A new study conducted by Karolinska Institutet and Karolinska University Hospital in Sweden reveals that individuals with mitral annular disjunction (MAD), a specific heart valve abnormality, face a significantly higher risk of severe heart rhythm disorders, even after successful valve surgery. The findings, published in the European Heart Journal, underscore the long-term risks associated with the condition, particularly for younger patients and women.
Mitral annular disjunction, characterized by the displacement of the attachment point of the mitral valve, has been previously linked to an increased risk of severe cardiac arrhythmias. Despite advancements in surgical treatments, it was unclear whether the risk of arrhythmias would persist after correction of the abnormality.
An Elevated Risk for Vulnerable Patients
MAD often occurs alongside mitral valve prolapse (MVP), a condition affecting 2.5% of the population, where one of the heart’s valves leaks, causing blood to flow backward. This backward blood flow can contribute to heart failure and arrhythmias, which may result in symptoms like shortness of breath and palpitations. The abnormality is particularly concerning as it can lead to sudden cardiac arrest in severe cases.
In this study, researchers tracked 599 patients diagnosed with mitral valve prolapse who underwent heart surgery at Karolinska University Hospital between 2010 and 2022. Approximately 16% of these patients also had MAD. The team sought to determine whether surgery could reduce the heightened risk of arrhythmias in patients with this dual condition.
Persistent Risk of Ventricular Arrhythmias
The study’s findings are compelling. Patients with MAD had a significantly higher risk of developing ventricular arrhythmias—a dangerous and often fatal type of heart rhythm disorder—during a five-year follow-up period after surgery. Even after successful surgery to correct MAD, these patients were more than three times as likely to experience arrhythmias compared to those without MAD.
The study also highlighted that patients with MAD tended to be younger—on average, eight years younger—than those without the condition. Additionally, they exhibited more extensive mitral valve disease, making them even more vulnerable to complications. Women were also disproportionately affected by MAD.
Ongoing Research to Understand the Underlying Causes
Dr. Bahira Shahim, an associate professor at the Department of Medicine at Karolinska Institutet and a cardiologist at Karolinska University Hospital, emphasized the importance of monitoring patients with MAD, even after successful surgeries. “Our results show that it is crucial to closely follow patients with this condition over the long term,” she said.
The study has prompted further research into potential underlying causes of the persistent risk. One theory being explored is that MAD may induce lasting changes in the heart muscle over time. Another hypothesis is that MAD may signal an undiagnosed heart muscle disease. To investigate these possibilities, the researchers are using MRI technology to study heart scarring and analyzing tissue samples from the heart muscle.
The research was led by Dr. Bahira Shahim, in collaboration with Dr. Magnus Dalén, a cardiac surgeon at Karolinska University Hospital, and Klara Lodin, a Ph.D. student at Karolinska Institutet.
The ongoing investigation aims to deepen the understanding of MAD and its long-term impacts on heart health, offering valuable insights for improving patient care and treatment outcomes.
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