What criteria can lead to termination of exercise due to ventricular ectopy?

The termination of exercise due to ventricular ectopy is primarily focused on specific and potentially serious arrhythmias that can indicate a higher risk for complications. When considering the criteria leading to the cessation of exercise, sustained ventricular tachycardia and multifocal PVCs are significant because they suggest a level of cardiac instability that warrants concern.

Sustained ventricular tachycardia is a rapid heart rate that can compromise cardiac output and lead to decreased perfusion of vital organs. Multifocal premature ventricular contractions (PVCs) indicate that there are multiple irritable foci within the ventricles leading to abnormal heartbeats, which could be symptomatic of underlying heart disease. When these two factors occur, they signal a potential for arrhythmic events that could be harmful to the patient during exercise.

The other options do not present the same level of risk for immediate cardiac issues during exercise. An increased heart rate can be a normal physiological response to exercise and does not, by itself, necessitate stopping the activity. Similarly, patient complaints of fatigue may relate to various reasons not directly tied to life-threatening arrhythmias, and abnormal blood pressure changes are important but can often be managed without terminating exercise unless they are marked or accompanied by other serious symptoms. Therefore, the