PHOTOGRAPH BY TREY CLARK
Dr. Frank McGrew with Stern Cardiovascular Center.
The history of cardiology research has seen procedures become more precise and powerful as well as accessible. And what’s on the horizon is nothing less than revolutionary, according to Dr. Frank McGrew, the director of clinical research at Stern Cardiovascular. McGrew been at the forefront of finding ways to treat heart conditions. In a recent interview, he spoke of several areas where significant strides are being made.
“About 25 percent of people with bad heart failure will have an electrical condition within their heart where the impulse is slow getting from one side to the other,” he says. “We can help them by putting in a three-lead pacemaker to artificially get the signal to the left side of the heart, and we don’t have to depend on the heart’s nerve to do it.”
McGrew says that about 75 percent of the time, that is significantly effective to make the heart pump better. But the other 25 percent of the time, he and his colleagues require a different approach. A recent research study aimed to address that issue by putting in a fourth pacemaker lead. “This lead can be put anywhere we want in the left side of the heart, which gives us the ability to pick and choose areas that will provide us the best electrical flow to make the heart muscle pump better.”
PHOTOGRAPH COURTESY TOM WANG / DREAMSTIME
The study, detailed in a recent issue of the journal Heart Rhythm, shows that the added flexibility of lead placement works with the pacemaker. “The pacemaker itself is small, like a grain of rice,” McGrew says. “It doesn’t have a battery. It gets its energy from a source outside the chest wall that’s embedded under the skin, which sends an ultrasound energy wave to that pacemaker. So, the pacemaker itself travels without baggage; it doesn’t need a wire on it. And because of that, we can put it pretty much where we want within the heart, which is important because a lot of these people will have scar tissue that will impede the ability of an extra wire to work.”
McGrew points out that the study was not so much about showing that the technique worked, which doctors already knew, but that surgeons who were new to the procedure could achieve a good degree of success. “Newcomers, having never used the technique, can pick it up quickly and make it work,” he says. And that suggests the possibility of more widespread use of the procedure.
“There are programs available, which we hope to have soon at our hospital, that can look at the electrocardiogram of a patient when they’re in normal rhythm and predict that they could develop, or have developed, an abnormal rhythm in the past or future.” — Dr. Frank McGrew
He mentioned yet another benefit. “Normally when you put something into the left side of the heart — because blood from there goes to the brain directly — in general any object there is a source of clots that could cause strokes, whether it’s a heart valve or a stitch or a pacemaker wire,” he says. “People get pacemaker wires in the left side, but you have to give the patient a very strong blood thinner. But this particular pacemaker is so small and does not have a wire attached to it, so we do not need to give an additional blood thinner to these patients.”
It’s an example of refining existing technology to achieve other material benefits. But sometimes new and rapidly developing technology provides almost futuristic advantages. Artificial intelligence (AI) is much in the news lately, and much of that coverage deals with some of the alarming possibilities of how the technology might take over humanity. But McGrew notes that there are uses of AI being refined now that may save lives.
AI, he says, can go through medical records to find patients with certain conditions that may predict future cardio problems. “There’s a disease called amyloidosis, where proteins are deposited in the heart muscle and make the heart muscle weak and less effective. It was felt that this disease may account for 4 percent or 5 percent of all patients with heart failure. However, it’s now thought that it probably could be much, much greater. And by using this computerized artificial intelligence program, we’ll be able to go through thousands of patients’ records and identify those that have a higher probability of this disease. Now, for the first time, we have a specific targeted treatment for this disease.”
This is a whole new wave of innovation, McGrew says. “There are programs available, which we hope to have soon at our hospital, that can look at the electrocardiogram of a patient when they’re in normal rhythm and predict that they could develop, or have developed, an abnormal rhythm in the past or future. That will tremendously enhance our ability to prevent strokes and heart attacks and other problems that dramatically impair survival or quality of life.”
INFOGRAPHIC COURTESY OF STERN CARDIOVASCULAR
Studies have shown success when using a small pacemaker without a battery that instead uses energy from a source embedded under the skin. An ultrasound energy wave is transmitted to the pacemaker that does not require a wire, making placement much more flexible.
Furthermore, AI can add significant information to routine procedures in other areas. “Pretty soon we’ll have AI that can evaluate your EKG when you’re in good health and feeling good and predict your need for a pacemaker within the next two to three years,” McGrew says. “Or alternatively, and more immediately, if you come into the emergency room with chest pain and your EKG is normal — which it frequently is — we’ll be able to determine if that chest pain was for an impending heart attack or from your gallbladder.”
McGrew, a careful scientist with a long track record of research, is not given to overstatement. So it is worth paying attention when he says, “Imagine how that’s going to change efficiency, and how lives will be saved, and how medical care will be cheaper and more available to everyone. It’s going to be a revolution.”
And that’s not all to look forward to. One area is high cholesterol treatment, which has grown enormously over the decades. “We’ve evolved through different types of drugs like the statins, which are truly miracle drugs,” McGrew says. “We now have drugs that act on the liver to enable it to remove cholesterol from the blood and dramatically reduce the risk of heart disease. And we’re not too far away from gene editing techniques where we can actually go in and remove a gene out of a chromosome and cure a patient’s disease.”
Clinical trials have been able to put new enzymes in the heart that enhance the right kind of chemical reaction to make the heart pump stronger. “That works because certain patients have a defective gene in their chromosome,” he says. “We take a virus particle, a first cousin to the virus that causes a common cold. We go inside of it and remove the virus’s own DNA, and we put in the human piece of DNA that contains the gene that we want to put into the patient.”
When these special viruses are injected, “they latch onto heart blood vessel cells and stimulate them to make more of the right kind of protein to make the heart better.”
A few years ago, McGrew was quoted in The Commercial Appeal as saying cardio research had provided “a pretty effective therapy for keeping people alive, but not making them well.”
But now, it seems a revolution is underway.
photograph by lzf / dreamstime
When an Athlete Falls
Research continues to find new ways of dealing with heart issues.
On January 2nd of this year, during an NFL game between the Buffalo Bills and the Cincinnati Bengals, Bills safety Damar Hamlin collapsed. He had tackled an opponent, stood up, and then fell to the ground right away, suffering from cardiac arrest.
Hamlin was hospitalized and has since been released and is recovering. The incident put the spotlight on the issue of cardiology in rough sports, and Dr. Frank McGrew, director of clinical research at Stern Cardiology, has done research in the area.
“In the broader picture of sudden death in athletes, we made a major step about 20 years ago by screening athletes with echocardiograms and stress tests,” he says. “And by doing that, when they begin an athletic pursuit, that alone will probably remove two-thirds of players who would be destined to have trouble. I was fortunate to be a member of the team that did those tests on the football team at Ole Miss and it was one of the very few schools in the country doing that type of evaluation.” Eventually, it was widely adopted and doing that allows the identification of athletes that have certain abnormal problems.
McGrew says that a thickened heart muscle — hypertrophic cardiomyopathy — accounts for the majority of sudden death in athletes. “But the echocardiogram almost always identifies that and helps us screen those players out.” There are, he says, some patients who either die or almost die as a result of trauma of their athletic pursuit. “When you have a force hitting the chest, it actually creates an electrical current within the heart — very minimal. And if that current happens to fall at a precise time in the heart cycle, it can trigger a life-threatening irregular rhythm that, without a defibrillator present, can be fatal. That’s called commotio cordis, and that’s been well recognized for decades, but almost always occurs with a forceful blow of a small object like a baseball or a lacrosse ball.”
McGrew says the night before the game, his grandson was showing him a new lacrosse outfit that had a foam triangle in the middle of the chest. As it happened, it was there to prevent commotio cordis. “It’s common to have that, with baseball catchers, lacrosse players, and hockey goalies, because they’re the ones that bear the brunt of fast localized heart injuries. Like all the commentators said, it’s very rare to occur from a football helmet because the force is dissipated over a much larger area.”
“It’s important to remember that a third of the time, the first manifestation of artery blockage is either sudden death or a bad heart attack. They have cholesterol deposits in the arteries that become unstable and plaques rupture. Not everybody who has a heart attack has recognized predictive signs like high cholesterol, high blood pressure, diabetes, or a sedentary lifestyle.”
— Dr. Frank McGrew, Stern Cardiovascular
He says other possibilities could be considered in a case like Hamlin’s: a genetic defect in the electrical system of the heart, a cerebral hemorrhage due to a ruptured aneurysm, or a heart attack where there is cholesterol in the heart arteries. The latter has happened to marathon runners who often run but experience no symptoms.
“It’s useful to screen adults who do strenuous activities like that with a stress test periodically,” McGrew says. “It’s important to remember that a third of the time, the first manifestation of artery blockage is either sudden death or a bad heart attack. They have cholesterol deposits in the arteries that become unstable and plaques rupture. Not everybody who has a heart attack has recognized predictive signs like high cholesterol, high blood pressure, diabetes, or a sedentary lifestyle.”
And there is another test that McGrew says is important. “The calcium score is a CAT scan of the chest. It’s very simply done and not reimbursed by insurance, but almost always costs under a hundred dollars. That picks up calcium in the wall of the heart arteries years before it causes blockage and years before it shows up on any other tests. For many people, the calcium score is an important part of their risk stratification.”
Promising research is being done in cholesterol. “There’s one component called lipoprotein (a) and if you have that in an elevated form, it predicts increased risk of heart disease, like heart attack and death,” says McGrew. “It doesn’t say you’ll always get it, it just increases a statistical risk. Now for the first time we think we have a medicine that can lower that protein. We’re doing two clinical trials in patients that are at risk from that protein to see if we can prevent their heart or vascular disease.”
In Europe, adults have a series of tests, including periodic cholesterol checks and the lipoprotein (a) check that help interpret other numbers in the cholesterol profile. It’s also useful in evaluating if a patient’s children are at risk.
Current research, McGrew says, is showing promise. “We have five or six medicines that make a major impact on heart muscle performance,” he says. “And we have different types of devices to do that. For example, we’re doing research now on a device that’s like a pacemaker and has an electrode in the heart, but unlike a pacemaker, it doesn’t cause the heart to beat faster. It delivers electrical current to get more calcium in the heart cell to make it beat stronger. And there’s a device that stimulates the nerve in the neck, which sends impulses to the brain, which sends them back to the heart to make the heartbeat stronger and more efficient.”
