If Your Heart Could Speak

Artist: Malika Kumar, UCLA David Geffen School of Medicine, Department of Human Genetics

An EKG (from the German “elektrokardiogramm”, meaning “electrical heart log”) is a tool that people use to monitor and understand heart activity. Each heartbeat is initiated by electrical signals from one part of the heart to the other, and the EKG records these signals by noting:

  • the direction across the heart of the electrical impulse (graphed as the line going up or going down)
  • the magnitude (graphed as the height of the peak or curve. The vertical dimension refers to voltage)
  • when it’s happening (graphed as position along the horizontal axis of each peak or curve)

Each normal heartbeat consists of what looks like three parts:

  •  a low rounded curve, which is the signal for the upper part of the heart (right and left atria) to contract
  • a high, sharp peak and dip, signaling the lower part (ventricles) to contract while the atria relax
  • another rounded curve, signaling the ventricles to relax

To analyze an EKG, one compares the reading to a normal or standard EKG. Are the peaks too high or low, or too far apart? Too close together? Do each of the segments look normal, or is one part of the heartbeat signal (the top contracting, the bottom contracting, or the reset) occurring abnormally? Does the pattern look like heartbeats or frantic electrical signaling? What can we gather from putting together this information?