The emerging role of magnetic resonance imaging and multidetector computed tomography in the diagnosis of dilated cardiomyopathy

Magnetic resonance imaging and multidetector computed tomography are new imaging methods that have much to offer clinicians caring for patients with dilated cardiomyopathy. In this article we briefly describe the clinical, pathophysiological and histological aspects of dilated cardiomyopathy. Then we discuss in detail the use of both imaging methods for measurement of chamber size, global and regional function, for myocardial tissue characterisation, including myocardial viability assessment, and determination of arrhythmogenic substrate, and their emerging role in cardiac resynchronisation therapy

CMR-determined scar volume: predictive for ventricular tachycardias?

The interesting data reported by Bernhardt et al. strengthen the diagnostic benefit of CMR in patients with ischemic cardiomyopathy. Consequently, the presence, location and size of the CMR-determined scar tissue may be used for better risk stratification in patients with ischemic cardiomyopathy eligible for ICD therapy

Cardiac MRI visualization for ventricular tachycardia ablation

Objective The integrated visualization of cardiac MRI during a ventricular tachycardia (VT) mapping and ablation procedure would provide improved catheter guidance and tissue assessment. We developed a system for and explored the added value of simultan o s visualization of intracardiac voltage measurements and MRI-derived myocardial scar information during VT ablation procedures. Method We propose the use of a synchronized 3D and 2D view. In 3D, the catheter will be guided optimally by assessing 3D scar characteristics and its relation to the ventricular anatomy. In 2D, a detailed assessment of the tissue can be made. We developed several 3D visualization techniques, including volume rendering of the scar and myocardial surfaces colored according to the voltage measurements. We also visualized context structures in the heart. For the 2D view, we proposed showing three adjacent slices simultaneously. To link the 3D with the 2D view, we added a linking plane and linking contours; the slice level shown in the 2D view is indicated in the 3D view. Results We evaluated our method via a case study during which we simulated the visual environment of an ablation procedure. The MRI-based volume rendering of scar tissue and the linking between the 3D and 2D views were both positively received. However, the visualization of the voltage measurements was found to be hard to interpret, partly due to the perceptually suitable but non-standard colormap. Conclusions Based on this study, we can conclude that our approach of displaying MRI data and integrating it with voltage measurements has potential to improve VT ablation procedures.Intelligent SystemsElectrical Engineering, Mathematics and Computer Scienc

The diagnosis and management of ventricular arrhythmias

The term ‘ventricular arrhythmias’ incorporates a wide spectrum of abnormal cardiac rhythms, from single premature ventricular complexes to sustained monomorphic ventricular tachycardia (VT), polymorphic VT, and ventricular fibrillation. Sustained ventricular arrhythmias are the most common cause of sudden cardiac death. These arrhythmias occur predominantly in patients with structural heart disease, but are also seen in patients with no demonstrable cardiac disease. The diagnosis of VT can be made reliably using electrocardiographic criteria, and a number of algorithms have been proposed. Among patients with VT and a structurally normal heart, the prognosis is usually benign and treatment is predominantly focused on the elimination of symptoms. Patients who have VT in the presence of structural heart disease are often managed with implantable cardioverter-defibrillators. These devices are effective for both primary and secondary prevention of VT and sudden cardiac death. Pharmacological therapy for VT has limited efficacy and is associated with a high incidence of adverse effects. Radiofrequency catheter ablation is useful for controlling recurrent episodes of monomorphic VT; however, research is needed to define the role of catheter ablation in the treatment of other ventricular arrhythmias.Kurt C. Roberts-Thomson, Dennis H. Lau and Prashanthan Sander