The First In Vivo Imaging Agent for Electrical Signaling in the Heart

The new radiotracer could help to advance diagnosis and prognosis of heart failure, cardiac arrhythmia and more.

Reliable and accurate functioning of the heart is vital for health and well-being. According to the World Health Organization, cardiovascular disease contributes to one third of all deaths worldwide. Unfortunately, currently used diagnostic methods are insufficient for early detection of the risk of heart failure or arrhythmia, which would enable life-saving treatment. Now, though, researchers from the Martinos Center for Biomedical Imaging at Massachusetts General Hospital have developed Radiocaine, a positron emission tomography (PET) radiotracer that can measure cardiac ion channels in vivo and thus make such early detection possible. They describe the technology in a Scientific Reports study published today.

Radiocaine uptake in the heart represents the density of NaV_1.5 – ion channels that shuttle sodium. NaV_1.5 channels underlie the electrical signaling and initiate the electromechanical coupling in the heart, which is responsible for its fundamental function of pumping blood to the lungs and peripheral organs. In the past, cardiac ion channels could only be investigated in detail in vitro or in invasive tissue preparations, leading to a large knowledge gap in humans. For instance using their new imaging technique, the MGH team found for the first time a reduction in ion channel density in human failing heart explants. The Martinos Center’s Jacob Hooker, the first author of the study, emphasized that “the exciting feature of our new tool is that it may be powerful not only for heart failure diagnosis/prognosis, but also for cardiac arrhythmia such as Brugada and long-QT Syndromes, which have high prevalence of sudden cardiac death.” In general, said Matthias Schoenberger, the lead author of the study and now an assistant professor at KU Leuven in Belgium, Radiocaine imaging could open the door for translational electrophysiology research, which is based on noninvasive molecular imaging instead of electrode recordings.

The team is currently working to translate Radiocaine imaging to clinical imaging in humans, and identifying the role of cardiac ion channels in a broad range of human cardiovascular disease.