Match each of the following terms with its appropriate definition. drag the terms on the left to the appropriate blanks on the right to complete the sentences. view available hint(s) 1. an intracellular recording of electrical activity in either a contractile cell or autorhythmic cell is known as a(n) action potential. 2. lead is an electrode placement technique that uses three leads in order to record an electrocardiogram. 3. a two electrode pair constitutes a einthoven's triangle, which records the electrical activity of the heart. 4. an extracellular recording of electrical activity of both autorhythmic and contractile cells of the heart is known as a(n) electrocardiogram.