Should HCM Treatment Differ by Sex?

According to a recent study by doctors in the Netherlands published in the journal Circulation: Heart Failure, women who had undergone septal myectomy had more diastolic dysfunction and myocardial fibrosis than men who had also undergone myectomy.

Hence, the researchers suggest that sex-specific treatment for HCM may become customary and should be a subject for future inquiry.

These findings raise concern, especially when looked at in conjunction with a recent study by doctors at the Mayo Clinic who found that women with hypertrophic cardiomyopathy have a statistically reduced rate of survival when compared to men with HCM.  

Here’s hoping that upcoming researchers will focus their efforts on improved outcomes for women with HCM.

MyoKardia Drug Moves to Next Phase

According to this press release, MyoKardia expects to dose the first patient in the EXPLORER-HCM trial of mavacamten (formerly known as MYK-461) for obstructive HCM in the second quarter of 2018.

MyoKardia says that it expects 220 patients to enroll in the 30 week long trial.  These patients will be randomly assigned to receive either mavacamten or a placebo.  Participants will also be able to continue on their normal beta blockers or calcium channel blockers.

 

Electric & Hybrid Cars: A Safe Choice for ICD & Pacemaker Patients

Car Shopping

Recently, I began shopping for a new car.  The process is overwhelming! There are so many factors to consider when looking for a new vehicle: gas mileage, sedans vs. hatchbacks, SUVs…the list goes on and on.  Electrics and hybrids are all the rage here in Southern California, but I wasn’t sure if they would be safe for me to drive because I have an implantable defibrillator which also functions as a pacemaker.

German Study: Safety of Popular European Electric Cars

Lucky for me, I didn’t have to wait too long for an answer to my question.  According to a recent German study published in the Annals of Internal Medicinepeople with implanted cardiac devices can safely drive the most common electric cars on the market today.  This study measured the magnetic field strength in four electric cars with the largest market share in Europe: the BMW i3, Nissan Leaf, Tesla Model 85S, and the Volkswagen e-up!  Though the study found that recent models of all of these cars were safe, the authors of this study did caution that future models could potentially cause interference with implantable cardiac devices, depending on  their design.

For more on the recent German study, see these articles at Reuters, Medical Xpress.com and TechTimes.

2017 AHA Preliminary Data – Tesla

The findings from the German study added to preliminary data presented at a 2017 meeting of the American Heart Association.

Tesla Charging

Participants’ devices were monitored for electromagnetic interference while they sat in or stood near a Tesla S P90D.  Testing was done with the study participants situated in a variety of positions—sitting in the driver’s seat, passenger seat, backseat and standing next to the charging port.

The study found that sitting in, or standing close to the charging port of a Tesla while the car was charging at a 220 volt charging station did not trigger an ICD shock or cause interference with the assorted implantable defibrillators. 

2013 Mayo Clinic Study – Toyota Prius

Lastly, Mayo Clinic cardiologists presented similar findings at the American College of Cardiology meeting in 2013.

56050078 - gray toyota prius hybrid - sideviewThat early study found no issues when patients implanted with ICDs and/or pacemakers drove a 2012 Toyota Prius hybrid at 30 mph, 60 mph and at variable speeds of acceleration and deceleration, as well as sitting in the driver’s seat, the front passenger seat, the left and right rear seats and in front of and behind the car from the outside.  Although the researchers found that the implantable devices were exposed to electromagnetic fields inside the car, the amount of interference wasn’t significant enough to cause problems with the devices.

For more on the 2013 Mayo study, see this article in Popular Science.

 

Now that I know that driving these cars is safe for me, I will be out on a test drive trying to narrow down my options!

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.

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