Thee heart

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Across
  1. 1. Inferior vena ______
  2. 3. A-V tricuspid _______
  3. 4. The node that is the natural Pacemaker
  4. 7. Two bottom chambers of the heart
  5. 8. Coronary _____
Down
  1. 1. The QRS ______
  2. 2. The valve between the upper and lower chambers
  3. 5. The deoxygenated blood first enters the Left ____
  4. 6. Purkinje __________