I'd be cautious with the lidoderm patch b/c of the location of your pain, and lidocaine is an antiarrythmic drug.
Tramadol is indicated for chronic severe pain, but has no specific indication for neuropathic pain.
Lyrica and Neurontin ( gabapentin ) are used for neuropathic pain, with varying degrees of success.
There is another class of drugs, called tricyclic antidepressants, and these are commonly used for neuropathic pain. They do interact with some medications, so they might not be for you.
Another drug, Cymbalta, is commonly used for neuropathic pain, and does have an FDA indication for neuropathic pain associated with diabetic peripheral neuropathy.
Because of your heart condition, I would strongly urge you to discuss the use of lidoderm patch with your cardiologist.
If he advises against the lidoderm, your best bet would be to seek a referral to a pain management specialist. This is probably the most qualified MD to help you.
Good luck and let us know how it turns out.