risque de récurrence de la TV, et les premières données sur l'innocuité du traitement sont encourageantes. Dans notre revue, nous précisons le cadre d'application de la radiochirurgie stéréotaxique visant à réséquer le tissu responsable de l'arythmie, et nous présentons les résultats prometteurs des premières applications de la technologie à cette fin.

Lack of Equity in the Cardiology Physician Workforce: A Narrative Review and Analysis of the Literature.

The gender and racial diversity in the cardiology workforce in Canada does not reflect that of the population we serve. As social awareness of the principles of equity, diversity, and inclusion rises, our profession must rise to meet the challenges they present. We detail contemporary examples of publication bias in the cardiac sciences literature and describe the factors that led to oversight in the peer-review process. We performed a narrative review to summarize the published literature on equity and diversity among cardiac physicians. We also summarize the challenges faced by women and racial-minority physicians when pursuing and thriving in a career in cardiology, and the systemic barriers to their success. In the past decade, social justice movements have advanced. Professionalism standards are changing, and awareness and understanding of these advances in terminology is imperative for all physicians. In this review, we summarize key language and concepts, with cardiology-specific examples, and propose a new paradigm of professionalism.

Au Canada, la diversité des genres et des races au sein de la main-d'œuvre en cardiologie ne reflète pas celle qui existe dans la population que nous servons. La prise de conscience sociale des principes d'équité, de diversité et d'inclusion gagne du terrain, et notre profession doit se montrer à la hauteur des défis qui s'y rattachent. Nous abordons des exemples contemporains de biais de publication dans la littérature cardiologique et décrivons les facteurs qui ont mené à des omissions dans le processus d'examen par les pairs. Une revue narrative de la littérature publiée sur l'équité et la diversité parmi les cardiologues nous a permis de résumer l'information publiée sur le sujet. Nous résumons également les difficultés auxquelles sont confrontés les femmes et les médecins issus des minorités raciales qui choisissent et mènent avec brio une carrière en cardiologie, de même que les obstacles systémiques à leur réussite. Au cours de la dernière décennie, les mouvements de justice sociale ont progressé. Les normes de professionnalisme évoluent, et tous les médecins doivent connaître et comprendre les avancées terminologiques. Dans le présent article, nous résumons les termes et les concepts clés, en y adjoignant des exemples propres au domaine de la cardiologie. Nous proposons aussi un nouveau paradigme de professionnalisme.

Epidemiology of cardiac implantable electronic device infections in the United States: A population-based cohort study.

BACKGROUND: Trends in cardiac implantable electronic device (CIED) infections have been studied previously. However, coding for administrative data is more granular in contemporary data sets and indications for CIED implantation have expanded. OBJECTIVE: The purpose of this study was to provide an update on the rates of CIED infection and the influence of different variables including sex, length of stay (LOS), and costs in the United States. METHODS: Data from the 2016 Healthcare Care and Utilization Project National Inpatient Sample database were utilized. International Classification of Diseases, Tenth Revision codes were used to track CIED infections. Demographic and clinical characteristics were collected including Elixhauser comorbidities. The univariate and multivariate logistic and linear regression models were used to assess mortality, costs, and LOS. RESULTS: Of 191,610 CIED implantations identified in the Healthcare Cost and Utilization Project National Inpatient Sample database in 2016, 8060 infections (4.2%) were identified. The in-hospital mortality rate for these patients was 4.7%. The majority of patients (68.9%) with CIED infection had ≥3 Elixhauser comorbidities. Women had decreased LOS and costs compared with men, and patients with ≥3 comorbidities had increased costs and LOS. CONCLUSION: We identified that the majority of patients with CIED infection had ≥3 comorbidities that were associated with increased costs and LOS. The observed sex differences in health care resource utilization and in-hospital costs among patients admitted with CIED infection requires further exploration. Patients with increased numbers of comorbidities should be recognized and managed carefully peri-CIED implantation given their increased risk of infection and use of health care resources.

Current concepts in the evaluation and management of syncope.

Syncope is a very common presentation with a wide differential diagnosis and equally wide prognostic implications. Recent work has highlighted the importance of an accurate history and physical examination as the basis of diagnosis, prognosis, and treatment. Several centers have evaluated the role of structured histories and comprehensive syncope evaluation guidelines and units in managing syncope. Although these do provide comprehensive care, whether they improve overall outcome and reduce costs is far from clear. This is partly because there are few effective treatments for the major cause of fainting, vasovagal syncope. Recent randomized trials have highlighted the roles of physical counterpressure maneuvers and midodrine and the limitations of treatment with beta blockers and permanent cardiac pacing.

A Case of Palpitations Due to T-Wave Oversensing Caused by Sacubitril/Valsartan.

A 58-year-old man with previous mitral/aortic mechanical-valve replacement, aortic root repair, and coronary disease developed severe left-ventricular dysfunction following AV-node ablation/single-chamber pacemaker implantation for management of atrial fibrillation. He then underwent an upgrade to cardiac resynchronization therapy with a defibrillator. To manage his heart failure better, angiotensin-receptor blocker therapy was changed to sacubitril/valsartan, after which symptomatic palpitations with T-wave oversensing occurred. The resolved T-wave oversensing and palpitations stopped upon discontinuation of sacubitril/valsartan and recurred upon rechallenge, requiring a switch back to valsartan monotherapy. Our report presents the first known case of T-wave oversensing due to sacubitril/valsartan.

Multiple Thromboembolic Events from a Left Atrial Appendage Occlusion Device.

Left atrial appendage occlusion devices are an alternative to oral anticoagulation in patients with nonvalvular atrial fibrillation who are at risk of ischemic stroke. Thromboprophylaxis after implantation is recommended, but the optimal regimen is unknown. We report a clinicopathologic case in which thrombus adherent to an incompletely endothelialized WATCHMAN device (Boston Scientific, Marlborough, MA) resulted in multiple thromboembolic events, contributing to a fatal outcome. This case illustrates uncertainties regarding the device's endothelialization process.

Feasibility of extravascular pacing with a novel substernal electrode configuration: The Substernal Pacing Acute Clinical Evaluation study.

BACKGROUND: Subcutaneous implantable cardioverter-defibrillators provide an alternative to transvenous defibrillation but require higher shock outputs and offer no antitachycardia pacing. The Substernal Pacing Acute Clinical Evaluation (SPACE) study evaluated the feasibility of pacing from an extravascular substernal location. OBJECTIVES: The primary purpose of the SPACE study was to characterize pacing from the substernal space. Secondary objectives included evaluating extracardiac stimulation and recording electrograms. METHODS: The SPACE study prospectively evaluated the feasibility of pacing with a commercially available electrophysiology catheter acutely implanted in the substernal space via minimally invasive subxiphoid access. Pacing data were collected in ≥7 vectors using constant current stimulation up to 20 mA and pulse width up to 10 ms. RESULTS: Catheter placement was successful in all 26 patients who underwent the procedure, with a mean placement time of 11.7 ± 10.1 minutes. Eighteen patients (69%) had successful ventricular capture in ≥1 tested vector. The mean pacing threshold at a pulse width of 10 ms was 7.3 ± 4.2 mA across all vectors (5.8 ± 4.4 V). Failed capture was generally associated with suboptimal catheter placement or presumed air ingression. A low level of extracardiac stimulation was observed in 1 patient. The mean R-wave amplitude ranged from 2.98 to 4.11 mV in the unipolar configuration and from 0.83 to 3.95 mV in the bipolar configuration. CONCLUSION: The data from the SPACE study demonstrate that pacing is feasible from the extravascular substernal location. A substernal electrode configuration has the potential to provide pacing in a future extravascular device without need for intracardiac hardware placement.

The use of dronedarone for recurrent ventricular tachycardia: a case report and review of the literature.

BACKGROUND: Dronedarone is a benzofuran derivative resembling amiodarone that was intended to reduce the iodine-associated tissue deposition and organ toxicity seen with the latter. The utility of dronedarone for patients with ventricular arrhythmias has not been thoroughly evaluated. We present our experience with its use to treat refractory ventricular tachycardia storm and review the literature. CASE PRESENTATION: An 85 year-old gentleman with multiple medical comorbidities including ischemic and non-ischemic cardiomyopathy with severe biventricular systolic dysfunction presented with ventricular tachycardia storm. Therapeutic options were limited given his frail medical status, failures of sotalol, mexilitine, and catheter ablation therapies along with drug-toxicities from amiodarone. Dronedarone was thus considered as off-label use following informed consent. The patient unfortunately developed fatal multisystem organ failure including acute severe hepatotoxicity from dronedarone. CONCLUSION: Novel therapies for drug-refractory ventricular arrhythmias are long overdue given the limitations of available pharmacologic and non-pharmacologic options. Off-label use of antiarrhythmic agents such as dronedarone is considered a treatment of last-resort in patients who otherwise have no therapeutic options. Given the paucity of reported cases regarding dronedarone for the treatment of ventricular tachyarrhythmias, no conclusive recommendations can be made at this time aside from words of caution. Despite the potential ventricular antiarrhythmic effects of dronedarone, careful patient evaluation is required to identify those at greatest risk of drug-related adverse events particularly in those patients with significant comorbidities such as advanced hepatic, renal, and cardiovascular disease.

Troubleshooting during a challenging high-risk pacemaker lead extraction: a case report and review of the literature.

BACKGROUND: The use of cardiac implantable electrical devices continues to increase with the validation of new beneficial indications. While the risks of device implantation decreased significantly over time, significant risk remains associated with their extraction when indicated. A high-risk pacemaker lead extraction case is described, wherein a chronically implanted lead that had perforated the right atrium was successfully removed without the need for cardiopulmonary bypass. In this report we share our approach to this challenging extraction case and describe an infrequently utilized off-pump hybrid technique that we term the "lead-inverting stitch". CASE PRESENTATION: A 74 year-old Caucasian woman with complete heart block and remote pacemaker implantation presents with a swollen and erythematous infected pacemaker pocket necessitating device extraction. Chest computerized tomographic imaging revealed a chronically perforating right atrial lead tip approximately 2 cm within the pericardial space. A successful hybrid transvenous and open surgical extraction approach was undertaken without the need for cardiopulmonary bypass; this was made possible due to a successfully positioned "lead-inverting stitch". CONCLUSION: Implantable cardiac electrical device infections are amongst the most dreaded post implant complications. Risks of device extraction are further complicated in cases of chronic lead perforations. Extraction strategies that avoid cardiopulmonary bypass initiation are preferred.