In February, former UFC middleweight Chris Leben and Bellator MMA announced 'The Crippler' would return to mixed martial arts under the auspices of Scott Coker's circular cage. Yet, less than a month later, it was revealed Leben's return to the sport would be shortlived. In pre-fight medical exams, doctors found Leben had a debilitating and dangerous heart condition, prompting Bellator to pass on bringing Leben back.

On Friday, Leben appeared on The Luke Thomas Show on SiriusXM to detail the nature of his physical condition, the struggle to end his physical dependency on prescription medication and more.

Below is a short clip of the interview, followed by a partial transcript of the larger conversation:

What did the doctors find was wrong with your heart?

Basically, I was doing my pre-fight stuff. I failed the EKG, so I took four more, continued to fail as my left ventricle was putting out too much electricity. They did a cardio-ecogram where they went in and actually look. They do an ultrasound of your heart while it's pumping.

Unfortunately, my left ventricle is oversized, misshapen and not pumping correctly. It's pumping at 18 percent, which I'm told is not a good thing.

Have you been feeling symptoms of this before the exam?

You know, that's the crazy thing. I've never felt better. That was the big thing about this comeback was I'm off the Suboxone, I'm off the medications the doctors have been giving me. I'm 100 percent drug, alcohol free and eating healthy. I'm in the gym, I'm beating up all the 20-year-olds. I'm a little leaner than I used to be and I'm back to eating meat again, but that's great for fighting.

I was doing awesome. I would come in in the morning, I'd do jiu-jitsu with Baret Yoshida, then I'd come and do my kickboxing with Vince, then I'd do go over with Andy and do my strength and conditioning, so three hours in the morning and I was back for team practice at night.

So, what are the doctors saying would happen if you kept fighting?

The doctors were like, 'You don't have a problem walking up these stairs?' That's the way they're looking at it. They're blown away that I'm performing the way that I am, that I can do the things I can do with my heart, because it's just not pumping the blood and apparently that's an important thing. It's definitely extremely frustration.

What are they worried about, specifically? Heart attack, heart failure?

Stroke, heart attack, yeah. Heart failure is actually the condition. Basically, my heart is failing. It's got dead tissue on it, it's oversized. There's plethora of reasons this can happen. It happens more commonly to athletes.

They're not saying it's linked to alcohol or anything like that, but my guess is I train my ass off when I'm in the gym. I never miss a day in the gym, but for a long time, I also took advantage of the night life as well. So, I'm kinda burning the candle from both ends for years. I think my heart just couldn't take it.

Is there any way to say there could be genetic factors playing a role?

My uncle had the same heart condition. He had open heart surgery and everything else. My family has a history of high blood pressure. Everybody has that. There's definitely some genetic factors in there as well.

I believe, after I fought [Mark] Munoz and I tested positive for painkillers, I went to rehab. Well, after I got out of rehab, the doctors put me on a drug called Suboxone. Everybody I know that takes that drug, their blood pressure shoots through the roof.

It wasn't until about 9 months ago I was finally able to quit the drug the doctors gave me, which, by the way, is the hardest drug to come off in the world. You can Google it. It's got a horrible failure rate and it was nightmare coming off of this, but I was able to come off this. I wanted so badly to just be somewhat of an example with the book out and with my new lifestyle comeback, fight, do well and use that to hopefully inspire some people.

Unfortunately, I ran a little too hard for a little too long. I think the Suboxone and training hard on top of it - I was taking it while I was fighting in the UFC - the hard training with that. Your blood pressure's high and when you train, it only gets higher.

What is your long-term prognosis?

I've been to four different cardiologists. One of them was saying, 'You made need a heart transplant. We may need to get you on the list for a heart transplant.'

The other doctor said, 'Well, I think this is attributable to training too hard, but with consumption of alcohol. I think if you never drink again and you take the medicine we're going to give you, you take it easy in the gym, then your heart can somewhat of a recovery.'

Do you think we'll see other fighters as they age see they've damaged their hearts from overuse?

I think so. Let's face it, professional athletics is no not necessarily the most...I would never change anything, how much I've learned. I've grown both mentally, spiritually. I think everything happens for a reason, but with that being said, professional athletics is hard on your body. That's especially if you're fighting.

The huge weight cuts, another thing I did. I blew out my thyroid cutting weight, so I have to take thyroid medication the rest of my life. The huge weight cuts, the insane training you do for MMA. There's not a sport in the world, nobody that trains as hard as we do.

When you push your body to the limit and you're getting ready to go fight in the UFC, Bellator event, it's a tightrope walk between overtraining and not training enough. You want to be the absolute best, but you push everything to the limit. You combine that with a less than healthy lifestyle and I think it's a no brainer. To me, I feel like hopefully with my lifestyle changes, I can make some recovery.

I'm also trying to go the naturopathic route. I'm obviously doing what the doctors tell me, but I'm doing a bunch of extra herbs and supplements. Organic cayenne pepper, I got a whole stack of stuff that I'm on here now. Hopefully with some good energy coming from some other people, me staying diligent on taking care of myself, I hope that I'll be fine.

It's always bothered me when others say, 'I have no regrets'. I don't live with regret, but there are moments in my life I regret. Do you live with regret?

No. No, I don't. My book is out, it's crushing it and I'm getting massive feedback from social media, how many that book has inspired and how many people have changed their lives and have realized for me to do what I did and go through what I've go through, and the situations I was in - not in the cage, but outside of the cage - the battles that I faced.

What I've been able in some aspect is to give back to society that way. I couldn't go back and change it. I don't think so. Besides that, stepping into the Octagon for a main event at a sold out MGM. That's a feeling not too many people in this world can ever say they've hand anything even close to how powerful that moment is. I wouldn't change anything.

Were you sober before the attempted return to MMA?

I was sober before. Basically I was able with my girlfriend's help - and it was a nightmare, horror story trying to come off Suboxone - but we were able to get me off of that. Every couple of weeks, I'd have a few drinks. I wasn't doing that AA-hardcore route, but certainly I was cleaner than I'd ever been in my life, by far.

I really don't miss it at all. I feel great. I wake up in the morning and there was a time in my life where it'd cost me $100 to feel as good as I feel when I wake up in the morning. Yeah, I feel great.

Suboxone, as I read it, has a high risk of dependency. How hard was it to get off and what'd you have to do to do it?

I was slowly weening myself down and I would take just enough to get through work, through the day, then I would get back and my girlfriend would sit next to me for the first month. I'd just sit on the bathroom floor and just vomit all night. It's like coming off of heroin, but coming off of heroin lasts three days. Suboxone lasts two months.

Every night, she would take care of me all night while I laid there and she'd have to change the sheets twice a night because the whole bed would be soaked in sweat. I'd be there shivering and shaking. I wouldn't wish it on my worst enemy.

I'm not exaggerating. I feel like I'm a pretty tough guy. It was absolutely terrible.

The Luke Thomas Show airs Monday, Wednesday and Friday on SiriusXM 93.