Medtronic ICD Advisory Expanded

The January recall of 48 Medtronic CRT-D and ICDs has now been expanded to include 752 additional devices at lower risk than those involved in the January recall,.  There is an issue that occurred during the manufacturing process of these devices which could result in an unexpected loss of device functionality.  If you have one of these devices, you should contact your doctor to discuss next steps.

You can see the advisory here.

To look up your device by product name, model or serial number to see whether it is impacted, click here.

The box in the upper right corner labeled “Advisories For This Model” will tell you if there are any advisories for your device.

If you are affected, the search page would look like this:

Hugo MDT

This example shows that currently there are no advisories for my model.

Protecta MDT page

As always, you can call Medtronic Patient Services with any questions at: (800) 551-5544 (M – F, 8am – 5pm Central)



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.


**Because so much HCM information was presented at the Summit, this is the second of multiple blog entries.  Stay tuned to HCMBeat for more highlights from the HCM Summit.  To see Part I of this series of highlights from the HCM Summit VI, click here.**

The 6th International HCM Summit was held October 27, 28 and 29th in Boston, Massachusetts.  This symposium brings together HCM professionals from around the world who are there to learn about and discuss the latest developments in the treatment of HCM.

The symposium was organized by long time HCM expert Dr. Barry Maron and his son, Dr. Martin Maron.  Both Marons are now affiliated with Tufts Medical Center’s Hypertrophic Cardiomyopathy Center.

What follows are summaries from selected talks presented at the meeting.  The presenter and their hospital affiliation are noted below, along with the topic of their presentation.  When possible, you may access the presenters’ slides via hyperlink by clicking on the name. (Note that not all presenters made their slides available).


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”

ICD May Not Bar Competitive Sports

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.




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.

Fewer Double Gene Defects Doing Less Harm?

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.