Premature ventricular contractions are often triggered by which factors?

Premature ventricular contractions are often triggered by which factors?

• A. Stress or stimulants
• B. Regular, orderly sleep
• C. High potassium diet
• D. Exercising in cool weather

Answer: (A)

Premature ventricular contractions happen when ventricular tissue becomes irritable and fires an extra beat. This irritability is often driven by increased sympathetic activity and substances that stimulate the heart. Stress raises catecholamines, boosting automaticity in ventricular cells and making an ectopic focus fire earlier than normal. Stimulants such as caffeine, nicotine, cocaine, and amphetamines similarly raise sympathetic drive and calcium handling in heart cells, increasing the chance of a PVC. Regular sleep tends to calm autonomic fluctuations, so it doesn’t typically provoke PVCs. A high potassium diet isn’t a usual trigger (in fact, electrolyte imbalances—often low potassium—are more linked to ectopy). Exercising in cool weather isn’t a recognized specific trigger, though physical activity can provoke PVCs in some individuals due to general sympathetic and metabolic effects. Thus, stress and stimulants best explain why PVCs occur.

Premature ventricular contractions happen when ventricular tissue becomes irritable and fires an extra beat. This irritability is often driven by increased sympathetic activity and substances that stimulate the heart. Stress raises catecholamines, boosting automaticity in ventricular cells and making an ectopic focus fire earlier than normal. Stimulants such as caffeine, nicotine, cocaine, and amphetamines similarly raise sympathetic drive and calcium handling in heart cells, increasing the chance of a PVC.

Regular sleep tends to calm autonomic fluctuations, so it doesn’t typically provoke PVCs. A high potassium diet isn’t a usual trigger (in fact, electrolyte imbalances—often low potassium—are more linked to ectopy). Exercising in cool weather isn’t a recognized specific trigger, though physical activity can provoke PVCs in some individuals due to general sympathetic and metabolic effects. Thus, stress and stimulants best explain why PVCs occur.