A recent story in the Wall Street Journal about genetic testing shows the speed of changes in the medical community’s understanding of how and whether certain genes cause hereditary disease.
When Stanford biochemist Jim Spudich settled down in bed with a book recommended by his wife, he had no idea that the book would inspire one of the biggest discoveries of his career. Spudich drifted off to sleep while reading The Haunted Mesa, a science fiction novel by Louis L’Amour. His scientific discovery was based on an image he saw in his dreams when the image of a mesa morphed into a myosin molecule.
Myosins are proteins that make the contraction of heart muscle possible. In hypertrophic cardiomyopathy, these proteins work too well, causing a heartbeat that is too strong.
The mesa in the book inspired Spudich to look at the head of the myosin. His previous research had focused on random locations along the entire length of the myosin.
Today, it was announced by the U.S. Department of Homeland Security that 750,000 implantable defibrillators manufactured by Medtronic could potentially be vulnerable to hacking.
As reported by the Minneapolis Star-Tribune, many Medtronic implantable defibrillators currently in use may contain vulnerabilities which could potentially be exploited by hackers via their use of programmer devices or bedside monitors. According to Medtronic, no such episodes have been reported and such interference is extremely unlikely because any would-be hacker would have to be within 20 feet of a patient and would also need in-depth and specialized knowledge of the device’s programming features.
Medtronic has assured patients that there is no imminent danger and it promises that the issue will be solved with a programming patch that will be forthcoming. No action is required by patients other than keeping their bedside monitors plugged in and secure in their homes. Patients should discuss any specific concerns with their physician.
You can read the security bulletin issued by Medtronic here.
After 6 months on the drug, of the 13 patients enrolled in the open label extension to the Pioneer study, NYHA Class improved in 8 of 10 patients, while 7 of the 8 patients were considered asymptomatic by the end of the study.
In addition to seeing an improvement in symptoms, patients also showed improvement to certain markers of cardiac function including left ventricular filling pressure,
NT-proBNP, a marker of cardiac wall stress, and left atrial volume index. Ejection fractions remained within normal levels for all patients in the study.
The complete results of this study will be presented by Oregon Health & Science University’s Dr. Steven Heitner at next weekend’s meeting of the American College of Cardiology in New Orleans.
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 by several HCM genetics researchers around the globe, led by Australia’s Dr. Jodie Ingles, found that 2/3 of genetic mutations previously reported to patients as HCM causative may actually NOT trigger HCM.
Dr. Ingles and the researchers looked at 33 genes frequently reported to patients as causative for HCM in commercial genetic tests. Surprisingly, of the 33 genes tested, only 8 were found to be definitively associated with HCM, 3 had moderate evidence to support their association with HCM and a whopping 22 or 66% of these genes were found to have limited or no association with HCM.
Mutations Definitive for HCM
Mutations with Moderate Evidence for HCM
These results should raise a red flag for consumers about genetic testing. Results of genetic tests require careful and informed interpretation. For accurate results, HCM patients should undergo genetic testing under the supervision of a genetic counselor with experience in HCM.
Not all genetic counselors are alike!
A recent study conducted in the U.K. evaluated whether the anti-anginal drug trimetazidine would improve symptoms and exercise capacity for those patients with non-obstructive hypertrophic cardiomyopathy.
Unfortunately, this study which was conducted by Dr. Perry Elliott and his colleagues at University College London, found that trimetatazidine did not improve exercise capacity in these patients. Following the results of this study, trimetazidine will now join ranolazine and spironolactone in the compost heap of drugs which tried and failed to improve HCM symptoms. While a third drug, perhexiline, was found to improve symptoms for non-obstructive HCM, its limitations, including potentially serious side effects, stand in the way of its common usage.
In a companion editorial to this study entitled “Non-Obstructive Hypertrophic Cardiomyopathy-the High Hanging Fruit,” Dr. Sharlene Day of the University of Michigan’s HCM Center discusses the difficulties seen in drug trials related to non-obstructive HCM.
Though seemingly a more benign form of the disease, in fact, patients with non-obstructive HCM share a similar risk of sudden death and heart failure with their obstructed counterparts. Because treatments available to treat non-obstructive disease have been largely limited to beta blockers, calcium channel blockers and diuretics, there is a great need for new medications directed at this problem.
The problem with setting up HCM Drug trials is complicated by several factors:
- Different Types of HCM: There appear to be multiple kinds of HCM. Some are genetic and some are not. We are now at a place where treatments for HCM should become more individualized.
- Difficulty in Recruitment: It is difficult to recruit enough patients to take part in these trials. Patients often travel considerable distances for care at dedicated HCM Centers. Multi-center trials provide a potential way to get around this issue.
- Duration of HCM: HCM is a disease process which takes place over decades which is not easily studied in a clinical trial of limited duration.
- The Unknown: Timing of interventions may be critical, and it is hard to know the proper window of time to target. The bottom line is that there is still so much that is unknown, HCM researchers much continually adapt as knowledge of the disease process unfolds.
In conclusion, Dr. Day suggests that while medical researchers continue to test new drugs and push forward studies of HCM, physicians should counsel their patients that in addition to medication, lifestyle choices like proper nutrition and exercise will improve their clinical course and the overall outlook for HCM patients.
I had open heart surgery (a septal myectomy) to treat my hypertrophic cardiomyopathy in 2006. I went back to Mayo twice for the two years following the surgery, but after that I hadn’t felt the need to return since I was regularly following up with my local cardiologist. In April of 2018, it had been almost ten years since I had been back to Rochester. So, I decided it was time to take a trip and make sure that all was in order.
This article by Dr. Stephen Heitner of Oregon Health & Science University covers some simple lifestyle changes that can help HCM patients feel much better. In particular, Dr. Heitner mentions:
- Eating smaller meals and avoiding large carbohydrate rich meals.
- Avoiding dehydration
- Limiting alcohol
- Avoiding exercise after eating
- Engaging in moderate intensity exercise
- Managing weight
- Evaluating and treating sleep apnea and other sleep breathing disorders
- Getting appropriate treatment for anxiety and depression
The above lifestyle changes, combined with appropriate medical treatment, will keep HCM patients feeling their best.
This article, by Drs. Julio Panza and Srihari Naidu of New York’s Westchester Medical Center, describes early efforts to diagnose, categorize and treat hypertrophic cardiomyopathy, while explaining how these methods have evolved over time. A very interesting and informative read.
The software update which allows the Apple Watch 4 to take an EKG and to detect atrial fibrillation went live last week. In anticipation of the availability of these functions, I purchased an Apple Watch 4. As soon as the software was available, I downloaded it and have used it every day since. So far, I am quite pleased with my purchase. The technology works very well, even despite the fact that I have an implantable pacemaker/defibrillator.
The strip it takes looks like this:
You can send a strip via email to your doctor, and all are saved for posterity on your Iphone. (NOTE: YOU MUST HAVE AN IPHONE CAPABLE OF RUNNING THE SOFTWARE IN ORDER TO USE THE WATCH).
And, as long as you tell the software that you have never been diagnosed with atrial fibrillation, if it detects atrial fibrillation while you wearing the watch, it will send you an alert. I haven’t gotten such an alert yet and hope not to!
And here is a story about a man whose watch spotted his previously undiagnosed Afib. After a trip to the emergency room, he was able to receive proper treatment and avert a potential health crisis.
In May of this year, HCMBeat published this interview with Yale’s Dr. Daniel Jacoby and Dr. Nikolaos Papoutsidakis about their online survey of HCM patients who engage in risk-taking activities.
In this conversation, Drs. Jacoby and Papoutsidakis emphasized that the shared decision making process is an important facet of the patient/physician relationship for HCM patients. Risks should be explained, and decisions made with each patient’s set of values and priorities in mind. The doctors hoped that the results from their study would help to inform the shared decision-making process as applied to activities that involve any amount of patient risk-taking.
After analyzing data from 633 patients (282 men and 351 women), 556 patients reported participating in thrill-seeking activities, while 331 continued such participation after their HCM diagnosis. The doctors found that only 33.6% of the patients who engaged in the thrill-seeking activities experienced such minor adverse events as dizziness, nausea, palpitations or chest pain, while only .02% experienced significant events during or within an hour following the activity. Only one ICD shock was reported.
Hence, the doctors concluded that the risks associated with such activities appear to be low.