There are a few clear signs

The actor, producer and musician, starred in the popular teen series Saved By The Bell in the early ‘90s and soap opera Days Of Our Lives.

While there is no official cause of death yet, Muldoon died of a heart attack, it has been reported.

The late actor was described as “stylish, charismatic, and full of life”, with a friend adding that he “embraced each day with a full-tilt, rock ’n’ roll spirit.”

Born in California, Muldoon started his career in the early 90s, and made his TV debut that same year by appearing in two episodes of popular sitcom Who’s The Boss, before landing a small part in Saved By The Bell as Jeff, alongside Mark-Paul Gosselaar, Mario Lopez, Dustin Diamond and Tiffani-Amber Thiessen.

However, in 1992 he was given one of the biggest roles of his career as Austin Reed in Days Of Our Lives.

One of his more famous roles on the big screen is that in the cult sci-fi film Starship Troopers, in which he appeared alongside ex-girlfriend Denise Richards.

He is survived by his partner, Miriam Rothbart and his parents, Deanna and Patrick Muldoon Sr.

A heart attack, which the late actor reportedly suffered, is a life-threatening emergency, also known as a myocardial infarction, which requires speedy medical intervention for the best chances of survival.

What causes heart attacks?

According to the NHS, heart attacks occur when the supply of blood to the heart is blocked, usually by a blood clot.

The people at a higher risk of experiencing a heart attack are those who smoke, have high blood pressure or cholesterol, are overweight or obese, suffer from diabetes or have a close relative who's experienced one.

Signs and symptoms of a heart attack to look out for:

- Chest pain which may feel like crushing or squeezing on your chest - the pain may also spread to your arm, neck and jaw
- Feeling short of breath
- Feeling sick (nausea) or being sick (vomiting)
- Feeling like you have indigestion – you may have a burning feeling in your chest and feel full or bloated
- Sweating
- Pale, blue or grey skin – on black or brown skin this may be easier to see on the palms of the hands

According to the British Heart Foundation (BHF), symptoms can “vary from person to person”.

It adds that “it's possible to have a heart attack without experiencing all these symptoms, and it’s important to remember everyone experiences pain differently”.

The UK cardiovascular research charity says that “quick treatment to get the blood flowing to your heart muscle again is important”, as this can reduce the amount of permanent damage to your heart and save your life.