Feasibility of using his bundle pacing with boston scientific generators

Introduction

His bundle pacing (HBP) aims to deliver physiological activation of the ventricles via the native His-Purkinje conduction system. A challenge of HBP is the limited market of implantation tools, pacing leads and specifically designed pacing algorithms.

Purpose

Over the last three years both Medtronic (MDT) and Boston Scientific (BSC) generators have been used for HBP in a large tertiary centre. We examined whether there was any difference between lead parameters and battery longevity depending on the type of manufacturer used.

Methods

Patients implanted with a MDT Select Secure model 3830 lead were included in this retrospective study. Data collected included HBP thresholds (analysed at 1ms pulse width) at implant and at the most recent device check, HBP percentages and battery longevity (months). Battery longevity were calculated by adding duration of follow up and estimated battery life at last follow up.

Results

A total of 31 patients were included for data analysis (58% male and mean age 72 years). 18 patients had MDT generators of which 3 were PPMs, 5 were CRT-Ps and 10 were CRT-Ds. 13 patients had BSC generators of which 5 were PPMs, 5 were CRT-Ps and 3 were CRT-Ds. Mean follow up of the cohort was 12.7±9.02 months.

Mean HBP percentages were 77±37% and 72.2±42.1% for MDT and BSC, respectively (p=0.430). Mean HBP threshold (Volts) at implant was significantly lower with BSC vs MDT (0.85±0.58 vs 1.84±1.06, p=0.01), and similar after follow up (1.01±0.91 vs 1.32±0.73, p=NS). There were no statistically significant differences between mean HBP threshold at implant compared to follow up for both manufacturers.

Interestingly, mean battery longevity for BSC vs MDT generators was significantly higher (136±29.3 vs 90.5±29.1, p<0.001). Longevity was also compared for PPM/CRT-P and CRT-D separately. For PPM/CRT-P, BSC generators had significantly higher longevity as compared to MDT (141.6±33.1 vs 91.6±34.5, p=0.009). This difference was not observed for CRT-Ds between the 2 manufacturers (p=0.068).

Conclusion

Our results suggest HBP with MDT Select Secure 3830 lead is feasible with BSC generators. There is potentially greater battery longevity with BSC compared to MDT generators. Further studies are needed with greater numbers and longer follow up to confirm this finding.

Funding Acknowledgement

Type of funding sources: None.

Long-term outcomes of catheter ablation for ventricular arrhythmias in post- myocarditis patients; Insights from a meta-analysis of current datv

Background

In the past decade, catheter ablation (CA) has become a rapidly expanding treatment option for ventricular tachycardia (VT), however it is not commonly utilized for patients with post-myocarditis VT. We aimed to systematically review up-to-date evidence regarding feasibility, effectiveness, and safety of CA, with a specific focus on long-term relapse rate and procedural complications.

Methods

A structured electronic database search (PubMed, Embase, Cochrane) of the scientific literature was performed for studies describing outcomes at up to 7.3 years after CA. The primary outcome measured was VT recurrence post-ablation. Procedural success was defined as freedom of ventricular arrhythmias (at the end of follow-up after an ablation procedure). The secondary outcome was significant procedural complications which included procedural death, stroke, cardiac tamponade, acute myocardial infarction, major vascular complications, and major bleeding, assessed on a study-by-study basis.

Results

A total of 186 patients were included in analysis with most patients (88%) being male.

Over the follow up period there was a 18% relapse rate (n=34) (Confidence Interval (CI); 0.12–0.24, I2≈0, p=0.77) with the majority of patients remaining VT free for the duration of follow up. Only one study recorded the percentage of re-do procedures. The overall procedural complication rate was 3.0% (n=7, (CI; 0.01–0.07, I2≈0, p=0.44) and of note, there were no peri-procedural deaths or heart transplant surgeries reported. However, a single study reported a mortality of 10% (n=2) during the follow up period.

Conclusions

CA is an effective and durable long-term therapeutic strategy for post myocarditis VT patients with limited relapse rate and very low complication rates based on these non-randomised data. Larger randomised-controlled trials with standardised treatment and long follow-up are required to compare CA versus conventional treatment in the post-acute myocardial phase.

Funding Acknowledgement

Type of funding sources: None. Relapse rate during follow-upProcedural complication rate

Initial experience with the convergent procedure for longstanding persistent atrial fibrillation: A 5 year dataset

In patients with longstanding persistent atrial fibrillation (AF), outcomes from catheter ablation remain suboptimal. The convergent procedure combines minimally invasive surgical ablation with subsequent catheter ablation, and may contribute towards maintenance of sinus rhythm in this patient group. We performed the convergent procedure on 43 patients with longstanding persistent AF from 2013–2018. Patients underwent clinical review at 3, 6, and 12 months and thereafter as necessitated by their symptoms. Our dataset describes patients’ baseline characteristics and rhythm control protocols, as well as outcomes including arrhythmia recurrence, the need for antiarrhythmic drugs, requirement for repeat rhythm control procedures, and complications. These data provide a real world insight into the risks and benefits of the convergent procedure in patients with longstanding persistent AF.

2229Apoptotic and non-apoptotic circulating microparticles in patients with acute coronary syndromes

Background

Circulating microparticles (MP) are surrogate biomarkers of atherosclerosis but their role in patients with acute coronary syndromes (ACS) remain unknown.

Purpose

To explore the levels of apoptotic and non-apoptotic MP in patients with ACS.

Methods

We enrolled a total of 153 patients as follows: 49 patients with STEMI, 35 NSTEMI, 38 with unstable angina (UA), 15 with stable CAD (SCAD) and 16 non-CAD (controls). Flow cytometry analysis was used to quantify circulating apoptotic (annexin+) and non-apoptotic endothelial cell (EMP), red blood cell (RMP) and platelet (PMP) derived microparticles. Circulating C-reactive protein (hsCRP) levels and cardiac troponin I (cTnI) were also assessed. Brachial FMD was also determined as a marker of endothelial function.

Results

There was a stepwise increase in the total number of EMP, RMP and PMP in patients with ACS (STEMI/NSTEMI) compared to UA, SCAD and non-CAD patients. This was mainly explained by the increase in the number of apoptotic EMP, RMP and PMP (a-c), while there were no significant differences in the level of apoptotic EMP, RMP or PMP between patient subgroups (not shown). There was no association between circulating levels of apoptotic or non-apoptotic EMP, RBP or PMP with hsCRP (p=NS for all). Apoptotic EMP only were negatively associated with brachial FMD (rho=−0.185, p=0.04) and positively with cTnI levels (rho= 0.307, p<0.0001).

Conclusions

Circulating apoptotic (but not non-apoptotic) MP are increased in patients with ACS. A negative association is observed between the numbers of circulating apoptotic EMP only and systemic endothelial function. The biological role of circulating apoptotic microparticles' in the pathogenesis of ACS merits further investigation.

P6506Circulating microparticles preceding endothelial dysfunction and inflammatory process in patients with pseudoexfoliative glaucoma

Background

Pseudoexfoliative glaucoma (PEX) is a type of glaucoma characterized by the secretion of a grey-white, fibrogranular material in several tissues. Microparticles are shed membrane vesicles released from a variety of cell types in response to cellular activation or apoptosis and correlate with the pathogenesis of cardiovascular diseases. Endothelial MPs may be used as biomarkers of endothelial function.

Purpose

To evaluated the role of endothelial dysfunction, arterial stiffness and systemic inflammation in patients with PEX compared to patients with Primary open angle glaucoma (POAG) and control subjects as well as the possible pathophysiologic role of a specific microparticle profile associated with endothelial damage.

Methods

We enrolled 29 subjects with PEX, 57 subjects with POAG and 44 control subjects. Endothelial function was evaluated by flow-mediated dilation (FMD). Pulse wave velocity (PWV) was measured as an index of aortic stiffness and augmentation index (AIx) as a measure of arterial wave reflections. Growth differentiation factor-15 (GDF-15) and intercellular adhesion molecule1 (ICAM1) were measured to evaluate systemic inflammatory status. Total circulating MPs and EMPs were isolated and analysed by flow cytometry, utilizing specific labels for EMPs (CD 144+) and Annexin V staining for phospatidylserine bearing-MPs (AnnexinV + MPs).

Results

There was a linear impairment in FMD (p=0.005), PWV (p=0.007) and Aix (p=0.02) and a stepwise increase in GDF-15 (p=0.001) and sICAM-1 levels (p=0.08) between the three study groups (control, POAG, PEX). Interestingly, the PEX subjects expressed greater levels of total circulating MPs (Annexin V+) [1698 (1199–5894) MPs/μL vs. 1641 (1470–2705) MPs/μL. vs 493 (417–1512) MPs/μL, p=0.004] and EMPs (CD144+)[1412 (645–1760) MPs/μL3 vs 1380 (498–2496) MPs/μL vs 34 (184–870) MPs/μL, p<0.001] compared to POAG and control subjects.

Conclusion

Pseudoexfoliative glaucoma is associated with impaired endothelial function, arterial wall properties and vascular inflammation with a parallel increase in EMPs. Our findings indicate the significant role of endothelial damage in the progress of glaucomatous disease especially in subjects with pseudoexfoliative glaucoma.

Long-term changes in the structure of benthic communities: Revisiting a sampling transect in Crete after 24 years

A bathymetric transect in the north coast of Crete first studied in 1989, was revisited 24 years later. Identical sampling design, season, techniques and protocols were followed in both studies in order to minimize bias in the long-term comparisons. This comprehensive macrofaunal dataset (4 stations, 2 sampling seasons, 7 replicates in each study) revealed changes in benthic diversity and community composition between the sampling periods. The recorded changes were higher at the stations located close to the coastal zone. In addition, while benthic communities showed lower total abundance during the recent sampling period, species abundances were more evenly distributed indicating that some species dominated the historical communities. In spite of these changes, the ecological status remained above the threshold values for good ecological status. The results indicated that changes in the benthic community seem to have been driven by local anthropogenic factors and natural variability rather than by large-scale factors such as nutrients influxes in the entire Mediterranean Basin.

Registry report of the prevalence of ECG abnormalities and their relation to patient characteristics in an asymptomatic population

BACKGROUND

Cardiovascular disease is the leading cause of morbidity and mortality in developed countries. Many patients do not experience symptoms before a first major cardiovascular event. Resting electrocardiogram (ECG) may help identify asymptomatic individuals with a high risk of cardiovascular disease.

OBJECTIVE

We sought to determine the prevalence of ECG abnormalities in an apparently symptom-free adult population within a prospective registry.

METHODS

The registry consisted of 4739 consecutive apparently healthy individuals [age 62.8 ± 6.2 (SD) years; 54% female], referred by their General Practitioners between 2009 and 2013. Patient demographics, and clinical data were obtained, alongside blood tests and a resting ECG.

RESULTS

ECG abnormalities were present in 1509 (31.8%) subjects and were commoner with increasing age (F = 0.161, p = 0.01), systolic (F = 0.134, p = 0.01) and diastolic (F = 0.44, p = 0.01) blood pressure and waist circumference (F = 0.53, p = 0.01). Left ventricular hypertrophy (LVH) was the most common abnormality (n = 281) and was positively associated with systolic (F = 0.12, p = 0.01) and diastolic blood pressure (F = 0.99, p = 0.01) and male gender (X2 = 60.5, p < 0.01). All ECG abnormalities (except for LVH) were associated with an increasing age, while right bundle branch block (F = 0.041, p = 0.01) and atrial fibrillation (n = 29; F = 0.036, p = 0.05) were associated with the presence of diabetes mellitus (n = 211). Only left bundle branch block (n = 50) was associated with angina (F = 0.05, p = 0.01).

CONCLUSIONS

Unrecognized cardiac abnormalities are common in middle-aged men and women with no overt symptoms. ECG offers the potential to identify these abnormalities and provide earlier intervention and treatment, and possibly improve cardiovascular outcome.

Metals in tissues of seabass and seabream reared in sites with oxic and anoxic substrata and risk assessment for consumers

Twenty-eight metals and elements were measured in the muscle, liver, gills, bone and intestine of farmed seabass and gilthead seabream from four Mediterranean fish farms. The influence of fish species and the effect of environmental conditions on the metal accumulation in fish tissues was investigated. Most concentrations were lower in muscle and higher in liver and bone than in other body tissues. Seabass accumulates more elements in its tissues than seabream. Fish reared in coarse, oxic sites accumulate more elements with higher concentrations in muscle, bone and intestine and with lower concentrations in liver and gills than fish reared in silty, anoxic sites. This may be attributed to feed type and sediment properties. According to the metal pollution index, hazard quotient, selenium health benefit values, carcinogenic risk of arsenic, maximum safe consumption and the permitted limits, the consumption of both farmed species should be considered as safe for human health.

Metals in benthic macrofauna and biogeochemical factors affecting their trophic transfer to wild fish around fish farm cages

Benthic macroinvertebrates and wild fish aggregating in the vicinity of four Mediterranean fish farms were sampled. Concentrations of metals and other elements were measured in macrofaunal taxa and in fish tissues (muscle, liver, gills, bone, gonad, stomach, intestine, and stomach content). Biological and geochemical characteristics play an important role in metal accumulation in benthic invertebrates, and consequently in metal transfer to higher trophic levels. Macroinvertebrates accumulated lower concentrations of most metals and elements than their respective sediment, except As, P, Na, Zn and Cd. Elemental concentrations of benthic organisms increased with increasing sediment metal content, except Cd, and with % silt, refractory organic matter and chlorophyll-a of sediment due to the influence of sediment geochemistry on metal bioavailability. Tolerant species were found to accumulate higher concentrations of most metals and elements, except for Cd, than equilibrium species. The ecological and morphological characteristics of the benthic invertebrates can affect the bioaccumulation of metals and elements in macrobenthos. Hg and P were found to increase their concentrations from zoobenthos to wild fish aggregating around fish cages feeding on macrofauna.

Heavy metals, trace elements and sediment geochemistry at four Mediterranean fish farms

Trace element concentrations in sediment were investigated at four fish farms in the Eastern Mediterranean Sea. Fish farms effects were negligible beyond 25-50 m from the edge of the cages. Based on elemental distribution, sediments from the farms were separated into coarse oxidized and silty reduced ones. Fish feed is richer in P, Zn and Cd than reference and impacted stations. Comparison among impacted stations and the respective reference stations shows that, in anoxic sediments, all elements had higher concentrations at the impacted stations than at reference stations while in oxic sediments, many elemental concentrations were lower at impacted stations than at reference stations. The behavior of elements and therefore their distribution is affected by changes in sediment grain size, organic content and redox regime. Elements in sediments around fish farms can be clustered into five groups according to these environmental variables. In silty and anoxic sediments, element concentrations were higher than in coarse and oxic ones. Several approaches were used to assess potential sediment toxicity (enrichment factors, geoaccumulation indices, contamination factors) as well as to assess the potential danger to aquatic life (Sediment Quality Guidelines, SQG). Cu, Zn and Fe can cause from threshold to extreme effects on aquatic life in anoxic, fine-grained sediments and As can cause threshold effects in all types of sediment around fish farms. Other elements (Cr, Pb, Mn) can also cause unwanted effects when compounded with elevated background levels.

The role of microRNAs in cardiovascular disease

Cardiovascular disease, which is multifactorial and can be influenced by a multitude of environmental and heritable risk factors, remains a major health problem, even though its pathophysiology is far from been elucidated. Discovered just over a decade ago, microRNAs comprise short, non-coding RNAs, which have evoked a great deal of interest, due to their importance for many aspects of homeostasis and disease. Hundreds of different microRNAs are constantly being reported in various organisms. According to a growing body of literature, they have been implicated in the regulation of human physiological processes. More specifically, miRNAs are expressed in the cardiovascular system and could have crucial roles in normal development and physiology, as well as in disease development. Furthermore, they have been shown to participate in cardiovascular disease pathogenesis including atherosclerosis, coronary artery disease, myocardial infarction, heart failure and cardiac arrhythmias. In contrast to our original thought, miRNAs exist in circulating blood and are relatively stable, thus, they could be proved useful as biomarkers in that state. Understanding the underlying mechanisms, in which these major regulatory gene families are implicated, will provide novel opportunities for diagnosis and therapy of cardiovascular diseases.

Monitoring calcific aortic valve disease: the role of biomarkers

Calcific aortic valve disease is a common disease in the elderly associated with significant morbidity and mortality. It was once described as a passive degenerative process during which serum calcium attaches to the valve surface and binds to the leaflet. However, during the last decade mounting evidence demonstrated that this disease has an active biologic process with numerous signaling pathways. The histological hallmarks seem to be inflammation, oxidized lipids-also detectable in aortic valve lesions-and a remodeling of the extracellular matrix leading to bone formation. Over the years, growing evidence has indicated the risk factors for calcific aortic stenosis including lipids, hypertension, male gender, renal failure, and diabetes. Additional monitoring tools, such as molecular imaging, could improve risk stratification, while assessment of severity and prognosis of patients with chronic aortic regurgitation, is desirable. Also, several studies have investigated the role of biomarkers regarding their utility in the screening of calcific aortic valve disease and their putative clinical value, though their role still remains undetermined.

The role of microRNAs in cardiovascular disease

Cardiovascular disease, which is multifactorial and can be influenced by a multitude of environmental and heritable risk factors, remains a major health problem, even though its pathophysiology is far from been elucidated. Discovered just over a decade ago, microRNAs comprise short, non-coding RNAs, which have evoked a great deal of interest, due to their importance for many aspects of homeostasis and disease. Hundreds of different microRNAs are constantly being reported in various organisms. According to a growing body of literature, they have been implicated in the regulation of human physiological processes. More specifically, miRNAs are expressed in the cardiovascular system and could have crucial roles in normal development and physiology, as well as in disease development. Furthermore, they have been shown to participate in cardiovascular disease pathogenesis including atherosclerosis, coronary artery disease, myocardial infarction, heart failure and cardiac arrhythmias. In contrast to our original thought, miRNAs exist in circulating blood and are relatively stable, thus, they could be proved useful as biomarkers in that state. Understanding the underlying mechanisms, in which these major regulatory gene families are implicated, will provide novel opportunities for diagnosis and therapy of cardiovascular diseases.

Methionine-induced homocysteinemia impairs endothelial function in hypertensives: the role of asymmetrical dimethylarginine and antioxidant vitamins

BACKGROUND

Nitric oxide synthase (NOS) inhibitor asymmetrical dimethylarginine (ADMA) is synthesized by the methylation of arginine as part of the methionine/homocysteine cycle. However, the mechanisms regulating ADMA synthesis in hypertension are unclear.

METHODS

We investigated the role of ADMA and antioxidants in endothelial dysfunction during methionine-induced homocysteinemia in hypertensives. Thirty-nine hypertensives and forty-nine normotensive controls underwent methionine loading (100 mg methionine/kg BW), after being randomized to receive vitamin C (2 g) and E (800 IU) or placebo. Endothelium-dependent dilation (EDD) was evaluated by plethysmography (baseline and 4-h post-methionine loading (4-h PML)).

RESULTS

Hypertensives had higher homocysteine at baseline (P < 0.001) and 4-h PML (P < 0.05), whereas methionine increased homocysteine in all groups. EDD was decreased in both vitamins and placebo groups in controls (P < 0.01 for both) and vitamins- and placebo-treated hypertensives (P < 0.05 and P < 0.01, respectively). In controls, ADMA was increased in both vitamin- and placebo groups (P < 0.01 for both) at 4-h PML. Hypertensives had higher ADMA at baseline (P < 0.01 vs. normotensive) and remained unchanged at 4-h PML (P = NS in placebo and vitamins treated).

CONCLUSIONS

ADMA is elevated in hypertensives but remains unchanged after methionine loading, suggesting that ADMA plays an important role in endothelial dysfunction in hypertensives, but it is not responsible for homocysteine-induced endothelial dysfunction in these patients.

The role of the cytochrome P450 polymorphisms in clopidogrel efficacy and clinical utility

Clopidogrel, an antiplatelet agent, prevents platelet aggregation by inhibiting the adenosine disphosphate (ADP) P2Y12 receptor, which is located on the platelet surface. Although dual antiplatelet therapy appears to be efficient, a considerable number of patients continue to experience adverse cardiovascular events, such as stent thrombosis. The percentage of low response to antiplatelet therapy varies from 4% to 30% of patients depending on the cut-off values. In addition, several factors such as poor absorption, drug-to-drug interactions, inadequate dosing, elevated body mass index, insulin resistance and the nature of acute coronary syndromes have been implicated in low clopidogrel response. Recently, studies have focused on the role of genetic polymorphisms encoding enzymes that participate in clopidogrel hepatic metabolism or receptors involved in intestinal absorption and ADP induced platelet aggregation, which may affect the percentage of platelet inhibition after clopidogrel administration. The management of clopidogrel resistance remains a controversial issue and additional studies are required to evaluate the safety and efficacy of increased loading of clopidogrel or replacement with other new antiplatelet agents such as prasugrel.

Infant colonization by Staphylococcus aureus: role of maternal carriage

Infant colonization by Staphylococcus aureus has not been adequately investigated. In this study, we aimed to define determinants associated with the carriage of S. aureus in early infancy. Serial nasal swabs were collected from 128 infants and their mothers at months 0, 6, and 12 postpartum. S. aureus isolates were characterized by pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), spa typing, and the presence of chromosomal mecA and of Panton-Valentine leukocidin (PVL) genes. S. aureus was isolated in 17.7% and 15.7% of swabs from infants and mothers, respectively. Carriage rates were higher in infants with carrier mothers, non-smoking mothers, and many siblings. Persistent carriage rates were higher in infants with carrier or non-smoking mothers. S. aureus typing revealed identical strains in 10/15 investigated infant-mother pairs. Among 19 investigated S. aureus isolates from infants, ten harbored mecA and two harbored PVL genes, and these determinants were concomitantly present in isolates from mothers. Resistance to methicillin was 43.6% among all isolates from infants. In conclusion, isolates from infants were commonly identical to isolates from their mothers, pointing to a principal role of maternal carriage in S. aureus colonization in infants.

Endothelial dysfunction: potential clinical implications

Vascular endothelium is responsible for the secretion of several substances exerting anti-atherogenic effects. Endothelial damage is also crucial for the progress of atherosclerosis and risk factors for atherosclerosis represent crucial factors associated with endothelial dysfunction. Studies have shown that patients with cardiovascular disease are characterized by impaired endothelial function (EF). Therefore, several agents have been proposed as potential modulators of EF. Most of the available approaches include pharmaceutical agents routinely used such as statins, angiotensin converting enzyme inhibitors, antioxidants, L-arginine, insulin sensitizers or others still under investigation such as tetrahydrobiopterin or folic acid (folate). Despite of the fact that there are several strategies aiming to improve endothelial dysfunction by enhancing nitric oxide bioavailability, it is still unclear whether they could be beneficial at a clinical level.

A Chryseobacterium meningosepticum colonization outbreak in a neonatal intensive care unit

PURPOSE

To report the epidemiologic, bacteriologic, and clinical features of a Chryseobacterium meningosepticum outbreak in a neonatal intensive care unit (NICU) of a referral teaching hospital.

PATIENTS AND METHODS

From April to October 2002, a strain of C. meningosepticum was isolated from four neonates in the NICU. All neonates were colonized in the endotracheal tubes and respiratory secretions, but none of them progressed to clinical infection. Multiple samples were obtained for cultures.

RESULTS

Pulsed-field gel electrophoresis (PFGE) of isolates showed them to be representatives of a single strain. Environmental surveillance did not reveal the C. meningosepticum source. None of the neonates received specific treatment. The outbreak was only controlled by reinforcement of the usual measures and no additional colonization/infection was confirmed for more than a year after the last case.

CONCLUSION

This study suggests that C. meningosepticum colonization in neonates does not necessarily lead to infection and that such colonization outbreaks may be controlled with emphasis on the standard precautions.