Researchers at Seoul National University Hospital have developed a simple method to predict the risk of heart failure in patients with hypertrophic cardiomyopathy.
According to the hospital, people with hypertrophic cardiomyopathy need to take special care as it can lead to end-stage heart failure. Heart failure occurs when there is a problem with the contraction and relaxation of the heart, which prevents the proper supply of blood to the body. In addition, hypertrophic cardiomyopathy patients’ heart walls become thick and stiff. As a result, they do not stretch well, so the diastolic function of the left ventricle decreases, increasing the risk of heart failure.
To predict the risk of heart failure in patients with hypertrophic cardiomyopathy, hospitals have conventionally measured the left ventricular diastolic function. However, as there are no non-invasive methods to evaluate this function, the hospitals have no choice but to use a deep invasive catheterization, greatly burdening patients.
To resolve this issue, the research team, led by Professors Kim Hyung-kwan and Lee Hyun-jung of the Department of Cardiology at SNUH, focused on the left atrial strain rate that can be measured by echocardiography. They measured the left atrial deformity and cardiac function of 414 patients diagnosed with hypertrophic cardiomyopathy between 2007 and 2019 and followed up for about seven years for heart failure.
As a result, they found the patients' average left atrial strain rate was 23 percent, lower than the average of normal subjects (35 percent). Also, the lower the left atrial strain rate, the lower the left ventricular diastolic function, the thicker the heart wall, and the wider the area of fibrosis.
The research team conducted follow-up studies to determine the occurrence of heart failure according to the left atrial strain rate.
The team classified patients with hypertrophic cardiomyopathy into four groups --normal (35 percent or more), grade 1 (24-35 percent), grade 2 (19-24 percent), and grade 3 (less than 19 percent) according to the degree of diastolic dysfunction, and compared and analyzed the 10-year event-free survival rate.
As a result of the analysis, the 10-year accident-free survival rate related to heart failure in the normal group was 100 percent, showing that even with hypertrophic cardiomyopathy, patients with left atrial strain rate within the normal range did not experience any hospitalization or death due to heart failure for 10 years.
In contrast, the 10-year accident-free survival rate of the other grades showed that the lower the left atrial strain rate, the higher the rate of heart failure.
“This study confirmed that the diastolic function of patients with hypertrophic cardiomyopathy can be evaluated non-invasively through the left atrial strain rate,” Professor Kim said. “When using this indicator, the team expects hospitals to predict heart failure relatively easily without additional tests such as invasive cardiac catheterization, thereby greatly reducing the burden on patients.”
Circulation Cardiovascular Imaging published the result of the study.