What indicates a split S2 heart sound on an EKG?

What indicates a split S2 heart sound on an EKG?

• A. Normal conduction
• B. Heart block
• C. Increased intrathoracic pressure
• D. Right and left ventricular systole occurring at slightly different times

Answer: (D)

A split S2 heart sound is characterized by the closure of the aortic valve (A2) and the closure of the pulmonic valve (P2) occurring at slightly different times. This is typically seen during normal physiological conditions, especially during inspiration when increased venous return to the right side of the heart leads to a slight delay in the closure of the pulmonic valve compared to the aortic valve. The physiological mechanism behind this involves the timing of right and left ventricular systole, where the right ventricle experiences a longer ejection time due to increased blood return during respiration.

Understanding the dynamics of the heart’s chambers and the timing of valve closures is crucial in interpreting EKG readings associated with heart sounds. The identification of split S2 is important in clinical practice as it can provide insights into the functioning of the heart and the conduction pathways involved during different phases of the cardiac cycle.