Acute pacing threshold elevation during simultaneous Micra leadless pacemaker implantation and AV node ablation: Clinical cases, computer model and practical recommendations.

BACKGROUND: In patients with refractory atrial fibrillation (AF), atrioventricular nodal (AVN) ablation and permanent pacemaker implantation is recommended. The Micra Transcatheter Pacing System (Micra) is a single chamber leadless pacemaker (LPM) and thus offers the possibility of AV node (AVN) ablation in the same procedure. Pacing threshold (PT) elevation after radiofrequency (RF) ablation is a potential complication. METHODS: We conducted a single center retrospective cohort study. Patients implanted with a Micra (n = 84) and concomitant or delayed AVN ablation (n = 12) from 2014 to 2022 were included. Two cases of acute Micra PT elevation immediately following RF AVN ablation required device retrieval and implantation of a new Micra. Procedural characteristics and electrophysiological parameters were analyzed, and a computer model was performed to determine factors responsible for acute PT elevations. RESULTS: A total of 84 patients were included. Mean age was 74 ± 10 and 48% were women. Twelve patients (14%) underwent AVN ablation. Two patients had acute PT elevation requiring device retrieval despite no direct contact of the ablation catheter with the Micra. Computer modeling shows that significant dissipated power due to electrical field coupling can occur at the tip or ring electrode if the catheter is not kept at a safe distance (≥35 mm) from the Micra when a maximum power of 100 W is delivered. CONCLUSION: Concurrent AVN ablation and Micra implantation is safe in most patients. To prevent acute PT elevation, keeping a safe distance of ≥35 mm from the tip and ring electrodes of the Micra and using lower power output may prevent this complication.

Leucocyte-derived micro-RNAs as candidate biomarkers in Brugada syndrome.

AIMS: Risk stratification for sudden cardiac death in patients with Brugada syndrome remains a major challenge. Contemporary risk prediction models have only modest predictive value. The aim of this study was to assess the role of micro-RNAs from peripheral blood as candidate biomarkers in Brugada syndrome. METHODS AND RESULTS: In this prospective study, Brugada patients and unaffected control individuals were enrolled for analysis of leucocyte-derived microRNAs (miRNAs) levels. Expression levels of 798 different circulating miRNAs were analysed on the NanoString® nCounter platform. All results were cross-validated by using a quantitative polymerase chain reaction. Micro-RNA expression levels of Brugada patients were compared with clinical data. A total of 21 definite Brugada patients (38% with a history of ventricular arrhythmia or cardiac arrest) and 30 unaffected control individuals were included in the study. Micro-RNA analysis showed a distinct expression profile in Brugada patients with 42 differentially expressed markers (38 up-regulated, 4 down-regulated miRNAs). The symptom status of Brugada patients was associated with a distinct miRNA signature. Micro-RNAs 145-5p and 585-3p were significantly up-regulated in symptomatic Brugada patients (P = 0.04). Incorporating miRNAs 145-5p and 585-3p into a multivariable model demonstrated significantly increased symptom prediction (area under the curve = 0.96; 95% confidence interval: 0.88-1.00). CONCLUSION: Brugada patients display a distinct miRNA expression profile compared with unaffected control individuals. There is also evidence that certain miRNAs (miR-145-5p and miR-585-3p) are associated with the symptom status of Brugada patients. The results suggest the principal utility of leucocyte-derived miRNAs as prognostic biomarkers for Brugada syndrome.

Superior vena cava tear during transvenous lead extraction: Medical management in hemodynamically stable patients.

INTRODUCTION: Superior vena cava (SVC) tear is the most lethal complication during transvenous lead extraction (TLE) with a mortality rate as high as 50%. Treatment involves aggressive attempts to maintain cardiac output and immediate sternotomy to localize and repair the vascular tear. Occlusion balloons have been developed to provisionally occlude the lacerated SVC and to provide hemodynamic stability allowing time for surgery. In case of mediastinal hematoma without hemodynamic instability, the strategy remains unclear. METHODS AND RESULTS: We describe two cases of SVC tear during TLE. The first case was a 60-year-old man who presented with a right ventricular single-chamber defibrillator lead fracture and innominate vein stenosis. The RV lead was removed using a laser sheath causing a mediastinal hematoma with no active bleeding during surgical exploration few hours later. The second case was a 28-year-old man that presented with a right atrial (RA) lead fracture and RV lead insulation failure in a dual-chamber defibrillator (ICD). CONCLUSION: Both the RA and RV leads were removed with mechanical sheaths, and a mediastinal hematoma was medically managed.

Acute transvenous pacemaker lead thrombosis early after implantation: A rare clinical scenario.

Symptomatic thrombus formation due to a permanent pacemaker (PM) lead is a rare complication. It could be associated with serious outcome and should be suspected in patients who present with unexplained right heart failure, dyspnea, or syncope following dual-chamber PM implantation. A timely decision to perform an echocardiographic examination, followed by medical, thrombolytic, or surgical treatment can be necessary. We describe the case of an 84-year-old man who presented with syncope and hypotension a few days after PM implantation. A transesophageal echocardiography revealed a mobile mass in the right atrium attached to the pacemaker lead. Intravenous heparin allowed a complete resolution of the thrombus.

Safety of Cefazolin Test Dose in Patients With Penicillin Allergy Just Prior to Cardiac Device Implantation: A Single-Centre Experience.

Background: Cephalosporins are the cornerstone of cardiac device infection prophylaxis. Owing to fears of cross-reactivity, penicillin-allergic patients are exposed to potentially more-toxic drugs, with decreased efficacy. We evaluated the safety of a cefazolin test dose (CTD) in self-reported penicillin-allergic patients. Methods: In this single-centre study, we evaluated consecutive patients with chart documentation of penicillin allergy undergoing cardiac device implantation, over a 2-year period. A CTD was performed if no cephalosporin allergy or severe anaphylactic reaction to penicillin had been documented. Patients were given 2 doses of 100 mg IV cefazolin, and if no allergic reaction occurred after 5 minutes, the full dose (1800 mg) was administered in the electrophysiology laboratory just before the implantation procedure. Results: A total of 2200 patients were included. The frequency of reported penicillin allergy was 9.3% (n = 204). In 80% of cases, the type of allergic reaction was not reported in medical notes or was unknown by the patient. A CTD was performed in 67.6% of patients with a penicillin allergy (n = 138). A total of 5 adverse events occurred (3.6% of patients [95% confidence interval, 1.1%-6.1%]) - 4 skin rashes and 1 tongue edema. These 5 patients became asymptomatic after antihistaminic and corticosteroid IV treatment. Even if the test dose was negative, 79% of patients also were administered vancomycin before the procedure, as it requires a 1-hour infusion prior to the CTD in the implantation procedure room. Conclusion: A CTD in most penicillin-allergic patients appears to be safe and allows its use per recommended guidelines.

Contexte: Les céphalosporines sont la pierre angulaire de la prophylaxie des infections des dispositifs cardiaques. En raison du risque appréhendé de réactivité croisée, les patients allergiques à la pénicilline se trouvent exposés à des médicaments potentiellement plus toxiques, qui s'avèrent aussi moins efficaces. Nous avons évalué l'innocuité d'une dose d'essai de céfazoline chez des patients qui s'étaient dits allergiques à la pénicilline. Méthodologie: Dans cette étude monocentrique, nous avons suivi pendant deux ans des patients consécutifs dont le dossier médical faisait état d'une allergie à la pénicilline et chez qui un dispositif cardiaque devait être implanté. Une dose d'essai de céfazoline a été administrée aux patients sans antécédents documentés d'allergie aux céphalosporines ou de réaction anaphylactique sévère à la pénicilline. Deux doses de 100 mg de céfazoline ont été administrées par voie intraveineuse. En l'absence de réaction allergique après cinq minutes, les patients recevaient la dose complète (1 800 mg) au laboratoire d'électrophysiologie juste avant l'implantation du dispositif cardiaque. Résultats: Au total, 2 200 patients ont été inscrits à l'étude. Le taux de signalement de l'allergie à la pénicilline était de 9,3 % (n = 204). Dans 80 % des cas, le type de réaction allergique n'a pas été précisé dans les notes médicales ou était inconnu du patient. Une dose d'essai de céfazoline a été administrée à 67,6 % des patients allergiques à la pénicilline (n = 138). Au total, cinq événements indésirables se sont produits (3,6 % des patients [intervalle de confiance à 95 % : 1,1-6,1 %]) ­ quatre éruptions cutanées et un œdème de la langue. Les cinq patients touchés par ces événements sont devenus asymptomatiques après avoir reçu un antihistaminique et un corticostéroïde par voie intraveineuse. Même en l'absence de réaction allergique à la dose d'essai, 79 % des patients ont reçu de la vancomycine avant l'intervention, cet agent devant être administré par perfusion durant une heure avant la dose d'essai de céfazoline dans la salle d'intervention. Conclusion: Chez la plupart des patients allergiques à la pénicilline, une dose d'essai de céfazoline semble sans danger et permet d'avoir recours à ce médicament conformément aux lignes directrices.

Left common carotid artery to left innominate vein arteriovenous fistula after transvenous laser lead extraction.

Transvenous lead extraction (TLE) is used for lead infection, lead debulking, venous recanalization and device upgrades. Lead extraction is performed using specialized tools including locking stylets, mechanical or rotating sheaths, femoral snares or laser sheaths. The most feared complications associated with lead extraction are bleeding, vascular tear, cardiac avulsion and tamponade. Despite technological progress, the incidence of major procedural complications including death remains slightly above 1%. This case depicts an asymptomatic left common carotid artery (LCCA) to left innominate vein arteriovenous fistula (AVF) after laser-assisted TLE successfully treated with an endovascular covered stent.

Lead extraction of an unintentional pacemaker lead implantation in the left ventricle from the left subclavian artery.

INTRODUCTION: Inadvertent implantation from the subclavian/axillary arteries is uncommon and has been rarely reported. Complications are frequent, mainly driven by thromboembolic events. Lead extraction, depending on the dwell time may be challenging and associated with thromboembolic events Case Report: We report the case of an 87-year-old man who had involuntarily pacemaker lead implanted into the left ventricle through the left subclavian artery. An extraction procedure was performed with surgical dissection to the artery and simple traction of the probe without complication. CONCLUSION: Percutaneous lead extraction using surgical dissection is a therapeutic option for less than one year old left ventricle inadvertent lead implantation.

DREAM-ICD-II Study.

BACKGROUND: Regulatory authorities of most industrialized countries recommend 6 months of private driving restriction after implantation of a secondary prevention implantable cardioverter-defibrillator (ICD). These driving restrictions result in significant inconvenience and social implications. This study aimed to assess the incidence rate of appropriate device therapies in contemporary recipients of a secondary prevention ICD. METHODS: This retrospective study at 3 Canadian tertiary care centers enrolled consecutive patients with new secondary prevention ICD implants between 2016 and 2020. RESULTS: For a median of 760 days (324, 1190 days), 721 patients were followed up. The risk of recurrent ventricular arrhythmia was highest during the first 3 months after device insertion (34.4%) and decreased over time (10.6% between 3 and 6 months, 11.7% between 6 and 12 months). The corresponding incidence rate per 100 patient-days was 0.48 (95% CI, 0.35-0.64) at 90 days, 0.28 (95% CI, 0.17-0.45) at 180 days, and 0.21 (95% CI, 0.13-0.33) between 181 and 365 days after ICD insertion (P<0.001). The cumulative incidence of arrhythmic syncope resulting in sudden cardiac incapacitation was 1.8% within the first 90 days and subsequently dropped to 0.4% between 91 and 180 days (P<0.001) after ICD insertion. CONCLUSIONS: The incidence rate of appropriate therapies resulting in sudden cardiac incapacitation in contemporary recipients of a secondary prevention ICD is much lower than previously reported and declines significantly after the first 3 months. Lowering driving restrictions to 3 months after the index cardiac event seems safe, and revision of existing guidelines should be considered in countries still adhering to a 6-month period. Existing restrictions for private driving after implantation of a secondary prevention ICD should be reconsidered.

Twiddler Syndrome without Lead Dislodgment Discovered by Remote Monitoring.

Twiddler syndrome is an uncommon yet dangerous phenomenon usually resulting in lead displacement with loss of capture of cardiac implantable electronic devices. In this case report, we present an interesting case of Twiddler syndrome without lead dislodgment which was detected by an alert triggered by an increase in impedance on remote monitoring.

Ventricular Arrhythmia in Septal and Apical Hypertrophic Cardiomyopathy: The French-Canadian Experience.

Background: Apical hypertrophic cardiomyopathy (aHCM) is thought to have a more benign clinical course compared to septal HCM (sHCM), but most data have been derived from Asian cohorts. Comparative data on clinical outcome in Caucasian aHCM cohorts are scarce, and the results are conflicting. The aim of this study was to estimate the prevalence and outcome of aHCM in French-Canadians of Caucasian descent. Methods and results: We conducted a retrospective, single-center cohort study. The primary endpoint was a composite of documented sustained ventricular arrhythmia (VA), appropriate ICD therapy, arrhythmogenic syncope, cardiac arrest, or all-cause mortality. A total of 301 HCM patients (65% males) were enrolled including 80/301 (27%) with aHCM and 221/301 (73%) with sHCM. Maximal wall thickness was similar in both groups. Left ventricular apical aneurysm was significantly more common in aHCM (10 vs. 0.5%; p < 0.001). The proportion of patients with myocardial fibrosis ≥ 15% of the left ventricular mass was similar between aHCM and sHCM (21 vs. 24%; p = 0.68). Secondary prevention ICDs were more often implanted in aHCM patients (16 vs. 7%; p = 0.02). The primary endpoint occurred in 26% of aHCM and 10.4% of sHCM patients (p = 0.001) and was driven by an increased incidence of sustained VA (10 vs. 2.3%; p = 0.01). Multivariate analysis identified apical aneurysm and a phenotype of aHCM as independent predictors of the primary endpoint and the occurrence of sustained ventricular tachycardia. Unexplained syncope and a family history of sudden cardiac death were additional predictors for sustained VA. Apical HCM was associated with an increased risk of ventricular arrhythmia even when excluding patients with apical aneurysm. Conclusions: The phenotype of apical HCM is much more common in French-Canadians (27%) of Caucasian descent compared to other Caucasian HCM populations. Apical HCM in French-Canadians is associated with an increased risk for ventricular arrhythmia.

Findings of remote monitoring of implantable cardioverter defibrillators during the COVID-19 pandemic.

BACKGROUND: Monitoring of cardiac implantable electronic devices was highly impacted by the COVID-19 pandemic considering the high volume of in-person visits for regular follow-up. Recent recommendations highlight the important role of remote monitoring to prevent exposure to the virus. This study compared remote monitoring of implantable cardioverter defibrillators (ICDs) in patients whose in-person annual visit was substituted for a remote monitoring session with patients who were already scheduled for a remote monitoring session. METHODS: This was a cross-sectional observational study of 329 consecutive patients between 20 March and 24 April 2020. Group 1 included 131 patients whose in-person annual visit was substituted for a remote monitoring session. Group 2 included 198 patients who underwent a remote monitoring session as scheduled in their usual device follow-up. The time interval since the last in-person visit was 13.3 ± 3.2 months in group 1 and 5.9 ± 1.7 months in group 2 (P < .01). RESULTS: In group 1, 15 patients (11.5%) experienced a clinical event compared to 15 patients (7.6%) in group 2 (P = .25). Nineteen patients (14.5%) required a physician intervention in group 1 compared to 19 patients (9.6%) in group 2 (P = .22). Two patients (1.5%) in group 1 and four patients (2.0%) in group 2 required an early in-person follow-up visit during the pandemic (P > .99). CONCLUSION: Remote monitoring of ICDs is useful to identify clinical events and allows physicians to treat patients appropriately during the COVID-19 pandemic regardless of the time interval since their last in-person visit. It reduces significantly in-person visit for regular follow-up.

Driving Restrictions and Early Arrhythmias in Patients Receiving a Primary-Prevention Implantable Cardioverter-Defibrillator (DREAM-ICD) Study.

BACKGROUND: Current guidelines recommend 4 weeks of private driving restriction after implantation of a primary-prevention implantable cardioverter-defibrillator (ICD). These driving restrictions result in significant inconvenience and social implications. Advances in medical treatment and ICD programming have lowered the overall rate of device therapies. The objective of this study was to assess the incidence of ICD therapies at 30, 60, and 180 days after implantation. METHODS: Driving Restrictions and Early Arrhythmias in Patients Receiving a Primary-Prevention Implantable Cardioverter-Defibrillator (DREAM-ICD) was a retrospective cohort study conducted at 2 Canadian university centres enrolling patients with new implantation of a primary-prevention ICD. Device programming was standardised according to current guidelines. A total of 803 patients were enrolled. RESULTS: The cumulative rates of appropriate ICD therapies at 30, 60, and 180 days were 0.12%, 0.50%, and 0.75%, respectively. There was no syncope during the first 6 months. The median duration to the first appropriate ICD therapy was 208 (range 23-1109) days after implantation. The rate of inappropriate ICD therapies at 30 days was only 0.2%. Overall, < 13.6% of all appropriate ICD therapies occurred within the first 6 months after implantation. CONCLUSIONS: The rate of appropriate ICD therapies within the first 30 days after device insertion is extremely low in contemporary primary prevention cohorts with guideline-concordant device programming. There was no increased risk for ventricular arrhythmia early after ICD insertion. The results of DREAM-ICD suggest the need for a revision of the existing driving restrictions for primary-prevention ICD recipients.

A Novel Wearable Device for Continuous Ambulatory ECG Recording: Proof of Concept and Assessment of Signal Quality.

Diagnosis of arrhythmic disorders is challenging because of their short-lasting, intermittent character. Conventional technologies of noninvasive ambulatory rhythm monitoring are limited by modest sensitivity. We present a novel form of wearable electrocardiogram (ECG) sensors providing an alternative tool for long-term rhythm monitoring with the potential of increased sensitivity to detect intermittent or subclinical arrhythmia. The objective was to assess the signal quality and R-R coverage of a wearable ECG sensor system compared to a standard 3-lead Holter. In this phase-1 trial, healthy individuals underwent 24-h simultaneous rhythm monitoring using the OMsignal system together with a 3-lead Holter recording. The OMsignal system consists of a garment (bra or shirt) with integrated sensors recording a single-lead ECG and an acquisition module for data storage and processing. Head-to-head signal quality was assessed regarding adequate P-QRS-T distinction and was performed by three electrophysiologists blinded to the recording technology. The accuracy of signal coverage was assessed using Bland-Altman analysis. Fifteen individuals underwent simultaneous 24-h recording. Signal quality and accuracy of the OMgaments was equivalent to Holter-monitoring (84% vs 93% electrophysiologists rating, p = 0.06). Signal coverage of R-R intervals showed a very close overlay between the OMsignal system and Holter signals, mean difference in heart rate of 2 5 bpm. The noise level of OMgarments was comparable to Holter recording. OMgarments provide high signal quality for adequate rhythm analysis, representing a promising novel technology for long-term non-invasive ECG monitoring.

Validation of a novel single lead ambulatory ECG monitor - Cardiostat™ - Compared to a standard ECG Holter monitoring.

BACKGROUND: Cardiostat™ is a single lead ambulatory ECG monitor. Recording is made through 2 electrodes positioned in a lead 1-like configuration. We first validated its accuracy for atrial fibrillation detection compared to a 12-lead ECG. In the second phase of the study, arrhythmia detection accuracy was compared between Cardiostat™ ambulatory ECG and a standard 24 h Holter ECG monitoring. METHOD/RESULTS: Phase one of the study included patients undergoing cardioversion for atrial fibrillation (AF) or atrial flutter. Cardiostat™ tracings were compared with standard 12-lead ECG. In the second phase, patients undergoing 24 h ambulatory Holter ECG monitoring for control or suspicion of atrial fibrillation (AF) were included. Simultaneous Holter monitoring and Cardiostat™ ECG recordings were performed. Tracings were analysed and compared. Two hundred twelve monitoring were compared. AF was diagnosed in 73 patients. Agreement between Cardiostat™ ECG and standard Holter monitoring was 99% for AF detection with kappa = 0.99. Kappa correlation for atrial flutter detection was only moderate at 0.51. AF burden was similar in both recordings. Noise hindered analysis in a greater proportion with Cardiostat™ compared to Holter ambulatory ECG (8.5 vs 3.8%). CONCLUSION: Cardiostat™ ambulatory ECG device showed excellent correlation with the standard Holter ECG monitoring for AF detection. Holter monitoring was however superior to discriminate premature atrial and ventricular beats and to qualify the morphology of PVCs since it has more vectors for analysis. Added value of Cardiostat™ includes longer monitoring duration, less cumbersome installation and water resistance.

Cardiac Implantable Electronic Device Infection: Detailed Analysis of Cost Implications.

BACKGROUND: Infections of cardiac implantable electronic devices (CIED) are associated with significant morbidity and mortality. Despite many preventive measures, this condition is associated with significant costs for the health care system. METHODS: We retrospectively analyzed all infection cases referred for lead extraction at a single university hospital over 1 year (2015-2016). We then calculated all costs related to the infection episode per patient using hospital databases and charts review. RESULTS: Thirty-eight patients with CIED infections (29% women-mean age 71 ± 14 years) were referred for lead extraction (27 pocket infections, 11 endocarditis). Devices were mainly pacemakers (60%). When the pathogen was identified, Staphylococcus aureus methicillin sensitive was the main cause. Extraction was performed in all but 3 cases (92%). One death occurred in the nonextracted group. Respective durations of hospitalization and intravenous and antibiotic administration for patients undergoing extraction were 21 and 36 days. The calculated mean total cost for CIED infection management was CAD$29,907 (median: 26,879; range: CAD$4,827-$62,585). Mean hospital charges were CAD$12,291, accounting for 41% of the total costs. CONCLUSIONS: This study represents the first analysis of the direct costs associated with lead extraction in Canada. Device infections are associated with significant costs and increased morbidity. Any preventive measure will have a significant impact on the economic burden of the health care system and patient outcome after lead extraction.

Sudden cardiac death and obesity.

For individuals and the society as a whole, the increased risk of sudden cardiac death in obese patients is becoming a major challenge, especially since obesity prevalence has been increasing steadily around the globe. Traditional risk factors and obesity often coexist. Hypertension, diabetes, obstructive sleep apnea and metabolic syndrome are well-known risk factors for CV disease and are often present in the obese patient. Although the bulk of evidence is circumstantial, sudden cardiac death and obesity share common traditional CV risk factors. Structural, functional and metabolic factors modulate and influence the risk of sudden cardiac death in the obese population. Other risk factors such as left ventricular hypertrophy, increased number of premature ventricular complexes, altered QT interval and reduced heart rate variability are all documented in both obese and sudden cardiac death populations. The present review focuses on out-of-hospital sudden cardiac death and potential mechanisms leading to sudden cardiac death in this population.