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.

Newest HCM Research Focuses on Exercise

Two articles published this week highlight how attitudes relating to exercise and HCM have changed in recent years.  Older recommendations that HCM patients should refrain from exercise appear to be outdated.

The first article, an editorial published in Circulation by Drs. Sara Saberi and Sharlene Day from the University of Michigan’s HCM Center, reviews the statistics relating to sudden death of athletes and questions the long held notion that participation in vigorous activity or competitive sports is dangerous in HCM.  This editorial also points out that moderate exercise is the only non-surgical intervention proven to increase exercise capacity in patients with HCM.

See this HCMBeat interview with Drs. Saberi and Day for more details about their groundbreaking study.

A second article from researchers in Australia used the number of a patient’s steps per day as an indicator of HCM disease severity and the patient’s functional limitations.

It seems that the time has come for HCM patients to get up off their couches and get moving!

Are HCM Kids With MYH7 Gene at Increased Risk?

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.

Restyle HCM Study: Ranolazine Doesn’t Improve HOCM Heart Failure Symptoms

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.

ESC Risk Assessment Tool Comes Up Short in Study

A recent study published in the American Journal of Cardiology found that the standards propounded by the American College of Cardiology Foundation with the American Heart Association (ACC/AHA) were superior in predicting which patients would benefit from an implantable cardiac defibrillator (ICD) compared to the calculator set forth by the European Society of Cardiology (ESC).  According to the study, the use of the ESC tool will result in more high-risk patients going unprotected against sudden death.

Specifically, the study found that out of a group of 288 HCM patients, 14 who experienced aborted sudden cardiac arrest (or 43%) would not have qualified for an ICD under the ESC risk model compared to 7% of patients under the ACC/AHA guidelines.

The ACC/AHA guidelines are:

ICD Guidelines rev.

A companion editorial by Dr. Andreas S. Barth pointed out the shortcomings of both models, and reaffirmed the necessity for shared decision making between physicians and patients.  Dr. Barth also expressed hope that a more accurate predictive model will evolve, though he acknowledged the impossibility of designing a model which could predict future events with certainty.

 

Chapter 4: MRI Safety for ICD & Pacemaker Patients

Yet another study has confirmed the safety of MRIs in patients with non-MRI conditional ICDs and pacemakers.

The latest study, from the University of Pennsylvania and published in the New England Journal of Medicine, found no adverse effects from 1.5 Tesla MRI scans performed on 1509 patients who underwent a total of 2103 scans.  58% had pacemakers and 42% had ICDs.

This study confirms previous findings relating to the safety of MRIs in ICD and pacemaker patients reported by HCMBeat here and here.

You can also read my personal experience trying to get a brain MRI in Los Angeles last year here.