Richard W. Watkin

Guidelines for the diagnosis and antibiotic treatment of endocarditis in adults: a report of the Working Party of the British Society for Antimicrobial Chemotherapy

The BSAC guidelines on treatment of infectious endocarditis (IE) were last published in 2004. The guidelines presented here have been updated and extended to reflect developments in diagnostics, new trial data and the availability of new antibiotics. The aim of these guidelines, which cover both native valve and prosthetic valve endocarditis, is to standardize the initial investigation and treatment of IE. An extensive review of the literature using a number of different search criteria has been carried out and cited publications used to support any changes we have made to the existing guidelines. Publications referring to in vitro or animal models have only been cited if appropriate clinical data are not available. Randomized, controlled trials suitable for the development of evidenced-based guidelines in this area are still lacking and therefore a consensus approach has again been adopted for most recommendations; however, we have attempted to grade the evidence, where possible. The guidelines have also been extended by the inclusion of sections on clinical diagnosis, echocardiography and surgery.

Guidelines for the diagnosis, prevention and management of implantable cardiac electronic device infection. Report of a joint Working Party project on behalf of the British Society for Antimicrobial Chemotherapy (BSAC, host organization), British Heart Rhythm Society (BHRS), British Cardiovascular Society (BCS), British Heart Valve Society (BHVS) and British Society for Echocardiography (BSE)

Infections related to implantable cardiac electronic devices (ICEDs), including pacemakers, implantable cardiac defibrillators and cardiac resynchronization therapy devices, are increasing in incidence in the USA and are likely to increase in the UK, because more devices are being implanted. These devices have both intravascular and extravascular components and infection can involve the generator, device leads and native cardiac structures or various combinations. ICED infections can be life-threatening, particularly when associated with endocardial infection, and all-cause mortality of up to 35% has been reported. Like infective endocarditis, ICED infections can be difficult to diagnose and manage. This guideline aims to (i) improve the quality of care provided to patients with ICEDs, (ii) provide an educational resource for all relevant healthcare professionals, (iii) encourage a multidisciplinary approach to ICED infection management, (iv) promote a standardized approach to the diagnosis, management, surveillance and prevention of ICED infection through pragmatic evidence-rated recommendations, and (v) advise on future research projects/audit. The guideline is intended to assist in the clinical care of patients with suspected or confirmed ICED infection in the UK, to inform local infection prevention and treatment policies and guidelines and to be used in the development of educational and training material by the relevant professional societies. The questions covered by the guideline are presented at the beginning of each section.

Evaluation of PCR in the molecular diagnosis of endocarditis

OBJECTIVE Infective endocarditis (IE) is diagnosed by the Duke criteria, which can be inconclusive particularly when blood cultures are negative. This study investigated the application of polymerase chain reaction (PCR) to identify bacterial DNA in excised valvular tissue, and its role in establishing the diagnosis of IE. METHODS Ninety-eight patients undergoing valve replacement surgery were studied. Twenty-eight patients were confirmed as definite for endocarditis by the Duke criteria; nine were considered as possible and 61 had no known or previous microbial infection of the endocardium. A broad-range PCR technique was used to amplify prokaryotic 16S rRNA genes present within homogenised heart valve tissue. Subsequent DNA sequencing of the PCR amplicon allowed identification of the infecting microorganism. RESULTS PCR results demonstrated the presence of bacterial DNA in the heart valves obtained from 14 out of 20 (70%) definite IE patients with positive blood cultures preoperatively. The causative microorganism for one patient with definite culture negative endocarditis was identified by PCR. Two out of nine (22%) of the valves from possible endocarditis patients also had bacterial DNA present converting them into the definite criteria whereas in the valves of seven out of nine (78%) of these patients no bacterial DNA was detected. CONCLUSION The application of PCR to the explanted valves in patients with possible or confirmed diagnosis can augment the Duke criteria thereby improving post-surgical antimicrobial therapeutic options.

The microbial diagnosis of infective endocarditis

This review suggests an evidence-based algorithm for sequential testing in infective endocarditis. It discusses blood culture and the merits and drawbacks of serology in making the diagnosis. Newer techniques are briefly reviewed. The proposed algorithm will complement the Duke criteria in clinical practice.

Cardiovascular MRI for Assessment of Infectious and Inflammatory Conditions of the Heart

OBJECTIVE This article reviews the role of cardiovascular MRI in the diagnosis and characterization of the spectrum of infectious and inflammatory disorders of the heart. An imaging protocol is described, and typical MRI findings are discussed and illustrated. CONCLUSION Radiologists should be aware of the spectrum of infectious and inflammatory conditions that can affect the heart and the role of MRI in conjunction with other imaging techniques in their assessment.

Aortic intramural haematoma: pathogenesis, clinical features and imaging evaluation

Intramural haematoma (IMH) is a localised haemorrhage within the aortic wall. Imaging plays a central role in diagnosing IMH, differentiating it from aortic dissection (AD) and assessing for complications. Imaging is also important for prognostication and to help guide clinical decision making as a number of imaging characteristics have been correlated with increased mortality rates including location, mural thickness and aortic diameter. Multidetector CT is the leading technique for diagnosis and classification of IMH owing to speed of image acquisition, multiplanar capabilities and excellent spatial resolution. MRI is rarely used to investigate the initial presentation of IMH but is frequently used for serial follow-up studies. The clinical outcome of IMH may be favourable, with spontaneous regression over time, or it may be complicated by pericardial tamponade, aortic regurgitation and development of AD. Early surgical management is the treatment of choice for patients with Stanford type A IMH whereas most patients with Stanford type B IMH have a good short-term outcome with aggressive control of hypertension. This article reviews the pathogenesis, clinical features and complications of IMH as well as the role of advanced imaging techniques in its evaluation.

The emerging role of cardiovascular MRI for risk stratification in hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is the most common inheritable cardiovascular disorder. Although many HCM patients remain asymptomatic, sudden death (SD) can occur as the initial manifestation of the disease. It has been hypothesized that myocardial architectural disorganization and scarring represent an unstable electrophysiological substrate that creates susceptibility to malignant ventricular arrhythmias. Cardiovascular magnetic resonance imaging (CMR) is widely used for the diagnosis of HCM, especially in patients with an incomplete or inconclusive echocardiography study. CMR can provide precise non-invasive assessment of biventricular function, wall thickness, and assessment of myocardial fibrosis, using inversion recovery gadolinium-enhanced sequences. CMR is also one of the most promising avenues of research in HCM, and in recent years, has provided many new insights and identified a number of potential adverse prognostic indicators for SD. Future work is still needed to integrate CMR findings into traditional risk assessment algorithms. This paper reviews the evolving role of CMR for risk stratification in HCM including assessment of myocardial hypertrophy, fibrosis and ischaemia.

The role of multi-modality imaging for sinus of Valsalva aneurysms

Sinus of Valsalva aneurysms (SVAs) are uncommon but important entities. They are most often congenital in origin, resulting from incomplete fusion of the aortic media to the aortic valve annulus. Less frequently, they may be acquired, usually secondary to infective endocarditis. Unruptured aneurysms may be clinically silent and diagnosed incidentally, but can also produce symptoms as a consequence of mass effect on related structures. Rupture may present with sudden hemodynamic collapse but can have a more insidious onset depending upon the site and size of the perforation. Early diagnosis is imperative and can usually be made reliably by transthoracic echocardiography. However, transesophageal echocardiography may sometimes be required for confirmation. Cardiovascular magnetic resonance imaging (CMRI) and multi-detector computed tomography are being increasingly utilized for evaluation of SVAs and can offer valuable complimentary information. CMRI in particular enables a comprehensive assessment of anatomy, function and flow in a single sitting. Surgical repair forms the mainstay of treatment for both ruptured and unruptured aneurysms and has low complication rates. This article provides an overview of the pathological and clinical aspects of SVAs and discusses in detail the role of advanced imaging modalities in their evaluation.

The role of magnetic resonance imaging in hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is the most common inheritable cardiac disorder, with an estimated prevalence of 1:500 in the general population. Most cases of HCM are phenotypically expressed in adolescence or early adulthood but age-related penetrance with certain phenotypes is increasingly recognized. Clinical manifestations of HCM are usually the result of systolic and/or diastolic dysfunction, left ventricular outflow tract (LVOT) obstruction, arrhythmias and sudden cardiac death (SCD). In recent years magnetic resonance imaging (MRI) has become established as an important tool for the evaluation of suspected HCM as it can reliably establish the diagnosis, help distinguish HCM from other causes of left ventricular hypertrophy (LVH) and identify those patients at greatest risk of SCD. This article reviews the current status of MRI in the evaluation of the HCM patient including imaging protocols, disease characterization and the emerging role of MRI for risk stratification and proband screening.

British Society of Antimicrobial Chemotherapy (BSAC) guidelines for the diagnosis and treatment of endocarditis: what the cardiologist needs to know

Clinicians who care for patients diagnosed with infective endocarditis (IE) are (un)fortunate to be able to refer to several guidelines about its diagnosis and treatment.1–3 The guidelines vary considerably, especially with regards to antibiotic prescribing recommendations, which generally reflect local practice and expert opinion in light of largely observational data. All guidelines recommend a multidisciplinary approach to the management of IE. The ‘team’ should include a cardiologist, a cardiac surgeon and an infection specialist. In the UK, antibiotic choices within this team are often determined by a consultant microbiologist, and treatment, as outlined by the British Society for Antimicrobial Chemotherapy (BSAC), may be followed in preference to guidelines produced by the European Society of Cardiology (ESC)1 or American Heart Association.3 The latest iteration from the BSAC was published early this year.2 Importantly, and for the first time, the working party included representation from the British Cardiac Society (BCS). The reported incidence of IE is increasing steadily in England and Wales.4 This trend may be due to an ageing population with relatively greater prevalence of degenerative valve disease, prosthetic valves and intracardiac devices. Additionally, more patients are receiving haemodialysis, and periodontal disease remains common.5 Establishing the diagnosis of IE can be difficult and is often delayed. Oslerian signs of IE are now uncommon and their emphasis in undergraduate medical texts needs to change. A lack of ‘peripheral stigmata of endocarditis’ is often misinterpreted to mean that IE is unlikely. The revised BSAC guidelines point out that the Duke criteria were developed as a research tool and therefore have a high specificity but lower sensitivity. Failure to meet criteria for definite IE does not mean a patient does not have IE. The Duke criteria are limited when blood cultures are negative …