Cardiac Resynchronization Therapy for Heart Failure
Zubin Agarwal, MD, helps us to understand how dysynchrony is measured. He defines the mechanism of action of resynchronization therapy and offers providers advice on how to recognize when a patient would benefit from referral for device therapy.
Featuring:
Zubin Agarwal, MD
Zubin Agarwal, MD is an Electrophysiologist and Assistant Professor.
Transcription:
Introduction: The University of Florida College of Medicine is accredited by the accreditation council for continuing medical education, ACC M E to provide continuing medical education for physicians, the University of Florida College of Medicine designates this enduring material for a maximum of 0.25 AMA PRA category one credit. Physician should claim only the credit commensurate with the extent of their participation in this activity.
Melanie Cole: Welcome to USF Health MedEd Cast with USF Health Shands hospital. I'm Melanie Cole. And I invite you to listen in, as we discuss cardiac resynchronization therapy for heart failure. Joining me is Dr. Zubin Agarwal. He's an Electrophysiologist at USF Health Shands Hospital and an Associate Professor in the Division of Cardiology at the University of Florida College of Medicine. Dr. Agarwal, it's a pleasure to have you join us today. Give us a little background on refractory heart failure and what's been the standard therapy?
Dr. Agarwal: So, I'm, I'm really excited to talk about cardiac resynchronization therapy, cardiac resynchronization therapy, or CRT for short is one of the most exciting advancements in the treatment of heart failure. And it's not a novel advancement it's been around for 20 years, but we've really learned a lot from our experience with CRT in the last 20 years. And we have shown that it works for patients with difficult to treat heart failure. So we use it for patients who have some form of the dysynchronous left ventricular contraction. So when I say that I'm talking about patients that have a ventricle, that doesn't contract in coordination with each other. And typically we see this when patients have heart failure and their right side of their heart does not contract in synchrony with the left side of their heart. And that's the goal of cardiac resynchronization therapy is to help improve the coordination of those two ventricles by placing a device that helps time the contraction of each ventricle.
Host: Well then help us to understand how dysynchrony is measured?
Dr. Agarwal: When cardiac resynchronization therapy was first developed, we used ECG to measure dysynchrony. So an ECG is a global recording of a heart's electrical impulses. And based on the width of the QRS complex on the ECG, we can determine whether the heart is beating in synchrony or not. And we typically use a cutoff of 150 milliseconds as a measure of dysynchrony. So if the heart is beating with 150 seconds or longer of delay, we believe that the right ventricle is not beating synchronously with the left ventricle.
Host: So then speak about cardiac resynchronization therapy. What are the benefits of this procedure? What have the mechanistic studies, observational evaluations, and randomized trials demonstrated about this? Have they shown significant improvement in quality of life, functional status, and even exercise capacity in patients? Summarize this therapy for us.
Dr. Agarwal: There have been a lot of studies on CRT in the last 19 years. The very first study was a study called Mustic, that's the multisite stimulation and cardiomyopathy trial. And it showed that in a select group of patients, there was improvement in exercise tolerance and quality of life in patients with CRTs compared to patients with a right ventricle only pacing. That was followed by other studies, including the Miracle Trial and the Companion Trial that showed benefit, not just in quality of life, but in hospitalization for heart failure and morbidity and mortality. These results of duplicated and multiple studies that show a benefit of CRT in a select group of patients. Now there's been a lot of research to see exactly which patients benefit, and it has been shown that patients who have desynchronized left ventricle and with a low ejection fraction are the patients who benefit the most. But there has been a lot of research into whether this therapy can be applied to patients with less severe heart failure symptoms. And so far, we haven't seen a significant benefit in those patients, but there are ongoing trials to determine whether there might be some role for CRT in that group as well.
Host: Thank you for telling us what echocardiographic criteria have to be present and what has to have occurred for this procedure to be considered. Please tell us what would warrant consideration for the procedure? Give us the rationale for cardiac resynchronization therapy doctor?
Dr. Agarwal: This therapy is really reserved for patients with severe heart failure. And those are patients that have already seen a heart failure specialist or a cardiologist, and they're on medications for heart failure. Those medications typically have been changed multiple times to determine what the best medical regimen is for them. And they're still having symptoms that include shortness of breath or trouble climbing stairs. And when they get to that point, they are referred to an electrophysiologist for consideration of this therapy. And the electrophysiologist will take into account a number of variables, including their age to severity of their symptoms, the findings on their echocardiogram and the patient's ability to undergo procedures. And they'll make a recommendation as to whether they think the patient will benefit from CRT.
Host: Then tell us a little bit what happens after the CRT device is inserted what's life like for the patient, how soon can they resume normal activities and what things should patients avoid or be careful of?
Dr. Agarwal: Well, a CRT is a device that is typically along the left chest and it hires three wires that go into the heart. Two wires go into the right side of the heart. And one wire goes into the left side of the heart. These wires are placed there carefully by the electrophysiologist doing the procedure and following the procedure, we wanted to make sure that the wires don't move. So we asked the patient to wear a sling for the first 24 to 48 hours so that their left arm doesn't move. And we'll have them come back typically in a week to make sure that the devices are working appropriately and that the wound is healing appropriately. But after that first week, patients are really able to live their life. Normally we hope that they can normal activities and that they don't even know that their device is there.
Host: What is the follow-up? If the program has a focus, that's engaging a multidisciplinary approach. Tell us what that looks like for these patients.
Dr. Agarwal: CRT is a therapy that requires a multidisciplinary team. So for patients with heart failure that require a CRT. They need to work very closely with their primary care provider, as well as their heart failure specialist and an electrophysiologist. And all three providers play a very important role in managing them as they receive treatment for their condition. So their primary care provider deals with the day to day issues that can come up during the patient's care with heart failure, the general cardiologists or their heart failure specialists will manage the medications that they're on. And like I mentioned before, they'll often change the dose of their medications to make sure that they find the correct dose for these patients. And the electrophysiologist, he manages the device itself and we'll check the device every three months to make sure that it's working appropriately and can change the parameters in the device to help improve the way that it paces the heart. And it's very important for patients who have a CRT to follow with an electrophysiologist very closely so that if there is an issue with their device state, it can be detected early and the appropriate adjustments can be made.
Host: How have been your outcomes, Dr. Agarwal?
Dr. Agarwal: Our outcomes have an excellent. And we can tell when a patient has responded right after the procedure. So when we're placing the device, we can visualize the device on x-ray and we monitor their EKG and we can see that the device is working right after we turn it on. And so we are able to determine whether a patient has been successfully treated with a CRT.
Host: Doctor, what would you like to tell other physicians about this therapy? And when you feel it's important to refer?
Dr. Agarwal: Early referral is very important because patients with heart failure, because heart failure is a progressive condition and these patients will often become slowly more debilitated, referring them to see a heart failure specialist or an electrophysiologist early allows us to manage their condition much more aggressively. If they are a candidate for a CRT, then we'd like to place it earlier to help them either prevent further decline or to improve their heart failure status as early as possible.
Host: Do you have any new techniques still under active evaluation that you'd like to mention? Is there anything exciting in your field? You'd like other providers to know?
Dr. Agarwal: Yes. There's actually been a great deal of research in CRT and there have been a few developments in the field. One is the use of MRI to determine which patients will respond best to CRT. Most patients with heart failure have a lot of scar around their heart that can sometimes make the procedure complicated. Doing an MRI beforehand will allow us to see which patients may benefit more than others. The other thing that's very interesting or very exciting about CRT is that we've developed a new leads for placing the left ventricular lead. And the new leads have multiple sites that allows pace from different parts of the heart, and that helps improve the response to CRT in a way that we haven't seen before.
Host: Thank you so much, Dr. Agarwal for joining us today. It's absolutely fascinating and referring physicians can visit ufhealth.org/heart for more information. And to learn more about other healthcare topics at UF Health Shands Hospital, please visit uf.org/medmatters to get connected with one of our providers. And that concludes today's episode of USF Health MedEd Cast with USF Health Shands Hospital. Please remember to subscribe, rate, and review this podcast and all the other UF Health Shands Hospital podcasts. I'm Melanie Cole.
Introduction: The University of Florida College of Medicine is accredited by the accreditation council for continuing medical education, ACC M E to provide continuing medical education for physicians, the University of Florida College of Medicine designates this enduring material for a maximum of 0.25 AMA PRA category one credit. Physician should claim only the credit commensurate with the extent of their participation in this activity.
Melanie Cole: Welcome to USF Health MedEd Cast with USF Health Shands hospital. I'm Melanie Cole. And I invite you to listen in, as we discuss cardiac resynchronization therapy for heart failure. Joining me is Dr. Zubin Agarwal. He's an Electrophysiologist at USF Health Shands Hospital and an Associate Professor in the Division of Cardiology at the University of Florida College of Medicine. Dr. Agarwal, it's a pleasure to have you join us today. Give us a little background on refractory heart failure and what's been the standard therapy?
Dr. Agarwal: So, I'm, I'm really excited to talk about cardiac resynchronization therapy, cardiac resynchronization therapy, or CRT for short is one of the most exciting advancements in the treatment of heart failure. And it's not a novel advancement it's been around for 20 years, but we've really learned a lot from our experience with CRT in the last 20 years. And we have shown that it works for patients with difficult to treat heart failure. So we use it for patients who have some form of the dysynchronous left ventricular contraction. So when I say that I'm talking about patients that have a ventricle, that doesn't contract in coordination with each other. And typically we see this when patients have heart failure and their right side of their heart does not contract in synchrony with the left side of their heart. And that's the goal of cardiac resynchronization therapy is to help improve the coordination of those two ventricles by placing a device that helps time the contraction of each ventricle.
Host: Well then help us to understand how dysynchrony is measured?
Dr. Agarwal: When cardiac resynchronization therapy was first developed, we used ECG to measure dysynchrony. So an ECG is a global recording of a heart's electrical impulses. And based on the width of the QRS complex on the ECG, we can determine whether the heart is beating in synchrony or not. And we typically use a cutoff of 150 milliseconds as a measure of dysynchrony. So if the heart is beating with 150 seconds or longer of delay, we believe that the right ventricle is not beating synchronously with the left ventricle.
Host: So then speak about cardiac resynchronization therapy. What are the benefits of this procedure? What have the mechanistic studies, observational evaluations, and randomized trials demonstrated about this? Have they shown significant improvement in quality of life, functional status, and even exercise capacity in patients? Summarize this therapy for us.
Dr. Agarwal: There have been a lot of studies on CRT in the last 19 years. The very first study was a study called Mustic, that's the multisite stimulation and cardiomyopathy trial. And it showed that in a select group of patients, there was improvement in exercise tolerance and quality of life in patients with CRTs compared to patients with a right ventricle only pacing. That was followed by other studies, including the Miracle Trial and the Companion Trial that showed benefit, not just in quality of life, but in hospitalization for heart failure and morbidity and mortality. These results of duplicated and multiple studies that show a benefit of CRT in a select group of patients. Now there's been a lot of research to see exactly which patients benefit, and it has been shown that patients who have desynchronized left ventricle and with a low ejection fraction are the patients who benefit the most. But there has been a lot of research into whether this therapy can be applied to patients with less severe heart failure symptoms. And so far, we haven't seen a significant benefit in those patients, but there are ongoing trials to determine whether there might be some role for CRT in that group as well.
Host: Thank you for telling us what echocardiographic criteria have to be present and what has to have occurred for this procedure to be considered. Please tell us what would warrant consideration for the procedure? Give us the rationale for cardiac resynchronization therapy doctor?
Dr. Agarwal: This therapy is really reserved for patients with severe heart failure. And those are patients that have already seen a heart failure specialist or a cardiologist, and they're on medications for heart failure. Those medications typically have been changed multiple times to determine what the best medical regimen is for them. And they're still having symptoms that include shortness of breath or trouble climbing stairs. And when they get to that point, they are referred to an electrophysiologist for consideration of this therapy. And the electrophysiologist will take into account a number of variables, including their age to severity of their symptoms, the findings on their echocardiogram and the patient's ability to undergo procedures. And they'll make a recommendation as to whether they think the patient will benefit from CRT.
Host: Then tell us a little bit what happens after the CRT device is inserted what's life like for the patient, how soon can they resume normal activities and what things should patients avoid or be careful of?
Dr. Agarwal: Well, a CRT is a device that is typically along the left chest and it hires three wires that go into the heart. Two wires go into the right side of the heart. And one wire goes into the left side of the heart. These wires are placed there carefully by the electrophysiologist doing the procedure and following the procedure, we wanted to make sure that the wires don't move. So we asked the patient to wear a sling for the first 24 to 48 hours so that their left arm doesn't move. And we'll have them come back typically in a week to make sure that the devices are working appropriately and that the wound is healing appropriately. But after that first week, patients are really able to live their life. Normally we hope that they can normal activities and that they don't even know that their device is there.
Host: What is the follow-up? If the program has a focus, that's engaging a multidisciplinary approach. Tell us what that looks like for these patients.
Dr. Agarwal: CRT is a therapy that requires a multidisciplinary team. So for patients with heart failure that require a CRT. They need to work very closely with their primary care provider, as well as their heart failure specialist and an electrophysiologist. And all three providers play a very important role in managing them as they receive treatment for their condition. So their primary care provider deals with the day to day issues that can come up during the patient's care with heart failure, the general cardiologists or their heart failure specialists will manage the medications that they're on. And like I mentioned before, they'll often change the dose of their medications to make sure that they find the correct dose for these patients. And the electrophysiologist, he manages the device itself and we'll check the device every three months to make sure that it's working appropriately and can change the parameters in the device to help improve the way that it paces the heart. And it's very important for patients who have a CRT to follow with an electrophysiologist very closely so that if there is an issue with their device state, it can be detected early and the appropriate adjustments can be made.
Host: How have been your outcomes, Dr. Agarwal?
Dr. Agarwal: Our outcomes have an excellent. And we can tell when a patient has responded right after the procedure. So when we're placing the device, we can visualize the device on x-ray and we monitor their EKG and we can see that the device is working right after we turn it on. And so we are able to determine whether a patient has been successfully treated with a CRT.
Host: Doctor, what would you like to tell other physicians about this therapy? And when you feel it's important to refer?
Dr. Agarwal: Early referral is very important because patients with heart failure, because heart failure is a progressive condition and these patients will often become slowly more debilitated, referring them to see a heart failure specialist or an electrophysiologist early allows us to manage their condition much more aggressively. If they are a candidate for a CRT, then we'd like to place it earlier to help them either prevent further decline or to improve their heart failure status as early as possible.
Host: Do you have any new techniques still under active evaluation that you'd like to mention? Is there anything exciting in your field? You'd like other providers to know?
Dr. Agarwal: Yes. There's actually been a great deal of research in CRT and there have been a few developments in the field. One is the use of MRI to determine which patients will respond best to CRT. Most patients with heart failure have a lot of scar around their heart that can sometimes make the procedure complicated. Doing an MRI beforehand will allow us to see which patients may benefit more than others. The other thing that's very interesting or very exciting about CRT is that we've developed a new leads for placing the left ventricular lead. And the new leads have multiple sites that allows pace from different parts of the heart, and that helps improve the response to CRT in a way that we haven't seen before.
Host: Thank you so much, Dr. Agarwal for joining us today. It's absolutely fascinating and referring physicians can visit ufhealth.org/heart for more information. And to learn more about other healthcare topics at UF Health Shands Hospital, please visit uf.org/medmatters to get connected with one of our providers. And that concludes today's episode of USF Health MedEd Cast with USF Health Shands Hospital. Please remember to subscribe, rate, and review this podcast and all the other UF Health Shands Hospital podcasts. I'm Melanie Cole.