Glossary of terms Atria- Top chambers of the heart Arrhythmia- An abnormal heart rhythm  Bradycardia – A slow heart rate, normally less than 60 beats per minute. Cardiac Arrest- When the heart is unable to pump blood around the body due to an abnormal heart rhythm.  Defibrillation- The use of a shock to stop fast heart rhythms. Heart Attack – Occurs … Continue reading Internal Cardiac Defibrillator (ICD)