Which one of the following will decrease with an increase in ejection fraction?
**Question:** Which one of the following will decrease with an increase in ejection fraction?
A. Heart rate
B. Pulmonary capillary wedge pressure
C. Diastolic dysfunction
D. Systolic blood pressure
**Core Concept:**
Ejection fraction (EF) is a measure of the percentage of blood that is ejected from the left ventricle of the heart during a single heartbeat. EF is calculated by dividing the total volume of blood ejected by the left ventricle by the total volume of blood the ventricle is capable of ejecting. A higher EF indicates improved cardiac output and a more efficient heart.
**Why the Correct Answer is Right:**
When the ejection fraction increases, it indicates that the left ventricle is pumping more blood out of the heart with each contraction. This means the heart is working more efficiently, allowing it to deliver more oxygenated blood to the body's tissues. Consequently, the heart rate (option A) will typically decrease as the heart adapts to handle the increased workload.
**Why Each Wrong Option is Incorrect:**
B. Pulmonary capillary wedge pressure (PCWP) typically increases during left ventricular hypertrophy and heart failure, not decrease. So, increasing ejection fraction would not lead to a decrease in PCWP.
C. Diastolic dysfunction is a term used to describe impaired relaxation of the left ventricle during diastole, not related to ejection fraction. An increase in ejection fraction would not lead to an improvement in diastolic function.
D. Systolic blood pressure (SBP) is influenced by cardiac output, and a higher ejection fraction indicates improved cardiac output. Therefore, increasing ejection fraction would not lead to a decrease in SBP.
**Clinical Pearl:**
An increase in ejection fraction is a common finding in response to various medical interventions, such as beta-blockers or ACE inhibitors in patients with heart failure. This adaptive response is an essential part of the heart's self-regulation mechanism, aiming to maintain cardiac output and blood pressure within normal limits despite increased workload.
In conclusion, the correct answer (A) is due to the heart rate adjusting to accommodate the increased workload caused by the improved cardiac output and blood flow, as the heart works more efficiently.