Premature ventricular contractions (PVCs) are a type of abnormal heartbeat. Your heart has four chambers: two upper atria and two lower ventricles. Normally, a special group of cells start the signal for your heartbeat. These cells are in the sinoatrial (SA) node in the right atrium. The signal quickly moves 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.

With a PVC, the signal to start your heartbeat comes from one of the ventricles instead. 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 and can cause a heartbeat that is different than normal. Depending on when the premature beat happens, you may feel nothing at all, a skipped heartbeat, lightheaded, short of breath, or even chest pain.

PVCs that happen only once in a while are common in people of all ages, but they're more common in older people. PVCs can happen in people without any heart disease, but they're more common in people with some kind of heart disease. PVCs rarely cause problems unless they occur again and again over a long period of time. In such cases, they can lead to a PVC-induced cardiomyopathy, or a weakening of the heart muscle from too many PVCs. Most often, this can go away once the PVCs are treated.

Certain things can help set off a premature signal in the ventricles, such as:

• Reduced blood flow to your heart for any reason
• Acute heart attack (myocardial infarction)
• Cardiomyopathy
• Heart failure
• Electrolyte problems, such as low magnesium or potassium levels
• Increased adrenaline, such as from stress or anxiety
• Some medicines
• Alcohol and illegal drugs

Many heart conditions increase the risk for PVCs. These include:

• High blood pressure
• Heart attack
• Coronary heart disease
• Dilated cardiomyopathy
• Hypertrophic cardiomyopathy
• Congenital heart disease
• Heart failure

Most people with occasional PVCs don't have symptoms. When symptoms do happen, they're usually minor. Sometimes PVCs cause an unpleasant awareness of the heartbeat (palpitations). Some people may describe feeling a skipped or extra heartbeat. Dizziness, near-fainting, anxiety, and a pounding sensation in the neck are other possible symptoms.

Generally, PVCs cause dangerous symptoms only if the person has another heart problem. For example, they might happen in someone whose ventricle already squeezes poorly. So if you have heart failure, you may notice more symptoms, like shortness of breath. You may also be more likely to have symptoms the more PVCs you have.

Your doctor will ask about your health history and give you a physical exam. An irregular heartbeat may be heard when the doctor listens to your heart with a stethoscope. An electrocardiogram (ECG) may be done. This is usually the first test for diagnosis. This test lets your doctor see the signal of your heartbeat as it moves through the heart during a short amount of time. If you have any PVCs while the ECG is being done, they will show up on the ECG. In some cases, your doctor might advise ECG monitoring over 1 or 2 days. But they may advise up to 30 days. This can be done with Holter monitors or other types of heart monitors. This can help to catch PVCs that don't happen often.

These may be the only tests your doctor will need. You may need more testing if you have PVCs often, or many in a row. Your doctor may do some testing to look for other causes, including potential heart problems. These tests might include:

• Echocardiography to evaluate heart 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 hormone levels

Most often, PVCs that happen only once in a while don't need any treatment. If you have another problem with your heart that is treated, your PVCs may decrease. For example, you might take a medicine to lower your blood pressure or lower your heart rate. This may lower how often you have PVCs.

In some cases, specific treatment may be done to help prevent PVCs. These are used only if you have symptoms from PVCs or if there is concern that the PVCs are frequent enough to be damaging your heart. Choices include:

• Beta-blockers or calcium channel blockers
• Medicines called antiarrhythmics to help prevent abnormal heart rhythms
• Catheter ablation to destroy the part of your heart responsible for the abnormal beats

Your doctor may give you more instructions about how to manage your PVCs and other medical conditions. These may include:

• Eating a heart-healthy diet
• Getting enough exercise and maintaining a healthy weight
• Not having too much alcohol and caffeine, which can trigger PVCs
• Not having too much stress and fatigue, which can also trigger PVCs
• Getting treatment for your other health conditions, such as high blood pressure
• Making sure to keep all your medical appointments

Call 911 for chest pain, lightheadedness, or sudden shortness of breath. It may be medical emergency that needs treatment if PVCs are happening too often or in a row.

• PVCs are a kind of abnormal heart rhythm. The signal to start your heartbeat starts somewhere in the ventricles instead of in the SA node. This can feel like a skipped heartbeat or an extra heartbeat.
• PVCs are very common in people of all ages. They're more common if you have other heart problems.
• PVCs can cause symptoms, but often they don't. When they happen only once in a while, PVCs don't need treatment.
• Medicines and catheter ablation are choices if you have PVCs that cause symptoms or occur often.
• Your doctor may want to check you for other heart conditions.
• Follow all your doctor's instructions about medicine, exercise, and lifestyle.

Tips to help you get the most from a visit to your doctor:

• Know the reason for your visit and what you want to happen.
• Before your visit, write down questions you want answered.
• Bring someone with you to help you ask questions and remember what your doctor tells you.
• At the visit, write down the name of a new diagnosis and any new medicines, treatments, or tests. Also write down any new instructions your doctor gives you.
• Know why a new medicine or treatment is prescribed, and how it'll help you. Also know what the side effects are and when they should be reported.
• Ask if your condition can be treated in other ways.
• Know why a test or procedure is advised and what the results could mean.
• Know what to expect if you don't take the medicine or have the test or procedure.
• If you have a follow-up appointment, write down the date, time, and purpose for that visit.
• Know how you can contact your doctor if you have questions, especially after office hours and on weekends or holidays.