Hypertrophic Obstructive Cardiomyopathy and Arrhythmias

Podcast Transcript

Announcer:

Welcome to Cleveland Clinic Cardiac Consult, brought to you by the Sydell and Arnold Miller Family Heart, Vascular & Thoracic Institute at Cleveland Clinic.

Nicholas Smedira, MD:

Hi. I am Dr. Nicholas Smedira and have been at the Cleveland Clinic for over 25 years. I have performed over 10,000 heart operations. My area of expertise is hypertrophic obstructive cardiomyopathy, performing over 3000 septal myectomies.

We talk about hypertrophic cardiomyopathy, but the way I think about it from a physiologic point of view is there is something getting in the way of blood getting out of the heart. The other thing is the conduction system. Atrial fib is real common in hypertrophic cardiomyopathy. One out of four patients, in their lifetime, will have atrial fib. So that is why you see a lot of maze procedures in these patients.

The bundle branches run through the septum, and this side shows the SA node here, which is up by the superior vena cava, goes to the AV node, and then right next to where we are doing the myectomy, it splits into a right bundle. So it goes on the right side of the septum, and this is the left bundle heading over underneath the aortic valve, coming and spreading throughout the septum. So when I do a myectomy, I cut right across here. So I always take out the left bundle. So when they come upstairs to the intensive care unit, you will see new left bundle branch block.

And that is why when they go into AFib rapidly and they have the new left bundle, it looks like V-tach because it is very wide. So you have somebody that is got 150, 170, it is a very wide complex thing. The impression is it is V-tach, and nine out of 10 times it's just AFib with a new left bundle.

What I tell patients is, if your right bundle is already out going into the operating room, so you have a complete right bundle branch block, and I am going to cut this out to give you a myectomy, you are going to need a pacemaker. Now, some patients have this great fear of pacemakers for a number of different reasons.

And so, they will ask, is there an alternative to get rid of my outflow tract obstruction without doing a myectomy and committing me to a pacemaker? And the answer is, yeah, I can replace your mitral valve like they did in the old days. Most of them want a biologic valve. Now you have got something that is going to last maybe eight or 10 years because tissue valves in the mitral position wear out much faster than in the aortic position because they’re under the direct stress. Every time the heart beats, it slams those leaflets shut. Whereas, in the aortic valve, that opens up, and then it drifts back and closes under diastolic pressure. But in the mitral position, it is open and then they are slammed under the force of contraction, 150, 180, 200 millimeters of mercury, so they wear out faster. So you are committing them to having a prosthetic valve in.

If they go into AFib, they got to be anticoagulated. Whereas, if you do a myectomy and a pacemaker, you do not have to worry about any of that stuff, with the exception of the battery life, which is seven or eight years. So those are the things that I am thinking about and patients are thinking about when they come in.

In minutes, that is years of myectomy. It has been a great journey. It is a fascinating disorder from a scientific perspective, the genetics of it, our evolution of it.

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