Narrative:

Going through about FL200 flight attendant informed me of a passenger at seat X was experiencing heart problems. I asked for more information. At about FL260 she called back and said that the passenger at seat X was experiencing heart problems and nausea and hypertension. There was a paramedic in seat Y; who immediately realized the urgency of the situation. I declared a medical emergency with ZZZ control and ask to return to ZZZ and have paramedics meet the flight upon landing. Passenger was deplaned in ZZZ.

Google
 

Original NASA ASRS Text

Title: A320 FLT CREW HAS A PAX MEDICAL EMER DURING DEP DIVERTS FOR LNDG.

Narrative: GOING THROUGH ABOUT FL200 FLT ATTENDANT INFORMED ME OF A PAX AT SEAT X WAS EXPERIENCING HEART PROBS. I ASKED FOR MORE INFO. AT ABOUT FL260 SHE CALLED BACK AND SAID THAT THE PAX AT SEAT X WAS EXPERIENCING HEART PROBS AND NAUSEA AND HYPERTENSION. THERE WAS A PARAMEDIC IN SEAT Y; WHO IMMEDIATELY REALIZED THE URGENCY OF THE SITUATION. I DECLARED A MEDICAL EMER WITH ZZZ CTL AND ASK TO RETURN TO ZZZ AND HAVE PARAMEDICS MEET THE FLT UPON LNDG. PAX WAS DEPLANED IN ZZZ.

Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.