AP & AA Defibrillation

Note that during AA (antero-apical) defibrillation, the positive "apex" paddle should be located at the left 8-10th intercostal area at the anterior or mid axillary line to ensure that energy passes through the left ventrical. The "Critical Mass theory" says that you must depolarize >75% of the LV myocardium to achieve successful defibrillation.