Detecting damage in the cardiac atrium through new markers

A team discovered a marker that quickly indicates the extent of developing wounds via the bloodstream. In this way, both the healing and therapeutic success of medical intervention can be precisely monitored.

Faster results in atrial fibrillation

Atrial fibrillation is a common cardiac arrhythmia. A team from the Clinic for Cardiovascular Surgery of the German Heart Centre Munich (In German: Klinik für Herz- und Gefäßchirurgie des Deutschen Herzzentrums München or DHM), at the Technical University Munich (TUM), has now discovered a marker that quickly indicates the extent of developing wounds via the bloodstream. In this way, both the healing and therapeutic success of medical intervention can be precisely monitored.

Atrial fibrillation leads to a constantly irregular, often accelerated heartbeat. The disease is not life-threatening but can lead to serious complications such as stroke or heart failure if left untreated. "It is caused by interference fields that prevent normal electrical transmission in the heart and prevent the atrium from contracting in a controlled manner," explains Prof. Rüdiger Lange, Director of the Clinic for Cardiovascular Surgery at the DHM. 

The "sclerotherapy" destroys certain areas in the atrium either with heat or cold stimuli in order to redirect the disturbed electrical transmission and thus repair it again.

Atrial protein as a possible biomarker

Dr. Markus Krane, deputy director of the Department of Cardiovascular Surgery at the DHM, and Prof. Matthias Mann from the Max Planck Institute for Biochemistry created a "Heart Atlas" two years ago. They found the protein Myosin Binding Protein H-like (MYBPHL), which exists in two forms and showed an important characteristic: One of the forms, isoform 2, was found exclusively in the atria of the human heart. Most of the other proteins in the heart were found equally in all investigated heart regions.

Thus the researchers wondered whether MYBPHL could serve as a marker in the blood for injuries in the atrial tissue. "Especially in cardiac medicine, markers are important for predicting and evaluating the course of a disease, because the rapid recognition of problems in such an essential organ as the heart can save many lives," explains Markus Krane.

Elevated blood values after injury

Over a hundred blood samples from patients who had suffered from atrial fibrillation and had been treated with sclerotherapy were examined. The scientists found that immediately after the procedure when the patients came to the intensive care unit, the concentration of MYBPHL protein in the blood was highest and decreased slowly over 24 hours. For example, patients who underwent heart valve surgery without atrial surgery did not have elevated levels of the protein but remained at the level of the healthy control group.

"A simple blood test enables us to assess the extent of the atrial damage and predict the success of the therapy. This is only possible because the new marker has the great advantage that it is highly specific for the tissue of the atrium. If the value of the new marker decreases and further markers for cardiac muscle damage remain elevated in the course of the procedure, it can be assumed that there are other problems during the procedure. We will then be able to take targeted countermeasures at an early stage with additional examinations and treatment measures," said Dr. Krane.

Development of quick blood tests planned

As a next step, Krane and his team now want to produce antibodies that only recognize isoform 2 and could thus be used for a rapid blood test. The development of such a standardized test would enable the widespread and routine use of the test after surgical or interventional interventions in the atrium.

Harald Lahm, Martina Dressen, Nicole Beck, Stefanie Doppler, Marcus-André, German, Shunsuke Matsushima, Irina Neb, Karl Christian König, Konstantinos Sideris, Stefanie Voss, Lena Eschenbach, Nazan Puluca, Isabel Deisenhofer, Sophia Doll, Stefan Holdenrieder, Matthias Mann, Rüdiger Lange, Markus Krane: Myosin binding protein H-like (MYBPHL): a promising biomarker to predict atrial damage, Scientific Reports, July 10, DOI: 10.1038/s41598-019-46123-w