Meghan Markle's Dad Thomas to Undergo Heart Surgery and Can't Attend Wedding

Thomas Markle is not going to walk his daughter, Meghan, down the aisle Saturday, nor will he travel to England, because we've learned he's dealing with something far more serious ... major surgery.

Thomas tells TMZ, he will go into surgery at 7:30 AM Wednesday. He tells us, "They [doctors] will go in and clear blockage, repair damage and put a stent where it is needed."

TMZ broke the story, Thomas had a heart attack a week ago and began having chest pains Monday. He checked himself into the hospital Tuesday and a battery of tests determined he needed surgery. Thomas said the heart attack did significant damage.

As we reported, he had decided Monday not to attend the wedding because he felt he had embarrassed Meghan and the Royal Family by staging a photo op with a paparazzi agency. Thomas' daughter, Samantha, tells us he received only $1,500 in payment plus a small percentage of the royalties.

Thomas had a change of heart Tuesday ... after receiving texts from Meghan saying she loved him and was concerned for his health. He told us he hoped he could get out of the hospital and travel to England to walk Meghan down the aisle, but now he realizes it's all but impossible given the upcoming surgery.