What is the deflection of the QRS complex like in leads I, II, III, aVL, aVF, V4 to V6?

What is the deflection of the QRS complex like in leads I, II, III, aVL, aVF, V4 to V6?

• A. Inverted
• B. Flat
• C. Upright
• D. Biphasic

Answer: (C)

The QRS complex represents ventricular depolarization on an electrocardiogram (EKG). In healthy individuals, the typical deflection of the QRS complex is upright in leads I, II, III, aVL, aVF, and V4 to V6. An upright QRS complex indicates a normal vector of depolarization moving through the heart, with the electrical activity predominantly moving downward and toward the left side of the heart, which corresponds with the standard lead placements in an EKG. Leads I and II pick up this downward and leftward activity effectively, showing a positive deflection. Similarly, aVL and aVF—as well as the precordial leads V4 to V6—also display an upright QRS complex due to the orientation of the heart and the positioning of the electrodes. An inverted QRS would suggest an abnormality in the conduction or position of the heart, and flat or biphasic deflections typically indicate either a technical error or pathology, such as ischemia or previous infarction. Therefore, the presence of an upright QRS complex in these leads is vital for interpreting a normal EKG and indicates that the electrical conduction system of the heart is functioning as expected.

The QRS complex represents ventricular depolarization on an electrocardiogram (EKG). In healthy individuals, the typical deflection of the QRS complex is upright in leads I, II, III, aVL, aVF, and V4 to V6. An upright QRS complex indicates a normal vector of depolarization moving through the heart, with the electrical activity predominantly moving downward and toward the left side of the heart, which corresponds with the standard lead placements in an EKG.

Leads I and II pick up this downward and leftward activity effectively, showing a positive deflection. Similarly, aVL and aVF—as well as the precordial leads V4 to V6—also display an upright QRS complex due to the orientation of the heart and the positioning of the electrodes. An inverted QRS would suggest an abnormality in the conduction or position of the heart, and flat or biphasic deflections typically indicate either a technical error or pathology, such as ischemia or previous infarction.

Therefore, the presence of an upright QRS complex in these leads is vital for interpreting a normal EKG and indicates that the electrical conduction system of the heart is functioning as expected.