What is the effect of cardiac ischemia on the heart?

Cardiac ischemia occurs when there is a reduction in blood flow to the heart muscle, which leads to a deficiency in oxygen supply. This insufficient blood flow can be caused by various factors, such as blockages in the coronary arteries due to plaque buildup or spasm. As the heart muscle does not receive enough oxygen, it can lead to symptoms such as chest pain, known as angina, and may result in damage to the heart tissue if the ischemia is prolonged.

In contrast, the other statements suggest scenarios that do not accurately describe the physiological effects of ischemia. Increased oxygen supply would imply an improvement or restoration of blood flow, which is contrary to the definition of ischemia. Normal blood flow indicates that the heart is receiving adequate oxygen, which is not the case during ischemia. A decreased heart rate does not directly stem from ischemia; while heart rate can vary based on many factors, ischemia is primarily characterized by reduced blood flow rather than changes in heart rate alone. Therefore, the correct understanding of cardiac ischemia is that it specifically results in decreased blood flow to the heart.