Cardiac MRI Helps Assess Sudden Death Risk

A recent study by doctors at the Cleveland Clinic suggests that the presence of late gadolinium enhancement  (LGE) should be added to the various risk factors currently used to assess patients who are at low or intermediate risk of sudden death.  The presence and balancing of these risk factors are used by patients and doctors to determine the need for implantable cardiac defibrillators (ICDs).   LGE is an indication of cardiac scar tissue and can be seen on cardiac MRI scans.  This study recommended that LGE comprising a total of 15% or more of left ventricular mass be used as an additional risk factor. The study found that this indicator worked equally well when applied to both obstructed and non-obstructive HCM patients.

Interestingly, an earlier but recent study published by Cleveland Clinic doctors found that the risk factors currently in use to determine the need for an ICD fall short as applied to patients with the obstructive form of HCM.

Risk factors in common use today have been propounded by the American College of CardiologyAmerican Heart Association (ACC/AHA) in the U.S., while a different set of guideline and a mathematical risk calculator was promulgated more recently in Europe by the European Society of Cardiology (ESC).  You can find more about the ACC/AHA and ESC guidelines here.

A second and related finding of this study by the Cleveland Clinic, known for its large HCM program and high volume of myectomies, was that patients who undego  myectomy appear to experience a protective effect from their surgeries.  Even when found to have 25% or more LGE, patients in this study who previously underwent myectomy experienced a lower than expected rate of adverse events.

SCD Risk Assessment Guidelines in HCM: Impact of Myectomy & AFib

A recent study by doctors at the Cleveland Clinic found that current guidelines used to assess risk of sudden cardiac death (SCD) in HCM fall short when applied to the population of patients with the obstructive form of HCM (HOCM).

The study looked at both the European Society of Cardiology (ESC) and American College of Cardiology (ACC)/American Heart Association (AHA) guidelines, and found that both sets of guidelines came up short in predicting SCD.  In particular, the study found that patients who had previously undergone myectomy had a reduced risk of SCD that is not accounted for in existing risk models.

Conversely, the study found that patients with atrial fibrillation had a higher risk of SCD, which is also not reflected in the existing risk models.

A companion editorial by Dr. Harzell Schaff of the Mayo Clinic explains the likely reasons for the myectomy findings, while a second accompanying editorial by Dr. John Jefferies of Cincinnatti Children’s Hospital (who has recently accepted an appointment at the U. of Tennessee Health Science Center in Memphis) maintains that the ESC and ACC/AHA guidelines should be changed to reflect the lower SCD risk following myectomy.

Click here for previous coverage of the ESC and ACC/AHA guidelines.  If you would like to try out the ESC Risk Calculator for yourself, click here.

 

 

CNN Chief Jeff Zucker Set for HCM Surgery

According to several news reports, CNN chief and former NBCUniversal head Jeff Zucker is taking six weeks off to undergo elective surgery to treat his hypertrophic cardiomyopathy.  Specific details about the surgery were not revealed.  New York Magazine reported that in 2010 he visited Minneapolis Heart Institute where he was told he needed an implantable defibrillator.

The most common surgery for the treatment of HCM symptoms is a septal myectomy.

See these stories for more info:

Wall Street Journal

Atlanta Journal Constitution

Los Angeles Times

Deadline

Variety

Hollywood Reporter

HCMBeat wishes Mr. Zucker the best of luck during his surgery and recovery.

Here is a link to some resources we have collected for patients who are going through myectomy:  Resources for Patients About Myectomy

The Business of HCM

This article in Cardiovascular Business discusses the financial benefit to a hospital that adds a center for the treatment of HCM.  In particular, hospitals can expect to see higher volumes in the areas of echocardiograms, cardiac MRI, and electrophysiology.

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.