✨ Ejection Fraction (EF) and Cardiomyopathy (CM)
⛽ Definition
The heart’s ejection fraction (EF or LVEF) is the estimated percentage of blood pumped out of the heart’s last chamber—the left ventricle—with each heartbeat to deliver oxygen and nutrients to the body and organs.
We measure EF by looking at how much blood fills the left ventricle between beats and how much of that blood is pushed out with each contraction.
A normal EF falls between 50–70%.
EF can be estimated or measured using a variety of imaging tests (such as echocardiograms, MRIs, or nuclear scans) and methods of calculation. As a result, some variation between tests is normal, depending on the technique and conditions under which the measurement is taken.
🏗️ How EF Becomes Reduced: The Remodeling Process
Changes leading to a low EF rarely happen overnight. Instead, the heart remodels over time—gradually adapting to ongoing injury, strain, or abnormal conditions.
Three main pathways by which the heart can remodel and develop a reduced EF include:
🌌 1. Ischemic Cardiomyopathy
Caused by reduced or restricted blood flow (ischemia) leading to tissue death (myocardial infarction or heart attack).
The damaged areas eventually scar over.
The heart adapts to the scar tissue and any remaining bottlenecks or blockages.
Adaptation helps—but it never functions as well as healthy heart muscle, ultimately leading to decreased pumping efficiency over time.
This is where areas of the heart had reduced or restricted blood flow to the point it caused heart tissue on the other side of the blockage/restriction to die (a heart attack), which over time will then turn into scar tissue. The heart adapts to this damage and the resulting restriction from the scar tissue (like many things in like, this doesn’t work as well as the original) and whatever bottlenecks, blockages, or restricted blood flow there may be, but this adaptation results in reduced function.
🌐 2. Non-Ischemic Cardiomyopathy
Not caused by blocked blood flow.
Can develop in response to:
Structural abnormalities present from birth
Genetic mutations (e.g., in proteins critical for muscle contraction)
Hormonal imbalances
Medication or substance toxicity (e.g., alcohol, chemotherapy)
Metabolic or infiltrative diseases (e.g., hemochromatosis, sarcoidosis)
Sometimes, despite extensive evaluation, no clear cause is found.
where it’s adapted to a longstanding structural issue, a genetic thing, hormone, drug, deposits, demands, or we just don’t know why.
⏩ 3. Tachycardia-Induced Cardiomyopathy
Caused by the heart running too fast for too long (sustained high heart rates).
Examples include atrial fibrillation with rapid ventricular response (AF with RVR) or supraventricular tachycardia (SVT).
Persistent rapid heart rates force the heart to adapt, but this compensation weakens it over time, lowering EF.
This should get it’s own acknowledgement, like a longstanding AF w/ RVR, or SVT that has ran the heart too fast for too long and it has adapted in response
🔍 Special Types of Cardiomyopathy to Recognize
In addition to the main paths above, several specific conditions deserve mention:
🧬Amyloid Cardiomyopathy
A complex, infiltrative disease where misfolded proteins (amyloid) deposit into the heart muscle.
These deposits stiffen and thicken the heart walls, interfering with normal function.
Amyloid is a whole wormhole. It’s a condition where broken bits of malformed protein get stuck in the muscle tissue and over time these fragments build up to cause problems.
🐙 Takotsubo Cardiomyopathy (Stress Cardiomyopathy)
Often triggered by severe emotional or physical stress.
Causes ballooning of the left ventricle, taking on a shape resembling a Japanese “takotsubo” octopus trap.
Typically reversible once the stressor resolves.
Takotsubo Cardiomyopathy is a stress or hormone induced rapid ballooning of the LV, to where it’s shape on an echo is similar to a Takotsubo octopus trap.
💪 Hypertrophic Cardiomyopathy (HCM)
A mostly genetic disorder causing abnormal thickening of the heart muscle.
Can obstruct blood flow out of the heart and cause arrhythmias or sudden cardiac death, especially in younger individuals.
Hypertrophic Cardiomyopathy (HCM) is often caused by a genetic condition.
✨ Mixed Cardiomyopathy
Some patients have features of multiple types of cardiomyopathy (e.g., ischemic injury plus a genetic predisposition).
Treatment strategies often need to address all contributing factors.
A little of one, a little of the other
🔮 Final Thoughts
Ejection fraction offers a critical window into how well the heart is working—but it’s just one piece of the overall picture.
Understanding what has caused the EF to fall helps guide treatment plans, expectations for recovery, and long-term management strategies.
