A recent study by doctors at Toronto’s Hospital for Sick Children suggests that current screening guidelines for children from HCM families are inadequate and should instead recommend earlier screening exams. In the U.S., screening begins at age 12 pursuant to American College of Cardiology (ACC)/American Heart Association (AHA) guidelines. In Europe, screening begins at age 10 pursuant to the European Society of Cardiology (ESC) guidelines.
In particular, the doctors found that out of 524 children who underwent
family screening prior to age 18, 9.9% showed evidence of HCM at first screening and only 1.1% of these children were symptomatic. An additional 28 (5.4%) children developed HCM over 3 years of follow-up, while 41% of major cardiovascular events [death, sudden cardiac death, or need for major interventions such as myectomy, ICD implantation, or heart transplant] occurred in children before the age of 10 year. Therefore, the doctors suggest that certain children appear to be at elevated risk and should be followed from earlier ages.
In particular, the study showed that children at greatest risk are:
- have a pathogenic genetic mutations in MYH7 or MYBCP3
- Have a family history of sudden cardiac death
A companion editorial by Dr. Christopher Semsarian of the University of Sydney in Australia and Dr. Carolyn Ho of the Brigham and Women’s Hospital in Boston points out that even under current guidelines, while screening is optional before age 12 (2011 ACC/AHA Guidelines) or age 10 (2014 ESC Guidelines), screening should still be considered if there is a particularly malignant family history, the child is an athlete or if there are symptoms or other indications of disease.
Semsarian and Ho note that even though screening tests (echocardiograms and EKGs) and non-invasive, there can be both monetary and emotional costs to the family resulting from screening. Hence, they recommend individualization in screening as opposed to a blanket rule; especially given that information relating to genetic status, gender and family history are easily available. Each family situation should be assessed individually, taking into consideration their own set of unique risk factors and their tolerance for risk.
Editor’s Note: HCMBeat recently highlighted this study from the U.K. which similarly concluded that the age of screening children in HCM families should be lowered.
According to a limited study recently published in Nature, researchers were able to detect obstructive HCM (HOCM) using a noninvasive optical sensor contained in many commercial smartwatches.
How the Technology Works
These watches used photoplethysmography, a noninvasive optical method used to detect blood volume changes in the microvascular bed at the skin surface. The same technology is used in clinical pulse oximeters and is now widely incorporated in commercial smartwatches that have heart rate detection.
For this limited study which was included as an adjunct to MyoKardia’s Phase 2 PIONEER-HCM study of the the drug mavacamten (formerly known as MYK-461), 5 HCM centers in the US obtained smart watch data and echocardiograms from 19 HCM patients who had left ventricular outflow tract obstruction. The researchers compared these readings to readings from a control group of 64 healthy volunteers. The researchers were able to identify significant differences between the heartbeats of those patients with HOCM and those of the healthy volunteers.
Potential for Widespread Use
Before this technology can be put into widespread use, more research is needed to support this limited sample. However, in the future, this technology could potentially prove to be an easy and inexpensive way to screen people for obstructive HCM.
DISCLOSURES: HCMBEAT HAS RECEIVED UNRESTRICTED EDUCATIONAL GRANTS FROM MYOKARDIA. ADDITIONALLY, CYNTHIA BURSTEIN WALDMAN OF HCMBEAT SERVES AS A PATIENT ADVISOR ON THE STEERING COMMITTEE FOR MYOKARDIA’S EXPLORER TRIAL.
A recent study published in Circulation suggests that clinical testing of kids who are first degree family members of HCM patients (i.e. siblings and children of those who have already been diagnosed with HCM) could be improved by starting testing at a younger age. And, genetic testing should further improve diagnosis and treatment for this group.
Continue reading “When Do You Screen Your Kids For HCM?”
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 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.
Editor’s Note: This post originally appeared on the blog of Dr. Howard J. Luks. Dr. Luks wrote this blog entry in collaboration with HCM expert Dr. Srihari S. Naidu of New York’s Westchester Medical Center. You can find the original post here. You can find both Dr. Luks and Dr. Naidu on Twitter @hjluks and @SrihariNaiduMD.
Sudden cardiac death in young athletes continues with alarming frequency. The most common cause of sudden death in the young athlete is hypertrophic cardiomyopathy or HCM. Simply put, HCM means the heart muscle is bigger. Many of us believe that bigger muscle means stronger muscle. That is not always the case with the heart. The heart is a mechanical pump with a complex arrangement of chambers which store the blood. How that pump works is controlled by a very complex electrical system. Hypertrophic cardiomyopathy can interfere with one or both of these critical functions of the heart and lead to sudden cardiac death.
Continue reading “Sudden Cardiac Death in Young Athletes”
According to researchers at the University of Michigan, family members of HCM patients who have tested negative for genes associated with HCM and without a family history of HCM will usually be found to be free of HCM during routine family screening. And, in accordance a recent Australian study, relatives of these patients may be able to benefit from less rigorous screening protocols.
Patients with a known sarcomere mutation appear to have a different clinical profile, according to the researchers: they have more hypertrophy; they are younger when diagnosed; they have a higher risk for adverse events; and they are more likely to have a family history for the condition.
In contrast, when the initial diagnosis is made in a patient who is 50 or older with no known genetic mutations, a negative family history, and sigmoidal septal pattern hypertrophy, reduced family screenings may be appropriate and less burdensome. In addition, hypertension, large family size with no other affected family members, less severe hypertrophy, and lack of life-threatening complications related to HCM may provide additional comfort to families of newly diagnosed HCM patients.
The reduced protocol would consist of a single screening of adult family members, with the caveat that if and when any additional family additional member is found to have HCM, a more traditional screening protocol be instituted.
(Note that standard screening guidelines recommend screening of all first-degree family members of patients beginning with adolescence, repeated annually through the end of adolescent growth, and repeated every 3 – 5 years for life.)
Lisa Yu, founder of Children’s Cardiomyopathy Foundation, posted this article today on Huffington Post. This piece summarizes the efforts currently being made to screen Olympic athletes and elaborates on how better screening and response protocols might help to avoid tragedies.
A recent study followed 14 patients carrying one of two known genes associated with HCM (MYBPC3 and MYH7) over a 10+ year period . At the time of gene identification, none of the patients shown clinical evidence of hypertrophy. Over the time span of the study, 3 patients, who were then adults, had developed signs of HCM. Hence, the study suggests that periodic screenings are necessary for gene positive individuals throughout adulthood.
According to Cardiomyopathy U.K., the researchers undertook this project due to the lack of information and guidelines available to patients who are gene positive but have no outward signs of the disease.