Sick Sinus Syndrome Research Articles

Background: Social determinants of health (SDOH) influence access to advanced cardiac interventions. We aimed to evaluate the association between SDOH and permanent pacemaker (PPM) utilization in patients hospitalized with sick sinus syndrome (SSS) in the United States. Methods: Using the National Inpatient Sample (2016–2021), we identified adult patients diagnosed with SSS using ICD-10-CM codes. PPM implantation was identified using ICD-10-PCS codes. Baseline characteristics, comorbidities, and SDOH, including race/ethnicity, income quartile, insurance status, and hospital features, were compared between patients with and without PPM. Multivariable logistic regression was used to assess independent predictors of PPM use. Propensity score matching was performed (1:1) to compare severe comorbidities, procedures, and in-hospital outcomes. Results: Among 1,462,220 SSS hospitalizations, 361,035 (24.7%) received a PPM. PPM recipients were younger (median age 78 vs. 80 years, p<0.001), more likely female (51.6% vs. 50.5%, p<0.001), and more often treated at large, urban teaching hospitals (p<0.001). In adjusted analysis, Black patients had lower odds of receiving PPM (aOR 0.81, 95% CI: 0.78–0.84), while Hispanic (aOR 1.10) and Asian/Pacific Islander (aOR 1.09) patients had higher odds compared to White patients (p<0.01). Female sex (aOR 1.11), private insurance (aOR 1.24), and residence in the highest income quartile (aOR 1.04) were associated with higher likelihood of PPM use. In propensity-matched cohorts (N=70,317 each), PPM implantation was associated with lower in-hospital mortality (0.85% vs. 3.61%), stroke (0.97% vs. 1.56%), and sepsis (2.29% vs. 5.72%) (p<0.001). PPM recipients had higher discharge-to-home rates (57.3% vs. 49.6%) and longer median hospitalization costs ($19,898 vs. $10,209, p<0.001). Conclusion: Significant disparities exist in the utilization of permanent pacemakers among patients with SSS. Black patients and those with Medicaid or from lower-income ZIP codes were less likely to receive PPM, despite worse clinical outcomes. These findings highlight a gap in equitable care delivery and underscore the need for health system and policy-level interventions to address structural disparities in cardiac device access.

Background and Aims: Glucagon-like peptide-1 receptor agonists (GLP-1RAs) have transformed the management of type 2 diabetes mellitus(T2DM) and overweight/obesity, and are increasingly used for the secondary prevention of atherosclerotic cardiovascular disease and heart failure. However, their effect on different types of cardiac arrhythmias is uncertain. Therefore, we conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to evaluate the anti-arrhythmic effect of GLP-1RA therapy. Methods: We performed a comprehensive systematic search following PRISMA guidelines across five electronic databases (Cochrane, Embase, PubMed, Scopus and Web of Science) to identify all RCTs that evaluated GLP-1RAs in individuals with T2DM or overweight/obesity. We included all placebo-controlled studies that reported data on the following cardiac arrhythmic events: atrial flutter/fibrillation, sick sinus syndrome, supraventricular tachycardia, premature depolarizations, conduction system disease (atrioventricular, bundle branch, and fascicular blocks), and ventricular arrhythmias (tachycardia and fibrillation). Meta-analyses were conducted using a random-effects model and subgroup analyses were performed to estimate odds ratios (OR). Results: The analysis included 39 RCTs that enrolled 79,674 participants, with an average follow-up time of 78.9 ± 54.5 weeks. Treatment with GLP-1RAs was associated with a 35% reduction in the risk of atrial fibrillation and atrial flutter compared to placebo (OR 0.65, 95% confidence interval [CI] 0.43–0.98; p =0.04) (Figure 1). No significant differences were observed between GLP-1RAs and placebo with respect to other cardiac arrhythmic events (Figure 2). In subgroup analyses, long-acting GLP-1RA use was related with a significantly lower incidence of sick sinus syndrome in individuals with overweight/obesity (OR 0.42, 95% CI 0.19–0.94; p = 0.03), an effect not observed in patients with T2DM (Figure 3). Conclusions: Our systematic review of all GLP-1RA RCTs reporting cardiac arrhythmic events found that treatment with GLP-1RA significantly reduces the incidence of atrial fibrillation and atrial flutter but not other arrhythmias. Subgroup analyses suggest a reduction in sick sinus syndrome in patients with overweight/obesity that are being treated with long-acting formulations. Our study provides additional evidence of the benefit of GLP-1RAs. Patients at increased risk of arrhythmias may be prioritized for GLP-1RA therapy.

Background: Evidence on the safety of atrial fibrillation (AF) catheter ablation in U.S. patients over 80 years old remains limited. With growing life expectancy, more elderly individuals are being considered for this intervention, underscoring the need for age-specific safety data to guide clinical decision-making. Hypothesis: Elderly age is associated with increased procedural complications and mortality, suggesting a higher-risk profile and reduced safety. Aim: To provide critical insights into the real-world risks and complications. Methods: In this U.S.-based multicenter cohort study using the TriNetX dataset, we identified adults (≥ 60 years old) with new-onset AF and underwent catheter ablation within 6 months. Patients were categorized by age into first AF between 60 to 79 years old (defined as older adults), and first AF older than 80 years old (defined as elderly adults). Propensity score matching (1:1) balanced groups by demographics, comorbidities, and medications. The primary end point was the risk of repeat AF ablation at 3-year intervals. Secondary endpoints included new or ongoing antiarrhythmic (AAD) use, ischemic stroke, safety outcomes including heart failure (HF) exacerbations, composite pericardial complications, new venous thromboembolism (VTE), cardiac arrest, vascular access complications and all-cause hospitalizations, and all-cause death. Falsification outcomes included urinary tract infections (UTI) and herpes zoster. Kaplan-Meier analysis and log-rank tests compared outcomes; hazard ratios (HRs) with 95% CI were calculated using Cox regression. Results: After propensity score matching into well-balanced groups (N= 5,032 per group at 3-year follow-up), elderly adults were more likely to receive repeat catheter ablation. There were no differences between groups in AAD, VTE outcomes. Elderly adults were at higher risk of ischemic stroke (HR = 1.75, 95% CI = 1.52-2.02, p=0.002), new HF exacerbation (HR=1.75, 95% CI = 1.52-2.02, p<0.01), and new complete heart block or sick sinus syndrome (HR=1.85, 95% CI =1.59-2.16, p<0.01). Elderly adults were also more likely to encounter all-cause hospitalizations (HR=1.39-1.48, p<0.01) and all-cause death (HR=1.98, 95%CI=1.71-2.30, p<0.01). Conclusion: Elderly adults (≥80 years) undergoing AF ablation had significantly higher risk of complications than older adults (60-79 years). This underscore the importance of further investigations to ascertain the risk factors and potential development of screening tool.

A 16-year-old-male presented in 2016 after a fall with a concussion due to dizziness. Chest X-ray showed a prominent cardiac silhouette. Further workup showed an echocardiogram with no left ventricular hypertrophy and mild left ventricular dilation. A Holter monitor recorded 1259 single PACs and 87 aberrantly conducted PACs. The patient was diagnosed with anxiety in 2017 and started on sertraline and later changed to fluoxetine. These medications were stopped at the end of 2022. In early 2023, he presented with symptomatic sinus bradycardia. A coronary angiogram revealed no obstructive CAD. MRI showed LV noncompaction towards the ventricular apex. Genetic testing showed a heterozygous HCN4 gene mutation. The HCN4 gene mutation variants affect the cyclic nucleotide-gated cardiac ion channels, potentially leading to arrhythmias. It is most associated with patients with sinus node dysfunction. Specific mutations have been known to also present with left ventricular noncompaction (like in our patient), sick sinus syndrome, and susceptibility to ventricular fibrillation. Emerging evidence suggests that HCN4 gene may have potential expression in the brain. It is known that the HCN1 and HCN2 genes are common in the brain, but they are finding that the HCN4 gene is used as an “on-off” button that can control the way neurons respond to synaptic input. This gene mutation, Gln375Ter, is associated with LV noncompaction or sinus node dysfunction. However, very few cases show an association of arrhythmias with mood disorders. There is evidence that the HCN4 gene may be associated with anxiety and depression because of its presence in the brain and specifically its location in the frontal cortex, and thalamocortical network. Our case illustrates how symptoms related to the mutation gradually emerged in the interval of presentation and diagnosis of the HCN4 gene mutation. For patients presenting with symptomatic bradycardia, screening for anxiety and depression using DSM-V criteria could be crucial in identifying a genetic basis for their condition. Given that the HCN4 gene mutation can manifest in diverse ways due to its expression in both the heart and brain, awareness of these potential symptoms can aid the care team in accurately diagnosing this mutation.

Background: Evidence regarding the safety profile of atrial fibrillation (AF) catheter ablation remains limited. As life expectancy increases, a rising number of elderly patients are considered candidates for this procedure. Research Question: What is the safety profile of AF ablation in elderly patients with new AF in a real-world setting? Methods: In this U.S.-based multicenter cohort study (TriNetX dataset), we identified adults (≥ 60 years old) with new AF who underwent catheter ablation within 6 months. Patients were grouped by age at first AF episode: 60–79 years (older adults) and ≥80 years (elderly adults). Patients with prior surgical ablation were excluded. Propensity score matching (1:1) balanced groups by demographics, comorbidities, and medications. The primary end point was repeat AF ablation at 1-year; secondary endpoints included new or ongoing antiarrhythmic (AAD) use, ischemic stroke, safety outcomes of heart failure (HF) exacerbations, pericardial complications (pericardial effusion, tamponade or hemopericardium), new venous thromboembolism (VTE), cardiac arrest, conduction disease (new complete heart block or sick sinus syndrome), vascular access complications (post-procedural hematomas or aneurysms), all-cause hospitalizations, and all-cause mortality. Falsification outcomes included urinary tract infections (UTI) and herpes zoster. Kaplan-Meier analysis and log-rank tests compared outcomes; hazard ratios (HRs) with 95% CI were calculated using Cox regression. Results: After matching (N= 5,032 per group), elderly adults were less likely to undergo repeat catheter ablation at 1-year. AAD use and VTE risks were similar between groups. Elderly adults had higher risk of ischemic stroke (HR=1.27, 95% CI = 0.91-1.01, p=0.12) and HF exacerbation (HR=1.67, 95% CI=1.39-2.0, p<0.01). Safety outcomes were similar, however elderly adults were at risk of new conduction disease (HR=1.91, 95% CI = 1.58-2.31, p<0.01). Elderly adults were more likely to be hospitalized (HR= 1.36, 95% CI = 1.26-1.46, p<0.01) and had higher risk of mortality (HR=1.78, 95% CI=1.45-2.22, p<0.01). Falsification outcomes found elderly adults had higher UTI risk (HR=1.68, 95% CI=1.43-1.97, p<0.01). Conclusion: Elderly adults (≥80 years) undergoing catheter ablation had significantly higher risk of complications compared to older adults (60-79 years), underscoring the need for further investigations to mitigate periprocedural risk in AF catheter ablation.

Introduction: Implanted vagus nerve stimulators (VNS) have become an established therapy for treatment-resistant epilepsy and major depressive disorder (MDD), and the scope of its potential applications continues to grow, particularly in the realm of neuropsychiatric conditions. As the scope of VNS expands, understanding the potential cardiac effects of VNS is essential. While isolated case reports have raised concern for arrhythmias following VNS implantation, large-scale studies examining arrhythmia risk are limited. Research Question: This study investigates whether VNS therapy alters the risk of developing cardiac arrhythmias in patients with epilepsy or MDD. Methods: Using the TriNetX national database, we identified adult patients (≥18 years) with epilepsy or MDD diagnosed between January 1, 2005 and December 31, 2024. Two cohorts were created: one with VNS implantation and one without. Propensity score matching controlled for baseline differences, yielding 8,911 patients per group. We analyzed the absolute risk and risk ratios of ten arrhythmia-related outcomes, excluding pre-existing outcomes diagnosed prior to VNS implantation (VNS cohort) or diagnosis of epilepsy or MDD (no VNS cohort). Results: Of the ten outcomes, two showed statistically significant reductions in risk among VNS patients. Atrial fibrillation occurred in 0.804% of VNS patients versus 1.127% without VNS (risk ratio [RR] 0.714, 95% CI: 0.527–0.966). Supraventricular tachycardia (SVT) occurred in 0.508% of VNS patients versus 0.814% without (RR 0.624, 95% CI: 0.431–0.905). Several other arrhythmias, including ventricular tachycardia (RR 0.857), ventricular fibrillation (RR 0.917), atrial flutter (RR 0.562), sick sinus syndrome (RR 0.828), and cardiac arrest (RR 0.923), were less common in the VNS group, though these findings were not statistically significant. Increased—but non-significant—risks were observed for atrioventricular block (RR 1.369), bradycardia (RR 1.153), and unspecified arrhythmias (RR 1.019). Conclusion: In summary, VNS therapy does not appear to significantly increase the risk of new cardiac arrhythmias and may, in fact, confer a protective effect against atrial fibrillation and SVT. These findings support the electrophysiological safety of VNS in patients without prior arrhythmia and warrant further investigation into its potential role in arrhythmia prevention.

This article presents the results of radiofrequency ablation of atrial fibrillation in elderly and geriatric patients. A total of 151 patients were included in the study. The subjects were divided into two groups: Group 1 consisted of patients aged 65 to 75 years, while Group 2 included those over 75 years of age. The follow-up period lasted for 1 year.BACKGROUND. According to the literature, the prevalence of atrial fibrillation (AF) in the population ranges from 1 % to 2 %. This frequency increases with age, from less than 0.5 % in individuals aged 40 to 50 years to 5 % to 15 % in those aged 80 years [1–8]. Considering the increase in life expectancy, we can also expect a rise in the number of elderly and senile patients with atrial fibrillation. [9–11, 22]. Given that pulmonary vein ostia isolation is the gold standard for treating this condition, there is a need for studies that reflect the profile of efficacy and safety of radiofrequency ablation for atrial fibrillation in patients within these age groups. [12–21].OBJECTIVE. To investigate the efficacy and safety of pulmonary vein ostia isolation in elderly and geriatric patients.MATERIALS AND METHODS. The study is retrospective in nature. It was conducted in 2022–2023 at the Pirogov University Russian Gerontological Scientific Clinical Center. The first group included 104 patients aged up to 75 years (42 men, 62 women, with a mean age of 62 years and a mean disease duration of 5.2 years). The second group comprised 47 patients over 75 years old (14 men, 33 women, with a mean age of 78 years and a mean disease duration of 8.2 years). Inclusion criteria for the study were: age over 18 years, indications for radiofrequency ablation of atrial fibrillation, symptomatic atrial fibrillation, and anticoagulant therapy for more than four weeks prior to the procedure. Exclusion criteria included any contraindications to surgical intervention. The primary efficacy endpoint was the absence of recorded atrial fibrillation lasting more than 30 seconds during the blind period (2 months). The secondary efficacy endpoint was the absence of atrial tachycardia, atypical atrial flutter, typical atrial flutter, atrial fibrillation after the blind period, death, stroke, or transient ischemic attacks (TIA). The assessment of the results was conducted using Holter monitoring and during clinic visits at 3, 6, and 12 months after the procedure. A significant portion of patients had paroxysmal atrial fibrillation, with 79 individuals in the first group (76 %) and 34 individuals in the second group (72 %). The most common comorbidity among patients in the first group was hypertension (97 patients, 93.27 %), followed by dyslipidemia (64 patients, 61.54 %). Chronic cerebral ischemia was observed in 48 patients (46.15 %), chronic heart failure in 46 (44.23 %), chronic kidney disease in 24 (23.07 %), diabetes mellitus in 14 (13.46 %), ischemic heart disease in 10 (9.62 %), and a history of stroke or TIA in 6 (5.77 %). Chronic obstructive pulmonary disease (COPD) was present in 5 patients (4.81 %), and post-infarction cardiosclerosis (PICS) in 4 (3.85 %). Implantation of a pacemaker due to sick sinus syndrome or atrioventricular block was performed prior to the study in 4 patients (3.85 %).In the group over 75 years of age, hypertension and dyslipidemia were present in 43 patients (91.45 %), chronic cerebral ischemia in 32 (68.09 %), heart failure in 35 (74.45 %), kidney disease in 9 (19.15 %), diabetes mellitus in 9 (19.15 %), ischemic heart disease in 8 (17.02 %), and a history of stroke or TIA in 9 (19.15 %). COPD was diagnosed in 5 patients (10.64 %), and PICS in 3 (6.38 %). Pacemaker implantation was performed in 7 patients (14.89 %).All patients underwent atrial isolation of the pulmonary vein orifices using a three-dimensional navigation system.RESULTS. The duration of the surgery in the first and second groups was comparable: (56 ± 14) minutes and (49 ± 13) minutes (p < 0.05). Criteria for the isolation of the pulmonary vein ostia were achieved in all patients. No serious complications, such as hemopericardium, ischemic stroke, or atrial-esophageal fistula, were recorded. The efficacy during the blind period was 78.8 % (82 patients) in the first group and 81.4 % (34 patients) in the second group, with χ² = 1.648, p = 0.194. The efficacy after 1 year of follow-up was 75.9 % (79 patients) in the first group and 76.7 % (33 patients) in the second group, with χ² = 0.003, p < 0.05.CONCLUSION. Radiofrequency ablation for atrial fibrillation in elderly and senile patients demonstrates a high profile of efficacy and safety. However, further studies are necessary to confirm this conclusion.

Pathogenic variants in SCN5A, encoding the cardiac sodium channel Nav1.5, are responsible for a diverse spectrum of potentially life-threatening arrhythmias in children. This review examines the molecular pathophysiology of SCN5A-related cardiac disorders in the pediatric population, focusing on genotype–phenotype correlations and emerging therapeutic approaches. Nav1.5 channels, with their complex four-domain structure, orchestrate the cardiac action potential by precisely regulating sodium currents. Mutations cause either gain-of-function effects (enhancing late sodium current) leading to Long QT Syndrome type 3, or loss-of-function effects (reducing channel availability or conductance) underlying Brugada syndrome, progressive cardiac conduction disease, and sick sinus syndrome. Notably, pediatric presentations often feature a high prevalence of conduction disorders and overlap syndromes, with diagnosis before one year of age and compound heterozygosity conferring particularly high risk. Advanced therapeutic strategies are evolving beyond conventional treatments, including mutation-specific pharmacotherapy (ranolazine, mexiletine), gene and RNA therapies (CRISPR/Cas9, antisense oligonucleotides), and cell-based approaches using induced pluripotent stem cell-derived cardiomyocytes. These precision medicine approaches hold promise for transforming the management of these disorders, though significant challenges remain in ensuring safety, efficacy, and equitable access, particularly for pediatric patients.

Association between modifiable risk factors and bradyarrhythmia: A Mendelian randomization study.

BackgroundDevice therapy for various cardiac rhythm disturbances has seen a tremendous increase in recent times, and so have the various complications associated with this therapy. Pacemaker lead perforation is one of the most feared complications associated with these device implantations. This prospective observational study was conducted to evaluate the clinical features, diagnosis, and outcome of pacemaker lead perforation in our setting.ResultsA total of 5493 patients were included in the study. It included 3438 temporary pacemaker (TPM) lead placements and 2055 patients who had undergone CIED implantation. The comorbidities of the study population include hypertension in 3582(65.21%), Diabetes in 2089(38%), dyslipidemia in 2293(41.74%) and hypothyroidism in 1527(42.6%). The indication of TPM lead implantation include complete heart block (CHB) in 1323(38.48%), TPM during CIED implantation in Sick sinus syndrome (SSS)/trifascicular block and high-grade AV block 766(22.28%), permanent pacemaker generator replacement 330(9.95%), EP study250(7.27%), drug induced heart block 13(0.38%). Indications of CIED implantation include CHB in 1103(53.67%), SSS in 221(10.75%), DCM in 132(6.42%) and ICD in 38(1.85%). There were 23 lead-induced RV perforations, with an incidence of 0.42%. There were 18(78.2%) perforations due to TPM Lead and 5(21.8%) due to CIED leads. Bradycardia was seen in 18(78.3%), hypotension in 8(34.8%), capture loss in 14(60.87%), pain abdomen in 4(17.4%). Pericardial effusion developed in 19(82.6%), tamponade needing pericardiocentesis was seen in 8(34.78%). Surgical intervention was required in 1(4.34%) case. With one death mortality in the study was 4.34%.ConclusionCareful monitoring and nonsurgical management of lead perforation has favourable outcomes.

Loss-of-function SCN5A variants are primarily associated with Brugada syndrome (BrS), but can also present with overlapping phenotypes. We investigated Cys1384Phe of SCN5A, a novel missense variant associated with BrS, sick sinus syndrome (SSS), and dilated cardiomyopathy (DCM). This study included a large 4-generation Japanese family consisting of 15 individuals (1 proband and 14 family members). Among them, the proband, a cousin, a second cousin and the second cousin's father were diagnosed with BrS. Two of these 4 BrS patients experienced VF events, while the other 2 remained asymptomatic. Another cousin was diagnosed with DCM, and 3 additional family members exhibited complete right bundle branch block and/or SSS. Comprehensive genetic analysis using a target panel sequencing identified a novel missense variant, Cys1384Phe in SCN5A, in the proband and affected family members; however, the phenotypes were different. Whole-cell patch-clamp experiments using HEK293 cells transfected wild-type or Cys1384Phe plasmid demonstrated a complete loss-of-function in the sodium current of the Cys1384Phe cells. Furthermore, the heterozygous expression of Cys1384Phe and wild-type (WT) channels showed a significant reduction of peak sodium current compared with the WT, suggesting a dominant-negative suppression, but no trafficking defect was observed. The novel Cys1384Phe variant in SCN5A is a complete loss-of-function mutation with dominant-negative suppression, and associated with overlapping phenotypes of BrS, SSS, and DCM.

Sick sinus syndrome (SSS) is a cardiac conduction disorder that often necessitates pacemaker implantation, especially in older adults. Emerging evidence suggests a potential association between coronavirus disease 2019 (COVID-19) infection and SSS, but the impact on SSS trends and permanent pacemaker (PPM) implantation rates remains unclear. This study compares the pre- and post–COVID-19 trends in SSS incidence and PPM implantation rates. Using the TriNetX Research Network, we analyzed the monthly incidence rate (IR) of SSS and the rate of PPM implantation in the overall population from January 2018 to December 2023. Additionally, we conducted a subgroup analysis focusing on patients >50 years of age to examine trends in IR and PPM implantations during the same period. To evaluate changes before and after COVID-19, we used interrupted time series analysis, with March 1, 2020, as the cutoff. In the overall SSS population, the IR increased significantly post–COVID-19 (IR, 1.80 cases/100,000 person-years [PY] per month; P < .001), which was accompanied by a significant rise in PPM implantation rates (119.16 cases/100,000 PY per month; P < .001). Among patients <50 years of age, the IR increased post–COVID-19 (IR, 0.355 cases/100,000 PY per month; P < .001), but PPM implantation rates in this subgroup remained unchanged (P = .897). Our findings suggest an increase in SSS incidence across all age groups post–COVID-19. However, the lack of increased PPM implantation in younger patients may reflect either a more transient disease course or a higher threshold for device implantation in this age group. Further research is needed to determine the prognosis of SSS in the recent era.

Optimization strategy for modeling sick sinus syndrome in rats: Balancing effect and animal care.

BackgroundThe use of nonbiopsy diagnosis of wild-type transthyretin cardiac amyloidosis (ATTRwt-CA) has grown worldwide. However, in specific scenarios, a biopsy of the myocardium or involved tissues must be conducted to confirm deposition of amyloid transthyretin (ATTR).Case reportAn 83-year-old woman was diagnosed with decompensated heart failure, sick sinus syndrome (SSS), and an atrial septal defect (ASD). Cardiac amyloidosis was also suspected. Technetium-99m-labelled pyrophosphate (Tc-99m-PYP) scintigraphy revealed that tracer uptake was greater in the right ventricular (RV) myocardium than in the left. Tc-99m-PYP uptake in many of the skeletal muscles, including the pectoralis major, was also observed. Permanent pacemaker implantation for SSS was performed without complications. A sample of the pectoralis major was resected while forming the pocket for the pacemaker and was used to confirm deposition of ATTR through Congo red staining and immunohistochemical analysis. No mutations were detected in the transthyretin gene. Therefore, the patient was diagnosed with ATTRwt-CA and treatment with tafamidis was initiated.ConclusionHistological confirmation of amyloid type is generally needed when a patient presents with suspected immunoglobulin light chain cardiac amyloidosis, visual grade 1 myocardial Tc-99m-bone-avid isotope uptake, visual grade 2–3 uptake with plasma cell dyscrasia, or suspected infrequent types of amyloidosis. In our patient, a rare Tc-99m-PYP uptake pattern due to RV overload from ASD was observed, and a biopsy was required to confirm amyloid type. A biopsy of the pectoralis major may be performed when a permanent pacemaker is implanted, and it can be useful for confirming deposition of ATTR.LEARNING POINTSSince 2016, wild-type transthyretin cardiac amyloidosis (ATTRwt-CA) has been diagnosed without biopsy; however, biopsy is still required in some cases to detect deposition of amyloid transthyretin (ATTR).Biopsies to confirm ATTR deposition should be performed at sites where technetium-99m-labelled pyrophosphate uptake indicates deposition.The pectoralis major has a high rate of technetium-99m-labelled pyrophosphate uptake and biopsy of this muscle, which can be performed when creating a permanent pacemaker pocket, may be useful for confirming ATTR deposition in patients with suspected ATTRwt-CA.

Sinoatrial node (SAN) dysfunction often accompanies supraventricular tachyarrhythmias such as atrial fibrillation (AF), which is referred to as tachycardia-bradycardia syndrome (TBS). Although there have been many studies on electrical remodeling in TBS, the regulatory mechanisms that cause electrical remodeling in the SAN and atrial muscles by chronic bradycardia or tachycardia have not yet been fully investigated. Here we hypothesized Pitx2c, a transcription factor that played a central role in the late aspects of left-right asymmetric morphogenesis, regulated an interrelationship between the SAN and the atrial muscles and was involved in TBS-like pathology. To test this hypothesis, we generated transgenic mice overexpressing Pitx2c specifically in the atria (OE mice). Although Pitx2c is normally expressed only in the left atria (LA), the expression levels of Pitx2c protein in the right atria (RA) were significantly increased to similar levels of those in the LA of non-transgenic control mice (WT). We found the heart rate of OE mice was significantly variable although the average heart rate was similar between WT and OE mice. Electrophysiological examination showed OE mice exhibited prolonged SAN recovery time and higher AF inducibility. Histological analysis revealed SAN-specific ion channel HCN4-positive cells were hardly detected in the SAN of OE mice, along with ectopic expression in the RA. Furthermore, transcription factors associated with SAN formation were down-regulated in the RA of OE mice. We conclude that SAN dysfunction by Pitx2 dysregulation predisposed OE mice to a TBS-like phenotype, and Pitx2c is a key regulator that defines SAN function in the atria.

To determine the safety and effectiveness of the KronoSafe® permanent pacemaker adapter for temporary cardiac pacing (TCP) with active-fixation leads (TCPAFL). This was a multicenter, prospective, descriptive clinical investigation involving a medical device (ClinicalTrials.gov Identifier: NCT05351658). Between January 2023 and December 2024, all consecutive patients who underwent implantation of a temporary active-fixation pacemaker were included. The devices were secured using the KronoSafe® adapter throughout the period of use. Complications during TCPAFL were recorded, and R-wave sensing, lead impedance, and pacing threshold were determined every 48 hours. Thirty patients (10 with atrioventricular block, 9 TAVI, 5 alcohol septal ablations, 2 slow atrial fibrillations, 2 bradycardia-tachycardia syndrome, and 2 pacemaker infections) who required TCP were included. Two centers participated in the study. The mean duration of TCP was 7.8 days (maximum 22 days), with 79.2% of the time spent in the cardiology ward. One complication (3%) was recorded, due to accidental traction of the system associated with an episode of agitation. TCPAFL using the KronoSafe® adapter is safe and effective, and its use can be extended outside the Intensive Care Unit.

Emerging epidemiological evidence implicates pulmonary dysfunction in cardiovascular pathogenesis, yet its arrhythmogenic potential remains poorly defined. We aimed to assess the link between ventilatory parameters, pulmonary disease phenotypes and risk of incident arrhythmias across diverse populations. We analyzed data from 17,684 adults in two prospective cohort studies-the Atherosclerosis Risk in Communities (ARIC; n = 12,929) and Cardiovascular Health Study (CHS; n = 4,755). Adjudicated arrhythmia diagnoses (atrial fibrillation/flutter [AF/AFL], ventricular arrhythmias [VAs], high-grade atrioventricular [AV] block, and premature atrial/ventricular complexes [PAC/PVC]) were identified via hospitalization records and mortality data. Multivariable-adjusted Cox proportional hazards models quantified associations between forced expiratory volume in 1s (FEV1%) predicted and forced vital capacity (FVC%) predicted quartiles with arrhythmia risk, adjusting for traditional cardiovascular risk factors. Over a median follow-up of 12.6years, impaired FEV1% and FVC% corresponded to a graded increase in arrhythmia risk. Compared to the highest quartile, the lowest FEV1% predicted quartile had elevated hazards for any arrhythmias (HR 1.32, 95% CI 1.23-1.42), AF/AFL (HR 1.68, 1.52-1.85), VAs (HR 1.55, 1.29-1.86), high-grade AV block (HR 1.37, 1.08-1.73), and PAC/PVC (HR 1.42, 1.20-1.69). Similar trends were observed for FVC% predicted quartiles. These associations remained consistent in never-smoking individuals and across cohorts. Obstructive spirometry pattern was associated with the strongest arrhythmia risk, while restrictive ventilatory patterns showed relatively lower risk elevations. No association was observed with sick sinus syndrome. Reduced pulmonary function suggested independent associations with incident arrhythmias across supraventricular, ventricular, and conduction system pathologies in two historical cohorts. These findings suggest that spirometric indices could potentially represent novel independent indicators for arrhythmia development worthy of further validation in contemporary settings,, with associations distinct from conventional cardiometabolic risk factors.

The first case of sick sinus syndrome with an adult Sanfilippo A syndrome: a case report with review of literature.

Comparison of clinical outcomes between catheter ablation and permanent pacemaker implantation in Tachycardia-Bradycardia Syndrome patients: a meta-analysis

Transcatheter correction (TC) of sinus venosus defects (SVD) is an emerging alternative to surgical correction (SC). Superior vena caval (SVC) or right upper pulmonary vein (RUPV) stenosis and sick sinus syndrome are complications of SC. This retrospective study analyzed the outcomes of SC and TC in the last 14years. TC was considered in children only when their parents refused surgery and accepted the follow-up imaging protocol. Follow-up Transesophageal echocardiography (TEE), computed tomography (CT), or magnetic resonance (MR) were performed after all TC to identify residual shunt, venous obstruction, and stent thrombosis. Follow-up after SC was limited to transthoracic echocardiography, unless patients consented for TEE or CT. The study compared 148 SC and 127 TC between 2011 and 2024. While SC group were significantly younger, TC groups were more symptomatic and more often had pulmonary hypertension. Comorbidities occurred in 14% of SC and 26% of TC. Pre-procedural CT/MR performed in 73.2% of TC identified additional pulmonary veins in 23.6%; advanced imaging was rarely performed before SC and identified additional veins in 5.3% only. Surgical and bypass times in SC far exceeded procedural and fluoroscopic times in TC. Hospital and intensive care stay were significantly lower in TC. Three procedural failures in TC (2.4%) due to stent embolization occurred in early learning curve. Acute complications in 18.1% of TC and 9.1% of SC were successfully managed. Late complications occurred in 23.8% of SC (SVC or RUPV stenosis, residual shunt, and sinus nodal dysfunction) and 12% of TC (stent thrombosis or residual shunt). Reinterventions were required in 4.6% after SC and 1.6% after TC. SC and TC had comparable outcomes, complications, and reinterventions. TC is an attractive option in adults especially with comorbidities and pulmonary hypertension. Continued surveillance is mandatory to determine the long-term outcomes.