Validation of the 2014 European Society of Cardiology guidelines risk prediction model for the primary prevention of sudden cardiac death in hypertrophic cardiomyopathy

BACKGROUND

The recently released 2014 European Society of Cardiology guidelines of hypertrophic cardiomyopathy (HCM) use a new clinical risk prediction model for sudden cardiac death (SCD), based on the HCM Risk-SCD study. Our study is the first external and independent validation of this new risk prediction model.

METHODS AND RESULTS

The study population consisted of a consecutive cohort of 706 patients with HCM without prior SCD event, from 2 tertiary referral centers. The primary end point was a composite of SCD and appropriate implantable cardioverter-defibrillator therapy, identical to the HCM Risk-SCD end point. The 5-year SCD risk was calculated using the HCM Risk-SCD formula. Receiver operating characteristic curves and C-statistics were calculated for the 2014 European Society of Cardiology guidelines, and risk stratification methods of the 2003 American College of Cardiology/European Society of Cardiology guidelines and 2011 American College of Cardiology Foundation/American Heart Association guidelines. During follow-up of 7.7±5.3 years, SCD occurred in 42 (5.9%) of 706 patients (ages 49±16 years; 34% women). The C-statistic of the new model was 0.69 (95% CI, 0.57-0.82; P=0.008), which performed significantly better than the conventional risk factor models based on the 2003 guidelines (C-statistic of 0.55: 95% CI, 0.47-0.63; P=0.3), and 2011 guidelines (C-statistic of 0.60: 95% CI, 0.50-0.70; P=0.07).

CONCLUSIONS

The HCM Risk-SCD model improves the risk stratification of patients with HCM for primary prevention of SCD, and calculating an individual risk estimate contributes to the clinical decision-making process. Improved risk stratification is important for the decision making before implantable cardioverter-defibrillator implantation for the primary prevention of SCD.

Tensor-based detection of T wave alternans using ECG

T wave alternans is defined as changes in the T wave amplitude in an ABABAB-pattern. It can be found in ECG signals of patients with heart diseases and is a possible indicator to predict the risk on sudden cardiac death. Due to its low amplitude, robust automatic T wave alternans detection is a difficult task. We present a new method to detect T wave alternans in multichannel ECG signals. The use of tensors (multidimensional matrices) permits the combination of the information present in different channels, making detection more reliable. The possibility of decomposition of incomplete tensors is exploited to deal with noisy ECG segments. Using a sliding window of 128 heartbeats, a tensor is constructed of the T waves of all channels. Canonical Polyadic Decomposition is applied to this tensor and the resulting loading vectors are examined for information about the T wave behavior in three dimensions. T wave alternans is detected using a sign change counting method that is able to extract both the T wave alternans length and magnitude. When applying this novel method to a database of patients with multiple positive T wave alternans tests using the clinically available spectral method tests, both the length and the magnitude of the detected T wave alternans is larger for these subjects than for subjects in a control group.

How to choose between a pacemaker or defibrillator for resynchronization therapy?

OBJECTIVE

The choice between a resynchronization pacemaker (CRT-P) or defibrillator (CRT-D) is still a matter of debate. We hypothesised that when selecting patients based on co-morbidities and age as proposed by the ESC-guidelines, there would be no long-term survival benefit of CRT-D compared to CRT-P.

METHODS

We performed a retrospective analysis of patients who received a CRT device at the University Hospitals Leuven between 2001 and 2007. For the analysis of the association between predictors and outcome, uni- and multivariate Cox regression analyses were performed. We present data from three multivariate models.

RESULTS

A total of 144 CRT devices were implanted (CRT-D n=98, CRT-P n=46). Patients who received a CRT-P were older and had a higher prevalence of co-morbidities. Patients who received a CRT-D had a significant lower mortality. When applying incremental multivariate analysis using 1st variables with a P < 0.05 in univariate analysis, 2nd variables with a P < 0.10 and 3rd adding on top all the baseline variables that were significantly different between the two groups, the significance of a possible survival benefit for CRT-D over CRT-P disappeared: risk model 1, hazard ratio 2.21 (P = 0.008), risk model 2, HR 1.81 (P = 0.069), and risk model 3, HR 1.85 (P = 0.091). The use of amiodarone and the presence of COPD or renal insufficiency remained associated with a significant, higher mortality risk, while the use of beta blockers was protective in all three models.

CONCLUSION

The choice of a CRT-D seemed a predictor of improved survival in simple but not in more complex multivariable analyses. The fact that the survival benefit strongly depended on the number of co-variables suggests that it is at most marginal.

Left and Right Ventricle Leads Switch as a Solution for TWave Oversensing - How a Good Idea Turned Out Bad

A 50-year-old male with a CRT defibrillator received inappropriate ICD shocks due to T-wave oversensing. Decreasing the sensitivity to avoid T wave oversensing was not an option due to a suboptimal R-wave sensing amplitude. We decided to re-plug the LV lead in the RV port and the RV lead in the LV port. This however led to intermittent phrenic nerve stimulation due to mandatory bipolar (tip-ring) or unipolar (tip-can) pacing on the LV-lead from the RV port. Re-intervention was necessary with the implantation of an additional pacing/sensing RV lead. A software programmable choice to switch sensing and tachycardia detection from RV to LV lead could be a valuable feature in future CRT devices.

Reduced Penetrance and Variable Expression of SCN5A Mutations and the Importance of Co-inherited Genetic Variants: Case Report and Review of the Literature

Mutations in the SCN5A gene are responsible for multiple phenotypical presentations including Brugada syndrome, long QT syndrome, progressive familial heart block, sick sinus syndrome, dilated cardiomyopathy, lone atrial fibrillation and multiple overlap syndromes. These different phenotypic expressions of a mutation in a single gene can be explained by variable expression and reduced penetrance. One of the possible explanations of these phenomena is the co-inheritance of genetic variants. We describe a family where the individuals exhibit a compound heterozygosity in the SCN5A gene including a mutation (R1632H) and a new variant (M858L). Individuals with both the mutation and new variant present with a more severe phenotype including spontaneous atrial tachyarrhythmia at young age. We give an overview of the different phenotypes of "SCN5A disease" and discuss the importance of co-inherited genetic variants in the expression of SCN5A disease.

Frequency of use of QT-interval prolonging drugs in psychiatry in Belgium

INTRODUCTION

Drug-induced QT-prolongation is an established risk factor for Torsade de pointes and sudden cardiac death. The list of QT-prolonging drugs is extensive and includes many drugs commonly used in psychiatry.

AIM

In this study we performed a cross-sectional analysis of medication profiles to assess the prevalence of drug interactions potentially leading to QT-prolongation.

SETTING

6 psychiatric hospitals in Flanders, Belgium.

METHODS

For each patient, the full medication list was screened for the presence of interactions, with special attention to those with an increased risk for QT-prolongation. Current practice on QT monitoring and prevention of drug-induced arrhythmia was assessed.

MAIN OUTCOME MEASURE

Number of drug interactions with risk of QT-prolongation.

RESULTS

592 patients (46 % female; mean age 55.7 ± 17.1 years) were included in the analysis. 113 QT-prolonging interactions were identified in 43 patients (7.3 %). QT-prolonging interactions occurred most frequently with antidepressants (n = 102) and antipsychotics (n = 100). The precautions and follow-up provided by the different institutions when combining QT-prolonging drugs were very diverse.

CONCLUSION

Drug combinations that are associated with QT-prolongation are frequently used in the chronic psychiatric setting. Persistent efforts should be undertaken to provide caregivers with clear guidelines on how to use these drugs in a responsible and safe way.

Heart rate turbulence predicts ICD-resistant mortality in ischaemic heart disease

AIMS

In high-risk patients, implantable cardioverter-defibrillators (ICDs) can convert the mode of death from arrhythmic to pump failure death. Therefore, we introduced the concept of 'ICD-resistant mortality' (IRM), defined as death (a) without previous appropriate ICD intervention (AI), (b) within 1 month after the first AI, or (c) within 1 year after the initial ICD implantation. Implantable cardioverter-defibrillator implantation in patients with a high risk of IRM should be avoided.

METHODS AND RESULTS

Implantable cardioverter-defibrillator patients with ischaemic heart disease were included if a digitized 24 h Holter was available pre-implantation. Demographic, electrocardiographic, echocardiographic, and 24 h Holter risk factors were collected at device implantation. The primary endpoint was IRM. Cox regression analyses were used to test the association between predictors and outcome. We included 130 patients, with a mean left ventricular ejection fraction (LVEF) of 33.6 ± 10.3%. During a follow-up of 52 ± 31 months, 33 patients died. There were 21 cases of IRM. Heart rate turbulence (HRT) was the only Holter parameter associated with IRM and total mortality. A higher New York Heart Association (NYHA) class and a lower body mass index were the strongest predictors of IRM. Left ventricular ejection fraction predicted IRM on univariate analysis, and was the strongest predictor of total mortality. The only parameter that predicted AI was non-sustained ventricular tachycardia.

CONCLUSION

Implantable cardioverter-defibrillator implantation based on NYHA class and LVEF leads to selection of patients with a higher risk of IRM and death. Heart rate turbulence may have added value for the identification of poor candidates for ICD therapy. Available Holter parameters seem limited in their ability to predict AI.

Work engagement supports nurse workforce stability and quality of care: nursing team-level analysis in psychiatric hospitals

Research in healthcare settings reveals important links between work environment factors, burnout and organizational outcomes. Recently, research focuses on work engagement, the opposite (positive) pole from burnout. The current study investigated the relationship of nurse practice environment aspects and work engagement (vigour, dedication and absorption) to job outcomes and nurse-reported quality of care variables within teams using a multilevel design in psychiatric inpatient settings. Validated survey instruments were used in a cross-sectional design. Team-level analyses were performed with staff members (n = 357) from 32 clinical units in two psychiatric hospitals in Belgium. Favourable nurse practice environment aspects were associated with work engagement dimensions, and in turn work engagement was associated with job satisfaction, intention to stay in the profession and favourable nurse-reported quality of care variables. The strongest multivariate models suggested that dedication predicted positive job outcomes whereas nurse management predicted perceptions of quality of care. In addition, reports of quality of care by the interdisciplinary team were predicted by dedication, absorption, nurse-physician relations and nurse management. The study findings suggest that differences in vigour, dedication and absorption across teams associated with practice environment characteristics impact nurse job satisfaction, intention to stay and perceptions of quality of care.

Implantable cardioverter-defibrillators in hypertrophic cardiomyopathy: patient outcomes, rate of appropriate and inappropriate interventions, and complications

BACKGROUND

Sudden cardiac death (SCD) is the most devastating complication of hypertrophic cardiomyopathy (HCM), but this can be prevented by an implantable cardioverter-defibrillator (ICD). The aim of this study is to evaluate HCM patients with ICDs for primary or secondary prevention of SCD.

METHODS

The study population consisted of all HCM patients with an ICD in 2 tertiary referral clinics. End points during follow-up were total and cardiac mortality, appropriate and inappropriate ICD intervention, and device-related complications. Cox-regression analysis was performed to identify predictors of outcome.

RESULTS

ICDs were implanted in 134 patients with HCM (mean age 44 ± 17 years, 34% women, 4.2 ± 4.8 years follow-up). Annualized cardiac mortality rate was 3.4% per year and associated with New York Heart Association class III or IV (HR 5.2 [2.0-14, P = .002]) and cardiac resynchronization therapy (HR 6.3 [2.1-20, P = .02]). Appropriate ICD interventions occurred in 38 patients (6.8%/year) and was associated with implantation for secondary prevention of SCD (HR 4.0 [1.8-9.1], P = .001) and male gender (HR 3.3 [1.2-9.0], P = .02). Inappropriate ICD intervention occurred in 21 patients (3.7%/year) and in 20 patients device related complications were documented (3.6%/year).

CONCLUSION

ICDs successfully abort life-threatening arrhythmias in HCM patients at increased risk of SCD with an annualized intervention rate of 6.8% per year. End-stage heart failure is the main cause of mortality in these patients. The annualized rate of inappropriate ICD intervention was 3.7% per year, whereas device-related complications occurred 3.6% per year.

Subchronic memantine induced concurrent functional disconnectivity and altered ultra-structural tissue integrity in the rodent brain: revealed by multimodal MRI

BACKGROUND

An effective NMDA antagonist imaging model may find key utility in advancing schizophrenia drug discovery research. We investigated effects of subchronic treatment with the NMDA antagonist memantine by using behavioural observation and multimodal MRI.

METHODS

Pharmacological MRI (phMRI) was used to map the neuroanatomical binding sites of memantine after acute and subchronic treatment. Resting state fMRI (rs-fMRI) and diffusion MRI were used to study the changes in functional connectivity (FC) and ultra-structural tissue integrity before and after subchronic memantine treatment. Further corroborating behavioural evidences were documented.

RESULTS

Dose-dependent phMRI activation was observed in the prelimbic cortex following acute doses of memantine. Subchronic treatment revealed significant effects in the hippocampus, cingulate, prelimbic and retrosplenial cortices. Decreases in FC amongst the hippocampal and frontal cortical structures (prelimbic, cingulate) were apparent through rs-fMRI investigation, indicating a loss of connectivity. Diffusion kurtosis MRI showed decreases in fractional anisotropy and mean diffusivity changes, suggesting ultra-structural changes in the hippocampus and cingulate cortex. Limited behavioural assessment suggested that memantine induced behavioural effects comparable to other NMDA antagonists as measured by locomotor hyperactivity and that the effects could be reversed by antipsychotic drugs.

CONCLUSION

Our findings substantiate the hypothesis that repeated NMDA receptor blockade with nonspecific, noncompetitive NMDA antagonists may lead to functional and ultra-structural alterations, particularly in the hippocampus and cingulate cortex. These changes may underlie the behavioural effects. Furthermore, the present findings underscore the utility and the translational potential of multimodal MR imaging and acute/subchronic memantine model in the search for novel disease-modifying treatments for schizophrenia.

Can body surface microvolt T-wave alternans distinguish concordant and discordant intracardiac alternans?

INTRODUCTION

There is convincing experimental evidence that cellular action potential duration (APD) alternans is arrhythmogenic but its relationship with body surface microvolt T-wave alternans (MTWA) remains unclear. We investigated the relationship between MTWA and APD alternans induced by alternating cycle length (CL) pacing in a pig model.

METHODS

In 10 pigs, catheters in the right atrium (RA) and right (RV) and left ventricle (LV) allowed pacing and recording of monophasic action potentials (MAP). During RA pacing at stable 500-ms CL, LV was paced at alternating CL (505 ms and 495 ms). Changing the alternating LV (A-LV) pacing delay changes the size of the region with alternating ventricular activation. Spectral analysis of intracardiac MAP was correlated with body surface MTWA. In a similar setup (during alternating pacing in RV and LV), we investigated concordant versus discordant APD alternans.

RESULTS

Pacing the LV with subtle alternating cycle lengths at short A-LV delay leads to broad QRS (97 ± 10 ms), body surface MTWA (mean Valt 4.2 ± 1.8 µV), and positive RR-interval alternans. At longer A-LV delay, not resulting in QRS widening (68 ± 5 ms), body surface RR alternans was absent but MTWA remained detectable and was even more pronounced (8.7 ± 5.1 µV, P < 0.01). During both concordant and discordant pacing MTWA was present. The precordial leads were better for detecting discordant APD alternans (8.0 ± 2.9 µV and 12.8 ± 4.52 µV, P = 0.02).

CONCLUSION

MTWA is a potent technique to detect subtle and isolated intracardiac APD alternans that is artificially induced by alternating pacing. In the same model, discordant activation alternans can only be discriminated from concordant when using a quantifying approach of MTWA analysis.

T-wave alternans and beat-to-beat variability of repolarization: pathophysiological backgrounds and clinical relevance

In this review, we focus on temporal variability of cardiac repolarization. This phenomenon has been related to a higher risk for ventricular arrhythmia and is therefore interesting as a marker of sudden cardiac death risk. We review two non-invasive clinical techniques quantifying repolarization variability: T-wave alternans (TWA) and beat-to-beat variability of repolarization (BVR). We discuss their pathophysiological link with ventricular arrhythmia and the current clinical relevance of these techniques.

Transvenous extraction of pacing and defibrillator leads--a single-centre experience

PURPOSE

Worldwide, the number of transvenous extractions of chronically implanted endocardial leads rapidly increases. Despite great technical progress, lead extraction remains a challenging procedure with possible life-threatening complications. We present the success and complication rate of lead extractions in the University Hospitals Leuven, and investigated a possible relationship between the use of powered sheaths and lead type, fixation, location and implantation time.

METHODS

We present an observational retrospective cohort study of 157 patients admitted to the University Hospitals Leuven between January 2005 and December 2010, for the transvenous removal of a total of 259 endocardial leads.

RESULTS

Complete procedural success was achieved in 92% of patients (n = 144). Of all leads, 94% (n = 243) were completely extracted. Only in 5 patients (3%), lead extraction failed. Leads that could not be removed were significantly older (134.1 +/- 90.7 months vs. 73.1 +/- 61.9 months; P = 0.02). In the other 8 patients the leads were partially removed with a remaining major retained lead fragment in 2 and a minor fragment in 6 patients. Major procedural complication rate was 2.5% (n = 4). There were no procedure-related deaths. Powered sheaths were used significantly more for the extraction of defibrillator leads (51%) (vs. pacing leads (33%; P = 0.015)) and right ventricular located leads (43%) (vs. other location (28%; P = 0.011)). However, when comparing the need of powered sheaths for the extraction of right ventricular defibrillator leads vs. right ventricular pacing leads, only a trend to higher use was noticed (51 vs. 39%; P = 0.146). Powered sheath use was not related to fixation type. Leads that required the use of a powered sheath were implanted significantly longer (112 +/- 69.5 months vs. 41.7 +/- 33.7 months; P = 0.001).

CONCLUSIONS

Chronically implanted endocardial leads can be transvenously extracted in a high number of cases and with a low risk of procedural complications. Powered sheaths proved to be a helpful tool to extract leads that could not be removed by manual traction. Powered sheaths are necessary for leads with longer implantation duration and are more often used for the extraction of defibrillator leads.

Preventing Sudden Cardiac Death in Patients with Ischaemic Cardiomyopathy

Sudden cardiac death (SCD) is an important cause of mortality. In this article, we review the definition, impact and underlying aetiology of SCD. Ventricular tachyarrhythmia accounts for the majority of SCDs and can be caused by various underlying heart diseases, the most frequent being ischaemic cardiomyopathy. The most effective ways to reduce the risk of SCD in ischaemic cardiomyopathy are the optimal prevention of recurrent coronary ischaemia and the use of an implantable cardioverter-defibrillator (ICD) in high-risk patients. We discuss current patient selection for ICD implantation and focus on the need for, and possibilities to improve, SCD risk stratification.

Rationale, objectives, and design of the EUTrigTreat clinical study: a prospective observational study for arrhythmia risk stratification and assessment of interrelationships among repolarization markers and genotype

Aims

The EUTrigTreat clinical study has been designed as a prospective multicentre observational study and aims to (i) risk stratify patients with an implantable cardioverter defibrillator (ICD) for mortality and shock risk using multiple novel and established risk markers, (ii) explore a link between repolarization biomarkers and genetics of ion (Ca²⁺, Na⁺, K⁺) metabolism, (iii) compare the results of invasive and non-invasive electrophysiological (EP) testing, (iv) assess changes of non-invasive risk stratification tests over time, and (v) associate arrythmogenomic risk through 19 candidate genes.

Methods and results

Patients with clinical ICD indication are eligible for the trial. Upon inclusion, patients will undergo non-invasive risk stratification, including beat-to-beat variability of repolarization (BVR), T-wave alternans, T-wave morphology variables, ambient arrhythmias from Holter, heart rate variability, and heart rate turbulence. Non-invasive or invasive programmed electrical stimulation will assess inducibility of ventricular arrhythmias, with the latter including recordings of monophasic action potentials and assessment of restitution properties. Established candidate genes are screened for variants. The primary endpoint is all-cause mortality, while one of the secondary endpoints is ICD shock risk. A mean follow-up of 3.3 years is anticipated. Non-invasive testing will be repeated annually during follow-up. It has been calculated that 700 patients are required to identify risk predictors of the primary endpoint, with a possible increase to 1000 patients based on interim risk analysis.

Conclusion

The EUTrigTreat clinical study aims to overcome current shortcomings in sudden cardiac death risk stratification and to answer several related research questions. The initial patient recruitment is expected to be completed in July 2012, and follow-up is expected to end in September 2014.

Clinicaltrials.gov identifier: NCT01209494.

Influence of percutaneous transcatheter closure of an atrial septal defect on the atrioventricular conduction

OBJECTIVE

This study aimed at determining the effect of percutaneous ASD closure on the AV conduction. Percutaneous closure of ostium secundum atrial septal defects (ASDs) has been widely accepted and has become the standard treatment of this malformation. However, some complications have been reported. Because of the close proximity between the discs of the device and the atrioventricular (AV) node, atrioventricular conduction disturbances (AVCD) are a likely complication.

METHODS AND RESULTS

From the database of congenital heart disease, 46 patients (mean age 54 +/- 12 y) who underwent percutaneous ASD closure and 46 patients who underwent a percutaneous patent foramen ovale (PFO) closure were matched according to age, gender and follow-up time. Demographic, clinical, biochemical, and ECG variables were compared. Before closure, the PR interval in the ASD group was significantly longer than in the PFO group (169 +/- 22 ms versus 158 +/- 25 ms, P= 0.031), which persisted after a mean follow-up time of 4.5 years (180 +/- 39 ms versus 163 +/- 23 ms, P= 0.007). PR interval increased significantly from closure to latest follow-up in the ASD (P=0.038), but not in the PFO group (P=0.058).

CONCLUSIONS

ASD patients presented with significantly longer PR interval than PFO patients before closure. In contrast with the PFO group, the PR interval increased in the ASD group after medium-term follow-up. These findings indicate the need for further follow-up after ASD repair in order to detect potential late AVCD.

First outbreak of VIM-2 metallo-β-lactamase-producing Pseudomonas aeruginosa in The Netherlands: microbiology, epidemiology and clinical outcomes

This study was designed to investigate the prevalence and characteristics of metallo-β-lactamase (MBL)-producing Pseudomonas aeruginosa in a tertiary care centre in The Netherlands, a country that is considered to have a low prevalence of antibiotic-resistant bacteria. Imipenem-resistant P. aeruginosa isolates cultured from clinical specimens during 2008-2009 were analysed phenotypically and molecularly by polymerase chain reaction (PCR) with sequencing. Genotyping was performed by multiple-locus variable-number tandem repeat (VNTR) analysis (MLVA). Clinical information was obtained by electronic chart review for all patients infected or colonised with an imipenem-resistant P. aeruginosa isolate that was included in the study. In total, 106 imipenem-resistant P. aeruginosa isolates were included. The bla(VIM-2) gene was detected in 35/106 isolates (33%) and was associated with integrons. Compared with non-MBL-producing imipenem-resistant P. aeruginosa, VIM-2 MBL-producing isolates showed higher rates of multidrug resistance. Patients with VIM-2 MBL-producing isolates were more likely to be admitted to the Intensive Care Unit (ICU) and had a higher risk of invasive infection, including development of bacteraemia. MLVA identified two separate VIM-2 MBL-producing clones, responsible for outbreaks in the ICU but also affecting 10 other departments. This is the first reported outbreak of VIM-2 MBL-producing P. aeruginosa in The Netherlands. Once introduced, VIM-2 MBL-producing P. aeruginosa cause significant infections and are easily spread within the hospital setting.

Implantable cardioverter/defibrillator interventions in primary prevention: do current implantation criteria really predict ICD interventions?

BACKGROUND

Randomized controlled trials have proven the efficacy of implantable cardioverter/defibrillators (ICDs) to prevent sudden cardiac death (SCD) in primary prevention. However,long-term data on the incidence of appropriate and inappropriate interventions in real life and on the predictive value of commonly used clinical variables to guide patient selection are scarce.

METHODS

We retrospectively studied 101 patients who received an ICD for primary prophylaxis of SCD: 63.4% with ischaemic heart disease (IHD) and 36.6% with idiopathic dilated cardiomyopathy (IDCM). The mean follow-up period was 26.2 (+/- 14.8; median 27.8; range 5.6-70.5) months. Age, left ventricular ejection fraction (LVEF), QRS duration, NYHA class and electrophysiological study (EPS) outcome were evaluated as predictors of ICD intervention.

RESULTS

At 2 years the cumulative incidence of appropriate (17.5% in IHD; 28% in IDCM; P= 0.63) and inappropriate (12.8% in IHD, 15.4% in IDCM; P = 0.62) interventions was similar in both groups. Atrial fibrillation was the most common cause of inappropriate interventions in the IHD group, sinus tachycardia in the IDCM group. Advanced age was associated with less inappropriate interventions (HR: 0.96 (95% confidence interval (CI) 0.94-0.98); P < 0.01), and a better LVEF with less appropriate interventions (HR: 0.97 (95% Cl 0.94-0.99); P < 0.01). This amounted in a significant absolute difference in the number of appropriate interventions between the group with a LVEF < 25% and 25-34% after 3 years of follow-up of 42% in IHD (48% vs 6%). A prolonged QRS duration was associated with a slightly elevated risk for appropriate interventions only in the IHD group (HR: 1.01 (95% CI 1.00-1.03); P = 0.04). On the other hand, increased NYHA class was only associated with increased risk for appropriate interventions in the IDCM group (HR: 5.24 (95% CI1.11-24.74); P= 0.04). No significant statistical association was found between a positive EPS and appropriate or inappropriate interventions.

CONCLUSIONS

In primary prevention, during a mean follow-up of 2 years, one in five patients had a possibly live-saving appropriate intervention. However, the incidence of inappropriate interventions was substantial. Predictors for appropriate interventions were: (i) LVEF in the total study group, (ii) NYHA class in the IDCM group and (iii) QRS duration in the IHD group.

Long-term endurance sport is a risk factor for development of lone atrial flutter

OBJECTIVE

To evaluate whether in a population of patients with 'lone atrial flutter', the proportion of those engaged in long-term endurance sports is higher than that observed in the general population.

DESIGN

An age and sex-matched retrospective case-control study.

SETTING

A database with 638 consecutive patients who underwent ablation for atrial flutter at the University of Leuven. Sixty-one patients (55 men, 90%) fitted the inclusion criteria of 'lone atrial flutter', ie, aged 65 years or less, without documented atrial fibrillation and without identifiable underlying disease (including hypertension). Sex, age and inclusion criteria-matched controls, two for each flutter patient, were selected in a general practice in the same geographical region.

METHODS

Sports activity was evaluated by detailed questionnaires, which were available in 58 flutter patients (95%). A transthoracic echocardiogram was performed in all lone flutter patients.

MAIN OUTCOME MEASURES

Types of sports, number of years of participation and average number of hours per week.

RESULTS

The proportion of regular sportsmen (≥3 h of sports practice per week) among patients with lone atrial flutter was significantly higher than that observed in the general population (50% vs 17%; p<0.0001). The proportion of sportsmen engaged in long-term endurance sports (participation in cycling, running or swimming for ≥3 h/week) was also significantly higher in lone flutter patients than in controls (31% vs 8%; p=0.0003). Those flutter patients performing endurance sports had a larger left atrium than non-sportsmen (p=0.04, by one-way analysis of variance).

CONCLUSION

A history of endurance sports and subsequent left atrial remodelling may be a risk factor for the development of atrial flutter.

Enterococcal surface protein contributes to persistence in the host but is not a target of opsonic and protective antibodies in Enterococcus faecium infection

Enterococci are important nosocomial pathogens with multiple intrinsic and acquired resistances to antibiotics. In the past, the majority of infections were caused by Enterococcus faecalis; however, an increase in Enterococcus faecium clinical isolates has been observed in recent years. The enterococcal surface protein (Esp) is expressed on the surface of most E. faecium clinical isolates and has been shown to be involved in biofilm formation. Here, E. faecium E1162 and its previously created insertion-deletion mutant of the esp gene, E. faecium E1162Δesp, were compared in a mouse bacteraemia model. Anti-Esp serum was tested for its capacity to mediate opsonophagocytic killing of E1162 in vitro and to protect against E. faecium bacteraemia. The inactivation of esp attenuated E. faecium virulence with reduced numbers of bacteria recovered from the kidneys in animals infected with the mutant compared to the wild-type strain (P=0.035). Passive immunization with rabbit polyclonal serum raised against the recombinant N-terminal Esp protein did not protect mice against E. faecium bacteraemia (P>0.05). In contrast, mice passively immunized with polyclonal antiserum raised against lipoteichoic acid (LTA) from E. faecalis had lower numbers of E. faecium E1162 in the blood compared to mice immunized with normal rabbit serum. These results suggest that Esp contributes to E. faecium persistence in the host. However, in contrast to LTA, Esp does not seem to be a target for protective antibodies in E. faecium strain E1162 in mouse bacteraemia.

Assessment of apical rocking: a new, integrative approach for selection of candidates for cardiac resynchronization therapy

AIMS

Current attempts of improving patient selection in cardiac resynchronization therapy (CRT) are mainly based on echocardiographic timing of myocardial velocity peaks. Regional myocardial function is neglected. Apical transverse motion (ATM) is a new parameter to quantify apical rocking as an integrative surrogate of both temporal and functional inhomogeneities within the left ventricle. In this study, we tested the predictive value of apical rocking for response to CRT.

METHODS AND RESULTS

Sixty-nine patients eligible for CRT were assessed by echocardiography before and 11 ± 5 months after pacemaker implantation. Response was defined as left ventricular (LV) end-systolic volume decrease >15%. Rocking was quantified (ATM) and visually assessed by four blinded readers. Predictive value for CRT response of both assessments was compared with conventional dyssynchrony parameters. ATM in the four-chamber view plane differentiated best between responders and non-responders (2.2 ± 1.5 vs. 0.06 ± 1.9 mm, P< 0.0001). Quantified ATM predicted reverse remodelling with a sensitivity, specificity, and accuracy of 75, 96, and 83% whereas visual rocking assessment resulted in 89, 75, and 83%, respectively. The accuracy of conventional parameters was significantly lower.

CONCLUSION

Apical rocking is a new marker to assess LV dyssynchrony and predict CRT response. It is superior to conventional parameters. Even its simple visual assessment may be sufficiently accurate in the clinical setting.

Lower than expected desmosomal gene mutation prevalence in endurance athletes with complex ventricular arrhythmias of right ventricular origin

OBJECTIVE

To determine the prevalence of desmosomal gene mutations in athletes with complex arrhythmias (VA) of right ventricular (RV) origin and structural RV abnormalities to evaluate whether there is sufficient genetic overlap with arrhythmogenic right ventricular cardiomyopathy (ARVC) to consider them the same or different entities.

DESIGN

Observational cohort

SETTING

Tertiary hospital referrals

PATIENTS

Forty-seven consecutive athletes (age 42 (11) years) with complex VA of RV morphology (excluding idiopathic right ventricular outflow tract ventricular tachycardia), who performed 14 (9) h/week of moderate to intense sport practise for 19 (9) years.

INTERVENTIONS

Clinical evaluation (detailed sports history, multi-modality imaging, electrophysiological study) and sequencing of five candidate desmosomal genes.

RESULTS

A clinical diagnosis of definite or suspected ARVC by task force criteria (TFC) was met in 24 (51%) and 17 (36%), respectively. ARVC classification was not related to the rate of major arrhythmic events (p=0.28). Pathogenic mutations (four novel) were identified in six athletes (12.8%), which is below published rates for familial ARVC (27-52%). Moreover, only two athletes had a suggestive family history. Severe RV dysfunction was more frequent in mutation carriers (33% vs 2%, p=0.04), but otherwise TFC features were similar to those without mutations. No mutations were found in the 20 athletes performing more than average weekly exercise, yet all met the criteria for definite or suspected ARVC.

CONCLUSIONS

In this athletic cohort, we found lower than expected rates of desmosomal gene mutations, particularly among those performing the most exercise. This adds further weight to the hypothesis that an ARVC-like phenotype may be acquired through intense exercise without an identifiable genetic predisposition.