What defines the sustained form of ventricular tachycardia (VT)?

Sustained ventricular tachycardia (VT) is defined as a form of tachycardia that lasts longer than 30 seconds, or as any VT that is associated with hemodynamic instability. When VT persists beyond this duration, it can lead to significant hemodynamic compromise because the heart may not have sufficient time to fill adequately between contractions, resulting in decreased cardiac output.

The correct definition aligns with the understanding that sustained VT can pose serious risks, including the potential for progression to ventricular fibrillation, especially if it occurs in patients with underlying heart disease. Recognizing this duration is crucial for healthcare professionals, as timely intervention is required to stabilize the patient's condition and mitigate the risks associated with prolonged tachycardia.

The other choices do not accurately represent sustained VT; for instance, less than 15 seconds is classified as non-sustained VT and does not typically elicit the same concerns for hemodynamic instability. Intermittent occurrences do not specifically define the sustained nature of the tachycardia, and the notion that it occurs exclusively in healthy individuals is misleading, as VT can occur in a variety of clinical settings, including in individuals with structural heart disease.