An Outbreak of Hepatitis A among Young Adult Men in Cyprus.

BACKGROUND: Outbreaks of acute hepatitis A (AHA) have recently been reported in Europe among men who have sex with men (MSM). The aim of this work was to evaluate, for the first time, trends in the reported cases of AHA in Cyprus over the last seven years. METHODS: We retrospectively studied all people reported with AHA in Cyprus between January 2013 and December 2019. Demographic data, type of transmission, vaccination status for HAV, laboratory and clinical data were analyzed. RESULTS: The asnalysis involved 33 AHA cases (age 32.7 ± 17.4 years, 78.8% males). An increase in AHA reports was observed between July 2017 and June 2018 when more than a third (n = 13) of the cases of the period 2013-2019 were reported. The reporting rate of AHA doubled from 0.52 cases per 100,000 population (before July 2017) to 1.12 cases per 100,000 population (July 2017-June 2018). The male/female (M/F) ratio increased from one in 2013 to eight in 2018. CONCLUSION: An increase in AHA reports occurred in Cyprus between July 2017 and June 2018. Many cases with AHA in that period were MSM. Enhanced surveillance and timely public health interventions, like vaccination and awareness promotion, are important for preventing future outbreaks.

Image Data Analysis for Quantifying Scar Transmurality in MRI phantoms for Cardiac Resynchronisation Therapy.

The use of implantable cardiac devices has increased in the last 30 years. Cardiac resynchronisation therapy (CRT) is a procedure which involves implanting a coin sized pacemaker for reversing heart failure. The pacemaker electrode leads are implanted into cardiac myocardial tissue. The optimal site for implantation is highly patient-specific. Most implanters use empirical placement of the lead. One region identified to have a poor response rate are myocardial tissue with transmural scar. Studies that precisely measure transmurality of scar tissue in the left ventricle (LV) are few. Most studies lack proper validation of their transmurality measurement technique. This study presents an image analysis technique for computing scar transmurality from late-gadolinium enhancement MRI. The technique is validated using phantoms under a CRT image guidance system. The study concludes that scar transmurality can be accurately measured in certain situations and validation with phantoms is important.

LV function validation of computer-assisted interventional system for cardiac resyncronisation therapy.

PURPOSE: Cardiac resynchronisation therapy (CRT) is an established treatment for symptomatic patients with heart failure, a prolonged QRS duration, and impaired left ventricular (LV) function; however, non-response rates remain high. Recently proposed computer-assisted interventional platforms for CRT provide new routes to improving outcomes. Interventional systems must process information in an accurate, fast and highly automated way that is easy for the interventional cardiologists to use. In this paper, an interventional CRT platform is validated against two offline diagnostic tools to demonstrate that accurate information processing is possible in the time critical interventional setting. METHODS: The study consisted of 3 healthy volunteers and 16 patients with heart failure and conventional criteria for CRT. Data analysis included the calculation of end-diastolic volume, end-systolic volume, stroke volume and ejection fraction; computation of global volume over the cardiac cycle as well as time to maximal contraction expressed as a percentage of the total cardiac cycle. RESULTS: The results showed excellent correlation ([Formula: see text] values of [Formula: see text] and Pearson correlation coefficient of [Formula: see text]) with comparable offline diagnostic tools. CONCLUSION: Results confirm that our interventional system has good accuracy in everyday clinical practice and can be of clinical utility in identification of CRT responders and LV function assessment.

3D/2D Registration with superabundant vessel reconstruction for cardiac resynchronization therapy.

A key component of image guided interventions is the registration of preoperative and intraoperative images. Classical registration approaches rely on cross-modality information; however, in modalities such as MRI and X-ray there may not be sufficient cross-modality information. This paper proposes a fundamentally different registration approach which uses adjacent anatomical structures with superabundant vessel reconstruction and dynamic outlier rejection. In the targeted clinical scenario of cardiac resynchronization therapy (CRT) delivery, preoperative, non contrast-enhanced, MRI is registered to intraoperative, contrasted X-ray fluoroscopy. The adjacent anatomical structures are the left ventricle (LV) from MRI and the coronary veins reconstructed from two contrast-enhanced X-ray images. The novel concept of superabundant vessel reconstruction is introduced to bypass the standard reconstruction problem of establishing one-to-one correspondences. Furthermore, a new dynamic outlier rejection method is proposed, to enable globally optimal point set registration. The proposed approach has been qualitatively and quantitatively evaluated on phantom, clinical CT angiography with ground truth and clinical CRT data. A novel evaluation method is proposed for clinical CRT data based on previously implanted artificial aortic and mitral valves. The registration accuracy in 3D was 2.94 mm for the aortic and 3.86 mm for the mitral valve. The results are below the required accuracy identified by clinical partners to be the half-segment size (16.35 mm) of a standard American Heart Association (AHA) 16 segment model of the LV.

A Planning and Guidance Platform for Cardiac Resynchronization Therapy.

Patients with drug-refractory heart failure can greatly benefit from cardiac resynchronization therapy (CRT). A CRT device can resynchronize the contractions of the left ventricle (LV) leading to reduced mortality. Unfortunately, 30%-50% of patients do not respond to treatment when assessed by objective criteria such as cardiac remodeling. A significant contributing factor is the suboptimal placement of the LV lead. It has been shown that placing this lead away from scar and at the point of latest mechanical activation can improve response rates. This paper presents a comprehensive and highly automated system that uses scar and mechanical activation to plan and guide CRT procedures. Standard clinical preoperative magnetic resonance imaging is used to extract scar and mechanical activation information. The data are registered to a single 3-D coordinate system and visualized in novel 2-D and 3-D American Heart Association plots enabling the clinician to select target segments. During the procedure, the planning information is overlaid onto live fluoroscopic images to guide lead deployment. The proposed platform has been used during 14 CRT procedures and validated on synthetic, phantom, volunteer, and patient data.

Real-Time X-MRI-Guided Left Ventricular Lead Implantation for Targeted Delivery of Cardiac Resynchronization Therapy.

OBJECTIVES: This study sought to test the feasibility of a purpose-built, integrated software platform to process, analyze, and overlay cardiac magnetic resonance (CMR) data in real time within a combined cardiac catheter laboratory and magnetic resonance imaging scanner suite (X-MRI) to guide left ventricular (LV) lead implantation. BACKGROUND: Suboptimal LV lead position is a major determinant of poor cardiac resynchronization therapy (CRT) response, and the optimal site is highly patient specific. Pacing myocardial scar is associated with poorer outcomes; conversely, targeting latest mechanical activation (LMA) may improve them. METHODS: Fourteen patients (age 74 ± 5.1 years; New York Heart Association functional class: 2.7 ± 0.4; 86% ischemic with ejection fraction 27 ± 7.6%; QRSd: 157 ± 19 ms) underwent CMR followed by immediate CRT implantation using derived scar and dyssynchrony data, overlaid onto fluoroscopy in an X-MRI suite. Rapid LV segmentation enabled detailed scar quantification, identification of LMA segments, and selection of myocardial targets. At coronary venography, the CMR-derived 3-dimensional shell was fused, enabling identification of viable venous targets subtended by target segments for LV lead placement. RESULTS: The platform was successful in all 14 patients, of whom 10 (71%) were paced in pre-procedurally defined target segments. Pacing in CMR-defined target segments (out of scar) showed a significant decrease in the LV capture threshold (mean difference: 2.4 [1.5 to 3.2]; p < 0.001) and shorter paced QRS duration (mean difference: 25 [15 to 34]; p < 0.001) compared with pacing in areas of CMR determined scar. In 5 (36%) patients with extensive scar in the posterolateral wall, CMR guidance enabled successful lead delivery in an alternative anatomically favorable site. Radiation dose and implant times were similar to historical controls (p = NS). CONCLUSIONS: Real-time CMR-guided LV lead placement is feasible and achievable in a single clinical setting and may prove helpful to preferentially select sites for LV lead placement.

Dynamic mapping of ventricular function from cardiovascular magnetic resonance imaging.

Heart failure is associated with substantial mortality and morbidity and remains the most common diagnosis in older patients. Based on experimental electrophysiologic studies, cardiac resynchronization therapy (CRT) for heart failure results in a maximum resynchronization effect when applied to the most delayed left ventricular (LV) site. Current clinical practice is to identify the optimal site using separate visualisation of scar and activation information. These must be mentally mapped into 3D, which is challenging and time-consuming for the electrophysiologist. The aim of this work is to improve patient planning for CRT by mapping propagation of mechanical activation from cardiac magnetic resonance (CMR) onto a three-dimensional plus time (3D+t) model map to assist the cardiologist in determining the optimal LV pacing site. Automatic motion analysis of the 16-segment patient-specific LV anatomical model, automatically segmented from cine MR data, was done and regional volume change curves as a function of the cardiac cycle along with intraventricular dyssynchrony indices were extracted. The regional volume information computed was then mapped onto all phases of the 3D+t CMR data, which provides a 3D+t mechanical activation map over the whole cardiac cycle. This workflow was tested on 7 patients and 3 healthy volunteers. This mapping of the regional change of volume across the LV during ventricular pacing could facilitate the selection of the optimum pacing segment at the planning stage of the procedure, and consequently decrease the number of inadequate responders to CRT.

Image-based view-angle independent cardiorespiratory motion gating and coronary sinus catheter tracking for x-ray-guided cardiac electrophysiology procedures.

Determination of the cardiorespiratory phase of the heart has numerous applications during cardiac imaging. In this article we propose a novel view-angle independent near-real time cardiorespiratory motion gating and coronary sinus (CS) catheter tracking technique for x-ray fluoroscopy images that are used to guide cardiac electrophysiology procedures. The method is based on learning CS catheter motion using principal component analysis and then applying the derived motion model to unseen images taken at arbitrary projections, using the epipolar constraint. This method is also able to track the CS catheter throughout the x-ray images in any arbitrary subsequent view. We also demonstrate the clinical application of our model on rotational angiography sequences. We validated our technique in normal and very low dose phantom and clinical datasets. For the normal dose clinical images we established average systole, end-expiration and end-inspiration gating success rates of 100%, 85.7%, and 92.3%, respectively. For very low dose applications, the technique was able to track the CS catheter with median errors not exceeding 1 mm for all tracked electrodes. Average gating success rates of 80.3%, 71.4%, and 69.2% were established for the application of the technique on clinical datasets, even with a dose reduction of more than 10 times. In rotational sequences at normal dose, CS tracking median errors were within 1.2 mm for all electrodes, and the gating success rate was 100%, for view angles from RAO 90° to LAO 90°. This view-angle independent technique can extract clinically useful cardiorespiratory motion information using x-ray doses significantly lower than those currently used in clinical practice.

A statistical method for retrospective cardiac and respiratory motion gating of interventional cardiac x-ray images.

PURPOSE: Image-guided cardiac interventions involve the use of fluoroscopic images to guide the insertion and movement of interventional devices. Cardiorespiratory gating can be useful for 3D reconstruction from multiple x-ray views and for reducing misalignments between 3D anatomical models overlaid onto fluoroscopy. METHODS: The authors propose a novel and potentially clinically useful retrospective cardiorespiratory gating technique. The principal component analysis (PCA) statistical method is used in combination with other image processing operations to make our proposed masked-PCA technique suitable for cardiorespiratory gating. Unlike many previously proposed techniques, our technique is robust to varying image-content, thus it does not require specific catheters or any other optically opaque structures to be visible. Therefore, it works without any knowledge of catheter geometry. The authors demonstrate the application of our technique for the purposes of retrospective cardiorespiratory gating of normal and very low dose x-ray fluoroscopy images. RESULTS: For normal dose x-ray images, the algorithm was validated using 28 clinical electrophysiology x-ray fluoroscopy sequences (2168 frames), from patients who underwent radiofrequency ablation (RFA) procedures for the treatment of atrial fibrillation and cardiac resynchronization therapy procedures for heart failure. The authors established end-systole, end-expiration, and end-inspiration success rates of 97.0%, 97.9%, and 97.0%, respectively. For very low dose applications, the technique was tested on ten x-ray sequences from the RFA procedures with added noise at signal to noise ratio (SNR) values of √50, √10, √8, √6, √5, √2 and √1 to simulate the image quality of increasingly lower dose x-ray images. Even at the low SNR value of √2, representing a dose reduction of more than 25 times, gating success rates of 89.1%, 88.8%, and 86.8% were established. CONCLUSIONS: The proposed technique can therefore extract useful information from interventional x-ray images while minimizing exposure to ionizing radiation.

Automatic image-based retrospective gating of interventional cardiac X-ray images.

Gating of X-ray fluoroscopy images is required for catheter reconstruction for registration of pre-procedural images with fluoroscopy for guidance and biophysical modelling. We propose a novel and clinically useful retrospective method for automatic image-based cardiac and respiratory motion gating. The technique is based on tracking and statistical analysis of the shape of the coronary sinus catheter. We applied our method on five mono-plane imaging sequences comprising a total of 322 frames from five different patients undergoing radiofrequency ablation for the treatment of atrial fibrillation. We established systole, end-inspiration and end-expiration gating with success rates of 100%, 89.47% and 81.25% respectively.

Evolution and conservation in human parechovirus genomes.

Human parechoviruses (HPeVs) are frequent pathogens with a seroprevalence of over 90% in adults. Recent studies on these viruses have increased the number of HPeV types to eight. Here we analyse the complete genome of one clinical isolate, PicoBank/HPeV1/a, and VP1 and 3D protein sequences of PicoBank/HPeV6/a, isolated from the same individual 13 months later. PicoBank/HPeV1/a is closely related to other recent HPeV1 isolates but is distinct from the HPeV1 Harris prototype isolated 50 years ago. The availability of an increasing number of HPeV sequences has allowed a detailed analysis of these viruses. The results add weight to the observations that recombination plays a role in the generation of HPeV diversity. An important finding is the presence of unexpected conservation of codons utilized in part of the 3D-encoding region, some of which can be explained by the presence of a phylogenetically conserved predicted secondary structure domain. This suggests that in addition to the cis-acting replication element, RNA secondary structure domains in coding regions play a key role in picornavirus replication.