A recent study by doctors at the Cleveland Clinic found that current guidelines used to assess risk of sudden cardiac death (SCD) in HCM fall short when applied to the population of patients with the obstructive form of HCM (HOCM).
The study looked at both the European Society of Cardiology (ESC) and American College of Cardiology (ACC)/American Heart Association (AHA) guidelines, and found that both sets of guidelines came up short in predicting SCD. In particular, the study found that patients who had previously undergone myectomy had a reduced risk of SCD that is not accounted for in existing risk models.
Conversely, the study found that patients with atrial fibrillation had a higher risk of SCD, which is also not reflected in the existing risk models.
A companion editorial by Dr. Harzell Schaff of the Mayo Clinic explains the likely reasons for the myectomy findings, while a second accompanying editorial by Dr. John Jefferies of Cincinnatti Children’s Hospital (who has recently accepted an appointment at the U. of Tennessee Health Science Center in Memphis) maintains that the ESC and ACC/AHA guidelines should be changed to reflect the lower SCD risk following myectomy.
Click here for previous coverage of the ESC and ACC/AHA guidelines. If you would like to try out the ESC Risk Calculator for yourself, click here.
According to this study published recently in the Journal of the American College of Cardiology, whole genome testing may sometimes be used to identify the gene(s) responsible for HCM when targeted genetic testing (the type used in the clinical setting) has been inconclusive.
In particular, the study found the responsible gene(s) in 9 of 26 families (20%) in whom targeted testing had previously been inconclusive.
When used as the initial form of genetic testing, whole genome sequencing identified the responsible HCM gene in 5 of 12 families, or 42%.
According to this article in Wired U.K., a whole genome sequencing test costs about $600 and takes just a few weeks to complete. On the other had, the cost of data storage necessary to store such a large amount of collective data is, according to this article, prohibitively high.
If not for everyone, perhaps whole genome sequencing could be used in families where traditional genetic testing has proven inconclusive. Time will tell.
According to several news reports, CNN chief and former NBCUniversal head Jeff Zucker is taking six weeks off to undergo elective surgery to treat his hypertrophic cardiomyopathy. Specific details about the surgery were not revealed. New York Magazine reported that in 2010 he visited Minneapolis Heart Institute where he was told he needed an implantable defibrillator.
The most common surgery for the treatment of HCM symptoms is a septal myectomy.
See these stories for more info:
Wall Street Journal
Atlanta Journal Constitution
Los Angeles Times
HCMBeat wishes Mr. Zucker the best of luck during his surgery and recovery.
Here is a link to some resources we have collected for patients who are going through myectomy: Resources for Patients About Myectomy
This article in Cardiovascular Business discusses the financial benefit to a hospital that adds a center for the treatment of HCM. In particular, hospitals can expect to see higher volumes in the areas of echocardiograms, cardiac MRI, and electrophysiology.
A recent editorial published in Circulation: Genomic and Precision Medicine suggests that current HCM screening protocols may need adjustment to account for recent findings by a study by researchers in the Netherlands. The Dutch study, published in the same journal, found that of 620 relatives of HCM patients who underwent genetic testing, 43% were found to be genetically positive for HCM, while 30% were diagnosed with HCM at the initial screening. 16% more went on to develop HCM during 7 years of repeated cardiac evaluation.
On the other hand, the 57% of relatives found to be genotype-negative were released from clinical HCM follow-up.
The Australian authors of the editorial, Semsarian and Ingles, note that current screening protocols would have failed to identify the 6 children (15%) who were diagnosed under the age of 12, half of which had a particularly malignant family history.
Additionally, few teens were diagnosed with HCM, which stands in contrast to current opinion that HCM is most likely to develop during adolescence. Indeed, most newly diagnosed family members were older than the age of 36, with 44% being over the age of 50.
Lastly, Semsarian and Ingles note their concern with general utilization of the Dutch practice of releasing a gene negative family member from serial follow up since the impact of all genes which have a role in causing HCM is not yet known while new genes which may cause HCM are still being identified.
Semsarian and Ingles also note that the Dutch patient sample differs from more typical patient populations found in the U.S. and Australia where causes of HCM are more diverse and cannot be easily tied to a specific gene.
A recent article by doctors from the University of Utah Health Sciences Center found that patients with HCM who are in need of heart transplantation may wait longer for a new heart than patients with other cardiomyopathies. Additionally, HCM patients may experience stroke or other adverse consequences while awaiting transplant.
The discrepancy is attributable, in part, to the fact that HCM patients are not often candidates for LVADs (left ventricular assist devices) and other types of mechanical circulatory support devices which are used to bridge patients awaiting transplant.
Hence, the article argues, United Network for Organ Sharing (UNOS -the organization responsible for the allocation of donor organs in the U.S.) should take these factors into consideration as it revises its system of heart allocation for patients awaiting transplant.
On a positive note, the article points out that long-term survival in HCM patients has improved over time, and HCM patients now do as well or better following transplant than patients who have been transplanted for other types of cardiomyopathy.
An article entitled Psychosocial Impact of a Positive Gene Result for Asymptomatic Relatives at Risk of Hypertrophic Cardiomyopathy was published in this week’s Journal for Genetic Counseling.
The article focuses on the motivation for and the impact of HCM genetic testing on family members. The 32 participants in the study all encouraged family members to undergo genetic testing with the hope that the knowledge gained would benefit family members down the line. However, the study found that the psychological impact of a positive result, in the absence of overt disease, was highly variable. Some gene positive individuals perceived that they had an absolute risk of developing HCM, with substantial detriment to their lifestyle choices, while others were not at all affected by the result and made no lifestyle changes.
Continue reading “Continuing Genetic Counseling Helpful for Silent HCM Gene Carriers”
A recent Canadian study found that children with HCM who carry a single mutation in the MYH7 gene or who have multiple HCM-causative genetic mutations are at increased risk of major adverse cardiac events when compared to children who carry a single mutation in another gene.
Of the 98 gene positive children in this study, those with a MYH7 mutation or those with multiple mutations were more likely to need a myectomy or an ICD or to experience a sudden cardiac arrest or a heart transplant when compared to children with other HCM causative mutations.
The article also suggests that current screening protocols which recommend clinical and genetic screening for HCM beginning at age 12 may be insufficient.
Dr. Iacopo Olivotto and a team of Italian researchers conducted a recent multi-center trial of the late sodium channel blocker ranolazine. The results of the trial showed that the drug failed to improve functional capacity, diastolic function, quality of life or brain natriuretic peptide (BNP) levels in 80 non-obstructive HCM patients.
Nevertheless, the researchers found that ranolazine is a very safe drug which may still be useful in the treatment of HCM by reducing arrhythmias and improving angina.
A companion editorial by Dr. Perry Elliot from the U.K. shed light on the difficulties inherent in designing clinical trials for HCM. Dr. Elliot noted that Restyle HCM was the third unsuccessful attempt at finding a new drug for HCM in the past year since a study on eleclazine, a drug with similar properties, and another for the drug perhexilene were both halted last year due to lack of efficacy.
Regardless, Dr. Elliot stated that increasing worldwide collaboration between HCM centers and expanding knowledge of certain sub-types of HCM treatable with specifically targeted therapies substantially improve the outlook for upcoming HCM drug trials.