Northern Chique
To have a chardiogram is to have an ultrasound machine monitor and record your hearts function. It looks for holes' in the heart in babies and children.
As for grown ups, It will confirm or dismiss the results of an 12 lead ECG that indicates an abnormal rythum.
If a chardiogram is required you are possibly in a bit of trouble as the results need to be intrupreted by a chardiologist, or you should maybe look for a new GP who can read ECG's
Cheers
Leatherdog