Which chest lead placement is at the 5th intercostal space along the midaxillary line?

• A. V4 placement
• B. V6 placement
• C. V5 placement
• D. V3 placement

Answer: (B)

Chest precordial leads sit on the left chest along specific horizontal levels. The 5th intercostal space is the level, and the line you place the electrode on determines the exact lead. V6 is placed at the 5th intercostal space along the midaxillary line, which runs down the side of the chest near the armpit. This position gives a lateral view of the heart, mainly reflecting left ventricular activity. V4 sits at the same level but along the midclavicular line, and V5 sits along the anterior axillary line. V3 is between V2 and V4. So the lead at the 5th intercostal space on the midaxillary line corresponds to V6.