Understanding Premature Ventricular Contractions (PVCs)
Premature ventricular contractions (PVCs) are a type of abnormal heartbeat (arrhythmia). They are very common. They can occur in people of all ages from time to time. They usually cause only mild symptoms.
How PVCs happen
Your heart has 4 chambers: 2 upper atria and 2 lower ventricles. Normally, a special group of cells begins the signal to start your heartbeat. These cells are in the sinoatrial (SA) node in the right atrium. The signal quickly travels down your heart’s conducting system. It travels to the left and right ventricle. As it travels, the signal triggers nearby parts of your heart to contract. This allows your heart to squeeze in a coordinated way.
During a premature ventricular contraction, the signal to start your heartbeat instead comes from one of the ventricles. This signal is premature, meaning it happens before the SA node has had a chance to fire. The signal spreads through the rest of your heart, causing a heartbeat. If this happens very soon after the previous heartbeat, your heart will push out very little blood. This causes a feeling of a pause between beats. If it happens a little later, your heart pushes out an almost normal amount of blood. This leads to a feeling of an extra heartbeat. So, the heart has a “premature” heartbeat in between normal heartbeats.
What causes PVCs?
Certain things can help set off a premature signal in the ventricles. These include:
Reduced blood flow to your heart
Scarring after a heart attack (myocardial infarction)
Electrolyte problems, such as low sodium or potassium levels
Increased adrenaline, such as with anxiety
Certain medicines, like digoxin
Many heart conditions raise the risk for PVCs. These include:
They often happen in people without any heart disease. However, PVCs are somewhat more common in people with some kind of heart disease.
Symptoms of PVCs
Most people with occasional PVCs don’t have symptoms. You are also more likely to have symptoms if you have PVCs often. When symptoms do happen, they are usually minor. Symptoms may include:
An awareness of the heart beating
A fluttering or flip-flop feeling in your chest
Feeling of a “skipped” or “extra” heartbeat
Dizziness and near-fainting
A pulsing sensation in the neck
PVCs may cause more severe symptoms if you have another heart problem, such as heart failure.
Your healthcare provider will ask about your health history and give you a physical exam. An electrocardiogram (ECG) is the main test for diagnosis. This test allows your provider to look at the signal of your heartbeat for a brief time. Any PVCs that occur during this time will show up on the ECG. In some cases, your healthcare provider might advise ECG monitoring over a day or more, up to 30 days. This can help to catch PVCs that don’t happen often. This is done with a monitor you wear night and day for the test period.
These may be the only tests your healthcare provider will need. You may need more testing if you have PVCs often, or many in a row. Your provider may look at other causes, including possible heart problems. These tests might include:
Echocardiography, to look at your heart’s structure and function
Cardiac stress testing, to see how your heart responds to exercise and to evaluate blood flow through your heart
Blood tests, to check potassium and thyroid levels