LaMarcus Aldridge retires: what's an irregular heartbeat & what other athletes have suffered from it?

Brooklyn Nets star LaMarcus Aldridge announced his retirement from NBA on Thursday in the wake of a health scare, having played against the Los Angeles Lakers last Saturday while dealing with an irregular heartbeat.

Aldridge suffers irregular-heartbeat symptoms during and after game

It what was just his fifth game with the Nets since signing a free-agent deal with the team, Aldridge, a seven-time NBA All-Star, played 23 minutes and scored 12 points in a loss to the Lakers but continued to feel worse after the game. He informed the Nets of his symptoms the next morning, and the team arranged medical assistance for him right away.

"It is time to put my health and my family first"

"Though I'm better now, what I felt with my heart that night was still one of the scariest things I've experienced," Aldridge, 35, said in a social-media post. "With that being said, I've made the difficult decision to retire from the NBA. For 15 years, I've put basketball first, and now, it is time to put my health and family first.

Aldridge, the No. 2 overall pick in the 2006 NBA Draft, became a free agent in late March after the San Antonio Spurs bought out the remainder of his $72 million contract. He immediately stepped into a starting role with the Nets, filling in for an injured Kevin Durant. Aldridge played for the Portland Trail Blazers between 2006 and 2015, before signing with the Spurs in July 2015.

"I'm thankful for everything this game has given me: the great memories, including all the ups and the downs, and the friendships I've made and will keep with me forever," Aldridge said. He concluded: "You never know when something will come to an end, so make sure you enjoy it everyday. I can truly say I did just that."

What is an irregular heartbeat?

Also known as an arrhythmia, an irregular heartbeat occurs when the heart beats either too slowly, too quickly or erratically. Per the American Heart Association, there are several types of arrhythmias, including atrial fibrillation - the most common kind - tachycardia, bradycardia and ventricular fibrillation.

Atrial fibrillation causes the heart to beat erratically and faster than normal, while sufferers of tachycardia experience a very fast heart rate. Bradycardia is a heart rate that’s too slow, and ventricular fibrillation - seen as the most serious form of arrhythmia - is a disorganised, rapid heartbeat that can lead to sudden cardiac arrest if not adequately treated.

According to the US Centers for Disease Control and Prevention, having atrial fibrillation increases a person’s risk of suffering a stroke four or five-fold, with the condition contributing to over 150,000 deaths per year in the country. In some cases, tachycardia and bradycardia can, like ventricular fibrillation, lead to cardiac arrest.

According to the UK's National Health Service, symptoms of arrhythmias include "palpitations, feeling dizzy, fainting and being short of breath".

More information about arrhythmias courtesy of the American Heart Association

What other sportspeople have suffered from arrhythmias?

NBA great Larry Bird was diagnosed with atrial fibrillation in 1995, three years after his retirement - having experienced symptoms during his playing career - while tennis legend Billie-Jean King was found to have the condition in 2015.

King, who won 12 grand slam titles between 1966 and 1974, revealed she first noticed signs that she had a heart issue after playing tennis with a friend. “[I] got out of the taxi, and I got really dizzy and I thought I was going to black out and I never get dizzy. I’ve never fainted,” she told FoxNews. “My heart was beating, I thought it was going to come out of my chest and I could tell it wasn’t regular.”

Other well-known sports figures to have been affected by an irregular heartbeat include retired tennis player Mardy Fish, who underwent surgery in 2012 after he was diagnosed with atrial fibrillation. In an interview with USA Today, Fish said he became aware of the problem when he began to be woken at night by extreme palpitations.

"It felt like my heart was going to jump out of my chest," he said. "During days, I'm totally fine. I can track it and work out fine. But every time I would go to bed my mind would start racing. Is this going to happen tonight? Is this going to be another night like that? It was super hard to go to sleep."