When does the vulnerable period of a T wave occur?

When does the vulnerable period of a T wave occur?

• A. During the initial phase of the T wave
• B. The entire duration of the T wave
• C. The peak and second half of the T wave
• D. Only in the first half of the QRS complex

Answer: (C)

The vulnerable period of a T wave refers specifically to the phase when the heart is more susceptible to arrhythmias, particularly due to the potential for unidirectional block or reentry circuits. This period typically occurs during the peak of the T wave and extends into the latter part of the T wave.

During this time, the myocardial cells are transitioning from the relative refractory phase of repolarization, which is when they are still recovering, making them vulnerable to premature stimuli. If a strong enough electrical impulse occurs during this susceptible phase, it may trigger dangerous arrhythmias such as Torsades de Pointes or other ventricular tachycardias.

Thus, identifying that this vulnerable period is linked to the peak and the second half of the T wave highlights the significance of recognizing these intervals during EKG interpretation to assess the risk of arrhythmias effectively.