ICDs Don’t Diminish Quality of Life in HCM Patients

A retrospective study of HCM patients with implantable defibrillators conducted at eight centers worldwide  has demonstrated that ICDs are not only lifesaving, the shocks they generate are not harmful to those in whom they are implanted.

The study looked at 486 patients with HCM with an ICD implanted for either primary or secondary cardiac arrest prevention.  Of the 486 patients, 94 (19%) experienced at least one appropriate shock from their ICDs.  44 of those who had been shocked had experienced one or more shocks over the period of the study, including 6 patients who had at least 3 shocks over a 24 hour period.  Inappropriate shocks occurred in 96 patients (20%).

Despite the shocks, appropriate or not, at the end of the follow-up period the ICD discharges did not appear to cause the patients to suffer from increased heart failure or sudden cardiac arrest. Furthermore, their general health and well-being were good:  they did not suffer from significant degrees of anxiety and depression.

 

Do HCM Family Screening Protocols Need Adjustment?

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.

Does the Heart Transplant Allocation Process Discriminate Against HCM Patients?

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.

A Close Look at Alcohol Septal Ablation and Mitra-Clip for HOCM

This recent article by Dr. Srihari Naidu of New York’s Westchester Medical Center uses great detail in describing the technique used to perform alcohol septal ablation in treating obstructive HCM.

The article also describes what is involved with the newer, experimental Mitra-Clip procedure, and discusses appropriate patient selection for both procedures.

Medtronic ICD Advisory Expanded

The January recall of 48 Medtronic CRT-D and ICDs has now been expanded to include 752 additional devices at lower risk than those involved in the January recall,.  There is an issue that occurred during the manufacturing process of these devices which could result in an unexpected loss of device functionality.  If you have one of these devices, you should contact your doctor to discuss next steps.

You can see the advisory here.

To look up your device by product name, model or serial number to see whether it is impacted, click here.

The box in the upper right corner labeled “Advisories For This Model” will tell you if there are any advisories for your device.

If you are affected, the search page would look like this:

Hugo MDT

This example shows that currently there are no advisories for my model.

Protecta MDT page

As always, you can call Medtronic Patient Services with any questions at: (800) 551-5544 (M – F, 8am – 5pm Central)

 

 

Limited Recall of Medtronic ICDs and CRT Devices

Medtronic has recalled a small number of ICDs and CRT-D devices.  A total of 48 devices implanted in patients may contain a manufacturing defect which would prevent the device from delivering an appropriate shock if needed.

This is a Class I recall, which is the most serious as determined by the FDA.

Physicians of record of those affected by the recall should have already been notified by Medtronic.  

You can find a list of affected devices and serial numbers here.

You can also contact Medtronic Patient Services at 800-551-5544 (Monday-Friday, 8am-5pm Central Time).

Continuing Genetic Counseling Helpful for Silent HCM Gene Carriers

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”

HCM Patients with Scarring More Likely to Have Genetic Mutations

A recent Japanese study found that HCM patients who demonstrated late gadolinium enhancement (LGE) on MRI (which is indicative of myocardial scarring) were more likely to carry a genetic mutation associated with HCM than others who did not show LGE.

Can Fitness Tracker Biometrics Spot HOCM?

MyoKardia, a San Francisco biotech company currently in clinical trials on a HCM drug called Mavacamten, has come up with a way to spot HOCM simply by using a wristband fitness monitor. The wristband works through the use of optical biosensors which monitor arterial pulse waves.  

During MyoKardia’s trials, the bracelet biosensors were used on HOCM patients and non-affected controls.  The algorithm was able to distinguish HOCM patients from unaffected individuals more than 95% of the time, suggesting that a non-invasive way to screen for HOCM may not be too far in the future.

The linked article at Medgadget contains an interview with MyoKardia’s Dr. Robert McDowell, MyoKardia’s Chief Scientific Officer, and Dr. Eric Green, MyoKardia’s Senior Director of Translational Research with more on the happenings at MyoKardia.

 

Australian Summary of Standards for HCM Diagnosis and Management

A summary of current standards for the proper diagnosis and management of patients with hypertrophic cardiomyopathy was recently published by Australian HCM doctor Chris Semsarian in the journal Heart, Lung and Circulation.