Cardiac emergency or heart emergencies include: heart attack, sudden cardiac arrest,  an angina attack.  The two most cardiac emergencies are heart attack and cardiac arrest. 

Emergency treatment

Signs of cardiac arrest:

• Loss of responsiveness. Person does not move, speak, blink or react.
• No normal breathing. 

What to do:

My notes based on  Heart.org page on emergency treatment for cardiac arrest:

• Ensure the place is safe.
• Check for response.
• Shout for help. Call the emergency number (112)/ambulance number (108). 
• Ask someone to bring you an AED (automated external defibrillator)
• Check for no breathing or only gasping.
• Begin CPR (cardio pulmonary resuscitation) with compressions, 100 to 120 pushes a minute.  Allow the chest to come back up to its normal position after each push.
• Use an AED. Turn it on and follow the prompts.
• Continue CPR.

In a response on Twitter, Dr Deepak Krishnamurthy @DrDeepakKrishn1 said:

A tablet of aspirin- Crushed and dissolved in water and consumed can help to some extent.

On WhatsApp there are forwards that Sorbitrate could help.

But Dr Somalaram Venkatesh, @serioustaurean,  responded on Twitter:

No. In fact I advice patients NOT to take nitrates when heart attack is suspected.

Soluble or Dispersible Aspirin 350 mg is the medicine given as a first aid. Taking patient straight to a well equipped tertiary hospital is the other (Dr Deepak made a video on the ‘fire escape’)

He went on to explain that it is OK to take nitrates  under the guidance of a specialist:

On the other hand, Nitrates are advised as SOS medicine for patients with chest pain that comes with physical stress (“effort angina”). 

Patients with known coronary blocks who get chest pain at rest are asked to take nitrates under the tongue & reach hospital especially  if there is no relief.