Berita Tren Hari Ini: Schoolgirl, 17, so worried about detention after sneaking out of school to buy food she collapsed with a HEART ATTACK

Ticking time bomb: Tabatha McElligott's undiagnosed heart condition was triggered when a teacher shouted at her

A diligent schoolgirl became so worried about being given her first-ever detention she collapsed and suffered a heart attack.

Sixth-form student Tabatha McElligott, then 17, had slipped out of school during a free lesson to go and buy some snacks with her friend.

But when the group were caught by a teacher, Tabatha panicked so much she collapsed - and an undiagnosed heart condition triggered a massive cardiac arrest.

Teachers dialled 999 - and an emergency first aider restarted her heart in the playground with a defibrillator, before rushing the teen to hospital last July.

Medics realised Tabatha, now 19, had been living with a deadly heart condition since she was a baby - which could have killed her at any time.

But after major surgery, she is now able to lead a normal life - and has trained as an emergency first aider.

Tabatha, from Leigh-on-Sea, Essex, said: 'I was stunned when I was told I'd had a heart attack - I was only 17.

'In my mind, heart attacks were something that overweight middle-aged men worried about - not something that happened to active teenagers like me.

'I'd never really been in trouble at school, so I was mortified when we started getting shouted at, and my heart obviously couldn't cope with it.

'I know now that my heart was basically a ticking time bomb waiting to go off.'

Tabatha and her best friend Catherine Newton, 17, had sneaked out of school to go and treat themselves to some chocolate from the supermarket - but were caught out by teachers when the school fire alarm was triggered.

Conscientious Tabatha said: 'We knew it was against the school rules, but we never thought anyone would miss us for a few minutes.

'We were on the way back to school when we heard the fire bell ringing - and we ran back.

'When we got to the gates, I could hear my teacher calling my name, and my heart started hammering.

'She began to tell us off, but my heart just kept beating harder and harder, and her voice sounded really distant.

'I felt my legs turning to jelly, and then everything went black.'

Lucky escape: The schoolgirl's condition causes her body to pump blood around her heart the wrong wa

Her hero: Tabatha with paramedic Steve Hockley who restarted her heart in the school playground. She still bears a severe scar from the incident

ANOMALOUS LEFT CORONARY ARTERY FROM THE PULMONARY ARTERY (ALCAPA)

Cathy Ross, senior cardiac nurse at the British Heart Foundation, said: 'ALCAPA is a very rare condition some people are born with where the left coronary artery that usually carries oxygen-rich blood from the aorta to a large portion of the heart muscle, is connected to the pulmonary artery instead.

'The pulmonary artery carries deoxygenated blood meaning the left side of the heart receives much less oxygen than it needs to be able function properly often resulting in a heart attack or leading to heart failure.

'Most people with this condition are diagnosed at birth, so it's incredibly rare to survive until your teenage years without knowing about it.'

Trained emergency responder Steve Hockley was on the scene within three minutes and restarted the schoolgirl's heart in the playground within minutes.

She was rushed to Southend Hospital, where doctors were baffled as to what had caused her condition.

Tabatha was transferred to University College London Heart Hospital, where heart experts told her she was suffering from a rare heart condition called Anomalous Left Coronary Artery from the Pulmonary Artery (ALCAPA).

The condition causes her body to pump blood around her heart the wrong way - and doctors warned that only 10 per cent of people who have alcapa survive if they are not diagnosed by their first birthday.

The schoolgirl was given open heart surgery and now survives on a cocktail of medicine to keep her heart pumping: 'I discovered I could have dropped dead at any moment,' she said.

'I have to take a daily beta blocker to slow down my heart rate, and aspirin to thin my blood, but apart from that, I'm able to lead a normal life.'

Panic: Tabatha McElligott was so 'mortified' at being scolded for sneaking out that she felt her 'legs turn to jelly' and she collapsed. dailymail.co.uk