“Your heart is pumping at only 30%.” For many families, that sentence on an echo report sounds like a verdict. Add blocked arteries to it, and they often hear a second one: “It is too risky to do anything.” The reality is more hopeful — and more nuanced — than either sentence suggests.

What does “ejection fraction” mean?

Each time your heart beats, the main pumping chamber (the left ventricle) pushes out a portion of the blood inside it. The ejection fraction is that portion, expressed as a percentage. It is measured with an echocardiogram (echo), cardiac MRI or a nuclear scan.

An EF of 30% does not mean “only 30% of your heart is working”. It means the heart is ejecting 30% of its blood volume per beat instead of the usual 55–70%. Many people with an EF of 30% live active lives with the right treatment.

Myth vs fact: weak heart and angioplasty

How blocked arteries weaken the heart muscle

Heart muscle needs a constant supply of oxygen-rich blood through the coronary arteries. When those arteries are blocked, the muscle can be affected in two ways:

Tests such as cardiac MRI, a PET scan or a dobutamine stress echo can help estimate how much of your heart muscle is alive and how much is scar. This is called a viability assessment, and it helps set realistic expectations.

Will opening the arteries make my weak heart stronger?

This is where honest advice matters most, because it is a common misconception.

For years, many doctors assumed that opening blocked arteries would automatically improve a weak heart. Two important studies tested this:

• STICH (bypass surgery): In patients with a weak heart (EF 35% or less) and blocked arteries, bypass surgery added to medicines improved long-term survival over about ten years compared with medicines alone.
• REVIVED-BCIS2 (angioplasty, 2022): In 700 patients with stable disease and a mean EF of 27%, angioplasty added to excellent medical therapy did not reduce deaths or heart-failure hospitalisations over about three and a half years, and EF did not improve more than with medicines alone. Repeat urgent procedures, however, were lower with angioplasty.

Medicines: the treatment everyone with a weak heart needs

Today’s guideline-directed medicines for heart failure with reduced EF are one of the great success stories of cardiology. They usually include four groups:

1. ARNI (sacubitril-valsartan), ACE inhibitor or ARB — reduce strain on the heart.
2. Beta-blockers (such as metoprolol succinate, bisoprolol, carvedilol) — protect the heart from stress hormones.
3. MRAs (spironolactone or eplerenone) — reduce scarring and fluid.
4. SGLT2 inhibitors (dapagliflozin or empagliflozin) — benefit the heart and kidneys, with or without diabetes.

Some patients also benefit from devices such as an ICD (to prevent sudden cardiac death) or CRT (a special pacemaker that coordinates the heart’s pumping). Never start or stop these medicines on your own — doses are increased gradually under supervision.

Why angioplasty is riskier when the heart is weak

During angioplasty, a balloon is briefly inflated inside the blocked artery. In a normal heart, the rest of the muscle easily compensates for those few seconds. In a heart that is already pumping weakly — especially when the artery being treated supplies a large area, or is the “last remaining” open artery — even a brief interruption can cause:

• A sudden drop in blood pressure
• Dangerous heart rhythm disturbances
• Fluid build-up in the lungs

This is why such cases fall under complex high-risk angioplasty (CHIP PCI) and need a team experienced in planning for — and preventing — these situations.

Protected PCI: support from a temporary heart pump

In carefully selected high-risk patients, the heart can be supported during the procedure with a mechanical device:

• Impella — a tiny pump, thinner than a pencil, placed through an artery in the groin into the heart. It pulls blood from the left ventricle and pushes it into the aorta, keeping circulation steady while the arteries are treated. It is usually removed at the end of the procedure.
• Intra-aortic balloon pump (IABP) — a balloon in the aorta that inflates and deflates with each heartbeat to reduce the heart’s workload.
• ECMO — a heart-lung support machine reserved for the very highest-risk or emergency situations.

Mechanical support is not needed for every patient with a low EF, and it carries its own risks, such as bleeding or problems at the leg artery. Research, including the ongoing international PROTECT IV trial, is still defining exactly which patients benefit most. The decision is individual, made after reviewing the angiogram, heart function, blood pressure and leg arteries.

Learn more in our article on advanced angioplasty when heart surgery is too risky.

Who may benefit from angioplasty despite a weak heart?

What to expect if protected angioplasty is planned

1. Evaluation: echo, angiogram review, kidney tests and often a viability test or CT of the leg arteries.
2. Heart Team decision: cardiologist and, when relevant, a cardiac surgeon agree on the safest strategy.
3. The procedure: usually under local anaesthesia with sedation; imaging (IVUS/OCT) is used to optimise stents.
4. Recovery: a day or two of monitoring in the cardiac care unit, followed by a short hospital stay.
5. Follow-up: medicines are optimised, and a repeat echo is typically done after about three months.

Frequently asked questions