The lab’s assets include three MRI systems available for pediatric studies, cardiac imaging processing, cardiovascular imaging and therapeutic ultrasound. A robust echocardiogram program conducts 10,000 transthoracic echocardiograms and 1,300 fetal echocardiograms per year, and maintains a database with 10 years of data.

The central theme of the CORE-320 Multicenter Trial Lab’s research is to support the Coronary Artery Evaluation Using 320-Row Multidetector CT Angiography (CORE 320) study, a multi-center multinational diagnostic study with the primary objective to evaluate the diagnostic accuracy of 320-MDCT for detecting coronary artery luminal stenosis and corresponding myocardial perfusion deficits in patients with suspected CAD compared with the reference standard of conventional coronary angiography and SPECT myocardial perfusion imaging. Armin Arbab-Zadeh, MD, PhD, is an associate professor of medicine at the Johns Hopkins University School of Medicine and Director of Cardiac Computed Tomography in the Division of Cardiology at the Johns Hopkins Hospital in Baltimore. Research Areas: coronary/cardiac imaging, coronary risk prediction, heart attack prevention, cardiac computed tomography, coronary circulation and disease

The Weiss Lab, which features a multi-disciplinary team at Johns Hopkins as well as at Cedars Sinai Medical Center in Los Angeles, is dedicated to identifying the most important clinical, genetic, structural, contractile and metabolic causes of sudden cardiac death as well as the means to reverse the underlying pathology and lower risk. Current projects include research into energy metabolism in human heart failure and creatine kinase metabolism in animal models of heart failure. Robert G. Weiss, MD, is professor of medicine, Radiology and Radiological Science, at the Johns Hopkins University.

The O’Rourke Lab uses an integrated approach to study the biophysics and physiology of cardiac cells in normal and diseased states. Research in our lab has incorporated mitochondrial energetics, Ca2+ dynamics, and electrophysiology to provide tools for studying how defective function of one component of the cell can lead to catastrophic effects on whole cell and whole organ function. By understanding the links between Ca2+, electrical excitability and energy production, we hope to understand the cellular basis of cardiac arrhythmias, ischemia-reperfusion injury, and sudden death. We use state-of-the-art techniques, including single-channel and whole-cell patch clamp, microfluorimetry, conventional and two-photon fluorescence imaging, and molecular biology to study the structure and function of single proteins to the intact muscle. Experimental results are compared with simulations of computational models in order to understand the findings in the context of the system as a whole. Ongoing studies in our lab are focused on identifying the specific molecular targets modified by oxidative or ischemic stress and how they affect mitochondrial and whole heart function. The motivation for all of the work is to understand • how the molecular details of the heart cell work together to maintain function and • how the synchronization of the parts can go wrong Rational strategies can then be devised to correct dysfunction during the progression of disease through a comprehensive understanding of basic mechanisms. Brian O’Rourke, PhD, is a professor in the Division of Cardiology and Vice Chair of Basic and Translational Research, Department of Medicine, at the Johns Hopkins University.

Research in the Mary Beth Brady Lab focuses primarily on topics within the fields of anesthesiology, imaging and cardiology. Our work has explored transesophageal echocardiography simulation, echocardiography, cardiac and vascular-thoracic anesthesiology, and other areas within critical care medicine. A recent study involved obtaining 3-D images of the heart, which were then used to build computer programs to help cardiac surgeons improve their treatment of heart defects.

The Cardiology Bioengineering Laboratory, located in the Johns Hopkins Hospital, focuses on the applications of advanced imaging techniques for arrhythmia management. The primary limitation of current fluoroscopy-guided techniques for ablation of cardiac arrhythmia is the inability to visualize soft tissues and 3-dimensional anatomic relationships. Implementation of alternative advanced modalities has the potential to improve complex ablation procedures by guiding catheter placement, visualizing abnormal scar tissue, reducing procedural time devoted to mapping, and eliminating patient and operator exposure to radiation. Active projects include • Physiological differences between isolated hearts in ventricular fibrillation and pulseless electrical activity • Successful ablation sites in ischemic ventricular tachycardia in a porcine model and the correlation to magnetic resonance imaging (MRI) • MRI-guided radiofrequency ablation of canine atrial fibrillation, and diagnosis and intervention for arrhythmias • Physiological and metabolic effects of interruptions in chest compressions during cardiopulmonary resuscitation Henry Halperin, MD, is co-director of the Johns Hopkins Imaging Institute of Excellence and a professor of medicine, radiology and biomedical engineering. Menekhem M. Zviman, PhD is the laboratory manager.