Your Heart At Work

All of the parts of your heart, like the chambers and valves, work together to ensure that blood always flows on the same path on its way through your heart and lungs.

Blood flows through each chamber one time on its way through your heart – first through the right side of your heart and then through the left.

During a single heartbeat (one "lubb-dubb"), the chambers contract and relax, the valves open and close, and blood flows through. This sequence of events is called the cardiac cycle.

Your heart pumps a little more than half of the blood volume with each beat. This is called your ejection fraction (EF); the EF is the percentage of blood pumped out of the left ventricle with every heartbeat.

• A normal EF is 50% or higher. For example, an EF of 55% means that 55% of the total amount of blood in the left ventricle is pumped out with each heartbeat.
• A lower than normal EF, less than 40%, indicates that the left ventricle is weakened.^¹
• Importantly, if your EF is 35% or less, you are at a higher risk of experiencing life-threatening irregular heartbeats that can cause sudden cardiac arrest and sudden cardiac death.¹

Ejection Fraction - Watch the Video - 00:15

Play the animation to see the cardiac cycle in action. You'll see blood flow plus the movement of the heart's chambers and valves.

You can click the Step Through button repeatedly to see the animation play one step at a time.

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