in the fourth intercostal space to the left of the sternum
in the fourth intercostal space to the right of the sternum
Number 1 is correct.
The V5 lead should be placed in the left midaxillary line. The V4 lead is placed in the fifth intercostal right midclavicular line. The V2 lead is placed in the fourth intercostal space to the left of the sternum. The V1 lead is placed in the fourth intercostal space to the right of the sternum.
