40% of cardiomyopathies stem from genetics

Four in ten cardiomyopathies are familial, suggesting an urgent need for more widespread genetic testing, a team of cardiologists reported in the European Heart Journal this week.

“We were surprised to see how frequently the disease is inherited,” first author Philippe Charron, MD, PhD, said in a release from the European Society of Cardiology (ESC). “About 40 percent of patients had familial disease. As a consequence it is very important to improve screening to detect the disease in the relatives who are apparently healthy.”

Charron and colleagues worked with the ESC’s EURObservational Research Programme cohort, which included 3,208 patients enrolled by 69 centers across 18 countries. Two-thirds of relatives in the study were diagnosed with cardiomyopathy through family screening, which included echocardiography and an electrocardiogram (ECG). Many cases were as severe as the first family member who was identified, the authors wrote, with similar frequency of symptoms and life-threatening arrhythmias.

According to the ESC, around one in 300 European residents has a cardiomyopathy. Familial screenings for the condition generally start around 10 years of age and stretch into a person’s 50s and 60s, though Charron et al. suggested starting screenings earlier and halting them later.

“The cardiac expression of these genetic diseases starts early in some patients,” Charron said. “In other it is delayed for many decades—longer than previously thought.”

The earlier clinicians can identify cardiomyopathies in a patient’s relatives, he said, the earlier they will be able to take the necessary precautions—including implanting a cardioverter defibrillator (ICD)—to prevent cardiac arrest.

Of the full study pool, genetic testing was performed in 36 percent, according to the paper. This is an increased percentage from a decade ago, but the authors wrote it could be better.

“The frequency of arrhythmias in the study was high,” Charron said. “In one cardiomyopathy subtype, 39 percent of patients had potentially deadly arrhythmias. But diagnostic testing for arrhythmias was suboptimal and patients may be missing out on lifesaving treatment with an ICD or pacemaker.”

When one family member is identified as having a cardiomyopathy, Charron and co-authors wrote, first-degree relatives can then be tested for the condition. If they test positive for the mutation, their next steps should include regular cardiovascular check-ups to monitor changes in heart muscle and function.

Charron said in the ESC release he’s vying for more expert medical centers focused on cardiomyopathies. Specialized institutions would be able to conduct the necessary cardiac tests, have the ability to use magnetic resonance imaging when necessary, complete extensive genetic testing and manage cardiomyopathy patients better than a generalized hospital could.

“Expert centers for cardiomyopathies would improve the diagnosis and management of these diseases in patients and their family members, and help to prevent heart failure and sudden death,” he said.