Related Clues:

• Pacemaker's place
• Shape carved on a tree, often
• Pressure around referee, initially, to give red card
• Symbol after 'I' on many a bumper sticker
• Cupid's target
• Tin Woodman's need
• Warmth gets right into the centre
• Organ with chambers
• The centre of Earth is molten
• Soul partner
• The Tin Man wanted one
• Earth-shattering at the centre
• Card obviously not concealed up one's sleeve
• Judge with little time for compassion
• Cardiac organ