Stephen Harden

The Extent of Left Ventricular Scar Quantified by Late Gadolinium Enhancement MRI Is Associated With Spontaneous Ventricular Arrhythmias in Patients With Coronary Artery Disease and Implantable Cardioverter-Defibrillators

Background—Characterization of sudden cardiac death (SCD) risk remains a challenge in the application of implantable cardioverter-defibrillator (ICD) therapy. Late gadolinium enhancement cardiac MRI (LGE-CMR) can accurately identify myocardial scar. We performed a retrospective, single-center observational study to evaluate the association between the extent and distribution of left ventricular scar, quantified using LGE-CMR, and the burden of ventricular arrhythmias in patients with coronary artery disease and ICDs. Methods and Results—All patients included (2006 to 2009) had undergone LGE-CMR before ICD implantation. Scar (defined as myocardium with a signal intensity ≥50% of the maximum in scar tissue) was characterized in terms of percent scar, scar surface area, and number of transmural left ventricular scar segments. The end point was appropriate ICD therapy. Sixty-four patients (mean age, 66±11 years; male sex, 51) were included. During 19±10 months follow-up, appropriate ICD therapy occurred in 19 (30%) patients. In Cox regression analyses, both percent scar (hazard ratio per 10%, 1.75; 95% CI, 1.09 to 2.81; P=0.02) and number of transmural scar segments (hazard ratio per segment, 1.40; 95% CI, 1.15 to 1.70; P=0.001) were significantly associated with the occurrence of appropriate ICD therapy. Conclusions—In this pilot study, the extent of myocardial scar characterized by LGE-CMR was significantly associated with the occurrence of spontaneous ventricular arrhythmias. We hypothesize that scar quantification by LGE-CMR may prove a valuable risk stratification tool for the occurrence of ventricular arrhythmias, which may have implications for patient selection for ICD therapy.

Left Ventricular Scar Burden Specifies the Potential for Ventricular Arrhythmogenesis: An LGE-CMR Study

Late Gadolinium Enhancement and Arrhythmias. Introduction: The extent of left ventricular (LV) scar, characterized by late gadolinium enhancement cardiac MRI (LGE‐CMR), has been shown to predict the occurrence of ventricular arrhythmias in implantable cardioverter defibrillator (ICD) recipients. However, the specificity of LGE‐CMR for sudden cardiac death (SCD) versus non‐SCD is unclear. The aim of this retrospective, observational study was to evaluate this relationship in a cohort of ICD recipients.

Cardiac drugs used in cross-sectional cardiac imaging: what the radiologist needs to know

The demand for cross-sectional imaging of the heart is increasing dramatically and in many centres these imaging techniques are being performed by radiologists. Although radiologists are familiar with the computed tomography (CT) and magnetic resonance imaging (MRI) techniques to generate high-quality images and with using contrast agents, many are less familiar with administering the drugs necessary to perform CT coronary angiography and cardiac MR reliably. The aim of this article is to give an overview of the indications for and the contraindications to administering cardiac drugs in cross-sectional imaging departments. We also outline the complications that may be encountered and provide advice on how to treat these complications when they occur.

Left ventricular true and false aneurysms identified by cardiovascular magnetic resonance

Left ventricular aneurysms are uncommon complications of myocardial infarction. However, it is important to identify them because they are associated with increased morbidity and mortality. True aneurysms tend to be managed conservatively whereas false aneurysms, because of the risk of rupture, are usually treated with urgent surgery. Distinguishing these two subtypes is therefore critical and cardiovascular magnetic resonance (MR) is being used more frequently to characterise the type of aneurysm as well as to provide clear three-dimensional images of aneurysm morphology. We present a very rare case of a true and a false aneurysm of the left ventricle in the same patient. MR enabled accurate delineation of both aneurysms and the late gadolinium-enhancement images provided evidence confirming both true and false aneurysms to be present.

Cross-sectional imaging appearances of cardiac aneurysms

Cardiac aneurysms are an uncommon presentation of cardiac disease, but are important to identify and accurately characterise. Traditionally, these aneurysms have been investigated with plain radiography, angiography and echocardiography. With the significant recent technical improvements in cross-sectional cardiac imaging, computed tomography (CT) and magnetic resonance imaging (MRI) are now becoming established as the definitive investigations. This article reviews the spectrum of locations of cardiac aneurysms and their appearance with particular reference to CT and MRI. We describe the relative merits of each technique and discuss how they may be used to direct clinical practice.

MRI in adult patients with aortic coarctation: diagnosis and follow-up.

Aortic coarctation is a disease that usually presents in infancy; however, a proportion of patients present for the first time in adulthood. These lesions generally require repair with either surgery or interventional techniques. The success of these techniques means that increasing numbers of patients are presenting for follow-up imaging in adulthood, whether their coarctation was initially repaired in infancy or as adults. Thus, the adult presenting to the radiologist for assessment of possible coarctation or follow-up of coarctation repair is not an uncommon scenario. In this review, we present details of the MRI protocols and MRI findings in these patients so that a confident and accurate assessment can be made.

The relationship between left ventricular scar and ventricular repolarization in patients with coronary artery disease: insights from late gadolinium enhancement magnetic resonance imaging.

AIMS The markers of ventricular repolarization corrected QT interval (QTc), QT dispersion (QTD) and Tpeak-to-Tend interval (Tpeak-end) have shown an association with sudden cardiac death (SCD) in the general population. However, their mechanistic relationship with SCD is unclear. The study aim was to evaluate the relationship between QTc, QTD, and Tpeak-end, and the extent and distribution of left ventricular (LV) scar in patients with coronary artery disease at high SCD risk. METHODS AND RESULTS We included 64 consecutive implantable cardioverter defibrillator (ICD) recipients (66 ± 11 years, 80% male, median left ventricular ejection fraction 30%) who had undergone late gadolinium enhancement cardiac magnetic resonance (CMR) imaging prior to device implantation over 4 years. Scar was quantified using the CMR images and characterized in terms of percent LV scar and number of LV segments with subendocardial/transmural scar. Repolarization parameters were measured on an electrocardiogram performed prior to ICD implantation. After adjustment for potential confounders there was a strong association between the number of limited subendocardial (1-25% transmurality) scar segments and QTc (P = 0.003), QTD (P = 0.002), and Tpeak-end (P = 0.008). However, there was no association between the repolarization parameters and percent LV scar or the amount of transmural scar. During a mean follow-up of 19 ± 10 months 19 (30%) patients received appropriate ICD therapy, but none of the repolarization parameters were associated with its occurrence. CONCLUSION In this pilot study there was a strong association between limited subendocardial LV scar and prolonged QTc, QTD, and Tpeak-end. However, there was no association between any of these repolarization markers and the delivery of appropriate ICD therapy.

Large intra-cardiac benign fibrous tumour presenting in an adult patient identified using MRI

Cardiac fibromas are uncommon, benign, intramyocardial tumours that tend to present in childhood. The nature of their presentation is variable, with symptoms and signs that are often non-specific. These tumours may, therefore, be identified as incidental findings on imaging investigations in patients with non-specific symptoms. Cardiac magnetic resonance imaging (MRI) techniques are being used increasingly in non-invasive cardiac imaging, and the tissue-characterising capability of MRI makes it an important imaging technique in the assessment of cardiac tumours. We present the case of a large cardiac fibroma in an adult patient presenting with increasing shortness of breath. Cardiac MRI enabled a confident diagnosis and provided important anatomical detail that enabled successful excision.

Imaging hypertrophic heart diseases with cardiovascular MR

The assessment of ventricular hypertrophy is an increasingly common indication for cardiac MR (CMR) in every day clinical practice. CMR is useful to confirm the presence of hypertrophy and to help to define the underlying cause through a combination of a detailed assessment of ventricular function and tissue characterising sequences. As well as being a useful diagnostic tool, some CMR imaging features are of prognostic significance. In this article, we review the typical appearances of common forms of ventricular hypertrophy, focussing principally on left ventricular hypertrophy, and demonstrate the techniques that can be used to differentiate one form of hypertrophy from another.

Cardiac MRI of Lyme disease myocarditis

A 41-year-old man presented with chest pain and recent flu-like illness. ECG demonstrated inferolateral ST elevation and troponin I level was raised. A diagnosis of myocardial infarction was made and intravenous thrombolysis was administered. Catheter angiography did not demonstrate significant coronary artery disease, so cardiac MRI was performed to clarify the diagnosis. Late gadolinium enhancement (LGE) images revealed multiple discreet band-like regions of …