The global defibrillator market is expected to reach $12.9 billion by 2019, according to a MarketsandMarkets report. That’s partly due to newer, technologically- advanced defibrillators, the growing elderly population and the rising prevalence of cardiovascular diseases. Implantable cardioverter defibrillators (ICDs) and cardiac resynchronization therapy defibrillators (CRT-Ds) — which are pacemakers that deliver defibrillator therapy — have recently been developed to be MR-compatible. Thousands of patients who were previously unable to undergo MR exams now have the opportunity to do so.

However, challenges with the longevity of ICD battery life remain and experts in the field are calling for engineers to develop batteries that can last more than 25 years. Doing so would avoid the complications that patients face during replacement procedures. The external defibrillators haven’t experienced as much advancement as the implantable ones, but they are being used more at sporting events to address the growing sudden cardiac arrest problem among young athletes.

Even though the market is poised for significant growth in the coming years, factors including a lack of awareness about sudden cardiac arrest, issues with external and implantable defibrillators and health care reform in the U.S. are preventing the market from experiencing even more growth.

MR-compatible ICDs
According to data from the University of California, Los Angeles, out of the more than 200,000 patients who have a pacemaker or ICD implanted per year, about 75 percent of them will have a medical situation in their lifetime that may benefit from MR. Traditionally, patients with ICDs and pacemakers were unable to undergo MR exams, and underwent CT, cardiac catheterization, EKG and X-ray exams instead.

“Therefore, those patients whose physicians did not wish to entertain the presumed risks of MR with a pacemaker or defibrillator did not have the opportunity of having this superior diagnostic information that, in turn, could lead to a change in therapy and management,” says Dr. Robert Biederman, the medical director of the Cardiovascular MRI Center at Allegheny General Hospital (AGH) in Pittsburgh.

But MR-compatible ICDs made out of non-ferrous materials have recently come to market. In September 2015, Medtronic received FDA approval for its Evera MRI SureScan ICD System, which is the first MR-compatible ICD. In December 2015, Biotronik’s Iperia ICD system won approval to be used during MR exams. Many studies have investigated the safety of using those devices during MR exams, but no one had investigated the value that MR brings to patients with ICD. Biederman and fellow researchers at AGH decided to pioneer research in that area.
Biederman and his team evaluated 157 patients who were placed in one of three implantable cardiac device case groups. There were 114 patients put into the neurological group, 36 in the cardiovascular group and seven in the musculoskeletal group. In 88 percent of the neurology cases, the MR provided value for the final diagnoses, and in 18 percent of the cases the MR exam altered the diagnoses entirely. For the cardiac and musculoskeletal cases, the extra value percentage was even higher at 92 and 100 percent, respectively.

“There was a marked incremental value to perform the MR,” says Biederman. “We knew that just because we could do the MR, didn’t mean it was the right thing to do. In this case, however, we redirected appropriate care in a high-risk population comprising patients with neurosurgical, orthopedic and cardiac pathologies.” In late March, Biederman was referred to a patient at AGH who was believed to have had cardiac sarcoidosis for 15 years. One of the cardiologists at the hospital decided to have the patient, who had an ICD, undergo an MR exam, so they imaged his heart and found that he didn’t have the condition.

“In most cases, that information couldn’t be obtained with cardiac catheterization, echo or nuclear, so the MR added real value. Additionally, the patient did not have to have an open heart procedure or a biopsy of the heart muscle and [have the patient face] all of the attendant risks,” says Biederman.

Longer battery lives needed
The lithium battery in ICDs can last up to seven years, according to the Mayo Clinic. But an article published by the academic research website British Medical Journal in February stated that battery life needs to be extended to 25 years or more to avoid the risks associated with replacement. The risk of infection associated with replacing ICD batteries ranges from 1 to 5 percent, but that may be incorrect because there is no standard definition for what an infection is.

Dr. John Dean, a consultant cardiologist at Royal Devon and Exeter Hospital in the U.K., explained in the BMJ article that it’s important to minimize the amount of surgical interventions patients undergo because of the risk of complications and infections. Dean points out, however, that the current financial model discourages the development of longer life devices. “With financial disincentives for both manufacturers and purchasers it is hardly surprising that longer life devices do not exist,” he says.

For the purchaser, that disincentive would be a much higher initial price for a device that lasts 25 years. It’s also assumed that patients want smaller devices even though a study published in the journal Pacing and Clinical Electrophysiology in 2004 found that 90 percent of patients would prefer larger devices if they last longer. The authors of the study also reported that ICDs are usually replaced when they are still able to deliver at least six full energy shocks, which could equate to at least another six months of useful battery life. But the authors did caution that early replacement may be necessary for patients at high risk of cardiac problems.

S-ICDs
Patients with sudden cardiac arrest are traditionally treated with transvenous ICDs, but another option was introduced to the market when Boston Scientific received FDA approval for its subcutaneous ICD (S-ICD) system in 2012, which are essentially leadless ICDs. Boston Scientific scored approval for its second-generation S-ICD system, the EMBLEM S-ICD System, in March 2015.

The new generation is 20 percent thinner and is expected to last 40 percent longer than the previous system, but it is not MR compatible. S-ICDs utilize a pulse generator and electrode beneath the skin, instead of having a lead run through blood vessels. During the procedures, a shocking coil is implanted in the area under the left arm and tunneled through the soft tissues of the body.

Unlike S-ICDs, the leads are the biggest drawback for ICDs because they are susceptible to breaking and other complications. The patients also don’t have to undergo vascular surgery to have it implanted, which lessens the chances of systemic infections and complications that are associated with endovascular lead implantation or extraction.

However, one of the downsides of S-ICDs is that they don’t have some of the functionality that regular ICDs have. For example, ICDs are able to pace patients out of bad heart rhythms, but the current generation of S-ICDs can’t do that because they don’t have a lead that’s enough in contact with the heart. Medtronic is currently working on a new S-ICD that will still be placed outside of the vasculature and have all of the advantages of the current S-ICD, but will also be able to pace the patient’s heart out of a bad rhythm. It is not, however, intended to be MRcompatible.

CRT-Ds
In February, Medtronic announced that it received FDA approval for the first and only MR-compatible cardiac resynchronization therapy defibrillators (CRT-Ds) for treating heart failure. The Amplia MRI Quad CRT-D SureScan and Compia MRI Quad CRT-D SureScan systems are both approved for MR scans. Among the population of patients who have have defibrillators and CRT-Ds, about 40 percent of them will require an MR exam within the first four years of having the device implanted, according to Dr. David Steinhaus, vice president and general manager of the heart failure business and medical director for the cardiac rhythm and heart failure division of Medtronic.

CRT-Ds were previously not recommended by the FDA to be used during MR exams because of the potential interaction between the MR and device that could put the patients at risk. In addition, CMS doesn’t provide coverage for MR exams conducted on patients with non-MR-compatible implanted cardiac devices. The CRT-Ds have the same functionality as ICDs, but also have the ability to pace both sides of the heart. It’s used in patients when their heart contractions are out of sync. “A defibrillator is sort of an insurance policy — they are there in case you need it if your rhythm goes out of whack,” says Steinhaus. “The CRT defibrillator has that capability, but it is also used to pace the heart with every beat so that the heart will function better.”

AEDs at sporting events
Sudden cardiac death accounts for about 100 to 150 deaths per year at sporting events, according to the American Heart Association. Because of that, automated external defibrillators (AEDs) are becoming more prevalent at these events. “There are a couple of different disease factors that are usually inherited by young athletes that cause sudden cardiac deaths,” says Wayne Adams, clinical analyst at MD Buyline. “It’s usually at a sporting event that you see most of it happen.”

The majority of athletes who suffer sudden cardiac arrest on the field show no warning symptoms, according to USA Football. Because of that, the association believes it’s important that people know how to react if a cardiac event occurs and how to operate the AED equipment on-site. “We do see increased focus on sudden cardiac arrest and public access to defibrillation at all levels of sport, whether pro sports, youth leagues, at fitness centers or athletic clubs,” says Cam Pollock, executive vice president and chief marketing officer at Physio-Control.

Physio-Control has a partnership with USA Football that helps equip youth football teams with AEDs. The company is also working to expand awareness of the importance of having ready access to AEDs. In April the company provided equipment and support to the medical teams at the Boston Marathon. “In cases of undiagnosed hypertrophic cardiomyopathy, as just one example, a person may not know they are at risk for sudden cardiac arrest,” says Pollock. “Having a defibrillator nearby and in places where people are engaged in vigorous activity is an essential part of the chain of survival.”