The Beatles legend, who is currently embroiled in a bitter divorce battle with Heather Mills, is said to have recovered well after undergoing a coronary angioplasty at a private London hospital last autumn.
A source said: "Paul felt there was something not quite right and luckily sought some professional help."
"It's not something that can be left to chance. Thankfully the operation went well and Paul feels great."
The operation, which opens up arteries to increase the flow of blood, was performed after Paul, 65, saw a Harley Street specialist at the London Clinic.
The procedure involves surgeons passing a small tube through the groin to the aorta.
A tiny balloon at the tip of the tube is inflated to crush fatty deposits clogging the arteries, allowing blood to flow freely.
A stent - a short wire mesh tube - is often left in the artery to keep it open.
Paul's spokesman said: "It was a routine medical operation."
Next month, Paul and Heather will attend a five-day High Court hearing in a bid to finally agree on a divorce settlement.
Heather, 39, is set to be awarded more than $60 million following a four-year marriage to the musician.
