What condition signifies blockage in a pulmonary artery, which can lead to reversible cardiac arrest?

The condition that indicates a blockage in a pulmonary artery, leading to potential reversible cardiac arrest, is pulmonary embolism. This occurs when a blood clot or other material travels through the bloodstream and lodges itself in a pulmonary artery, obstructing blood flow to the lung. This reduction in blood flow can severely impair oxygenation and subsequently lead to cardiac arrest if not promptly treated.

Pulmonary embolism can cause sudden cardiac output reduction, resulting in signs of hypoxia or a drop in blood pressure. Immediate recognition and treatment are crucial, as rapid intervention can often reverse the cardiac arrest and lead to a better survival outcome. Therefore, it is vital to identify pulmonary embolism promptly in cases of unexplained cardiac arrest, especially in patients with risk factors such as recent surgery, long periods of immobilization, or active malignancies.