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December 03, 2021  
HEART1 HERO

Dr. Leonard Ganz

Dr. Leonard Ganz: Helping Heart Patients Keep Pace


October 01, 2002

What is your focus within cardiology and what are some of the major projects you are involved with at this time?

I'm a cardiac electrophysiologist, so I spend my time taking care of patients and thinking about ways to treat heart rhythm disturbances. Implantable defibrillators (ICDs) are part of it, and that's a fantastic therapy for treating patients who are at risk of sudden cardiac death. But we also take care of patients with heart rhythm disturbances like atrial fibrillation and super ventricular tachycardia and we can cure many of those rhythm disturbances with ablation procedures. We also put pacemakers in patients that have slow heart rhythms.

I'd say that what I find to be two of the most exciting things right now are primary prevention of sudden death with implantable defibrillators (ICD)and another procedure, which also relates to implantable devices, called cardiac re-synchronization therapy. That also goes by the name of biventricular pacing.

Traditionally we put in pacemakers for patients whose hearts are too slow and we electrically stimulate the heart and make it contract and it brings the heart rate and rhythm back to normal. But in many patients with severe cardiomyopathy and congestive heart failure, they can have electrical abnormalities in the conduction in the ventricles and have very slow conduction through those lower chambers. It turns out that may contribute to the mechanical dysfunction of the heart. They've got this big dilated heart and this dissynchronous contraction pattern of the ventricles can be making matters worse. And it's been learned that sometimes if you can pace the wall of the left ventricle in addition to the standard pacemaker leads in the right ventricle and right atrium, you can actually make the heart pump more efficiently. So this is actually pacing, not so much to correct a heart rate disturbance, but to make a sick heart pump more efficiently. And we've seen some tremendous improvements in patients' exercise capacity and quality of life. So this field of biventricular pacing has been
very exciting.

So the device used in biventricular pacing requires more leads than the traditional pacemakers?

Typically, with biventricular pacing, there would be three leads. A patient would have one in the right atrium and one in the right ventricle – which are the
typical leads for a dual chamber pacemaker or defibrillator. And then there's also a lead that paces the left ventricle and it's done via branches of the coronary veins which make up the venous system of the heart that kind of sits on the outside surface of the heart. This biventricular pacing can be done with a pacemaker system or, more commonly, in the context of an implantable defibrillator to also provide the protection against sudden cardiac death.

What type of patient would be a candidate for this treatment?

For biventricular pacing with ICD, which is the lion's share of these cases, the indication would be standard indications for an implantable defibrillator either for primary of secondary prevention of sudden death. But in addition, for the cardiac resynchronization part, the patient should have advanced cardiomyopathy; the patient should have a wide QRS complex (QRS complex reflects the electrical activation of the ventricles – a wide complex indicates they have slow electrical conduction through the ventricles);
and, they should have Class 3 or 4 heart failure. And those are the patients that have been shown to benefit from these biventricular pacing systems.

So these are pretty sick patients?

Yes. These are sick patients and they typically are patients who have had recurrent admissions to the hospital for congestive heart failure.

How far into development is biventricular pacing?

It's FDA approved. However, the devices are technically much more difficult to implant than standard pacemaker. So the rate of rise of implantation has been relatively slow. If you look at the pool of doctors who are implanting pacemaker and ICDs, there's a much smaller pool that is willing to take on biventricular pacing because its technically more demanding, it takes longer and patients are sicker. So you really have to make a commitment to it as a doctor and as a hospital. But I think that more and more people will learn that their patients can benefit substantially from this and that will help gather momentum for this therapy.

With MADIT II it's very clear cut. And loads of people know how to put in ICD's. Loads of doctors are accustomed to referring patients for ICD's. And we have now identified a much larger group of patients who can benefit.

Biventricular pacing in many parts of the country is a very new therapy. There are a lot of large hospitals that aren't doing it at all. So I think that the momentum for this has been a little slow to develop.

Now how does this device or procedure differ from the ICD used for the MADIT II study?

The MADIT II study used standard defibrillators. Defibrillators had been shown for a number of years to accurately detect life-threatening arrhythmias and correct them with a shock to the heart. The really exciting thing about MADIT II is that it showed that is now very easy to identify patients who might benefit from an implantable defibrillator. And that's by using ejection fraction.

The prior algorithm (after the MADIT I study) for identifying patients who would benefit from a prophylactic ICD (meaning primary prevention) suggested that you needed to have a poor ejection fraction (less than 35 percent), you needed to have spontaneous non-sustained ventricular tachycardia that was recorded either on a Holter monitor or on an exercise test. And then you needed to do an EP study (a diagnostic electrophysiologic study) which is a catheter–based procedure in which we see if we can induce these life-threatening arrhythmias by stimulating the heart. And if you did that you then you would give the patient an anti-arrhythmic drug call Procainimade, and if you could still induce the arrhythmia after the Procainimade, the MADIT 1 study suggested that patient would live longer if they got an implantable defibrillator.

That's very complicated and unwieldy. You have to find the non-sustained ventricular tachycardia and do an EP study, and no one's really using Procainimade anymore. So we estimated that maybe only about 20
percent of the patients who were eligible actually got treated.

The beauty of the MADIT II study is that there in no algorithm that could be simpler. You're looking of a patient with a prior heart attack and an ejection fraction less than or equal to 30 percent. So there's no
need to look for non-sustained ventricular tachycardia, there is no need to do the diagnostic EP study. Now it's very easy to identify patients who could benefit from this life-saving therapy.

What's being done to educate the public about the availability of these procedures?

One of the things that is incredibly important in terms of educating the public is that sudden cardiac death is the single biggest cause of death in the United States. Most people think its lung cancer, breast cancer or AIDS. It's not. It's sudden cardiac death. But it's a disease without a constituency, because 95 percent of the people who have this disease have it once and die.

So they clutch their chest and they die, because the likelihood of being resuscitated if you have an out-of-hospital cardiac arrest is very poor.
So although it's the single most important cause of death in the US, no one knows about it, no one hears about, there's no publicity about it because there are no patient groups that are petitioning the FDA to push drugs through more quickly, there's no patient groups that are hiring lobbyists to help raise money or publicize this disease. And that's because 95 percent of the victims die. So I feel very strongly that that medical community, and specifically cardiologists and cardiac electrophysiologists as well as the emergency medicine community have to become the constituents for the disease. We have to be the one's who lead the cause and educate the public and educate our lawmakers into recognizing that this is the most important cause of death in the country. I'm not saying it's not important to raise money for cancer and other sorts of diseases, but it's really important to focus attention on this problem.

And there's a number of different ways that we can help prevent sudden cardiac death. A lot of medications have been shown to be effective in different cardiovascular syndromes – like Beta blockers and ACE inhibitors and even statin drugs. Another thing that is vitally important is getting more AEDs (automated external defibrillators) out into the community, and teaching people how to do CPR. Improving first responder systems in different communities. Teaching people what an AED looks like and that they don't need to be afraid of it. One of the things we have at the University of Pittsburgh is the National Center for Early Defibrillation, which has done fantastic work at both a local and national level at disseminating information and helping communities get AED systems in place and improving their first
responder networks.

And the other incredibly important piece is identifying patients who have heart disease who are at risk for dying suddenly and getting them implantable defibrillators, because with sudden cardiac death, your first episode, unfortunately is usually your last.

By approximately what percentage does ICD therapy improve a patient's chance of survival?

Well in the MADIT II study it reduced the risk of dying by 31 percent over the course of the study. Now it may actually have more of an impact than that, but the nature of the trial design was to terminate the study as soon as a statistically significant difference was found. And the rationale for that was if the ICD was better, we want to minimize the number of deaths in the control group on our way to showing that. But if the survival curves are separating at the time the trial ends then the true impact with time may be greater, because once you've implanted an ICD in someone they're protected. But the trial lasted less than two years, so the only lives that could be saved during that period were the patients who were destined to have a cardiac arrest during that time. But the ICD's don't get pulled out at the end of the trial, so this trial design may actually have underestimated the treatment effect.

Now you could also make the argument, “Well if you wait long enough survival curves always come together because in the end everyone dies of something.” But if you look at the survival curves my suspicion is that they are going to continue to diverge for a while. So while we can't be certain, it's possible that the stopping rules for the MADIT II trial may actually underestimate the longer term survival benefit. Still – during the trial it was 31 percent. That's a lot of lives saved.

Where is the biggest gap in patient knowledge, in terms of what they should be doing to maintain a healthy heart?

I think that one of the downsides of how good we are at taking care of patients with heart attack and unstable angina is that they move through the hospitals very quickly. When I was in my training someone who had a heart attack might be in the hospital for seven or eight or maybe even 10 days. And during that time they were pondering their mortality and it was a big life changing event. Well now, they come into the hospital and they go to the Cath Lab and they may have an angioplasty or a stent and many patients are able to go home just a few days later. And while that's great, I think if you could come up with a downside to that, it's that the treatments are so good that the heart attack loses some of its impact on that patient.

Plus the statin drugs are so good at lowering cholesterol that patients in general make much less of an effort to change their diet than they did 10 years ago when the drugs weren't nearly as good. Between
stents and statins I think a lot of people come through this and they don't realize that this was a brush with death. And many people are left with the idea that if it happens again I'll get another stent. And I think we really need to work hard given how good all of these other therapies are to make people understand that they really do need to change they're lifestyle. You need to quit smoking. You need to exercise more. You need to change your diet. Yeah, the medicines are good and the stents are good, but if you could do the other stuff the aggregate picture is going to be better than if you just go about your business and depend on the interventional cardiologist to bail you our every 8 to 12 months with a stent.

With respect to the risk of sudden death and ICD's, that's a very abstract thing because what MADIT II tells us is you can pick up a patient anywhere following their MI (myocardial infarction). These are not patients who've just had an MI last week, last month or even last year – so these are for the most part patients who have chronic coronary artery disease and they may feel perfectly fine. They're on a medical regimen. They may not be having any symptoms.  They may not be having any heart failure. They may not be having any angina. But now we're telling them, “Well, you're feeling great. You're on the right medicines. You and your doctor are doing fine, but you still have a risk of dying. And we can reduce that risk substantially with an ICD.

But it's sometimes very hard for patients who feel like they've been doing well for the past several years since their heart attack and they've had no symptoms. “Why do I need this thing now,” they'll ask. Well, the truth is they've needed it all along, we just didn't know until now that patients like you need this thing. So I think that's also a knowledge gap that we have to work onto get across.

If there were one message you could leave readers and patients with today, what would it be?

It would be to emphasize that sudden cardiac death is the single biggest cause of death in the United States. But it's a silent epidemic. That's the message we have to get out there. If the lay public understands that even though they're feeling well, and they're having no symptoms and they're on the right medicine, this is still the biggest threat to their life then they'll be more interested in helping get more AED's into their community and having an ICD will suddenly make more sense for them.

One of the things that a lot people have talked about is patients need to know their numbers. Everyone needs to know their cholesterol. And people are really concerned about what their blood pressure is, and although it sounds trite a very important number for them to know – perhaps more important – is their ejection fraction. If their EF is low, even if they are doing well, they may be at risk for sudden death.


Last updated: 01-Oct-02

   
 
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