The team involved in the first implantation procedure at Morton Plant Hospital, including the research team, lines up for a group shot. From left are Amy Davidson, RN, lead clinical research coordinator, CCIC; Jose Gallastegui, MD, director of electrophysiology and arrhythmia at Morton Plant Hospital; Yves A. Gabriel, MD, vascular surgeon and chief, department of surgery at Morton Plant Hospital; Michele Cameron, MBA, BSN, RN and director of clinical research, CCIC.
CLEARWATER – More than 5 million people suffer from congestive heart failure in the United States, according to the National Heart, Lung and Blood Institute and the Centers for Disease Control and Prevention. Of those, about half who develop heart failure will die within five years of diagnosis, according to the CDC.
If the problem is not fixed or brought under control, then the patient will die, said Jose Gallastegui, director of electrophysiology at Morton Plant Hospital. Therefore, it is extremely important to discover the problem and take proactive measures to fix the problem. Morton Plant Mease Hospital is currently part of a national clinical study called INOVATE-HF that uses an electrical stimulation device called CardioFit to help fix the root cause of the problem.
“Congestive heart failure is a condition in which essentially the heart is not able to pump enough blood and maintain adequate perfusion – meaning circulation to the different organs,” Gallastegui said. “As a result, these patients have symptoms. The most frequent of these is shortness of breath. And they also feel light headed, they tend to feel fatigued, they tend to develop swelling of the legs – basically evacuation of fluid.”
The nervous system that controls all body functions is divided into three types, with two of those being the sympathetic and the parasympathetic systems. The sympathetic system controls the “fight or flight” type of actions, is generally what controls the speeding up of actions in the body, and primarily is more dominant during the day. The parasympathetic system is more in control of the “rest and digest” and “feed and breed” type of actions within the body as well as working to slow down functions, balancing out the work of the sympathetic system. The parasympathetic system also is more dominant at night.
In the case of congestive heart failure, some kind of damage has occurred to the heart, and that causes the sympathetic system to work extra hard. Soon it can get out of control, and as the sympathetic system throws itself into overdrive, the parasympathetic system retreats, causing an even deeper imbalance.
Dr. Yves Gabriel, vascular surgeon at Morton Plant Mease and the other doctor in charge of this study, put this occurrence in layman’s terms.
“If I could use the example of a car, what tends to happen with congestive heart failure is it’s like a car that’s been revved up and is working at high speed all the time,” Gabriel said. “In the sense of, either the brake is not working properly or there is no brake so it’s always going at a fast pace.”
The device that is being tested in this study will help reboot the brakes and get them to start working again, Gabriel said.
“The sympathetic branches are the branches that activate the fight or flight response. It increases your heart rate, it increases your blood pressure, it increases your heart function,” Gabriel continued. “So therefore, long-term, if you keep working at that pace, you tend to have more trouble. Just like the car, it tends to slow down and things break down. What this device does is it stimulates the brakes in the system, or what we call the parasympathetic branches, to produce a calming effect on the heart. To slow things down and let everything else catch up. And by slowing things down, we get to reserve long-term function to the heart.”
Another way to look at it is a game of tug of war, Gallastegui said.
“On one side, the sympathetic is pulling, and on the other, the vagal (parasympathetic) is pulling and you have to keep the little flag in the middle,” Gallastegui said. “When there’s congestive heart failure, the sympathetic is pulling from one side so the flag is moving all the way there, out of the circle.”
Congestive heart failure can occur for several reasons, Gallastegui said. The most frequent cause is having a previous heart attack. In that case, the heart attack damaged the walls of the heart and makes it less efficient to contract, he said. The second possibility is that there was some kind of condition, such as high blood pressure that has not been treated, that put tremendous effort on the heart so it damages the muscle of the heart. Instances such as high blood pressure makes the heart work extra hard, so the muscle gets weak from trying to keep up for so long. Similarly, an infection or other condition could affect the muscle and damage it. And finally, some patients may have mechanical issues such as a faulty or leaking valve that creates a lot of extra work for the heart. Once again, this tires out the heart, weakening it and causing congestive heart failure, Gallastegui said.
These problems are a big deal because it doesn’t only affect the heart. The problem gets compounded and affects system after system until – if not treated – something will critically fail and the patient will die.
“Eventually, the function of the heart will affect other organs,” Gallastegui said. “And the organ that is definitely affected as much or participates in congestive heart failure is the kidneys because once the heart is weak, it does not pump enough blood. Therefore there is not enough perfusion (circulation) to the kidneys. And the kidneys react in a way that stimulate more of the sympathetic system and tell the sympathetic, ‘Well, we have a problem here. We are not receiving enough blood,’ and they trigger the sympathetic to try to push the heart to give them more blood.”
This just makes the heart work even faster than it already was, which makes the problem worse and the heart becomes even weaker. Meanwhile, he added, the liver is like a reservoir, and when there is an excess of fluid that the heart cannot pump around the body, it goes into the liver, and that will eventually affect the function of the liver.
“So it’s kind of a vicious cycle, and that’s what we’re trying to interrupt,” Gallastegui said.
Clearly, it is imperative that this cycle is stopped so the patient will not die. However, there are currently limited ways to do this. If it is a mechanical problem, then invasive surgery can be done such as replacing heart valves or putting in a pacemaker, Gabriel said. But otherwise, almost all of the treatments are through medications.
“With medications, there are different types of medications that we can give patients that can help,” Gabriel said. “Some of them work by affecting calcium channels. Some of them work by affecting the kidneys and their hemodynamic channels. Some of them work directly on the heart themselves, like the heart rate or the vascular tone, to change the tone such as to decrease high blood pressure. Most of these affects are again from medications. If we are able to find the cause of the problem, then that’s when surgery comes in. And that’s when if a patient has a blocked artery, they can have a bypass procedure. If the patient has a leaking valve, we can either repair or replace those valves. Or if it’s a problem with the intrinsic electrical conduction of the heart, we can fix those things as well with things like defibrillators and pacemakers and those types of things.”
Often doctors use a combination of the above techniques to work to stem the problem. However, these don’t necessarily address the direct problem of the sympathetic and parasympathetic systems being out of balance. That is where the INOVATE-HF study comes in.
Going back to the example of the tug of war, the purpose of this study is to trigger the parasympathetic side – to wake it up – so it starts to work again, thus dragging the metaphorical flag back into the center of the tug-of-war ring.
“The way we do this is to implant a little machine that is similar to a pacemaker on the right side of the chest under the clavicle (collar bone) and under the skin,” Gallastegui said. “We do not have to go inside the chest. I put a special wire inside the heart. We go in through a vein, then the vein flows into the heart and I can float my lead inside the heart. And that lead is going to sense the beating of the heart, so that will tell the machine how many beats per minute, and things like that.”
Next, a vascular surgeon implants a second lead that touches the vagus nerve in the neck, he said. Both wires connect to the machine that is just under the skin. The machine senses every beat of the heart and then sends a message through the second lead to stimulate the nerve – in a sense, jump starting the parasympathetic system.
The patient still will receive medications, but this study will compare the long-term results of patients who only receive medications with those who receive medications and the device. The device is already approved for use in Europe and has been quite successful, Gallastegui and Gabriel said, but it still has to go through this last round of testing in the U.S. and get approved by the FDA. Gallastegui estimates that the study will last about six months. After that, experts will review the results and then hopefully present it to the FDA. The entire process takes time, and he estimates that the device would probably not be approved for general use until at least 2 years from now.
If approved, this would help long-term for patients because it could allow them to avoid some of the more invasive, aggressive – and risky – procedures, Gabriel said. Yet at the same time, it would help them preserve more heart function for the long-term, he said. For the most part, the goal is always to stabilize the heart. In some cases, people might be able to reverse the damage in some portions of their heart, but mostly it’s just preserving what is left and preventing the damage from spreading.
“The most important thing is to prevent further deterioration long-term,” Gabriel said. “So you won’t completely resolve everything. If you have a damaged portion of your heart that requires a bypass, that portion is dead. But the hope is that the portion next to it, the portion above it, the portion behind it will continue to sustain itself. Instead of having a ripple effect, going out from that portion to involve the rest of the heart (and the body.)”