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.

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

Guest Blogger Doug Rachac – Magnets and Airports: Should ICD Patients Be Afraid?

Editor’s Note:  Doug Rachac found out that he himself needed an ICD while employed by device manufacturer Medtronic.  He now uses his personal experiences to help other device patients learn how to live happily with their implantable devices.  

 

When cardiac patients receive a pacemaker or defibrillator, they often have questions about their new “friend.”  They wonder if this new device has limitations, and what those limitations might be.

And they may find that the internet can be, at the same time, both helpful and misleading.  Accurate information is out there, but separating truth from fiction is the hard part.  To learn the truth, patients turn to their doctors, nurses and clinic device techs for answers, not realizing that sometimes these professionals also give advice based on outdated or incorrect information.

When a patient wants to know if it is safe to scuba dive with their heart condition, they should ask their physician. However, if they want to know how deep it is safe for them to dive with their specific implanted device, instead of asking their physician, they should instead direct their question to the engineers of the device manufacturer who designed and tested the device.

Patients should speak with their doctor to learn if their health condition limits them from certain physical activities (such as scuba diving), but questions about the limitations or capabilities of devices and leads should usually first be directed to the manufacturer of the device – the best source of up-to-date, accurate information.  Whenever I am looking for up to date, accurate information about my device, I start with Medtronic, the manufacturer of my implanted device.

Patients can easily find the make and model of their device, as well as learn how to contact their device manufacturer, by calling the Patient Services number located on their Patient ID card.

In this blog article, I’d like to share with you some information regarding two of the most common misconceptions relating to implantable devices out there:  1) magnets are dangerous to implanted devices like pacemakers and defibrillators; and 2) it is unsafe to walk through airport/venue security.

All of the information I discuss below can be found, if you dig deep enough, on each specific manufacturer’s websites.

Magnets: Should We Be Afraid?

All companies advise patients to keep magnets at least 6-8 inches away from their devices for their safety.  But the simple answer to the question is NO!  You do not need to be afraid of magnets.  However, you do need to be aware of how a magnet interacts with your device when you come into contact with one.

A magnet will NOT:

  • Scramble the device programming
  • Turn the device off
  • Turn off pacing
  • Damage the device in any way

These common misconceptions are based on devices that are over 10 years old, or are based on a misunderstanding of the truth. In most industry devices a magnet will interact with a pacemaker and defibrillator in the following ways:

Pacemaker or Cardiac Resynchronization Therapy Pacemaker (CRT-P):

A magnet placed on or near a pacemaker/CRT-P device will force the device to pace at a constant, preset rate.  Different companies have different preset rates.  Medtronic is set to pace 100% of the time at 85 beats per minute (BPM).  When the magnet is moved away from the device, the device will immediately revert back to the programming that was input by the doctor or device tech at implant, or that was modified during a subsequent interrogation session.

Defibrillator or Cardiac Resynchronization Therapy Defibrillator (CRT-D):

In most industry devices, a magnet will “inhibit detection” which is a fancy way of saying the device won’t shock you if needed.  Once the magnet is removed, the shock function reverts back to normal.

This function is a normal design feature of the devices designed for use by clinicians and doctors.  In both types of devices, a magnet will in no way harm the device or alter the programming.  The effect of the magnet is only temporary.  Once the magnet is moved 6-8 inches away from the device, the device’s normal programming will resume.  Some everyday items such as iPad covers, purses, and children’s toys may contain magnets which are strong enough to trigger the magnet response in our devices. However, simply moving those items 6-8 inches away from your device will resolve the issue.  Remember, even if you do encounter a strong magnet or magnetic field, it will not harm your device in any way.  Simply move away from the magnet/magnetic field and your device will return to its normal operations.

Let me reiterate: a magnet will in no way harm your device, shut it off, or alter the programming.

Airport/Venue Security:

There was a time when walking through airport or venue security with an implanted device was considered dangerous.  This was back when our devices included an electrical component called a Reed Switch.  But, over a decade ago, devices evolved after safety issues forced industry to eliminate the Reed Switch in all implanted devices.  At the same time, a new international standard emerged setting limits for how much magnetic energy an implanted device needed to be able to withstand.  The level is high enough that most forms of magnetic energy encountered in our daily lives are insufficient to interact with our devices in any meaningful way.  There are a few exceptions, such as the electromagnetic energy generated by a hydroelectric dam.  But, airport archways and hand wands do not generate that level of energy.  Companies like Medtronic simply suggest that a patient walk through the airport archway at a normal pace, and that wands are not waved repeatedly over the device multiple times.  Aside from those precautions, patients do not need to avoid airport or venue security in any way.  Millimeter wave scanners (the one that rotates around you) are also safe to use.

Let me say it again: Pacemaker/ICD/CRT patients do not need to fear airport/venue security checkpoints.  Simply walk through the archway at a normal pace, and ask that wands not be waved back and forth over the device repeatedly.

Living with our devices can be stressful enough.  It’s my belief that having accurate information is the first step in being able to live the life we want to live, not the life we think we are now forced to live.

My physician was clear when he said, “Your device is there to protect you and allow you to live your life.  It is not there to restrict you in any way.”

It’s time to dispel the information of old, and to start living our lives without these old fears. Our devices have evolved over the years so we need not fear magnets or security lines any more.  If you would like to learn more about me and living with an implantable device, I have uploaded several videos to my YouTube Channel.  You can find specifically about  devices, magnetic fields and airport security here.

About Doug Rachac:

Doug Rachac received his implanted Medtronic defibrillator in 2014 due to several episodes of syncope and documented non-sustained ventricular tachycardia.  He spent 14 years working for Medtronic, where he worked in multiple areas, including Customer Service, Education, and Quality.  He left Medtronic in 2015 to recover, volunteer and to be the world’s best stay-at-home dad.  He now advocates for device patients and consults with the medical device industry on patient engagement and patient focused initiatives.  You can find him on Twitter @HankEPants.

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!

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).

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.

Chapter 3: MRI Safety for ICD & Pacemaker Patients

Long awaited results of the MagnaSafe study regarding the safety of MRIs in patients with implantable devices were published in February.   The MagnaSafe study established a multi-center prospective registry for patients undergoing MRI scans despite their having an implanted device not deemed safe for MRI scanning by the FDA.

Continue reading “Chapter 3: MRI Safety for ICD & Pacemaker Patients”

A Risk Calculator for Sudden Death -Results of HCM-EVIDENCE Study

The HCM Risk–SCD Score

In 2014, the European Society of Cardiology (ESC) introduced a numerical predictor (the “HCM Risk–SCD score”) to assist physicians in identifying those patients at highest risk for sudden cardiac death who would benefit from the implantation of a prophylactic implantable cardioverter-defibrillator.

Using an algorithm generated by the answers to a series of questions, the tool estimates the 5-year risk of sudden cardiac arrest for any particular patient.  You can find the tool online here.

Continue reading “A Risk Calculator for Sudden Death -Results of HCM-EVIDENCE Study”

Safety of MRIs With Abandoned Leads

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.