New mechanism for cardiac arrhythmia discovered

It has long been thought that virus infections can cause cardiac arrhythmia. But why has not been understood. Ulrike Lisewski, Dr. Yu Shi, Michael Radke and Professor Michael Gotthardt of the Max Delbrück Center for Molecular Medicine (MDC) Berlin-Buch, Germany, have now discovered the molecular mechanism. The researchers demonstrated that the receptor which the virus uses to infect heart cells is normally necessary for regular heart beat in mice. Likewise, when the receptor is absent or non-functioning, arrhythmia occurs. They assume that both the virus infection and the autoimmune disease can block the receptor which, in turn, disrupts the heart’s normal rhythm. The study has now been published online in the Journal of Experimental Medicine (10.1084/jem.20510iti3).

The heart consists of two ventricles and two atria. In order to beat correctly and to pump blood through the body, specialized heart fibres generate electric signals that control the heart beat. Cardiac arrhythmia occurs when these signals are not correctly generated or forwarded. There, a receptor, which scientists call CAR, plays an important role.

CAR stands for Coxsackievirus-Adenovirus-Receptor. It is embedded in specific cell-cell-contacts (tight junctions) of the specialized heart fibres. CAR was discovered as the critical protein responsible for virus entry during infection with Coxsackie and Adenoviruses. Its role in the adult heart was previously unknown.