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Sinus arrest and inappropriate sinus bradycardia are sinus node dysfunction (SND), which cause loss of consciousness. Cardiac pacing is recommended in patients with symptoms, such as syncope or dizziness. Several conditions can induce these arrhythmias; however, whether or not intracranial infectious diseases, such as herpes simplex encephalitis (HSE), can cause secondary SND is unclear. We encountered a patient with sinus arrest and transient sinus bradycardia associated with HSE. Since cardiac pause was never monitored and the bradycardia improved after HSE treatment, HSE was suspected to be the cause of SND. Although the underlying mechanisms have not yet been completely elucidated, HSE may cause secondary SND.

We herein report a 76-year-old woman with situs inversus and dextrocardia who underwent pacemaker implantation for sick sinus syndrome. Situs inversus with dextrocardia, which is frequently associated with cardiovascular malformation, is a rare congenital malformation wherein the thoracic and abdominal viscera are inverted compared with their normal positions. This renders the implantation of cardiac devices an arduous task. We therefore decided to gather preoperative anatomical information on patients with situs inversus and dextrocardia. We used three-dimensional computed tomography to collect preoperative information in order to facilitate the safe implantation of cardiac devices.

Clinically significant bradycardia is an uncommon problem in children, but one that can cause significant morbidity and sometimes necessitates implantation of a pacemaker. The most common causes of bradycardia are complete heart block (CHB), which can be congenital or acquired, and sinus node dysfunction, which is rare in children with structurally normal hearts. Pacemaker is indicated as therapy for the majority of children with CHB, and while early mortality is lower in postnatally diagnosed CHB than in fetal CHB, it is still up to 16%. In young children, less invasive transvenous pacemaker systems can be technically challenging to place and carry a high risk of complications, often necessitating surgical epicardial pacemaker placement, which usually entails a median sternotomy. We report three cases of pediatric patients referred for pacemaker implantation for different types of bradycardia, treated at our institution with oral albuterol with therapeutic results that avoided the need for surgical pacemaker implantation at that time., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Empty sella syndrome (ESS) is characterized by the herniation of cerebrospinal fluid into the sella, which results in the enlargement of the sella and compression of the pituitary gland. ESS commonly accompanies pituitary dysfunction and abnormal secretion of one or more hormones, which manifests as symptoms like cold intolerance, fatigue, and memory impairment. However, the occurrence of sick sinus syndrome (SSS) in ESS has not been reported. A 66-year-old female patient was admitted to the hospital with complaints of dizziness and fatigue. Electrocardiogram (ECG) revealed sinus arrest, junctional escape rhythm, and a heart rate of 40 bpm. Then, the patient was diagnosed with SSS. Thyroid function test indicated decreased thyroxine levels and slightly elevated thyroid-stimulating hormone levels. Additionally, hyposecretion of cortisol and insulin-like growth factors was observed. Magnetic resonance imaging of the pituitary gland confirmed the diagnosis of ESS. The patient was treated with hydrocortisone and euthyrox, relieving the symptoms of dizziness and fatigue. Thyroid function tests during the follow-up period showed normal hormone levels, and ECG examination revealed no abnormalities.

Background: Single chamber atrial pacemaker should be sufficient for patients with sinus node dysfunction (SND) with normal atrioventricular (AV) conduction. However, most patients undergo dual chamber pacemaker implantation because of concern of new onset AV block. The annual incidence of new AV block has been reported from 0.6 to 4.4 % in various studies., Objectives: Our aim is to assess mode survival in sinus node dysfunction with normal AV conduction patients implanted with AAIR., Methods: Patients who underwent single chamber atrial pacemaker implantation for SND with normal AV conduction between January 2014 and December 2021 were followed up for pacemaker device change, new onset AV block, bundle branch block, atrial fibrillation (AF), lead complications, reoperation and mortality rate., Results: A total of 113 patients underwent single chamber atrial pacemaker implantation for SND during the study period. Mean age was 55.6 ± 12.7 years. During a mean follow up of 48.7 ± 24.9 months, none of the patients required pacemaker device change to VVIR/DDDR. Nine patients underwent reoperation, 5 for lead dislodgment, 1 for high threshold, 1 for pocket site erosion and 3 for pulse generator change. None developed AV block or AF with slow ventricular rate. Only 4 patients developed AF (3 paroxysmal,1 permanent). There were 3 deaths during follow up and none were sudden deaths., Conclusion: Single chamber atrial pacing is an acceptable mode of pacing in patients with SND in developing countries. Development of AV conduction abnormalities is rare in this relatively younger population., Competing Interests: Declaration of competing interest None for any of the authors., (Copyright © 2023 Cardiological Society of India. Published by Elsevier, a division of RELX India, Pvt. Ltd. All rights reserved.)

Aims: Patients with systemic right ventricles are at high risk of sudden cardiac death. Arrhythmia is a significant risk factor. Routine Holter monitoring is opportunistic with poor adherence. The aim of this study was to determine if continuous rhythm monitoring with an implantable loop recorder (ILR) could allow early detection of clinically important arrhythmias., Methods and Results: Implantable loop recorder implantation was offered to patients with atrial switch repair for transposition of the great arteries. Recordings were made with symptoms or, automatically for pauses, significant bradycardia or tachycardia and reviewed by the multi-disciplinary team. Twenty-four out of 36 eligible patients underwent ILR implantation with no complication. Forty-two per cent had preserved ventricular function, 75% were NYHA functional class I, 88% had low sudden cardiac death risk, 33% had previous intra-atrial re-entrant tachycardia (IART), and none had known conduction disease. Eighteen out of 24 (75%) patients made 52 recordings (52% automated) over 39.5 months (1.6-72.5). Thirty-two out of 52 (62%) recordings in 15/24 (63%) of the cohort were clinically significant and included sinus node disease (two patients), atrioventricular block (two patients), IART (seven patients), and IART with sinus node disease or atrioventricular block (four patients). Implantable loop recorder recordings prompted medication change in 11 patients [beta-blockers (n = 9), anti-coagulation (n = 5), and stopping anti-coagulation (n = 1)] and device therapy recommendation in seven patients [five pacemakers (three: atrioventricular block) and two defibrillators]. Two patients declined intervention; one suffered an arrhythmic death. Intra-atrial re-entrant tachycardia and clinically relevant conduction disease were detected in patients irrespective of sudden cardiac death risk., Conclusion: Continuous monitoring with an ILR in patients with systemic right ventricle following atrial switch detects clinically relevant arrhythmias that impact decision-making. In this cohort, clinically relevant arrhythmias did not correlate with sudden cardiac death risk., Competing Interests: Conflict of interest: Dr Stephen Murray has received honoraria from Acutus Medical and Boston Scientific. Dr Louise Coats receives funding from the British Heart Foundation and collaborates with CardiacSense. All remaining authors have declared no conflicts of interest., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Sinus node dysfunction (SND) is a multifaceted disorder most prevalent in older individuals, but may also occur at an earlier age. In most cases, the SND diagnosis is ultimately established by documenting its ECG manifestations. EPS has limited utility. The treatment strategy is largely dictated by symptoms and ECG manifestations. Not infrequently, both bradycardia and tachycardia coexist in the same patients, along with other diseases common in the elderly (e.g., hypertension, coronary artery disease), thereby complicating treatment strategy. Prevention of the adverse consequences of both bradyarrhythmia and tachyarrhythmia is important to reduce susceptibility to syncope, falls, and thromboembolic complications., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Aims: In patients with prolonged atrioventricular (AV) conduction and pacemaker (PM) indication due to sinus node disease (SND) or intermittent AV-block who do not need continuous ventricular pacing (VP), it may be difficult to determine which strategy to adopt. Currently, the standard of care is to minimize unnecessary VP by specific VP avoidance (VPA) algorithms. The superiority of this strategy over standard DDD or DDD rate-responsive (DDD/DDDR) in improving clinical outcomes is controversial, probably owing to the prolongation of the atrialventricular conduction (PR interval) caused by the algorithms. Conduction system pacing (CSP) may offer the most physiological-VP approach, providing appropriate AV conduction and preventing pacing-induced dyssynchrony., Methods and Results: PhysioVP-AF is a prospective, controlled, randomized, single-blind trial designed to determine whether atrial-synchronized conduction system pacing (DDD-CSP) is superior to standard DDD-VPA pacing in terms of 3-year reduction of persistent-AF occurrence. Cardiovascular hospitalization, quality-of-life, and safety will be evaluated. Patients with indication for permanent DDD pacing for SND or intermittent AV-block and prolonged AV conduction (PR interval > 180 ms) will be randomized (1:1 ratio) to DDD-VPA (VPA-algorithms ON, septal/apex position) or to DDD-CSP (His bundle or left bundle branch area pacing, AV-delay setting to control PR interval, VPA-algorithms OFF). Approximately 400 patients will be randomized in 24 months in 13 Italian centres., Conclusion: The PhysioVP-AF study will provide an essential contribution to patient management with prolonged AV conduction and PM indication for sinus nodal disease or paroxysmal 2nd-degree AV-block by determining whether CSP combined with a controlled PR interval is superior to standard management that minimizes unnecessary VP in terms of reducing clinical outcomes., Competing Interests: Conflict of interest: G.D.: fee for lectures and proctorship for conduction system pacing by Biotronik Italia; G.K., Le.M.: fee for proctorship for conduction system pacing by Biotronik and Medtronic Italia; M.Z.: received speaker’s fees from Abbott Medical, Biotronik, and Boston Scientific; F.N.: fees for statistical and methodological consulting from Abbott Medical. All other authors have no conflicts to declare., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Although the anatomical basis of the pathogenesis of sinus node dysfunction (SND) and atrial fibrillation (AF) is located primarily in the left and right atria, increasing evidence suggests a strong correlation between SND and AF, in terms of both clinical presentation and formation mechanisms. However, the exact mechanisms underlying this association are unclear. The relationship between SND and AF may not be causal, but is likely to involve common factors and mechanisms, including ion channel remodeling, gap junction abnormalities, structural remodeling, genetic mutations, neuromodulation abnormalities, the effects of adenosine on cardiomyocytes, oxidative stress, and viral infections. Ion channel remodeling manifests primarily as alterations in the "funny" current (I f ) and Ca 2+ clock associated with cardiomyocyte autoregulation, and gap junction abnormalities are manifested primarily as decreased expression of connexins (Cxs) mediating electrical impulse propagation in cardiomyocytes. Structural remodeling refers primarily to fibrosis and cardiac amyloidosis (CA). Some genetic mutations can also cause arrhythmias, such as SCN5A, HCN4, EMD, and PITX2. The intrinsic cardiac autonomic nervous system (ICANS), a regulator of the heart's physiological functions, triggers arrhythmias.In addition, we discuss arrhythmias caused by viral infections, notably Coronavirus Disease 2019 (COVID-19). Similarly to upstream treatments for atrial cardiomyopathy such as alleviating CA, ganglionated plexus (GP) ablation acts on the common mechanisms between SND and AF, thus achieving a dual therapeutic effect., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: Operative repair of partial anomalous pulmonary venous connection (PAPVC) remains challenging due to risks of sinus node dysfunction, baffle obstruction, and superior vena cava (SVC) obstruction., Methods: Traditional or modified Warden procedures were performed in 75 of 318 consecutive patients (24%) with PAPVC repaired surgically at our institution during 1993 to 2021. Clinical characteristics, echocardiography data, operative details, and early and late outcomes were collected. Cumulative incidence of reintervention and Kaplan-Meier survival analysis are reported., Results: Median age was 39 years (interquartile range, 21-57 years). Fifty-nine (79%) had normal sinus rhythm preoperatively. Seventeen (23%) had intact atrial septa. Traditional and modified Warden procedures were performed in 15 (20%) and 60 (80%), respectively. Frequent concomitant procedures included 15 (20%) tricuspid valve repairs and 12 (16%) atrial fibrillation procedures. There were no early deaths. Postoperative complications included atrial fibrillation in 17 (23%), sinus node dysfunction in 15 (20%), pneumothorax in 3 (4%), pleural effusion in 2 (3%), and pacemaker implantation in 1 (1%). At hospital discharge, sinus node dysfunction persisted in 8 (11%). Over a median follow-up of 6 years (interquartile range, 4-10 years), baffle obstruction developed in 1 patient and SVC obstruction developed in 7. None required reoperation and 6 were treated with SVC stents. At 1, 5, and 10 years, the cumulative incidence of reintervention was 5%, 7%, and 14%, and survival was 99%, 94%, and 94%, respectively., Conclusions: Traditional and modified Warden procedures can be performed with satisfactory early and late survival. Persistent sinus node dysfunction and need for permanent pacing are low. Late SVC obstruction is uncommon and can often be managed nonoperatively., (Copyright © 2022 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Atrial fibrillation catheter ablation (AFCA) should be considered as a strategy to avoid pacemaker (PM) implantation for patients with bradycardia-tachycardia syndrome (BTS), but lack of evidence is remarkable., Methods: Our aim was to conduct a random-effects model meta-analysis on safety and efficacy data from controlled trials and observational studies. We compared atrial fibrillation (AF) recurrence, AF progression, procedural complication, additional procedure, cardiovascular death, cardiovascular hospitalization, heart failure and stroke in patients undergoing AFCA vs. PM implantation., Results: PubMed/MEDLINE, Cochrane Database and Google Scholar were screened, and four retrospective studies were selected. A total of 776 patients (371 in the AFCA group, 405 in the PM group) were included. After a median follow-up of 67.5 months, lower AF recurrence [odds ratio (OR) 0.06, confidence interval (CI) 0.02-0.18, I2 = 82.42%, P < 0.001], AF progression (OR 0.12, CI 0.06-0.26, I2 = 0%, P < 0.001), heart failure (OR 0.12, CI 0.04-0.34, I2 = 0%, P < 0.001), and stroke (OR 0.30, CI 0.15-0.61, I2 = 0%, P = 0.001) were observed in the AFCA group. No differences were observed in cardiovascular death and hospitalization (OR 0.48, CI 0.10-2.28, I2 = 0%, P = 0.358 and OR 0.43, CI 0.14-1.29, I2 = 87.52%, P = 0.134, respectively). Higher need for additional procedures in the AFCA group was highlighted (OR 3.65, CI 1.51-8.84, I2 = 53.75%, P < 0.001). PM implantation was avoided in 91% of BTS patients undergoing AFCA., Conclusions: AFCA in BTS patients seems to be more effective than PM implantation in reducing AF recurrence and PM implantation may be waived in most BTS patients treated by AFCA. Need for additional procedures in AFCA patients is balanced by long-term benefit in clinical end points., (Copyright © 2022 Italian Federation of Cardiology - I.F.C. All rights reserved.)

Short QT syndrome (SQTS) represents a diagnosis challenge where the symptoms may vary from palpitations in an otherwise asymptomatic patient to sudden death. Is a recently discovered rare channelopathy, identified by Gussak in 2000, characterized by short QT intervals on the electrocardiogram and a tendency to develop atrial and ventricular arrhythmias in the absence of structural heart disease, hyperkalemia, hypercalcemia, hyperthermia, acidosis and endocrine disorders. We present the case of a 16-year-old patient with short QT-type channelopathy, who presented with sinus arrest and junctional rhythm, who later developed atrial tachycardia and atrial flutter., (Copyright © 2022. Published by Elsevier Inc.)

Immune checkpoint inhibitor (ICI)-induced myocarditis is a potentially life-threatening adverse event. We herein report a rare case of sick sinus syndrome (SSS) co-occurring with ICI-associated myocarditis. A 71-year-old woman with lung cancer undergoing pembrolizumab monotherapy was admitted owing to a fever, worsening kidney function, and sinus bradycardia. She was diagnosed with multi-organ immune-related adverse events, including myocarditis. Pulse steroid therapy was initiated immediately under the support of a temporary pacemaker, which resulted in the resolution of SSS in a few days. Biopsy specimens of the endomyocardium showed active myocarditis. Thus, we should be aware that SSS can co-occur with ICI-induced myocarditis.

Background: Systemic sclerosis is a multisystemic character autoimmune disease. It is characterized by vascular dysfunction and progressive fibrosis affecting mainly the skin but also different internal organs. All heart structures are commonly affected, including the pericardium, myocardium, and conduction system. However, tachycardia-bradycardia syndrome is not common in the literature as a cardiac complication of systemic sclerosis. Case presentation We report a case of tachycardia-bradycardia syndrome in a 46-year-old Moroccan woman followed for systemic sclerosis with cutaneous, vascular, and articular manifestations. The diagnosis was based mainly on patient-reported symptoms and electrocardiogram data. A permanent pacemaker was implanted, allowing the introduction of beta-blockers with good outcomes., Conclusions: This case aims to show that even minor electrocardiogram abnormalities should be monitored in this group of patients, preferably by 24-hour ambulatory electrocardiogram because they could be a good indicator of the activity and progression of cardiac fibrosis., (© 2022. The Author(s).)

A 33-year-old woman with Sick Sinus Node syndrome and persistent atrial fibrillation underwent a Maze IV procedure in order treat atrial fibrillation and concomitant atrial epicardial implantation of a leadless pacemaker to manage her sinus node insufficiency. Last option has been chosen due to rare pocket complication after previous classic dual-chamber pacemaker implantation., (© The Author(s) 2022. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery.)

We herein report two cases of potentially life-threatening arrhythmia due to hyperkalemia triggered by the excessive consumption of "Hoshi-Imo" (dried sweet potato). Both patients with chronic renal disease on renin-angiotensin-aldosterone system inhibitors presented at the emergency room with non-specific symptoms. Electrocardiograms revealed potentially life-threatening arrhythmia due to hyperkalemia in both cases: sinus arrest with a ventricular escape rhythm, tall and peaked T waves; and a widened QRS complex in a nearly sine-wave configuration without discernible P wave. Both patients fully recovered after intensive care for hyperkalemia. Physicians should recognize the excessive consumption of "Hoshi-Imo" may lead to the development of life-threatening arrhythmia, especially in patients with risk factors for hyperkalemia.

We report a case of a previously healthy 47-year-old female with syncope due to multiple episodes of nodal dysfunction and asystole. During these brief episodes, she was hypoxic in the mid-80's as a result of COVID-19 pneumonia. The patient was admitted and treated for viral pneumonia and found to have normal electrocardiograms (ECG's), normal troponin levels and a normal echocardiogram during her hospital stay. As she recovered from COVID-19, no further episodes of bradycardia or bradyarrhythmia were noted. This case highlights a growing body of evidence that arrhythmias, specifically bradycardia, should be anticipated by prehospital providers as a potential cardiac complication of SARS-CoV-2 infection.

As the established surgical mitral valve replacement (MVR) expands toward various contemporary techniques and access routes, the predictors and burden of procedure-related complications including the need for permanent pacemaker (PPM) implantation need to be identified. Digital databases were searched systematically to identify studies reporting the incidence of PPM implantation after MVR. Detailed study and patient-level baseline characteristics including the type of study, sample size, follow-up, number of post-MVR PPM implantations, age, gender, and baseline ECG abnormalities were abstracted. A total of 12 studies, recruiting 37,124 patients were included in the final analysis. Overall, 2820 (7.6%) patients required a PPM with the net rate ranging from 1.7% to 10.96%. Post-MVR atrioventricular (AV) block was the most commonly observed indication for PPM, followed by sinoatrial (SA) node dysfunction, and bradycardia. Age, male gender, pre-existing comorbid conditions, prior CABG, history of arrhythmias or using antiarrhythmic drugs, atrial fibrillation ablation, and double valve replacement were predictors of PPM implantation post-MVR. Age, male gender, comorbid conditions like diabetes and renal impairment, prior CABG, double valve replacement, and antiarrhythmic drugs served as positive predictors of PPM implantation in patients undergoing MVR., (© 2022 Wiley Periodicals LLC.)

Dextrocardia is a congenital abnormal position of the heart in which the main part of the heart is in the right chest, and the long axis of the heart points to the lower right. Cases of a combination of dextrocardia and sick sinus syndrome are rare. A 65-year-old female patient was admitted to hospital with palpitations and dizziness for 1 week. Mirror-image dextrocardia and sick sinus syndrome were diagnosed by an electrocardiogram, echocardiography, Holter monitoring, and X-rays. Finally, we successfully implanted a dual-chamber pacemaker into the patient. The patient had an uneventful recovery and was discharged when her symptoms had greatly improved 1 week later. When dextrocardia is present, using active fixation leads in the atrial and ventricular leads is easier for finding the pacing position with optimal sensing and pacing thresholds, and they reduce the incidence of falling off.

Background and Objectives : Drug-related bradyarrhythmia is a well-documented major adverse event among beta-blocker users and a potential cause for hospitalization or additional interventions. Whether beta-blocker use is associated with specific bradyarrhythmia presentations, and how this relates to other predisposing factors, is not well known. We aim to evaluate the association between beta-blocker use and the type of atrioventricular (AV) conduction disorder in patients with symptomatic bradycardia. Materials and Methods : We conducted a retrospective cohort study on 596 patients with a primary diagnosis of symptomatic bradyarrhythmia admitted to a single tertiary referral center. Of the cases analyzed, 253 patients were on beta-blocker treatment at presentation and 343 had no bradycardic treatment. We analyzed demographics, clinical and paraclinical parameters in relation to the identified AV conduction disorder. A multivariate regression analysis was performed to explore factors associated with beta-blocker use. Results : Of the 596 patients (mean age 73.9 ± 8.8 years, 49.2% male), 261 (43.8%) had a third-degree AV block, 92 (15.4%) had a second-degree AV block, 128 (21.5%) had slow atrial fibrillation, 93 (15.6%) had sick sinus syndrome and 21 (3.5%) had sinus bradycardia/sinus pauses. Beta-blocker use was associated with the female gender ( p < 0.001), emergency admission ( p < 0.001), dilated cardiomyopathy ( p = 0.003), the lower left ventricular ejection fraction ( p = 0.02), mitral stenosis ( p = 0.009), chronic kidney disease ( p = 0.02), higher potassium levels ( p = 0.04) and QRS duration > 120 ms ( p = 0.02). Slow atrial fibrillation (OR = 4.2, p < 0.001), sick sinus syndrome (OR = 2.8, p = 0.001) and sinus bradycardia/pauses (OR = 32.9, p < 0.001) were more likely to be associated with beta-blocker use compared to the most common presentation (third-degree AV block), after adjusting for other patient characteristics. Conclusions : Beta-blocker use is more likely to be associated with slow atrial fibrillation, sick sinus syndrome and sinus bradycardia/pauses, compared to a second- or third-degree AV block, after adjusting for other patient factors such as gender, admission type, ECG, comorbidities, cardiac function and lab testing.

Background: Sick sinus syndrome (SSS) is known to occur due to lesions in the medulla oblongata. Although medullary lesions have occurred in patients with neuromyelitis optica spectrum disorder (NMOSD), there are few reports of SSS associated with NMOSD. We report a patient with NMOSD who developed refractory nausea, vomiting and SSS as the initial manifestation., Case Presentation: A 77-year-old female developed refractory nausea and frequent episodes of syncope. The patient was diagnosed with SSS because sinus pauses lasting five to six seconds were observed, and pacemaker implantation was performed. Two months later, she was referred to our hospital because of limb weakness and sensory impairment that progressed over a month. The patient was confirmed to have muscle weakness; manual muscle testing revealed grade 4 in the upper extremities and grade 3 in the lower extremities. Tendon reflexes were diminished, while no pathological reflexes were present. Thermal and pain sensations were impaired in the upper and lower extremities, and vibration sensation was impaired in both lower extremities. Bladder and rectal disturbances were also noted. Optic neuritis was not detected. T2-weighted magnetic resonance imaging (MRI) showed high-intensity lesions in the dorsal part of the medulla oblongata and C3-6 cervical cord. Her serum was positive for antibodies against aquaporin 4, and a diagnosis of NMOSD was made. She was treated with two courses of an intravenous methylprednisolone pulse and one course of plasma exchange. Then, she was transferred to another hospital for rehabilitation., Conclusions: Because SSS is a life-threatening complication, clinicians should be aware of the possibility that medullary lesions in NMOSD can cause SSS as the initial manifestation., (© 2022. The Author(s).)

Previous studies have reported that hypothyroidism can lead to sick sinus syndrome (SSS) or other rhythm disturbances. Variants in the alpha subunit of the cardiac sodium channel (SCN5A) are known to be among the genetic causes of SSS. We encountered an adolescent patient with SSS and hypothyroidism who also harbored an SCN5A variant. The patient was a 13-year-old girl who was referred to our hospital because of bradycardia identified during a school electrocardiography screening. Clinical examination revealed severe hypothyroidism due to Hashimoto thyroiditis and SSS. After levothyroxine supplementation, her symptoms of hypothyroidism improved; however, the SSS did not. Genetic testing revealed a heterozygous variant (c.1066 G>A, p.Asp356Asn) in SCN5A. This is the first report of the coexistence of SSS due to an SCN5A variant and severe hypothyroidism in an adolescent patient. While patients with SCN5A variants exhibit phenotypic heterogeneity due to the presence of various modifiers, the presence of severe hypothyroidism may affect the development of SSS. This case highlights the importance of genetic analysis, including testing for SCN5A variants, in patients with hypothyroidism complicated by SSS or cardiac conduction disorders.

Introduction: Sarcoidosis is a multisystemic granulomatous disease of unknown cause occurring in young adults. Cardiac sarcoidosis patients are at increased risk for atrioventricular blocks and ventricular arrhythmias. Sinus node dysfunction is scarcely reported., Observation: We report a case of cardiac sarcoidosis revealed by a sinus node dysfunction and focus on cardiac and thoracic imaging to guide diagnosis., Conclusion: Sinus node dysfunction may be the first manifestation of cardiac sarcoidosis. In unexplained sinus node dysfunction in young patients, advanced cardiac imaging is a key to cardiac sarcoidosis diagnostic. Early recognition of cardiac sarcoidosis enables to start immunosuppressive treatment and discuss implantable cardioverter defibrillator implantation., (Copyright © 2021 Société Nationale Française de Médecine Interne (SNFMI). Published by Elsevier Masson SAS. All rights reserved.)

Cardiac involvement of malignant lymphoma is relatively common, although such a phenomenon has subclinical manifestations that are difficult to detect. We herein describe a patient with atrial fibrillation and sick sinus syndrome as the main symptoms. Computed tomography showed a mass in the right atrium extending into the superior vena cava (SVC). We implanted the patient with a leadless pacemaker. Transvenous biopsy revealed a diffuse large B-cell lymphoma. The patient was treated successfully with chemotherapy including rituximab. This case suggested that cardiac lymphoma may cause sick sinus syndrome, and leadless pacemaker implantation is a safe treatment option in patients with partial SVC obstruction.

Aims: Many tachy-brady syndrome (TBS) patients, are implanted a permanent pacemaker (PPM) to allow continuation of anti-arrhythmic drug (AAD) therapy to maintain sinus rhythm. Many of these PPM's are implanted as a preventive measure, in absence of symptomatic bradycardia. Our primary aim was to evaluate pacing use among these patients and find predictors for PPM use. Our secondary aim was to appreciate the portion of these patients who progress to permanent atrial fibrillation (AF)., Methods: Retrospective study of TBS patients implanted a PPM as preventive measure, dividing cases into defined categories regarding highest percent atrial and ventricular pacing documented in PPM clinic visits during 3 year follow-up (F/U) period. Patients' baseline characteristics and AAD therapy were compared between cases with a major (>90%) pacing use and cases with <90% pacing use to find predictors for pacing use. Multivariable logistic regression was applied to identify independent variables associated with major pacing use., Results: Our study included 119 TBS patients. Most (86.5%) TBS patients had a moderate (>50%) pacing use and 58% had a major pacing use. Significant association was found between pre-implant severe sinus bradycardia (<40 bpm), first degree atrioventricular block and amiodarone treatment to major pacing use on univariate analysis and severe sinus bradycardia was significantly associated with major pacing on multivariate analysis as well. Only minority (16.8%) of TBS patients progressed to permanent AF during the study F/U period., Conclusion: Our study reveals most TBS patients succeed to maintain sinus rhythm using an AAD with a significant pacing use, suggesting preventive PPM implantation might be advantageous in these cases. Pre-implant severe sinus bradycardia (<40 bpm) is a possible predictor for major pacing use in this population., (© 2020 John Wiley & Sons Ltd.)

Background: Mutations in the nuclear envelope genes encoding LMNA and EMD are responsible for Emery-Dreifuss muscular dystrophy. However, LMNA mutations often manifest dilated cardiomyopathy with conduction disturbance without obvious skeletal myopathic complications. On the contrary, the phenotypic spectrums of EMD mutations are less clear. Our aims were to determine the prevalence of nonsyndromic forms of emerinopathy, which may underlie genetically undefined isolated cardiac conduction disturbance, and the etiology of thromboembolic complications associated with EMD mutations., Methods: Targeted exon sequencing was performed in 87 probands with familial sick sinus syndrome (n=36) and a progressive cardiac conduction defect (n=51)., Results: We identified 3 X-linked recessive EMD mutations (start-loss, splicing, missense) in families with cardiac conduction disease. All 3 probands shared a common clinical phenotype of progressive atrial arrhythmias that ultimately resulted in atrial standstill associated with left ventricular noncompaction (LVNC), but they lacked early contractures and progressive muscle wasting and weakness characteristic of Emery-Dreifuss muscular dystrophy. Because the association of LVNC with EMD has never been reported, we further genetically screened 102 LVNC patients and found a frameshift EMD mutation in a boy with progressive atrial standstill and LVNC without complications of muscular dystrophy. All 6 male EMD mutation carriers of 4 families underwent pacemaker or defibrillator implantation, whereas 2 female carriers were asymptomatic. Notably, a strong family history of stroke observed in these families was probably due to the increased risk of thromboembolism attributable to both atrial standstill and LVNC., Conclusions: Cardiac emerinopathy is a novel nonsyndromic X-linked progressive atrial standstill associated with LVNC and increased risk of thromboembolism.

Aims: Undiagnosed atrial fibrillation (AF) accounts for 6% of all strokes, therefore early detection and treatment of the arrhythmia are paramount. Previous research has illustrated that the Microlife WatchBPO3 AFIB, an automated blood pressure (BP) monitor with an inbuilt AF algorithm, accurately detects permanent AF. Currently, limited data exist on whether the modified BP monitor is able to detect paroxysmal AF (PAF). Therefore, this study aims to assess the accuracy of the Microlife WatchBPO3 AFIB monitor to detect PAF against a pacemaker reference standard over a 24-h period., Methods and Results: Forty-eight patients with a pacemaker implanted for sick sinus syndrome and previously documented fast AF participated. Sensitivity of the atrial pacemaker lead was set to allow detection of signals of ≥ 0.5 mV. Patients engaged in their normal daily routine whilst wearing the modified BP monitor. The modified BP monitor demonstrated an overall sensitivity of 76.0% and specificity of 80.8% for detecting PAF. This sensitivity and specificity increased to 100% and 83.1%, respectively, for patients that achieved more than 80% successful BP readings. Compared to day-time readings, night-time readings also demonstrated a lower proportion of movement artefact (14.4% vs. 3.4%), and therefore, a higher sensitivity and specificity of 100% and 84.9%, respectively, for detecting PAF., Conclusion: The Microlife WatchBPO3 AFIB device has an acceptable diagnostic accuracy to detect PAF; however, movement artefact affects the accuracy of the readings. This modified BP monitor may potentially be useful as a screening tool for AF in patients at high risk of developing stroke.

Background and Purpose- Atrial fibrillation (AF) is known to increase risk of ischemic stroke (IS), but the risk of IS in isolated sinus node disease (SND) is unclear. We compared the incidence of IS in patients with SND, patients with AF, and in a control population with other cardiac diseases (disease of the circulatory system using the International Classification of Diseases, Tenth Revision ). Methods- This French longitudinal cohort study was based on the national database covering hospital care for the entire population from 2008 to 2015. Results- Of 1 692 157 patients included in the cohort, 100 366 had isolated SND, 1 564 270 had isolated AF, and 27 521 had AF associated with SND. Incidence of IS during follow-up was higher in isolated patients with AF than in AF associated with SND (yearly rate 2.22% versus 2.06%) and in isolated patients with AF than in isolated patients with SND (yearly rate 2.22% versus 1.59%). The incidence of IS was lower in a control population with other cardiac conditions (n=479 108) compared with SND and patients with AF (0.96%/y, 1.59%/y, and 2.22%/y, respectively). After 1:1 propensity score matching, SND was associated with lower incidence of IS compared to AF (hazard ratio, 0.77 [95% CI, 0.73-0.82]) but higher incidence of IS compared to control population (hazard ratio, 1.27 [95%CI, 1.19-1.35]). Conclusions- Patients with SND had a lower risk of thromboembolic events than patients with AF but a higher risk than a control population with other cardiac diseases. Randomized clinical trial in a selected SND population, with, for example, a high CHA 2 DS 2 -VASc score, would be required to determine the value of IS prevention by anticoagulation.

To avoid the negative effects associated with pacing, pacemakers are designed to achieve a pacing cadence as close to physiological pacing as possible. In closed-loop stimulation (CLS; a type of rate-responsive functionality used in pacemakers), the changes in impedance (which correlates with the contractility of the myocardium around the lead tip electrode) are tracked, and the paced heart rate is adjusted accordingly. We herein report a case in which we implanted a pacemaker in a post-tricuspid valve replacement patient. A ventricular lead positioned in the coronary vein exhibited good CLS functionality, and the patient's dizziness and heart failure improved.

We present two cases with unexpected long sinus arrest resulting in syncope. There were no signs or symptoms of either sick sinus syndrome or increased vagal tone before the occurrence of pauses in these patients. The fact that these patients remained asymptomatic for quite long shows striking resemblance to paroxysmal sub-AV nodal block. We would therefore prefer to classify these cases as paroxysmal sinus arrest as a possible manifestation of the sick sinus syndrome., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Objective: Sick sinus syndrome (SSS) is associated with loss of HCN4 (hyperpolarization-activated cyclic nucleotide-gated potassium channel 4) function in the cardiac conduction system. The underlying mechanism for SSS remains elusive. This study is to investigate how mitochondrial oxidative stress induces HCN4 downregulation associated with in sick sinus syndrome., Methods and Results: Trx2 lox/lox mice were crossed with α-myosin heavy chain (α-Mhc)-Cre and Hcn4-CreER T2 deleter mice to generate Trx2 deletion mice in the whole heart (Trx2cKO) and in the conduction system (Trx2ccsKO), respectively. Echocardiography was applied to measure hemodynamics and heart rhythm. Histological analyses, gene profiling and chromatin immunoprecipitation were performed to define the mechanism by which thioredoxin-2 (Trx2) regulates HCN4 expression and cardiac function. Trx2cKO mice displayed dilated cardiomyopathy, low heart rate, and atrial ventricular block (AVB) phenotypes. Immunofluorescence revealed that HCN4 expression was specifically reduced within the sinoatrial node in Trx2cKO mice. Interestingly, Trx2ccsKO mice displayed low heart rate and AVB without dilated cardiomyopathy. Both mRNA and protein levels of HCN4 were reduced in the sinoatrial node, suggesting transcriptional HCN4 regulation upon Trx2 deletion. ChIP indicated that the binding of MEF2 to the HCN4 enhancer was not altered by Trx2 deletion; however, histone 3 acetylation at the MEF2 binding site was decreased, and expression of histone deacetylase 4 (HDAC4) was elevated following Trx2 deletion. Moreover, HDAC4 binding to the HCN4 enhancer was mediated by MEF2. Mitochondrial ROS were increased by Trx2 deletion and importantly, mitochondria-specific ROS scavenger MitoTEMPO suppressed HDAC4 elevation, HCN4 reduction, and sinus bradycardia in Trx2ccsKO mice., Conclusion: In the conduction system, Trx2 is critical for maintaining HCN4-mediated normal heart rate. Loss of Trx2 reduces HCN4 expression via a mitochondrial ROS-HDAC4-MEF2C pathway and subsequently induces sick sinus syndrome in mice., Competing Interests: Declaration of Competing Interest No conflict of interest exits in the submission of this manuscript, and manuscript is approved by all authors for publication., (Copyright © 2019. Published by Elsevier Ltd.)

Background: Cardiac arrhythmias are sometimes encountered in patients with hereditary myopathies and muscular dystrophies. Description of arrhythmias in myopathies and muscular dystrophies is very important, because arrhythmias have a strong impact on the outcomes for these patients and are potentially treatable., Case Presentation: A girl with severe congenital RYR1-related myopathy exhibited atrial tachycardia and sinus node dysfunction during infancy. She was born after uncomplicated caesarian delivery. She showed no breathing, complete ophthalmoplegia, complete bulbar paralysis, complete facial muscle paralysis, and extreme floppiness. At 5 months old, she developed persistent tachycardia around 200-210 beats per minutes. Holter monitoring revealed ectopic atrial tachycardia during tachyarrhythmia and occasional sinus pauses with junctional escape beats. Propranolol effectively alleviated tachyarrhythmia but was discontinued due to increased frequency and duration of the sinus pauses that led to bradyarrhythmia. There was no evidence of structural heart diseases or heart failure. The arrhythmia gradually resolved spontaneously and at 11 months old, she showed complete sinus rhythm., Conclusions: Although supraventricular arrhythmia is sometimes encountered in congenital myopathies, this is the first report of cardiac arrhythmia requiring drug intervention in RYR1-associated myopathy.

Aims: High demand right ventricular pacing may elicit left ventricular systolic dysfunction known as pacing-induced cardiomyopathy, increasing the risks of heart failure (HF) hospitalization. Percentage of demand ventricular pacing is different between patients with sick sinus syndrome (SSS) and those with complete atrioventricular block (CAVB). This study aims to compare the incidence of HF admission and pacing-induced cardiomyopathy between patients with SSS and CAVB., Methods and Results: A total of 824 patients who received single ventricular or dual-chamber pacemaker implantation at our hospital between January 2003 and December 2012 were recruited for the study. Patients with HF, those without complete cardiac echocardiography, and those with significant coronary artery disease were excluded. Finally, 315 patients with SSS and 289 patients with CAVB were enrolled in this study. The CAVB group had a higher pacing percentage (39.37 ± 9.17% vs. 83.82 ± 33.06%; P < 0.001), longer pacing QRS duration (142.56 ± 33.02 ms vs. 156.63 ± 25.18 ms; P < 0.001), and higher prevalence of follow-up left ventricular ejection fraction ≤40% (1.3% vs. 4.2%; P = 0.040). However, the incidence of HF admission was similar between the two groups (log-rank P = 0.647). Age [hazard ratio (HR), 95% confidence interval (CI): 1.121, 1.054-1.193], diabetes mellitus (HR, 95% CI: 2.667, 1.159-6.136), pacing QRS duration ≥163 ms (HR, 95% CI: 3.506, 1.491-8.247), and left atrial size (HR, 95% CI: 1.070, 1.012-1.131) were independent predictors of HF admission. The Kaplan-Meier curve showed a significant difference in HF admission over a 3.5 year follow-up period (3.5 years: P value = 0.004; 5 years: P value = 0.002) between patients with pacing QRS duration ≥163 and <163 ms., Conclusions: There was no difference in HF admission between patients with SSS and CAVB, although the CAVB group had a higher pacing percentage. Post-pacemaker implant pacing QRS duration ≥163 ms was the most important predictor of HF admission., (© 2019 The Authors. ESC Heart Failure published by John Wiley & Sons Ltd on behalf of the European Society of Cardiology.)

Flecainide intoxication is a severe intoxication that can lead to cardiogenic shock. We report on a 68-year-old female patient, who presented with a flecainide intoxication in the setting of renal failure. She was managed with invasive supportive therapy at the ICU and infusion of sodium bicarbonate and intravenous lipid emulsion (ILE, intralipid 20%), after which she made a complete recovery.

Sick sinus syndrome (SSS) frequently coexists with atrial fibrillation (AF). The results of AF ablation in patients with SSS have not been fully evaluated. We retrospectively investigated 65 patients with paroxysmal AF (PAF) and SSS who underwent AF ablation using either radiofrequency (n = 50) or cryoballoon ablation (n = 15) in our institute. Forty-nine (75.4%) patients had a median of 5.6 (4.8-6.0) s of documented sinus pauses prior to the procedure (42 patients on antiarrhythmic drugs), and were observed when AF terminated in 47 patients. Successful pulmonary vein isolation was achieved in all, and substrate modification was added in 3 patients. Freedom from recurrent atrial arrhythmias after single procedures was 58.7, 45.2, and 38.9% at 1, 2, and 3 years after the initial procedure. During a 23.4 (11.1-40.7) month median follow-up and after 1.4 ± 0.6 sessions, 80.6% of patients were free from arrhythmia recurrence; however, permanent pacemaker implantations were required in 9 (13.8%) patients at a median of 5.3 (2.9-21.0) months after initial procedures. The average heart rate did not significantly differ before or a median of 2.5 (1.2-5.3) months post-procedure (76.7 ± 17.4 vs. 73.5 ± 14.6 bpm, p = 0.90). Multivariate analyses revealed that larger left atrial diameters [odds ratio (OR) 1.21, 95% confidential interval (CI) 1.01-1.45, p = 0.042] were independent predictor of AF recurrence, and SSS type 1 was the sole predictor of pacemaker implantations (OR 10.30, 95% CI 1.38-76.7, p = 0.023), respectively. AF ablation obviated permanent pacemaker implantations in the majority of the patients with SSS and PAF, and SSS type 1 was a sole factor predicting pacemaker implantations.

Background: Carotid sinus syndrome accounts for one third of patients who presents with unexplained syncope. Prevalence of carotid sinus hypersensitivity (CSH) in Indians has not been studied till now., Objectives: To assess the prevalence and associations of CSH in symptomatic patients above 50 years and to study its prognostic significance pertaining to sudden cardiac death, syncope, recurrent pre syncope and falls on 1 year follow up., Methods: Patients above 50 years who presented with unexplained syncope, recurrent syncope or falls were considered cases and those without these symptoms were considered as controls. All the patients underwent carotid sinus massage and their responses noted. All symptomatic patients were followed up and observed for events like sudden cardiac death, syncope, recurrent pre syncope and falls during 1 year follow up. Patients with recurrent syncope and predominant cardioinhibitory syncope were advised permanent pacemaker implantation., Results: A total of 252 patients were screened, 130 patients constituted cases and 49 patients constituted controls. CSH was demonstrable in 32% (n = 42) of cases as compared to 8% (n = 4) in controls (p < 0.001). Cardioinhibitory response was the predominant response (88%, n = 38) followed by mixed response (12%, n = 4). CSH was associated with advancing age, male gender (93%, n = 39, p < 0.001) and history of smoking (63%, n = 27, p = 0.009). Composite outcomes of sudden cardiac death, syncope, recurrent pre syncope and falls were significantly higher in patients with symptomatic CSH than in those without it (45%, n = 16 vs. 6.8%, n = 6; p < 0.001)., Conclusions: In conclusion, the prevalence of CSH in patients above 50 yrs with unexplained syncope was high in our population. Patients with CSH and baseline symptoms developed recurrent syncope during follow up. Carotid sinus massage should be a part of routine examination protocol for unexplained syncope., (Copyright © 2019 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.)

Purpose: This study aimed to determine the incidence, prevalence, and predictors of atrial arrhythmias (AAs) in patients with symptomatic sinus node dysfunction (SND) who required permanent pacemaker implantation. Also, we evaluated the impact of atrial pacing (AP) on AAs., Methods: All consecutive patients who underwent pacemaker implantation from 2005 to 2011 were included. Atrial fibrillation (AF), atrial flutter (AFL), atrial tachycardia (AT), and AV nodal reentrant tachycardia (AVNRT) were detected via pacemaker interrogation and clinical documentation., Results: The study group included 322 patients (44% male) with mean age 68.8 ± 15 years and followed for an average of 5.6 ± 2.2 years (median 5.7 years). Overall, 61.8% were found to have any AA at follow-up. Individual prevalence of AAs was high as follows: AF 43.5%, AFL 6.5%, AT 25%, and AVNRT 6.8%. AF was documented in 23% of patients (n = 74) prior to pacemaker; among those, 15% (n = 11) had no recurrence of AF with average AP of 74%. The incidence of new-onset AF after pacemaker was 15.8%. In subgroup analysis, prevalence of AF was increased by 16% with high rate of AP (81-100%) and 17% with lower rate of AP (0-20%). Incidence of new-onset AF was not affected by AP. Diabetes, hypertension, and left atrial enlargement were predictors of AAs. White men and women had higher prevalence of AF., Conclusions: AAs are highly prevalent in SND, particularly in white patients. Paroxysmal AF is suppressed with AP in minority, but there is no impact of AP on new-onset AF. Patients with diabetes, hypertension, and dilated atria must be monitored closely for early detection of AAs.

Atrioventricular Septal Defect (AVSD) is a rare congenital heart defect (CHD) often associated with genetic syndromes, most commonly Down syndrome (DS). Over the last four decades, surgical repair has increased survival and improved quality of life in these patients. The prevalence of bradyarrhythmias namely, atrioventricular block (AVB) and sinus node dysfunction (SND) in AVSD is partially known. 522 cases with both partial and complete AVSD (38.7% with DS), undergoing intracardiac repair from 1982 to 2016 at our institution, were reviewed from our system database. 38 (7.3%) patients received permanent PM implantation for AVB (early or late) or SND. On one hand, AVB requiring PM was found in 26 (4.98%). This was further subdivided into early-onset 14 (2.6%) and late-onset AVB 12 (2.2%) (median 4 [IQR 1-7] years). On the other hand, 12 (2.3%) experienced late SND requiring PM (median 11 [IQR 3.5-15.2] years). Early and late AVB were independent from the type of AVSD (partial or complete), whereas the late SND was remarkably observed in complete AVSD compared to partial AVSD (p = 0.017). We classified the cohort into two main categories: DS (202, 38.7%) and non-DS (320, 61.3%). At Kaplan-Meier survival analysis, DS was significantly associated with late-onset bradyarrhythmias (p = 0.024). At Cox regression analysis, we identified DS as an independent predictor of PM implantation (HR 2.17). In conclusion, about 7% of repaired AVSD patients need PM implantation during follow-up. There are no differences in early and late AVB occurrence according to the type of AVSD. There is a higher incidence of late SND in repaired complete AVSD, with a later timing onset in patients with associated DS. Moreover, DS seems to be an independent predictor of PM implantation.

Although arrhythmias are frequent in patients with Takotsubo syndrome (TTS), data on sick sinus syndrome remain elusive. Here, we report a case of TTS initiated by a seizure as a physical trigger that led to sinus arrest. The patient presented with cardiogenic shock and bradycardia which required intensive cardiovascular care. However, in the subacute phase of TTS, the sinus function recovered significantly, and pacemaker implantation was deferred., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2018. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Silent atrial fibrillation (AF) episodes are common but the role of anticoagulation treatment is under debate., Methods: Consecutive patients with dual-chamber pacemakers for sinus node disease or AV block/bundle branch block were retrospectively enrolled and the development of silent AF, any anticoagulation and the incidence of ischaemic stroke and dementia were recorded., Results: In total 411 patients without and 267 with known AF at implant were included. During a median follow-up of 38 months, 30% (125/411) of patients without known AF at implant were diagnosed with silent AF, 62% of those had or were prescribed anticoagulation. Heart failure (p = 0.03) and age >75 years (p = 0.0002) were risk markers for incident silent AF. In patients with known AF at implant, 80% (216/267) were on anticoagulation at implant. The annual stroke incidence was 2.1% in patients with known AF at implant, as compared to 1.9% in patients who developed silent AF during follow-up, and 1.4% in patients without AF. Vascular dementia developed in 11.2% and 6.2% respectively in patients with known AF versus no AF (p = 0.048) as well as in 5.6% of those with silent AF (p = 0.09)., Conclusion: The stroke risk in our study population with an incident silent AF diagnosis may have been significantly decreased by the high proportion of anticoagulation treatment. This could imply that without this treatment the stroke risk might have been high enough to justify anticoagulation. Development of vascular dementia was twice as common among patients with known AF as compared to those witht silent AF or no AF. More data is needed to inform the optimal treatment for these patients., Competing Interests: Emma Sandgren and Nils Edwardsson has nothing to declare. Cecilia Rorsman has received consultant fees from Medtronic. John Engdahl has received speaker fees from Boehringer Ingelheim, Bayer, AstraZeneca, Bristol Myers Squibb, Roche, Merek Sharp and Dome and Consunltant fees from Sanofi, Pfizer and Merek Sharp and Dome. This does note alter our adherence to PLOS ONE policies on sharing data and materials.

Background Biatrial, extensive, and complex ablation strategies have been published for the treatment of neurally mediated syncope, sinus node dysfunction, and functional atrioventricular block. We have developed a less extensive and more specific approach compared with previously published cardioneuroablation strategies, called cardio-neuromodulation. It is based on tailored vagolysis of the sinoatrial node through partial ablation of the anterior right-ganglionated plexus, preferentially through a right-sided approach. Methods Patients with syncope were enrolled between December 2016 and December 2017. They were assigned to group A if they had a positive head-up tilt test and to group B if they presented with a pause ≥3 seconds. The area to target during cardio-neuromodulation was designed offline on a computed tomographic scan. Slow heart rates and pauses were compared during 24-hour rhythm registration at baseline, at 1-month follow-up, and 6-month follow-up. Syncope burden was assessed before the procedure and at 3- and 6-month follow-up. Results Twenty patients underwent cardio-neuromodulation through a right-sided approach (12 in group A, 8 in group B). The first application of radiofrequency energy led to a P-P interval shortening >120 ms in all 20 patients. After a mean±SD ablation time of 7±4 minutes and mean ablated surface area of 11±6 mm 2 , the P-P interval shortened by 219±160 ms ( P<0.001). The number of beats <50/min during 24-hour rhythm registration was reduced by a median of 100% at 6-month follow-up ( P<0.001). Syncope burden was reduced by 95% at 6-month follow-up ( P<0.001). Conclusions These data indicate that cardio-neuromodulation, through a right-sided and computed tomographic-guided procedure, is safe, fast, and highly reproducible in preventing inappropriate functional sinus bradycardia and syncope recurrence.

A 78-year-old woman had paroxysmal atrial fibrillation and effort angina. Two months before she was admitted for a coronary angiography, she had been feeling dizzy. A Holter 24-hour electrocardiography monitor exhibited an asymptomatic episode of 2.9 seconds of RR interval. She underwent a coronary angiography, which showed intermediate stenosis in the left descending artery. Fractional flow reserve (FFR) measurement using intracoronary papaverine administration was performed. After intracoronary papaverine (12 mg) administration, pause of 4 seconds led to polymorphic ventricular tachycardia (VT), although the VT terminated spontaneously. Premature ventricular beat occurred and led to sustained polymorphic VT. In cardiac electrophysiology study, pacing from the right atrium showed that the maximum sinus node recovery time (SRT) was 910 ms. After procainamide (10 mg/kg) administration, the maximum SRT was 16.3 seconds with some junctional escapes. After intravenous papaverine administration, there was a slight change. Intracoronary papaverine administration induced about 9-seconds pause with some junctional escapes. We conclude that intracoronary papaverine administration reveals potential sinus node dysfunction. The patient has been asymptomatic since the implantation of the pacemaker. Patients with suspicious sinus dysfunction should be careful.

Atrial electrical and structural remodeling is related to the perpetuation of atrial fibrillation (AF) subsequent to sinus node dysfunction. We investigated the relationship between AF recurrence after catheter ablation and sinus node dysfunction in long-standing persistent AF patients using the sinus node recovery time (SNRT) after defibrillation.Fifty-one consecutive patients who underwent a first ablation for long-standing persistent AF were enrolled. Intracardiac cardioversion was applied before ablation in the absence of any antiarrhythmic drugs, and the power required to defibrillate, number, and SNRT after defibrillation were measured. All patients underwent the same designed radiofrequency catheter ablation procedure.No patient required permanent pacemaker implantation due to sinus dysfunction after the ablation. During the follow-up period of 28.4 months (3.6-43.7), 35 out of 51 patients (69%) experienced an AF recurrence. The AF recurrence was significantly associated with an older age (60 ± 11 versus 52 ± 12 years in the non-recurrence group, P = 0.0196), longer SNRT after defibrillation (1722 [1410-2656] versus 1295 [676-1651] msec, P = 0.0125), and larger left atrial (LA) volume (59 ± 25 versus 41 ± 15 mL, P = 0.0119). There were no significant differences in the AF duration, AF cycle length, and right and total atrial conduction times between the 2 groups. A longer SNRT after defibrillation (adjusted HR 2.13, 95%CI 1.16-3.71, P = 0.0152) and larger LA volume (adjusted HR 1.03, 95%CI 1.01-1.04, P = 0.0054) were independent predictors of AF recurrence after ablation.Assessment of the SNRT after defibrillation may help to predict a successful ablation in patients with long-standing persistent AF.

: Modern pacemakers have an increasing number of programable parameters and specific algorithms designed to optimize pacing therapy in relation to the individual characteristics of patients. When choosing the most appropriate pacemaker type and programing, the following variables must be taken into account: the type of bradyarrhythmia at the time of pacemaker implantation; the cardiac chamber requiring pacing, and the percentage of pacing actually needed to correct the rhythm disorder; the possible association of multiple rhythm disturbances and conduction diseases; the evolution of conduction disorders during follow-up. The goals of device programing are to preserve or restore the heart rate response to metabolic and hemodynamic demands; to maintain physiological conduction; to maximize device longevity; to detect, prevent, and treat atrial arrhythmia. In patients with sinus node disease, the optimal pacing mode is DDDR. Based on all the available evidence, in this setting, we consider appropriate the activation of the following algorithms: rate responsive function in patients with chronotropic incompetence; algorithms to maximize intrinsic atrioventricular conduction in the absence of atrioventricular blocks; mode-switch algorithms; algorithms for autoadaptive management of the atrial pacing output; algorithms for the prevention and treatment of atrial tachyarrhythmias in the subgroup of patients with atrial tachyarrhythmias/atrial fibrillation. The purpose of this two-part consensus document is to provide specific suggestions (based on an extensive literature review) on appropriate pacemaker setting in relation to patients' clinical features.

: The purpose of this two-part consensus document is to provide specific suggestions (based on an extensive literature review) on appropriate pacemaker setting in relation to patients' clinical features. In part 2, criteria for pacemaker choice and programming in atrioventricular blocks and neurally mediate syncope are proposed. The atrioventricular blocks can be paroxysmal or persistent, isolated or associated with sinus node disease. Neurally mediated syncope can be related to carotid sinus syndrome or cardioinhibitory vasovagal syncope. In sinus rhythm, with persistent atrioventricular block, we considered appropriate the activation of mode-switch algorithms, and algorithms for auto-adaptive management of the ventricular pacing output. If the atrioventricular block is paroxysmal, in addition to algorithms mentioned above, algorithms to maximize intrinsic atrioventricular conduction should be activated. When sinus node disease is associated with atrioventricular block, the activation of rate-responsive function in patients with chronotropic incompetence is appropriate. In permanent atrial fibrillation with atrioventricular block, algorithms for auto-adaptive management of the ventricular pacing output should be activated. If the atrioventricular block is persistent, the activation of rate-responsive function is appropriate. In carotid sinus syndrome, adequate rate hysteresis should be programmed. In vasovagal syncope, specialized sensing and pacing algorithms designed for reflex syncope prevention should be activated.

A 74-year-old man with a past medical history of bradycardiac atrial fibrillation and an old cerebral infarction presented with dysarthria. He had been treated with warfarin and PT-INR on admission was 2.0. MRI of the head revealed an acute ischemic stroke involving the cerebellum and left occipital lobe. Because transesophageal cardiac echography showed a thrombus in the left atrial appendage, anticoagulant treatment with warfarin and heparin was initiated. The thrombus was enlarging; therefore, we changed the anticoagulant therapy to apixaban with heparin on day 11. On day 17, a hemorrhagic cerebral infarction occurred. After the hemorrhage diminished, we treated him with warfarin aiming for a PT-INR between 3 and 4. The thrombus gradually shrank and disappeared on day 110. Finally, a thoracoscopic left atrial appendectomy was performed as a secondary prevention, with no recurrence till date.