Swinging Heart Sign
Swinging Heart Sign
 “swinging heart” sign is a medical finding observed on an echocardiogram when the heart sways back and forth within a large pericardial effusion. This exaggerated, pendulum-like motion is caused by the heart being suspended in a large amount of fluid inside the pericardial sac. The sign is often seen in cases of severe fluid accumulation, which can lead to the life-threatening condition of cardiac tamponade.
The pericardium is a double-layered sac that surrounds and protects the heart, normally containing a small amount of lubricating fluid. In a pericardial effusion, excess fluid builds up in this space, putting pressure on the heart.
- Pendulum motion: With a significant amount of extra fluid, the heart—which is attached at the top by the great vessels—is no longer held firmly in place by the pericardium. Instead, it swings freely like a pendulum, displacing itself with every beat.
- Electrical alternans: The heart’s swinging motion is often reflected on an electrocardiogram (ECG), where it produces a classic finding called electrical alternans.
- This is a beat-to-beat change in the height, or amplitude, of the QRS complex.
- The change happens because the heart is moving relative to the ECG electrodes on the chest. The electrical signal appears stronger when the heart is closer to the chest wall and weaker when it swings away.
Medical significance
The “swinging heart” is a key indicator of a large pericardial effusion, which can lead to cardiac tamponade.
- Cardiac Tamponade: This is a medical emergency that occurs when the pressure from the fluid buildup becomes so great that it compresses the heart. The chambers are prevented from fully expanding and filling with blood, leading to dangerously low blood pressure (hypotension) and reduced blood flow to the body.
- Prompt Diagnosis and Treatment: Seeing the swinging heart sign on an echocardiogram is a critical finding that signals the need for immediate medical attention. Treatment typically involves a pericardiocentesis, a procedure to drain the excess fluid and relieve pressure on the heart.
What is the “Swinging Heart” Phenomenon?
- It describes the heart’s pendular motion within an abnormally large pericardial sac filled with fluid.
- This excessive fluid allows the heart to swing more freely, changing its axis relative to the recording electrodes with each beat.
- It is often seen in cases of cardiac tamponade, a severe complication of pericardial effusion where excess fluid compresses the heart.
What is Electrical Alternans?
- Electrical alternans: is the ECG finding of alternating amplitudes of the QRS complexes from one beat to the next.
- It can also manifest as a variation in the QRS axis or a wandering baseline.
- The “swinging heart” phenomenon is a primary cause of electrical alternans due to the changing distance between the heart and the electrodes.
