What occurs to cardiac performance when vascular resistance increases significantly?

When vascular resistance increases significantly, cardiac output is typically decreased. This is due to the heart having to work harder to pump blood against the higher resistance in the vascular system. In the context of the Frank-Starling law of the heart, as the afterload (which is a measure of the resistance the heart must overcome to eject blood) increases, the heart's ability to eject blood efficiently diminishes.

When vascular resistance rises, the workload on the heart increases, and the muscle may not be able to generate sufficient force to maintain normal cardiac output. As a result, there can be decreased stroke volume, which directly impacts the overall cardiac output. Additionally, prolonged periods of increased vascular resistance can strain the heart, potentially leading to heart failure over time if the underlying cause is not addressed.

In contrast, options suggesting increased cardiac output or improved ejection fraction do not align with the physiological response of the heart under increased resistance conditions, as the heart struggles to maintain effective circulation.