500
The chest electrodes located: at the level of the fifth intercostal space at midclavicular line; at the level of the fourth intercostal space to the right of the sternum; at the level of the fourth intercostal space to the left of the sternum; at the level of the fifth intercostal space at the left-anterior axillary line; at the level of the fifth intercostal space at the left-midaxillary line
What is V4, V1, V2, V5, V6