In addition to the presentation of the results of the VALOR-HCM study which compared mavacamten to septal reduction techniques, covered here in its own HCMBeat blog entry, ACC 2022 featured two other presentations about the new class of drugs known as myosin inhibitors, such as Bristol Myers Squibb’s mavacamten and Cytokinetics’ aficamten.
A recent study of identical twins with HCM found significant variation in the expression of hypertrophic cardiomyopathy, even between twins carrying the same HCM-causing genetic mutation.
This paper concludes that epigenetics (things which influence expression of DNA like behavioral and environmental factors) greatly influence the expression of HCM genetic mutations.
The researchers studied 11 pairs of twins with HCM. 9 of the twin pairs had known HCM sarcomere mutations while 2 of the pairs had HCM of unknown cause. The siblings were followed for a time frame of between 5 to 14 years.
Researchers compared left ventricular wall thickness, left atrial size and left ventricular ejection fraction. Differences were found in the left ventricular wall thickness of all 11 pairs of twins, while left atrial size was similar in 3 of the 9 twin pairs who carried HCM mutations. Left ventricular ejection fraction was different in 4 of 7 twin pairs.
The researchers theorize that similarities in left atrial size may be due to impaired ventricular relaxation directly tied to sarcomere dysfunction. In contrast, environmental factors yield more influence over ventricular function.
HCM epigenetics is a field ripe for research. As HCM patients, we hope that it will yield actionable data in the near future.
Researchers from the Sarcomere Human Cardiomyopathy Registry (or the acronym “SHaRe” for short) have again joined forces to look at a subset of hypertrophic cardiomyopathy (HCM) patients who have what is known as “end stage” HCM. This term, which is a bit of a misnomer, is used to describe patients who experience left ventricular systolic dysfunction (LVSD) which occurs when the left ventricular ejection fraction (LVEF) is less than 50%.
According to the study published last week in the journal Circulation, of a total of 6,793 HCM patients included in the study, 553 or 8% fell into this category. The paper goes on to highlight some important observations about patients that fall into this category which are highlighted below.