Source : Webster's Revised Unabridged Dictionary (1913)

Cardiogram \Car"di*o*gram`\, n. [Gr. ? heart + -gram.]
   (Physiol.)
   The curve or tracing made by a cardiograph.

Source : WordNet®

cardiogram
     n : a graphical recording of the cardiac cycle produced by an
         electrocardiograph [syn: {electrocardiogram}, {EKG}, {ECG}]