The obesity paradox in patients with atrial fibrillation: an insight from the Gulf SAFE registry

Background

The prognostic role of obesity among patients with atrial fibrillation (AF) is unclear.

Methods

A total of 1804 patients with AF had body mass index (BMI) measures from the Gulf survey of atrial fibrillation events (Gulf SAFE) registry were implied. A multivariable model was established to investigate the role of obesity on clinical outcomes, including stroke or systemic embolism, bleeding, admission for heart failure (HF) or AF, all-cause mortality and composite event.

Results

559 (31.0%) patients were identified as obesity (BMI over 30kg/m2). In multivariable analyses, obesity was associated with reduced risks of stroke/systematic embolism (hazard ratio [HR] 0.40, 95% confidence interval [CI] 0.18–0.89), major or clinical relevant bleeding (HR 0.44, 95% CI 0.26–0.74), HF admission (HR 0.61, 95% CI 0.41–0.90) and composite outcome (HR 0.65, 95% CI 0.50–0.84). Higher BMI was associated with lower risks of stroke/systemic embolism, bleeding, admission for HF, all-cause mortality, and composite outcomes as were demonstrated by accumulated incidence of events and restricted cubic splines.

Conclusion

Among patients with AF, higher BMI was associated with a more favorable prognosis.

The hazard ratio for BMI and outcomes

Funding Acknowledgement

Type of funding source: None

Symptom status, clinical subtypes and prognosis in Middle East patients with atrial fibrillation: a report from the Gulf-SAFE registry

Background

Atrial fibrillation (AF) is often asymptomatic. The prognosis of asymptomatic AF is similar or worse than symptomatic AF, but there are no such data from Middle East.

Method

The Gulf survey of AF events (Gulf SAFE) registry is a multi-center prospective survey of AF patients from six countries (23 centers) in the Gulf Region (n=2043). We investigated the prognostic outcomes of asymptomatic AF, in relation to clinical subtypes.

Result

541 (26.5%) AF patients were asymptomatic; they tended to be older, with higher prevalence of hypertension, heart failure (HF), diabetes, stroke, renal dysfunction, and higher CHADS2, CHA2DS2-VASc, and HAS-BLED scores (all p<0.05). After multivariable adjustment, asymptomatic AF was associated with higher risks of stroke/systematic embolism (SE) (odds ratio [OR] 2.18, 95% confidence interval [CI] 1.10–4.34), all cause-mortality (OR 2.85 [1.90–4.28]) and the composite outcome of stroke/SE, bleeding and all-cause mortality (OR 1.74 [1.26–2.41]).

Asymptomatic AF was associated with fewer admissions for AF (OR 0.53 [0.32–0.83]) and HF (OR 0.58 [0.38–0.86]).

The increased risk of stroke/SE in asymptomatic AF was associated with paroxysmal AF (Figure 1; P interaction=0.028).

Conclusion

In this large Middle East cohort, asymptomatic AF was common, less likely hospitalized but associated with unfavorable prognosis. When AF was asymptomatic, the paroxysmal subtype had a greater association with stroke/SE.

Adjusted odds ratio of clinical outcomes

Funding Acknowledgement

Type of funding source: None

Catheter ablation in highly symptomatic Brugada patients: a Dutch case series

AIMS

In the past few years, promising results were described in targeting the arrhythmogenic substrate of the epicardial right ventricular outflow tract (RVOT) region in patients with Brugada syndrome (BrS). In this report, we describe our experience with endo- and epicardial substrate mapping and ablation in a series of highly symptomatic BrS patients.

METHODS

This case series consists of seven patients with clinical BrS diagnosis who underwent catheter ablation in two Dutch hospitals (Isala hospital Zwolle; and Amsterdam University Medical Centre, location AMC, Amsterdam) and Hamad Heart Hospital in Qatar between 2013 and 2017. All patients had an ICD and recurrent ventricular arrhythmia (VA) episodes. All patients underwent endo-and epicardial mapping of the RVOT region. Elimination of all abnormal potentials and disappearance of BrS ECG pattern during the ablation procedure was the aimed endpoint.

RESULTS

The study group consisted of seven patients with mean age 45.6 ± 16.9 years. Five patients had SCN5A mutations. One patient was excluded from analysis, since ablation could not be performed due to a very large low-voltage area and was later diagnosed with arrhythmogenic right ventricular cardiomyopathy, associated with an SCN5A mutation. One patient underwent both endo- and epicardial ablation to eliminate VA. During a mean follow-up of 3.6 ± 1.5 years, 5/6 patients remained VA free with two patients continuing quinidine.

CONCLUSION

In patients with BrS and drug-refractory VA, ablation of the arrhythmogenic substrate in the RVOT region was associated with excellent long-term VA-free survival. The majority of these highly symptomatic BrS patients had an SCN5A mutation and also low-voltage areas epicardially.

Impact of Digoxin on Mortality in Patients With Atrial Fibrillation Stratified by Heart Failure: Findings From Gulf Survey of Atrial Fibrillation Events in the Middle East

OBJECTIVE

The use of digoxin in patients having atrial fibrillation (AF) with or without heart failure (HF) is not without controversy. The aim of this study was to examine the impact of digoxin therapy on mortality stratified by HF.

METHODS

Gulf Survey of Atrial Fibrillation Events was a prospective, multinational, observational registry of consecutive patients with AF recruited from the emergency department of 23 hospitals in 6 countries in the Middle East. Patients were recruited between October 2009 and June 2010 and followed up for 1 year after enrollment. Analyses were performed using univariate and multivariate statistical techniques.

RESULTS

The study included a total of 1962 patients with AF, with an overall mean age of 56 ± 16 years, and 52% (n = 1026) were males. At hospital discharge, digoxin was prescribed in 36% (n = 709) of the patients, whereas HF was present in 27% (n = 528) of the cohort. A total of 225 (12.1%) patients died during the 12-month follow-up period after discharge (5.3% [n = 104] were lost to follow-up). Patients with HF were consistently associated with higher mortality at 1 month (5.1% vs 2.1%; P < .001), 6 months (17.2% vs 5.0%; P < 0.001), and 12 months (24.3% vs 7.6%; P < .001) when compared to those without HF. When stratified by HF, digoxin therapy was associated with significantly higher mortality in those without HF at 6 months (8.7% vs 3.7%; adjusted odds ratio (aOR), 5.07; P < .001) and 12 months (12.3% vs 6.0%; aOR, 4.22; P < .001) but not in those with HF (6 months: 18.6% vs 14.7%; aOR, 1.62; P = .177 and 12 months: 25.4% vs 22.4%; aOR, 1.37; P = .317).

CONCLUSIONS

In patients with AF and HF, digoxin did not offer any survival advantages. However, in those without HF, digoxin therapy was, in fact, associated with significantly higher long-term mortality.

The prognostic implications of lack of palpitations in patients hospitalised with atrial fibrillation: observations from a 20-year registry

OBJECTIVES

It is well recognised that patients differ in the clinical presentation of atrial fibrillation (AF), ranging from the typical symptom of palpitations, atypical symptoms in others and a substantial that are asymptomatic. Whether the different patterns of presentation are associated with differences in outcomes is not known. The aim of this study was to evaluate the prevalence and the prognostic implications of lack of palpitations among patients hospitalised with AF in a large prospective registry.

METHODS

Retrospective analysis of all patients hospitalised with AF in Qatar from 1991 to 2010 was made. Patients were divided into two groups according to the presence or absence of palpitations on presentation. Clinical characteristics and outcome were analysed.

RESULTS

During the 20-year period, 3850 patients were hospitalised for AF; 1724 (44.8%) had palpitations on presentation while 2126 (55.2%) had no palpitations. Patients who lacked palpitations were 9 years older, had a higher prevalence of diabetes mellitus (64.7% vs. 35.3%), underlying coronary artery disease (CAD; 14.6% vs. 6.2%) and severe left ventricular dysfunction on echocardiography (25.5% vs. 6.6%), (all, p = 0.001). There were 141 deaths among the group with no palpitations compared with 19 among the group with palpitations (6.6% vs. 1.1%). Multivariate analysis of mortality predictors identified 'lack of palpitations' as an independent predictor of in-hospital mortality (relative risk 5.56; 95% confidence interval 1.20-25.0, p = 0.03).

CONCLUSIONS

Our study demonstrates for the first time that lack of palpitations as the presenting symptom of patients with AF is associated with worse in-hospital outcome independent of other risk factors or therapy. The underlying mechanisms and the role of confounders warrant further investigation.

In-hospital complications and 1-year outcome of acute coronary syndrome in patients with hypertension: findings from the 2nd Gulf Registry of Acute Cardiac Events

Using data from the 2nd Gulf Registry of Acute Coronary Events (Gulf RACE-2) in 2008-09 we investigated the in-hospital complications and 1-year outcome of acute coronary syndrome (ACS) in patients with systemic hypertension from 6 Gulf countries. Of 7847 consecutive patients admitted with ACS, 3746 (47.7%) had hypertension. Hypertension was more prevalent in women, in Arabs than non-Arabs and in older age groups. Patients with hypertension were more likely than those without hypertension to present with dyspnoea and advanced Killip class. Among hypertensive patients, the mortality rate was higher only among those admitted with ST-elevation myocardial infarction. After adjustment for baseline variables, hypertension was an independent predictive factor for heart failure (OR = 1.31) and stroke (OR = 2.47). here were no significant differences in mortality in hypertensive ACS patients when stratified by sex, age or ethnicity.

The impact of adaptive and non-targeted effects in the biological responses to low dose/low fluence ionizing radiation: the modulating effect of linear energy transfer

A large volume of laboratory and human epidemiological studies have shown that high doses of ionizing radiation engender significant health risks. In contrast, the health risks of low level radiation remain ambiguous and have been the subject of intense debate. To reduce the uncertainty in evaluating these risks, research advances in cellular and molecular biology are being used to characterize the biological effects of low dose radiation exposures and their underlying mechanisms. Radiation type, dose rate, genetic susceptibility, cellular redox environment, stage of cell growth, level of biological organization and environmental parameters are among the factors that modulate interactions among signaling processes that determine short- and long-term outcomes of low dose exposures. Whereas, recommended radiation protection guidelines assume a linear dose-response relationship in estimating radiation cancer risk, in vitro and in vivo investigations of phenomena such as adaptive responses and non-targeted effects, namely bystander effects and genomic instability, suggest that low dose/low fluence-induced signaling events act to alter linearity of the dose-response relation as supported by the biophysical argument. The latter predicts that increases in dose simply increase the probability that a given cell in a tissue will be intersected by an electron track, and by corollary, each unit of radiation, no matter how small would increases risk. These predictions assume that similar molecular events mediate both low and high dose radiobiological effects, and the cumulative risk from two sequential radiation exposures can never be less than one alone.

Microenvironmental Changes in DCIS: Myoepithelial Cells Change from Tumour Suppressor to Tumour Promoter

Background: The mechanism of transition of ductal carcinoma in-situ (DCIS) to invasive cancer is poorly understood but recently changes in the microenvironment have been implicated. A unique feature of the DCIS microenvironment is the presence of a myoepithelial population. Normal myoepithelial cells (MECs) have a broad tumour suppressor function but these cells show changes in gene expression and phenotype in DCIS.Hypothesis: We hypothesised that during the evolution of DCIS breast myoepithelial cells undergo a switch in gene expression profile that compromises their suppressor function and may lead to promotion of tumour progression.Materials and methods: To investigate this, Immuno-Laser Capture Microdissection was used to isolate MECs from normal and DCIS breast tissues followed by whole genome expression profiling using Affymetrix HGU-133 plus2.0 arrays. The data were analysed using Bioconductor (www.bioconductor.org) packages within the open source R statistical environment (www.r-project.org). We set a double threshold for significant changes in gene expression with a False Discovery Rate (FDR) &lt;= 0.05 and an absolute fold change ≥4.5.Results: Ingenuity Pathways software analysis showed clustering of most of the altered genes in cancer, cell death and cell-cell signalling networks, with the integrin pathway as the top canonical pathway. Validation using QRT-PCR and immunohistochemistry (IHC) revealed a 71.4% correlation rate with the array results. Most dramatic was up-regulation of Fibronectin-1 (FN1) in DCIS MEC. IHC analysis for FN1 on normal (n=88) and DCIS tissues with and without associated invasion (n=87) confirmed a strong correlation between FN1 protein expression by MEC and DCIS (p&lt;0.0001). We set cut off point of 50% for percentage of ducts showing positive staining for FN1 by MECs in pure DCIS cases and DCIS cases that have progressed to IDC and found a statistically significant correlation between high expression level (&gt;50%) and presence of invasion (p=0.006). Moreover, culture of normal and DCIS-modified MEC lines on a Fibronectin matrix revealed that FN1 modifies MEC function and abrogates their tumour suppressor activity.Other key alterations identified and validated include up-regulation of the recently characterised Nephronectin and down-regulation of PTHLH, FGFR2, ADAMTS5, TGFBR3, and CAV2, each of which has been implicated in suppressing tumour growth and invasion or inhibition of angiogenesis.Conclusion and significance: This is the first study to use this in-vivo technique to investigate molecular changes in MEC in DCIS and to reveal that DCIS associated MECs show up-regulation of the tumour-promoting molecule FN1. Our data support the hypothesis that there is switch in MEC function from suppressor to potential promoter activity that can influence the progression of in-situ to invasive disease and may lead to novel predictive and therapeutic targets.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4161.

Adaptive responses to low-dose/low-dose-rate gamma rays in normal human fibroblasts: the role of growth architecture and oxidative metabolism

To investigate low-dose/low-dose-rate effects of low-linear energy transfer (LET) ionizing radiation, we used gamma-irradiated cells adapted to grow in a three-dimensional architecture that mimics cell growth in vivo. We determined the cellular, molecular and biochemical changes in these cells. Quiescent normal human fibroblasts were irradiated with single acute or chronic doses (1-10 cGy) of (137)Cs gamma rays. Whereas exposure to an acute dose of 10 cGy increased micronucleus formation, protraction of the dose over 48 h reduced micronucleus frequency to a level similar to or lower than what occurs spontaneously. The protracted treatment also up-regulated the cellular content of the antioxidant glutathione. These changes correlated with modulation of phospho-TP53 (serine 15), a stress marker that was regulated by doses as low as 1 cGy. The DNA damage that occurred after exposure to an acute dose of 10 cGy was protected against in two ways: (1) up-regulation of cellular antioxidant enzyme activity by ectopic overexpression of MnSOD, catalase or glutathione peroxidase, and (2) inhibition of superoxide anion generation by flavin-containing oxidases. These results support a significant role for oxidative metabolism in mediating low-dose radiation effects and demonstrate that cell culture in three dimensions is ideal to investigate radiation-induced adaptive responses. Expression of connexin 43, a constitutive protein of gap junctions, and the G(1) checkpoint were more sensitive to regulation by gamma rays in cells maintained in a three-dimensional than in a two-dimensional configuration.

Epstein-Barr viral infection in extranodal lymphoma of the head and neck: correlation with prognosis and response to treatment

AIMS

To determine the prevalence of Epstein-Barr virus (EBV) infection in primary extranodal lymphoma of the head and neck (PELHN) in immunocompetent patients. PELHN represents 16.18% of all lymphoma diagnosed at the National Cancer Institute, Cairo. Although EBV infection is highly associated with lymphoma in immunocompromised patients, the situation in immunocompetent patients is still unclear.

MATERIAL AND METHODS

The study included 50 PELHN (11 cases in the nose and paranasal sinuses, 11 in the nasopharynx, 13 in the tonsils, seven in the oropharynx and eight in the oral cavity), five reactive lymph nodes, 15 normal nasopharyngeal tissue and 25 throat washes of healthy subjects from Egypt. Cases and controls were assessed for the presence of EBV by polymerase chain reaction (PCR) and in situ hybridization techniques, the presence of 30 base pair deletion of the LMP-1 (del-LMP1) gene and for the expression of p53, Ki67, bcl-2 and Bax by immunohistochemistry. This was also correlated with the clinical outcome of patients.

RESULTS

EBV was detected in 90% and 70% of the cases using EBER in situ hybridization and PCR, respectively. All cases of nasal type lymphoma were positive for EBV. del-LMP1 gene was detected in 24/35 of EBV+ cases (68.6%), whereas 11 cases had wild-type variant either alone or mixed with del-LMP1. There was a significant difference in the frequency of del-LMP1 between lymphoma and normal tissues. Overexpression of Ki67, p53 and bcl-2 was detected in 78.1%, 62.5% and 20% of cases, whereas loss of Bax was detected in 18% of the cases. Multivariate analysis showed that only p53 overexpression, del-LMP1 variant and advanced disease stage are independent prognostic factors.

CONCLUSION

EBV infection is frequent in PELHN in Egypt. Possible pathogenic mechanisms involve deregulation of p53 and enhanced proliferation (as detected by high Ki67 index). The presence of del-LMP1 variants, p53 overexpression and advanced disease stage are poor prognostic factors associated with reduced survival and poor response to therapy.

Medium-mediated intercellular communication is involved in bystander responses of X-ray-irradiated normal human fibroblasts

Although radiation-induced bystander effects have been demonstrated in a number of cell types, the studies have largely been performed using high linear energy transfer (LET) radiation, such as alpha-particles. The literature is contradictory on whether fibroblasts show bystander responses, especially after low LET radiation such as X- or gamma-rays and whether the same signal transmission pathways are involved. Herein, a novel transwell insert culture dish method is used to show that X-irradiation induces medium-mediated bystander effects in AGO1522 normal human fibroblasts. The frequency of micronuclei formation in unirradiated bystander cells increases from a background of about 6.5% to about 9-13% at all doses from 0.1 to 10 Gy to the irradiated cells. Induction of p21Waf1 protein and foci of gamma-H2AX in bystander cells is also independent of dose to the irradiated cells above 0.1 Gy. In addition, levels of reactive oxygen species (ROS) were increased persistently in directly irradiated cells up to 60 h after irradiation and in bystander cells for 30 h. Adding Cu-Zn superoxide dismutase (SOD) and catalase to the medium decreases the formation of micronuclei and induction of p21Waf1 and gamma-H2AX foci in bystander cells, suggesting oxidative metabolism plays a role in the signaling pathways in bystander cells. The results of clonogenic assay of bystander cells showed that survival of bystander cells decreases from 0 to 0.5 Gy, and then is independent of the dose to irradiated cells from 0.5 to 10 Gy. Unlike the response with p21Waf1 expression, gamma-H2AX foci and micronuclei, adding SOD and catalase has no effect on the survival of bystander cells. The data suggest that irradiated cells release toxic factors other than ROS into the medium.