Lesion metrics and 12-month outcomes of very-high power short duration radiofrequency ablation (90W/4 s) under mild conscious sedation

INTRODUCTION

Pulmonary vein isolation (PVI) is often performed under general anaesthesia (GA) or deep sedation. Anaesthetic availability is limited in many centers, and deep sedation is prohibited in some countries without anaesthetic support. Very high-power short duration (vHPSD-90W/4 s) PVI using the Q-Dot catheter is generally well tolerated under mild conscious sedation (MCS) though an understanding of catheter stability and long-term effectiveness is lacking. We analyzed lesion metrics and 12-month freedom from atrial arrythmia with this approach.

METHODS

Our approach to radiofrequency (RF) PVI under MCS is standardized and includes a single catheter approach with a steerable sheath. We identified patients undergoing Q-Dot RF PVI between March 2021 and December 2022 in our center, comparing those undergoing vHPSD ablation under MCS (90W/MCS) against those undergoing 50 W ablation under GA (50 W/GA) up to 12 months of follow-up. Data were extracted from clinical records and the CARTO system.

RESULTS

Eighty-three patients met our inclusion criteria (51 90W/MCS; 32 50 W/GA). Despite shorter ablation times (353 vs. 886 s; p < .001), the 90 W/MCS group received more lesions (median 87 vs. 58, p < .001), resulting in similar procedure times (149.3 vs. 149.1 min; p = .981). PVI was achieved in all cases, and first pass isolation rates were similar (left wide antral circumferential ablation [WACA] 82.4% vs. 87.5%, p = .758; right WACA 74.5% vs. 78.1%, p = .796; 90 W/MCS vs. 50 W/GA respectively). Analysis of 6647 ablation lesions found similar mean impedance drops (10.0 ± 1.9 Ω vs. 10.0 ± 2.2 Ω; p = .989) and mean contact force (14.6 ± 2.0 g vs. 15.1 ± 1.6 g; p = .248). Only median 2.5% of lesions in the 90 W/MCS cohort failed to achieve ≥ 5 Ω drop. In the 90 W/MCS group, there were no procedural related complications, and 12-month freedom from atrial arrhythmia was observed in 78.4%.

CONCLUSION

vHPSD PVI is feasible under MCS, with encouraging acute and long-term procedural outcomes. This provides a compelling option for centers with limited anaesthetic support.

Silent pulmonary veins at redo ablation for atrial fibrillation: Implications and approaches

BACKGROUND

Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation. Despite promising success rates, redo ablation is sometimes required. At redo, PVs may be found to be isolated (silent) or reconnected. We studied patients with silent vs reconnected PVs at redo and analysed associations with adverse outcomes.

METHODS

Patients undergoing redo AF ablations between 2013 and 2019 at our institution were included and stratified into silent PVs or reconnected PVs. The primary outcome was a composite of further redo ablation, non-AF ablation, atrioventricular nodal ablation, and death. Secondary outcomes included arrhythmia recurrence.

RESULTS

A total of 467 patients were included with mean 4.6 ± 1.7 years follow-up, of whom 48 (10.3%) had silent PVs. The silent PV group had had more often undergone >1 prior ablation (45.8% vs 9.8%; p<0.001), had more persistent AF (62.5% vs 41.1%; p=0.005) and had more non-PV ablation performed both at prior ablation procedures and at the analysed redo ablation. The primary outcome occurred more frequently in those with silent PVs (25% vs 13.8%; p=0.053). Arrhythmia recurrence was also more common in the silent PV group (66.7% vs 50.6%; p=0.047). After multivariable adjustment, female sex (aHR 2.35 [95% CI 2.35-3.96]; p=0.001) and ischaemic heart disease (aHR 3.21 [95% CI 1.56-6.62]; p=0.002) were independently associated with the primary outcome, and left atrial enlargement (aHR 1.58 [95% CI 1.20-2.08]; p=0.001) and >1 prior ablation (aHR 1.88 [95% CI 1.30-2.72]; p<0.001) were independently associated with arrhythmia recurrence. Whilst a finding of silent PVs was not itself significant after multivariable adjustment, this provides an easily assessable parameter at clinically indicated redo ablation which informs the clinician of the likelihood of a worse future prognosis.

CONCLUSIONS

Patients with silent PVs at redo AF ablation have worse clinical outcomes.

The oxygen uptake efficiency slope in adults with CHD: group validity

The maximal oxygen uptake (V02 max) is a well-validated measure of cardiorespiratory function that is calculated during a maximal cardiopulmonary exercise test. V02 max enables physicians to objectively assess cardiopulmonary function to aid in decision-making for patients with CHD. A significant proportion of these patients however are unable to achieve a maximal exercise test, and as such, there is a need for reliable submaximal predictors of cardiorespiratory reserve.The oxygen uptake efficiency slope represents a measure of how effectively oxygen is extracted from the lungs and taken into the body and can be calculated from a submaximal exercise test. Its reliability as a predictor of cardiorespiratory reserve has been validated in various patient populations, but there is limited evidence for its validity in adult patients with CHD.Retrospective analysis of cardiopulmonary exercise test data in 238 consecutive patients with CHD who completed a maximal cardiopulmonary exercise test at our tertiary cardiology centre demonstrated a strong correlation between peak V02 and the oxygen uptake efficiency slope (0.936). A strong correlation with peak V02 was also demonstrated when oxygen uptake efficiency slope was calculated at ventilatory anaerobic threshold (OUESVAT), 75% (OUES75), and 90% (OUES90) of the test (0.833, 0.905, 0.927 respectively).In adult patients with CHD who are unable to complete a maximal cardiopulmonary exercise test, the oxygen uptake efficiency slope is a reliable indicator of cardiopulmonary fitness which correlates strongly with peak V02 at or beyond the ventilatory anaerobic threshold. Further research is required to validate the findings in patients with less common anatomies and to assess the relationship between the oxygen uptake efficiency slope and mortality.

Novel approaches for leadless pacemaker implantation in the extra-cardiac Fontan cohort: Options to avoid leaded systems or epicardial pacing

BACKGROUND

Fontan surgery, a palliative procedure for single ventricle patients, often leads to the need for permanent pacing. Epicardial pacing has limitations, while transvenous pacing carries risks in the Fontan circulation. This case series introduces a novel approach of leadless pacemaker implantation in the extra-cardiac Fontan (ECF) cohort to overcome these limitations.

METHODS

The study includes four cases of leadless pacemaker (Micra™) implantation in patients with ECF. Procedures were performed under general anesthesia with guidance from trans-esophageal echocardiography. Various access routes were used, including trans-carotid and trans-fenestration approaches. Procedural details, parameters, and follow-up data were collected.

RESULTS

All leadless pacemaker implantations were successful, with satisfactory electrical parameters and stable pacing postprocedural outcomes during short-term follow-up. One patient required closure of their fenestration for symptomatic desaturation post procedurally.

CONCLUSIONS

Leadless pacemaker implantation via trans-carotid and trans-fenestration approaches appears to be a feasible back up option for pacing in Fontan patients where other options have been exhausted or there is a patient choice to avoid surgery. These techniques provide an option to avoid leaded systems or epicardial pacing, reducing the need for multiple thoracotomies and addressing challenges associated with surgical pacing leads. Further studies are needed to evaluate long-term outcomes and assess the broader application of leadless pacemakers in the Fontan population.

Coarctation of the Aorta: Diagnosis and Management

Coarctation of the aorta (CoA) accounts for approximately 5-8% of all congenital heart defects. Depending on the severity of the CoA and the presence of associated cardiac lesions, the clinical presentation and age vary. Developments in diagnosis and management have improved outcomes in this patient population. Even after timely repair, it is important to regularly screen for hypertension. Patients with CoA require lifelong follow-up with a congenital heart disease specialist as these patients may develop recoarctation and complications at the repair site and remain at enhanced cardiovascular risk throughout their lifetime.

Epidemiologic Pattern and Injury Mechanism of Intimate Partner Violence-Related Ocular Trauma in the US

Importance

Intimate partner violence (IPV) is an important cause of death and disability worldwide. The literature estimates that 45% of IPV injuries involve the eyes. Many medical fields have increased IPV-related research; however, ophthalmology IPV research remains rare.

Objective

To evaluate the epidemiologic pattern and injury mechanism of IPV related to ocular trauma.

Design, Setting, and Participants

This study was a retrospective cross-sectional analysis with deidentified data using the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Clinical Modification (ICD-10-CM) codes from the National Trauma Data Bank (NTDB), which is a data set collected by the American College of Surgeons. The NTDB is the largest US hospitalized trauma case database with submissions from more than 900 US facilities. Included in this analysis were the IPV-related ocular injuries of patients hospitalized between 2017 and 2019. Study data were analyzed from April 20 to October 15, 2022.

Exposures

IPV-related ocular injuries.

Main Outcomes and Measures

Ocular injuries and adult IPV trauma survivors were identified with the ICD-10-CM codes. The following demographic data were collected: sex, age, race and ethnicity, health insurance plan, substance misuse screening results, trauma level of hospital, the emergency department disposition, the total Glasgow Coma Scale score, the abbreviated injury scale, and caregiver at discharge.

Results

A total of 2598 of the recorded ocular injuries were associated with IPV. Patients had a mean (SD) age of 45.2 (18.4) years, and 1618 were female (62.3%). Most patients in the population sample (1195 [46.0%]) were aged 18 to 39 years. The race and ethnicity distribution was as follows: 629 Black (24.2%), 296 Hispanic (11.4%), 1358 White (52.3%), 229 other (8.8%), and 86 missing (3.3%). Insurance statuses were Medicaid (847 [32.6%]), Medicare (524 [20.2%]), private insurance (524 [20.2%]), and self-pay (488 [18.8%]). Women had greater odds of testing positive during alcohol screening (odds ratio [OR], 1.42; 95% CI, 1.21-1.67; P < .001). Black patients were most likely to have Medicaid (OR, 1.64; 95% CI, 1.35-1.99; P < .001), Hispanic patients were most likely to self-pay (OR, 1.96, 95% CI, 1.48-2.58; P < .001), and White patients were most likely to use Medicare (OR, 2.94, 95% CI, 2.33-3.73; P < .001).

Conclusions and Relevance

Social determinants of health were identified as key risk factors for IPV-related ocular injuries. Study findings highlight identifiable risk factors associated with IPV and ocular trauma that can contribute to IPV awareness among ophthalmologists.

A multidisciplinary approach to re-intervention in an Ebstein patient: a case report

Background

Ebstein's anomaly is a rare condition due to incomplete delamination of the tricuspid valve (TV) leaflets with downward displacement of the proximal leaflet attachments. It is associated with a smaller functional right ventricle (RV) and tricuspid regurgitation (TR) that is typically treated with TV replacement or repair. However, future re-intervention poses challenges. We describe a multidisciplinary team approach to re-intervention in a pacing-dependant Ebstein patient with severe bioprosthetic TV regurgitation.

Case summary

A 49-year-old female patient underwent bioprosthetic TV replacement for severe TR in Ebstein's. Post-operatively, she developed complete atrioventricular (AV) block necessitating the implantation of a permanent pacemaker which included a coronary sinus (CS) lead as the ventricular lead. Five years later, she presented with syncope due to a failing ventricular pacing lead, and a new RV lead was positioned across the TV bioprosthesis due to the lack of CS options. Two years later, she presented with breathlessness and lethargy with severe TR identified on transthoracic echocardiography. She successfully underwent a percutaneous leadless pacemaker implant, extraction of existing pacing system, and implantation of valve-in-valve TV.

Discussion

Patients with Ebstein's anomaly typically undergo TV repair or replacement. Following surgical intervention, owing to the anatomical location, patients can develop AV block requiring a pacemaker. Pacemaker implantation may involve a CS lead to avoid placing a lead across the new TV in efforts to avoid lead induced TR. Over time, these patients not uncommonly require re-intervention that can be challenging especially in pacing-dependant patients with leads across the TV.

Incidence of vascular complications for electrophysiology procedures in the ultrasound era: a single-centre experience over 10,000 procedures in the long term

BACKGROUND

Ultrasound (US) is being increasingly used to guide vascular access for electrophysiology (EP) procedures in many centres. Nonetheless, the incidence and predictors of vascular complications in the US era are limited. In this study, we describe our experience of vascular access-related complications associated with EP procedures which were performed with the routine use of US-guided vascular access.

METHODS

A total of 10,158 consecutive EP procedures in 8361 patients performed from April 2014 (when our centre moved to a policy of routine US-guided vascular access for EP procedures) to March 2022 were included. The outcome of interest was any vascular access-related complication that occurred within 7 days of the procedure; these were classified as severe if surgical intervention and/or blood transfusion was required, major if non-surgical intervention or delayed hospital discharge was required, or minor if it did not fulfil the criteria for severe or major.

RESULTS

During the study period, 2 (0.02%) severe vascular complications occurred, including 1 pseudo-aneurysm requiring surgery and 1 retroperitoneal haemorrhage requiring blood transfusion. Nine (0.09%) major complications occurred, including 6 hematomas managed by compression devices, 1 type B aortic dissection, 1 AV fistula managed conservatively and 1 haematoma managed conservatively but delayed hospital discharge. Eighteen (0.18%) minor haematomas were seen that did not require any intervention or delayed hospital discharge. On multivariable analysis, female sex [OR (95% CI): 2.5 (1.2, 5.4)] and use of an arterial access [OR (95% CI): 19.3 (7.1, 52.3)] were seen to be independent predictors of the 29 vascular complications.

CONCLUSION

With the use of US-guided vascular access in EP procedures, major vascular complications are exceedingly rare, particularly those needing surgical intervention. Our results provide additional evidence for scientific guidelines to support US use.

Impact of COVID-19 on patients awaiting ablation for atrial fibrillation

Objective

Atrial fibrillation (AF) ablation services were significantly affected by the COVID-19 pandemic. We aimed to evaluate a symptom-based clinician prioritisation scheme for waiting list management compared with patient-completed quality of life (QoL) scores. We also sought to understand factors influencing QoL, particularly the impact of COVID-19, on patients awaiting AF ablation, via a bespoke questionnaire.

Methods

Patients awaiting AF ablation were sent two QoL questionnaires (Atrial Fibrillation Effect on QualiTy of Life (AFEQT) and EuroQol 5D (EQ5D-5L)) and the bespoke questionnaire. At a separate time point, patients were categorised as C1—urgent, C2—priority or C3—routine by their cardiologist based on review of clinic letters.

Results

There were 118 patients included with priority categorisation available for 86 patients. Median AFEQT scores were lower in C2 (30.4; 17.2–51.9) vs C3 patients (56.5; 32.1–74.1; p<0.01). Unplanned admission occurred in 3 patients in C3 with AFEQT scores of <40. Although 65 patients had AF symptoms during the pandemic, 43.1% did not seek help where they ordinarily would have. An exercise frequency of ≥3–4 times a week was associated with higher AFEQT (56.5; 41.2–74.1; p<0.001) and EQ5D (0.84; 0.74–0.88; p<0.0001) scores.

Conclusion

The QoL of patients awaiting AF ablation is impaired and AFEQT helps to identify patients at risk of admission, over and above physician assessment. COVID-19 influenced patients seeking medical attention with symptomatic AF when they normally would. Regular exercise is associated with better QoL in patients awaiting AF ablation.

Assessing atrial fibrillation ablation priority during COVID-19 -does use of patient questionnaires help in stratification above physician assessment?

Funding Acknowledgements

Type of funding sources: None.

Introduction

Catheter ablation for atrial fibrillation (AF) is largely offered for symptomatic relief. The ORBIT registry has shown that patients with a higher EHRA class and lower quality of life (QoL) scores (AFEQT score <65.7) are more likely to suffer emergency hospital admissions. To help prevent unplanned AF admissions and to best utilise the reduced capacity for elective work during the COVID-19 pandemic, it has become even more important to prioritise the most symptomatic AF patients for ablation. Purpose: To evaluate the accuracy of a subjective symptom-based clinician prioritisation schema compared to objective patient-completed quality of life (QoL) scores. Methods: In July 2020, all elective cases awaiting AF ablation at our institution were categorised by their cardiologist as either category 1 (C1-urgent), category 2 (C2–priority, procedure to be done during the ongoing COVID-19 pandemic) or category 3 (C3–routine, procedure may be delayed until post pandemic). This categorisation was based on review of clinic letters where EHRA AF symptom class or PROMS are not routinely recorded.  All patients in C2 and C3 were then posted an AF specific (AFEQT) and a generic (EQ5D) QoL questionnaire to complete. Physicians were blinded to patient responses on the QoL questionnaires. Results: Details of physician prioritisation and completed questionnaires were available for 85 patients (62 ± 10 years, PAF in 61%, males 66%). The 18 patients that had been categorised in C2 (priority) group were found to have a significantly lower AFEQT score (30.4, IQR 17.2-51.9) compared to the 67 patients classed in C3 (routine) group (56.5, IQR 32.1-74.1; p < 0.01)(Figure 1a). EQ5D scores also tended to be lower in the C2 patients (0.7, IQR 0.4-0.8) compared to C3 (0.8, IQR 0.6-0.9; p = 0.056) (Figure 1c). 16 (89%) patients in C2 had significant AF-related impact on QoL (as defined as AFEQT score <65.7) compared to 42 (63%) of patients in C3.  However, there was significant overlap between groups (Figure 1b). 4 patients in C3 had unplanned AF related hospital admissions while awaiting ablation, as compared to none in C2. The median AFEQT score of these 4 patients was 23.3, indicating that they were highly symptomatic despite being classified in C3 by their cardiologist. Conclusion : Physician assessments are moderately accurate in prioritising patients awaiting AF ablation. The addition of formal patient-completed QoL assessment such as with AFEQT, helps to identify the most symptomatic patients at risk of emergency hospital admission, and physicians should consider using these as part of routine assessment, especially during the COVID pandemic.

Pulmonary barotrauma: assessment and investigation in divers

Decompression illness (DCI) is an uncommon problem but can be significant in terms of morbidity and, very rarely, mortality. The mechanisms of DCI are pulmonary barotrauma and decompression sickness due to inert gas supersaturation. After the initial management phase, identification of predisposing factors is important to help advise divers regarding future risk and avoidance. Here we present four cases of DCI where pulmonary barotrauma was the likely causative mechanism. We highlight the important features in assessment for pulmonary barotrauma and advising divers on the risk of a recurrence.

The Prognostic Value of Heart Type Fatty Acid Binding Protein in Patients with Suspected Acute Coronary Syndrome: A Systematic Review

Background:

Heart type fatty acid protein (HFABP) is a cytosolic protein released early after acute coronary syndrome (ACS) even in the absence of myocardial necrosis.

Objectives:

The purpose of this systematic review was to determine whether HFABP levels in patients with suspected, or confirmed ACS, improve risk stratification when added to established means of risk assessment.

Methods:

We searched Medline, Pubmed and Embase databases from inception to July 2015 to identify prospective studies with suspected or confirmed ACS, who had HFABP measured during the index admission with at least 1 month follow up data. A prognostic event was defined as all-cause mortality or acute myocardial infarction (AMI).

Results:

7 trials providing data on 6935 patients fulfilled inclusion criteria. There were considerable differences between studies and this was manifest in variation in prognostic impact of elevated HFABP(Odds ratio range 1.2-15.2 for death). All studies demonstrated that HFABP provide unadjusted prognostic information and in only one study this was negated after adjusting for covariates. A combination of both negative troponin and normal HFABP conferred a very low event rate. No study evaluated the incremental value of HFABP beyond that of standard risk scores. Only one study used a high sensitive troponin assay.

Conclusion:

There was marked heterogeneity in prognostic impact of HFABP in ACS between studies reflecting differences in sampling times and population risk. Prospective studies of suspected ACS with early sampling of HFABP in the era of high sensitivity troponin are necessary to determine the clinical value of HFABP. HFABP should not currently be used clinically as a prognostic marker in patients with suspected ACS.

Heart Disease and Pregnancy

Cardiac disease remains a major cause of morbidity and mortality in pregnant and post-partum women, although progress has been made, with specialist joint obstetric-cardiology clinics providing an integrated, safe and personalised service to these women. As a result, fewer non-specialist cardiologists are managing women in pregnancy with cardiovascular disease. The aim of this review is to provide a brief overview of current knowledge and practice in the field, with an emphasis on the major physiological changes which occur during pregnancy, focussing on progress through the trimesters, clinical assessment in pregnancy, management of delivery (concentrating on managed vaginal delivery), drug treatment, key conditions and risk assessment. The latter factor is particularly important in terms of being able to identify high-risk women earlier and to counsel them appropriately. Pregnant women with cardiovascular conditions can, with appropriate knowledge and counselling, be managed safely in specialist multidisciplinary services, but there is a need for cardiologists to understand the key changes and risks involved in pregnancy, delivery and the post-partum period.

Seroprevalence of Q Fever in Patients Undergoing Heart Valve Replacement Surgery

BACKGROUND AND AIM OF THE STUDY

Q fever, caused by the rickettsia Coxiella burnetii, is a worldwide zoonotic disease with both acute and chronic manifestations. Endocarditis is the principal chronic manifestation. Q fever can easily be mistaken for degenerative valve disease due to its indolent presentation, the fastidious nature of the organism (routine cultures are negative), and the absence of a typical echocardiographic and macroscopic appearance for endocarditis. Prosthetic valve failure, with associated morbidity and mortality, have been described following unrecognized infections.

METHODS

Previous studies have documented the value of screening strategies in areas of high prevalence. Hence, a pilot study was conducted in a low-prevalence setting, in which 139 patients at two tertiary cardiac centers attending for elective valve replacement for degenerative valvular disease underwent testing for chronic Q fever infection by serological and molecular methods on blood and valve tissue.

RESULTS

Five patients (3.7%) had serological evidence of past exposure to Q fever (consistent with rates in the literature). None had evidence of chronic Q fever endocarditis. The cost of adopting a universal screening strategy is around £40,000 per case (if serology is used to screen patients prior to surgery).

CONCLUSIONS

Alternative and more cost-effective methods for identifying clinically quiet cases of chronic Q fever endocarditis are required.

Altered Left Ventricular Ion Channel Transcriptome in a High-Fat-Fed Rat Model of Obesity: Insight into Obesity-Induced Arrhythmogenesis

Introduction. Obesity is increasingly common and is associated with an increased prevalence of cardiac arrhythmias. The aim of this study was to see whether in obesity there is proarrhythmic gene expression of ventricular ion channels and related molecules. Methods and Results. Rats were fed on a high-fat diet and compared to control rats on a normal diet (n = 8). After 8 weeks, rats on the high-fat diet showed significantly greater weight gain and higher adiposity. Left ventricle samples were removed at 8 weeks and mRNA expression of ion channels and other molecules was measured using qPCR. Obese rats had significant upregulation of Ca_v1.2, HCN4, K_ir2.1, RYR2, NCX1, SERCA2a, and RYR2 mRNA and downregulation of ERG mRNA. In the case of HCN4, it was confirmed that there was a significant increase in protein expression. The potential effects of the mRNA changes on the ventricular action potential and intracellular Ca²⁺ transient were predicted using computer modelling. Modelling predicted prolongation of the ventricular action potential and an increase in the intracellular Ca²⁺ transient, both of which would be expected to be arrhythmogenic. Conclusion. High-fat diet causing obesity results in arrhythmogenic cardiac gene expression of ion channels and related molecules.

Time-delay to intensity mapping based on a second-order optical integrator: application to optical arbitrary waveform generation

We propose and validate experimentally a time-delay to intensity mapping process based on second-order optical integrators. This mapping provides dynamic control of the intensity modulation profile of a waveform based on a purely passive and linear process. In particular, we can realize linear intensity control by tuning the time-delay between two optical pulses launched into a second-order optical integrator. We suggest and experimentally prove the use of this mapping process for reconfigurable optical arbitrary waveform generation.

Clinical disease registries in acute myocardial infarction

Disease registries, containing systematic records of cases, have for nearly 100 years been valuable in exploring and understanding various aspects of cardiology. This is particularly true for myocardial infarction, where such registries have provided both epidemiological and clinical information that was not readily available from randomised controlled trials in highly-selected populations. Registries, whether mandated or voluntary, prospective or retrospective in their analysis, have at their core a common study population and common data definitions. In this review we highlight how registries have diversified to offer information on epidemiology, risk modelling, quality assurance/improvement and original research-through data mining, transnational comparisons and the facilitation of enrolment in, and follow-up during registry-based randomised clinical trials.

Active Fabry-Perot cavity for photonic temporal integrator with ultra-long operation time window

In this paper, a photonic temporal integrator based on an active Fabry-Perot (F-P) cavity is proposed and theoretically investigated. The gain medium in the F-P cavity is a semiconductor optical amplifier (SOA) with high gain coefficient. Key feature of the proposed photonic integrator is that the length of integration time window is widely tunable and could be ideally extended to infinitely long when the injection current is approaching lasing condition. Based on an F-P cavity with practically feasible parameters, a photonic temporal integrator with an integration time window of 160 ns and an operation bandwidth of 180 GHz is achieved. The time-bandwidth product of this photonic temporal integrator is 28,800, which is about two-orders of magnitude higher than any previously reported results. Gain recovery effect has been also considered and analyzed for the impact on performance of the photonic integrator, followed by the simulation results of the impact of gain recovery.

The intersection of atrial fibrillation and heart failure in a hospitalised population

OBJECTIVES

This work set out to comprehensively characterize patients admitted to hospital with both atrial fibrillation (AF) and heart failure (HF) and to compare this cohort of patients to the global hospital population of patients with only one of these diagnoses.

METHODS AND RESULTS

This was a retrospective analysis of all in-patients with HF and AF admitted to a large urban hospital over a 3-month period. Patients with AF were identified by both discharge codes and electrocardiograms. HF patients were identified by means of discharge codes for HF and by screening all patients with AF, a common comorbidity of HF. Evidence for left ventricular (LV) dysfunction was sought. Of patients with AF (n = 453), 43% had symptoms of HF and LV dysfunction. Of patients with a discharge code and confirmed HF (n = 286), 34% had AF, 60% of whom were in chronic AF. Compared to HF patients in sinus rhythm those in AF were older (70 +/- 10 y vs 67 +/- 12 y, P < 0.02), had a higher prevalence of valvular heart disease (25% vs 7%, P < 0.0001) and a lower prevalence of ischaemic heart disease (17% vs 40%, P < 0.0001). HF patients identified by discharge codes in AF were more likely to have QRS > or = 120 msec (18% vs 12% in sinus rhythm; P= ns). Patients with AF and deemed to suffer concomitant HF, as opposed to AF alone, were significantly more likely to have QRS prolongation (QRS > or = 120 msec 27% vs 8%, P < 0.05). 8% of patients with AF and HF had a QRS > 150 msec.

CONCLUSIONS

AF and HF are frequent, concomitant pathologies in a hospitalised population. AF complicates HF assessment and treatment. Greater dyssynchrony, as denoted by ECG, in the AF and HF population suggests opportunities for treatment of HF by cardiac resynchronization therapy and ablative therapies.

Experimental demonstration of superluminal space-to-time mapping in long period gratings

We experimentally demonstrate a superluminal space-to-time mapping process in grating-assisted (GA) codirectional coupling devices, particularly fiber long period gratings (LPGs). Through this process, the grating complex (amplitude and phase) apodization profile is directly mapped into the device's temporal impulse response. In contrast to GA counterdirectional couplers, e.g., Bragg gratings, this mapping occurs with a space-to-time scaling factor that is much higher than the propagation speed of light in vacuum. This phenomenon has been used for synthesizing customized complex optical pulse data sequences with femtosecond features (3.5 Tbit/s data rate) using readily feasible fiber LPG designs, e.g., with subcentimeter resolutions.

Superluminal space-to-time mapping in grating-assisted co-directional couplers

A superluminal space-to-time mapping process is reported and numerically validated in grating-assisted (GA) co-directional couplers, e.g. fiber/waveguide long-period gratings (LPGs). We demonstrate that under weak-coupling conditions, the amplitude and phase of the grating complex apodization profile of a GA co-directional coupling device can be directly mapped into the device's temporal impulse response. In contrast to GA counter-directional couplers, this mapping occurs with a space-to-time scaling factor that is much higher than the propagation speed of light in vacuum. This phenomenon opens up a promising new avenue to overcome the fundamental time-resolution limitations of present in-fiber and on-chip optical waveform generation (shaping) and processing devices, which are intrinsically limited by the achievable spatial resolution of fabrication technologies. We numerically demonstrate the straightforward application of the phenomenon for synthesizing customized femtosecond-regime complex optical waveforms using readily feasible fiber LPG designs, e.g. with sub-centimeter resolutions.

Terahertz bandwidth all-optical Hilbert transformers based on long-period gratings

A novel, all-optical design for implementing terahertz (THz) bandwidth real-time Hilbert transformers is proposed and numerically demonstrated. An all-optical Hilbert transformer can be implemented using a uniform-period long-period grating (LPG) with a properly designed amplitude-only grating apodization profile, incorporating a single π-phase shift in the middle of the grating length. The designed LPG-based Hilbert transformers can be practically implemented using either fiber-optic or integrated-waveguide technologies. As a generalization, photonic fractional Hilbert transformers are also designed based on the same optical platform. In this general case, the resulting LPGs have multiple π-phase shifts along the grating length. Our numerical simulations confirm that all-optical Hilbert transformers capable of processing arbitrary optical signals with bandwidths well in the THz range can be implemented using feasible fiber/waveguide LPG designs.

Aneurysmal 'pepper-pot' atrial septal defect in an older gentleman with multiple cerebrovascular attacks

Our patient presented to a large university teaching hospital with a history of light-headedness, falls and multiple cerebrovascular ischaemic events. This caused a right sided hemiplegia and the patient experienced significant functional limitation. Extensive investigations were carried out to exclude any causative factors such as carotid artery disease and the patient had all identifiable cardiovascular risk factors identified and modified. No significant pathology was found and a referral was made to the cardiology service. Transthoracic echocardiography revealed a complex type 3 perforate 'pepper pot' atrial septal aneurysm with associated thrombus. The patient was commenced on warfarin and appropriate rate limiting medication. After discussion of all interventional modalities, the patient opted for conservative management.

Single-shot photonic time-intensity integration based on a time-spectrum convolution system

Real-time and single-shot ultra-fast photonic time-intensity integration of arbitrary temporal waveforms is proposed and demonstrated. The intensity-integration concept is based on a time-spectrum convolution system, where the use of a multi-wavelength laser with a flat envelope, employed as the incoherent broadband source, enables single-shot operation. The experimental implementation is based on optical intensity modulation of the multi-wavelength laser with the input waveform, followed by linear dispersion. In particular, photonic temporal intensity integration with a processing bandwidth of 36.8 GHz over an integration time window of 1.24 ns is verified by experimentally measuring the integration of an ultra-short microwave pulse and an arbitrary microwave waveform.

Long Term Outcomes in Stress Echocardiography: Ten Year Follow up of a Cohort in a Single Centre

Backgroud

The high service burden for acute admissions and referrals via rapid access chest pain clinics for evaluation of possible coronary artery disease means that many patients are now undergoing an investigation such as stress echocardiography as part of their evaluation. We aimed to see if the reassurance provided by negative stress echocardiography correlates with long-term event free survival.

Methods

A cohort of all patients who were referred at a single centre for stress echocardiography for diagnosis of coronary artery disease between January 1st 1999 and December 31st 2000 were followed up at least 10 years following theirs stress echocardiogram for further major cardiovascular events and mortality.

Results

A total of 64 patients were identified where records could be obtained for analysis. There were 16 positive scans, 37 negative scans and 11 inconclusive scans. The indeterminacy rate of scans was 17%, the sensitivity rate for detecting significant disease as indexed to invasive angiography was 88 % and the specificity rate compared with angiography was 75%. There were no myocardial infarctions or new diagnoses of heart failure in the negative echocardiogram group. There were seven deaths in the total population and only one death from cardiovascular causes in the negative echocardiogram group.

Conclusion

Stress echocardiography even in this small group predicts long-term outcomes as well as invasive coronary angiography.

Figure of merit for photonic differentiators

We introduce a universal figure of merit to evaluate the processing speed (operation bandwidth) performance of arbitrary-order optical differentiators. In particular, we define the maximum-to-minimum bandwidth ratio (MMBR) as a main figure of merit of these devices, which essentially informs about the broadness of the acceptable input pulse bandwidth range. We derive and numerically confirm a general analytical expression for the MMBR of an arbitrary optical differentiator, showing that this can be expressed simply as a function of the differentiator's amplitude resonance depth. The device MMBR can be improved by increasing the filter's resonance depth, depending also on the differentiation order; in particular, the MMBR quickly deteriorates as the differentiator order is increased. In our analysis, photonic differentiators are considered in two main groups, namely (i) non-minimum phase and (ii) minimum phase optical filtering implementations. The derived analytical expression for the device MMBR is generalized for these two different solutions, and the validity of the obtained analytical estimates is verified through numerical simulations, including results for the cases of 1st-, 2nd-, and 3rd-order differentiators.

Endocarditis in a large district general hospital: A study of the microbiological spectrum between 2000 and 2011

Infective endocarditis is one of three common cardiac infections in the United Kingdom, in addition to myocarditis and pericarditis, with a reported incidence of 1.7 to 6.2 cases per 100,000 patient years. Infective endocarditis can often have serious consequences and a wide variety of organisms may be the causative pathogen. There are little published data regarding the exact spectrum of organisms that cause endocarditis in the United Kingdom and whether organisms such as streptococci still dominate. In the present study, all cases of endocarditis at the authors' institution, representing a typical nontertiary centre, were retrospectively examined and audited to provide a snapshot of the organism spectrum in these patients. The cases of more than 120 patients who were coded as having endocarditis by the institution's clinical coding department during the period between December 2000 and January 2011 were examined. Microbiological tests and clinical case notes of all patients were reviewed. Of the 101 patients diagnosed with and treated for endocarditis, 64 were male, with a mean age of 60.57 years. The most common organisms identified were Streptococcus species (31%), Staphylococcus aureus (27%) and Enterococcus faecalis (21%). The organisms with the highest associated mortality rate were S aureus and the 'other organism' group, which included non-HACEK group (Haemophilus species, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens and Kingella species) pathogens such as Candida albicans. Streptococcus species and S aureus remain the main cause of endocarditis in a typical hospital setting in the United Kingdom, although in a smaller proportion of cases than historical data suggests. Overall, mortality remains high, and the clinician should remain vigilant to endocarditis in any patient with a positive blood culture because the number of cases of endocarditis caused by less typical organisms are increasing.

Effusive-constrictive pericarditis in the absence of overt pericardial disease on multiple imaging modalities

Effusive-constrictive pericarditis (ECP) is a rare condition that may prove fatal without appropriate treatment. In ECP, there is concomitant existence of a pericardial effusion and CP, that together lead to impaired cardiac filling. Therapeutic pericardiocentesis only addresses part of the problem; surgical pericardiectomy may be required to relieve the constrictive element. Imaging in ECP characteristically demonstrates calcification or thickening of the pericardium. The authors describe a case of ECP were a number of imaging modalities (including echocardiography, cardiac magnetic resonance and CT) did not identify overt pericardial disease. The patient underwent surgical pericardiectomy that led to a rapid resolution of symptoms and full recovery. Histopathological analysis of the pericardial biopsy indicated a non-specific pericardial fibrosis, in keeping with the final diagnosis of ECP.

Reconfigurable optical differential phase-shift-keying pattern recognition based on incoherent photonic processing

We propose and experimentally demonstrate asynchronous optical differential phase-shift-keying (DPSK) pattern recognition using a fully reconfigurable technique. The proposed method uses optical phase-to-bipolar intensity conversion through all-optical differentiation in conjunction with an incoherent time-spectrum convolution system where the pattern to be recognized is implemented directly in the spectral domain through optical amplitude-only linear filtering. Full reconfigurability in terms of bit rate, pattern sequence, and pattern length is achieved using electronically programmable optical filters. We demonstrate dynamically switching recognition of different 64 bit patterns in a continuous 12 Gb/s DPSK pseudorandom optical bit stream with contrast ratio up to 3.8 dB.

Aggressive cardiac involvement in systemic lupus erythematosus: a case report and a comprehensive literature review

Background. We present the case of a 35-year-old gentleman who presented with an aggressive cardiomyopathy with normal coronary arteries. He was later diagnosed with systemic lupus-related cardiomyopathy. Methods. We undertook an extensive review of the literature regarding cardiac manifestations of lupus and used over 100 journals to identify the key points in pathology, diagnosis, and treatment. Results. We have shown that cardiac lupus can be rapidly progressive and, unless treated early, can have severe consequences. The predominant pathologies are immune complex and accelerated atherosclerosis drive. Treatment comprised of high-level immunosuppression.