According to an editorial published in yesterday’s issue of Circulation by Drs. Barry and Martin Maron together with Dr. Ethan Rowin, the outlook for most HCM patients is much rosier than previously thought.
According to current estimates, which take into account contemporary disease treatments and risk management strategies, the risk of death from HCM is only .5% per year or 2.5% over 5 years, which is similar to the degree of risk in the general non-HCM population.
Hence, according to the editorial, HCM patients should be reassured about their long term prognosis.
Researchers from around the globe have joined together to study an unlikely subject in order to understand the genetics of HCM according to a paper published today in the journal eLIFE.
Dr. Christine Seidman, a cardiologist from Harvard Medical School, Dr. James Ware a geneticist from the MRC London Institute of Medical Sciences at Imperial College London, and Dr. Raúl Padrón, a structural biologist at the Venezuelan Institute for Scientific Research, have joined forces in order to study the tarantula.
The reason for their focus on the tarantula is because the proteins comprising the muscles inside the furry spider are actually very similar to proteins inside the human heart.
Dr. Seidman, who had taken note of Dr. Padrón’s work with spiders, sought him out at a meeting to discuss the similarity of heart proteins to those in tarantula muscles and asked him whether they might collaborate.
By studying the way that the spider proteins interact with one another, the scientists hope that they will gain further insight into whether and how certain genes cause different types of hereditary cardiomyopathy, including hypertrophic and dilated.
I hope that they find the answers soon, before any tarantulas escape from their lab!
It may be possible for some athletes to continue playing competitive sports despite having an implantable defibrillator according to a recent study published in this week’s Circulation.
The study followed 440 athletes with ICDs who participated in organized sports over a 4 year period. Diagnoses included HCM, Long QT Syndrome, and arrhythmogenic right ventricular cardiomyopathy (ARVC) . Common sports for the patient-athletes were running, basketball and soccer.
Over the period of the study, 121 of the patient-athletes received a total of 184 shocks: 7% while participating in competition or practice, 5% during other physical activities, and 6% while resting. No deaths were reported over the approximately 44 months study. “Even though some people did receive shocks while they were participating in sports, no harm came to patients,” said lead author Dr. Rachel Lampert, a professor of internal medicine at Yale School of Medicine.
The study did note that patients with ARVC who engaged in sports were more likely to experience life-threatening ventricular arrhythmias requiring therapy, and, were more likely to receive repeated shocks from their devices. Hence, competitive sports may be inadvisable for ARVC patients.
For more details about this study, see this story from Health Day News and from Yale News.
According to new research presented at last week’s meeting of the Heart Rhythm Society, aspirin is not effective in preventing strokes in patients with atrial fibrillation, and in some instances may actually do more harm than good.
Note that previous studies have demonstrated that aspirin is not effective in preventing strokes from Afib.
In fact, the study, led by Dr. Jared Bunch from Intermountain Healthcare system, Salt Lake City, UT, found that patients who were prescribed aspirin following catheter ablation procedures to treat atrial fibrillation were significantly more likely to suffer gastrointestinal or genitourinary bleeding than those who took other anticoagulants like warfarin, or those who received no treatment at all.
For more, see these articles from Medical News Today and Science Times (with link to video).
Researchers in Norway have demonstrated that patients who carry a HCM gene show reduced cardiac volume when compared to healthy individuals. Patients with overt HCM show even further reduction to their cardiac volume than those who merely carry the gene.
Although the gene positive individuals lacked the characteristic left ventricular wall thickening of HCM, diastolic and systolic volumes were reduced when compared to healthy individuals. Hence, the researchers concluded that a person who is gene positive for the disease may show reduced volume before developing hypertrophy.
The study included 180 patients with left ventricular hypertrophy, 100 patients who carried the HCM gene but did not show signs of left ventricular hypertrophy, and 80 healthy individuals.
The researchers theorize that early changes in HCM result from the gradual stiffening of the left ventricle, which contributes to filling changes before anatomical thickening is apparent. These changes will likely worsen as the disease progresses.
The researchers suggest future long term studies of gene positive individuals with small cardiac volume who show signs of diastolic and systolic dysfunction. These patients, they suggest, are the most likely to go on to develop HCM.
Two posters presented at this weekend’s Heart Rhythm Society meeting in Chicago show that patients who have abandoned pacemaker or ICD leads may safely undergo MRI exams.
These posters follow the earlier MagnaSafe study which demonstrated the safety of MRI for patients with pacemakers and ICDs, but which excluded patients with abandoned leads from the findings.
The first, by researchers at Mayo Clinic, included 57 patients with 63 abandoned leads who underwent 70 MRI exams in a 1.5 Tesla machine. The authors saw no clinical problems and no device malfunction following the scans.
The researchers also monitored blood troponin levels in 35 of the patients following the scans and did not see any elevation which could indicate distress to the heart from the scan.
The second poster, from the University of Pennsylvania, involved 24 patients with abandoned leads who underwent 34 MRI exams. The results of this study also failed to demonstrate any clinical problems or patient discomfort resulting from the MRI scans.
With any luck, everyone will soon be able to obtain an MRI and will not be denied due to any kind of implantable cardiac device.
For an account of my personal experiences seeking MRI with an ICD, read this.
According to preliminary data presented this week at the Heart Rhythm Society’s annual meeting, the Apple watch. together with an app called Cardiogram, spots atrial fibrillation with 97% accuracy.
Start-up tech company Cardiogram paired up with electrophysiologists at the University of California, San Francisco to try out the technology on patients awaiting cardioversion for atrial fibrillation. 51 patients at UCSF agreed to wear Apple Watches during their cardioversion procedures.
Heart rate samples were obtained before the procedure, when the patient was in atrial fibrillation, and again afterward when heart rhythm had been restored to normal. The researchers found that the Apple Watches were able to detect afib 97% of the time.
The Cardiogram and UCSF teams hope to publish their findings in a peer-reviewed journal while Cardiogram hopes it can make this information useful to consumers. One possibility would be to have the watch send a notification to the wearer that s/he appears to be in afib should contact her/his care provider immediately.
If you are interested in participating in this research, click here.
Read more about it at TechCrunch, BuzzFeed, Apple Insider and CNET,
A study published this week by HCM researchers in Canada found that double mutations in patients with hypertrophic cardiomyopathy are much less common than previously thought. In particular, researchers found that except for those with double mutations in the gene MYBPC3, there is not much data to support the finding that there is a worse clinical course for those patients who have double HCM mutations.
Hence, in the absence of extraordinary circumstances, such as two MYBPC3 mutations, the researchers caution that double mutations should not be the sole justification for the insertion of an implantable defibrillator.
The study looked at patients >18 years of age who underwent genetic testing at the Toronto General Hospital between January 2005 and June 2016. Out of a sample of 1411 patients, 9% of those who were gene-positive patients had 2 genes, but only in 1 case (0.4%) were both genes classified as those known to cause HCM.
In addition to looking at their own patients, the researchers also re-examined data from previously published studies. Similarly, they found when they re-analyzed the data that only 0.4% of the 8% of patients previously found to have double mutations in fact carried multiple pathogenic mutations.
When a patient is the only person in the family ever diagnosed with HCM, s/he will often wonder whether their disease is, in fact, genetic. S/he will also wonder whether it will be necessary for all first degree relatives to undergo serial screenings for the rest of their lives.
In answer to this concern, Australian researchers have recently identified a subset of HCM patients who appear to have a non-familial form of the disease and whose relatives may be candidates for less stringent screening protocols.
The study, just published in Circulation: Cardiovascular Genetics by Dr. Jodie Ingles and Dr. Chris Semsarian, found that this group, having neither genetic mutation associated with HCM nor family history of HCM, comprises approximately 40% of all HCM patients. Non-familial HCM patients are more likely to be older when diagnosed, and they often present with non-asymmetric hypertrophy and hypertension. And, these HCM patients appear to have a more favorable clinical course, with a better track record of survival from major cardiovascular events.
The researchers point out that by sorting patients into more distinct subgroups, doctors will be able to provide more personalized and evidence-based care to patients and their families. In particular, their recommendation is that first-degree relatives of non-familial HCM patients need only be screened one or more times in adulthood. Less frequent follow up surveillance is also suggested, in contrast with the more intensive screening guidelines recommended for family members of patients with familial HCM.
A study at the University of Amsterdam recently published in the Journal of Pediatrics found that most kids carrying a gene for HCM will not go on to develop HCM during their childhood.
The same study also found that gene positive children without overt signs of the disease are at relatively low risk for cardiac events.
The study included 119 children, positive for at least one HCM gene, with a median age of 12.1 years. 8 of these children (6.7%) received a HCM diagnosis within the time span of the study [which varied from 3.1 to 10.7 years]. 1 of the 8 diagnosed children suffered a cardiac event which necessitated implantation of an implantable cardioverter defibrillator or ICD.
The study did caution, however, that because severe hypertrophy and cardiac events may develop, it is important to refine risk stratification and long term follow up procedures for gene positive kids.