Post Coronary Bypass Depression

Is there a type of depression that is specific to having had Coronary Bypass?  I understand depression is relatively common during recovery, but I've heard that being on the bypass machine can change the chemical balance in the brain, causing depression.
I've never been able to find any information supporting this.
Thanks for your help.

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http://www.theheart.org/article/279563.do

One patient was a cardiologist himself and the level of depression shocked him. He knew patients went through it but he had no idea how bad it was until he experienced it for himself.

[ed34]

http://www.healthyplace.com/depression/main/causes-of-depression/menu-id-943/

More information about depression.