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.
Predictors of HCM with Left Ventricular Systolic Dysfunction:
- increased left ventricular cavity size and wall thickness
- ejection fraction of between 50-60% (notably, patients with low normal ejection fractions were approximately 3 times more likely to develop left ventricular systolic dysfunction)
- the presence of late gadolinium enhancement on cardiac magnetic resonance imaging
- the presence of a HCM gene, particularly if located inside the thin filament genes
Factors Justifying More Aggressive Treatment for Patients with LVSD Include:
- multiple HCM gene mutations
- atrial fibrillation
- a left ventricular ejection fraction lower than 35%.
Important Takeaways From this Study:
- Patients with “end-stage” HCM do not all follow the same course. Many of the patients in this study reported no serious events for many years following their decline in ejection fraction. Thus, the term “end-stage” does not accurately reflect the majority of patients. Further research is necessary to better understand this subset of HCM patients.
- Since patients with left ventricular ejection fractions of between 50 and 59% are at heightened risk for developing end stage disease, they should be closely followed by their HCM team.
- This study found that post-myectomy patients may have a higher incidence of end stage disease. Hence, the authors suggest that patients who have undergone septal reduction therapy, especially younger patients with one or more HCM gene mutations, continue to be closely monitored by their HCM team.
Another informative article focusing on the different stages and treatments for HCM can be found here.
A recent paper by doctors at Tufts University’s HCM Center found that transient episodes of atrial fibrillation (AF) are treatable and do not often progress to permanent AF.
This study found that AF was not a frequent cause of death by heart failure or sudden cardiac arrest. However, the researchers identified AF as an important cause of stroke in HCM patients. Therefore, they recommend a low threshold for starting HCM patients on anti-coagulants following an initial AF episode.
Researchers in this study analyzed statistics from 1558 HCM patients, 20% of whom experienced AF. 74% experienced only sporadic episodes, while 26% went on to develop permanent AF.
At the time of publication, 91% of the 277 of the patients included in the sample were still alive and between the ages 49 and 75 years old.
According to an accompanying editorial by Italian HCM expert Dr. Paolo Spirito, the outlook for HCM patients with atrial fibrillation has improved over the last twenty years due to significant advances in HCM treatment over that time period such as ICD implantation and myectomy, along with aggressive anti-coagulation for atrial fibrillation patients.
Spirito also noted that it is difficult to predict whether a given HCM patient will go on to develop permanent Afib after a single episode since many will not. Additionally, permanent afib can be well tolerated when there is contemporaneous control of heart rate. Therefore, anti-arrhythmic medications, which can cause unpleasant side effects, may not be necessary for HCM patients with afib as long as anti-coagulation measures are taken.
There are distinct stages of HCM and treatments will vary according to the stage. Therefore, it is important, according to a recent article in the Netherlands Heart Journal, for patients to seek treatment from teams experienced in the the treatment of HCM. These professionals are able to recognize transitions in the course of the disease as they occur, and then implement necessary changes in treatment.
In this thorough overview of HCM and its treatment, Dr. Iacopo Olivotto and his colleagues in the Netherlands observe that HCM is seen infrequently by community cardiologists (as compared to more common heart conditions like coronary artery disease). Hence, one of the major difficulties in HCM practice has been identification of patients at highest risk.
Continue reading “One Size Does NOT Fit All: Treatments Differ by Stage in HCM”