PVCs and PACs: Are extra heartbeats dangerous?
A skipped beat, flutter, or sudden thump in your chest can feel alarming. These sensations are often caused by common extra heartbeats called PVCs or PACs, but recurring symptoms or certain warning signs may need medical evaluation.
Premature atrial contractions (PACs) and premature ventricular contractions (PVCs) are extra heartbeats that begin in different areas of the heart. Both are common and usually harmless, but certain symptoms or a high number of extra beats may warrant further evaluation.
- PACs begin in the heart’s upper chambers, while PVCs begin in its lower chambers.
- Both can feel like a skipped beat, pause, flutter, or sudden thump in the chest.
- Occasional extra beats are common and usually do not require treatment.
- Extra beats should be evaluated if they happen repeatedly, affect your quality of life, or occur with dizziness, chest pain, or shortness of breath.
- Fainting or loss of consciousness with an abnormal heartbeat requires immediate medical care.
- A heart monitor can identify the type and frequency of the extra beats and help determine whether monitoring or treatment is needed.
Your heart has an electrical system that controls when each heartbeat occurs. A PVC or PAC happens when an electrical signal fires earlier than expected.
“Those are called extra beats because they come on top of the normal beat of the heart and reset the next beat,” says David Hamon, MD, a UI Health Care cardiac electrophysiologist.
After the premature beat, there may be a brief pause before the heart’s normal rhythm resumes. Many people do not feel the extra beat itself. Instead, they notice the pause or the stronger heartbeat that follows it.
You might describe the sensation as:
- A skipped or missed beat
- A pause in your heartbeat
- A sudden thump or pounding beat
- A fluttering sensation in your chest
- An unusual contraction
The beat after a PVC or PAC may feel stronger because the heart has had slightly more time to fill with blood before contracting.
“It can feel like a pounding or strong beat in the chest,” Hamon says.
Extra beats may occur one at a time or in small groups. When several occur close together, they may create a fluttering sensation.
The difference between PVCs and PACs
PVCs and PACs are named according to where the premature electrical signal begins:
- Premature ventricular contractions, or PVCs, start in a ventricle, one of the heart’s two lower chambers.
- Premature atrial contractions, or PACs, start in an atrium, one of the heart’s two upper chambers.
PVCs and PACs can cause similar sensations, so you usually cannot determine which type you are experiencing based on symptoms alone. An electrocardiogram (ECG or EKG) or heart monitor is needed to identify the rhythm.
PVCs and PACs can cause similar sensations, so you usually cannot determine which type you are experiencing based on symptoms alone. An electrocardiogram (ECG or EKG) or heart monitor is needed to identify the rhythm.
“Everyone has PVCs and PACs in low numbers, and they tend to increase with age,” Hamon says.
PACs are usually harmless and do not damage the heart. However, a very high number of PACs may sometimes be associated with the future development of atrial fibrillation.
PVCs are also often benign when the heart doesn’t have other problems. However, having a very high number of PVCs can sometimes weaken the heart muscle over time.
The percentage of total heartbeats that are PVCs is known as the PVC burden. When PVCs account for more than 10% of your heartbeats, providers may monitor your heart function more closely. This is the lowest PVC burden associated with PVC-induced cardiomyopathy, a weakening of the heart muscle.
Most people with PVCs do not develop this condition. A heart monitor is needed to measure PVC burden, so the number of sensations you notice does not necessarily indicate how many extra beats are occurring.
“The longer we monitor patients, the more we’ll find out about their PVCs and PACs,” Hamon says.
When extra heartbeats should be evaluated
An occasional skipped beat without other symptoms is common. Stress, poor sleep, or changes in your routine may make you more aware of these sensations.
“If these palpitations affect your quality of life, it’s important to get them checked,” Hamon says.
- Keep happening or become more frequent
- Cause ongoing fluttering or pounding
- Make you feel tired and weak, dizzy, or lightheaded
- Interfere with sleep, exercise, or daily activities
- Cause significant worry or affect your quality of life
- Occur when you have a history of heart disease
You should also contact a provider if a blood pressure monitor repeatedly shows an unusually low heart rate along with skipped beats. PVCs sometimes produce a weak pulse that an automated device does not count, making your heart rate appear lower than it is.
- Fainting or loss of consciousness
- Chest pain or pressure
- Severe dizziness
- Significant or worsening shortness of breath
- New swelling in the legs or other signs of fluid buildup
“Those are symptoms that should trigger an urgent evaluation,” Hamon says.
In rare cases, premature beats can be associated with a more serious rhythm problem. The symptoms occurring with the extra beats help determine how urgently you should seek care.
Learn what may be changing your heartbeat
UI Health Care arrhythmia specialists diagnose and treat common and complex heart rhythm conditions, including premature beats.
How PVCs and PACs are diagnosed
Your primary care provider is usually the best place to begin if skipped beats or fluttering sensations keep happening.
Your initial evaluation may include:
- A discussion of your symptoms and when they occur
- A physical examination
- An electrocardiogram (ECG or EKG)
- Blood tests to check electrolyte levels and thyroid function
- A Holter monitor to continuously record your heart rhythm
An EKG records only a short period of heart activity, so it may not capture extra beats that come and go. A Holter monitor can identify the type of premature beat and calculate how frequently it occurs.
A 48-hour monitor may be enough when symptoms happen frequently. If they occur only every few days, your provider may recommend monitoring for one or two weeks.
The results can show:
- Whether the extra beats are PVCs or PACs
- How often they occur
- Whether symptoms correspond with a rhythm change
- Whether PVCs begin in one area or several areas of the heart
- Whether the extra beats are related to activity, stress, rest, or sleep
Your provider may also recommend an echocardiogram to evaluate your heart’s structure and pumping ability. More advanced testing, such as cardiac MRI, may be needed if the monitor shows concerning patterns or your provider suspects an underlying heart condition.
A smartwatch or portable EKG device may provide helpful information if it records your rhythm while symptoms are occurring.
“When patients feel their symptoms, you can sometimes clearly see PVCs or PACs on the tracing from the watch,” Hamon says. “It is very important to correlate the symptoms with the tracing.”
If possible, save the tracing and note what you felt, how long the episode lasted, and what you were doing when it began. A smartwatch cannot replace a medical evaluation or Holter monitor because it usually cannot reliably measure the number of PVCs or PACs occurring throughout the day.
“The best workup we can do to characterize those PVCs is a Holter monitor — even a 48-hour monitor, or a longer one- or two-week monitor if the symptoms occur less often,” Hamon explains.
Managing and treating extra heartbeats
Extra beats can occur without an obvious cause. Possible triggers or contributing factors include:
- Stress
- Poor sleep
- Alcohol
- Energy drinks or excessive stimulant use
- Changes in exercise or routine
- Electrolyte imbalances
- An overactive thyroid
Although caffeine is often blamed for palpitations, it does not affect everyone in the same way.
“Some people are very sensitive to caffeine, but it is much less common than most people think,” Hamon says.
Keeping a record of your symptoms and possible triggers can help you and your provider identify patterns. Regular exercise, a balanced diet, adequate sleep, stress management, and limiting alcohol may also help.
Treatment depends on the type and number of premature beats, your symptoms, the health of your heart, and how much the condition affects your quality of life.
Reassurance and monitoring
When testing shows a low or moderate number of extra beats and no structural heart problem, treatment may not be necessary.
“When we don’t see any concerning features or structural abnormalities, the first step is really to reassure the patient that this is a benign condition,” Hamon says.
Your provider may recommend tracking your symptoms or repeating a heart monitor or echocardiogram later.
Medication
Medication may be considered when symptoms remain disruptive. Information from a Holter monitor can help an electrophysiologist choose a medication based on when the extra beats occur and how they relate to your heart rate.
Medication may reduce the number of premature beats or make them less noticeable, but it does not always eliminate them permanently.
Cardiac ablation
Cardiac ablation may be considered when:
- PVCs are weakening the heart
- Symptoms are severe or debilitating
- Medication has not helped
- Medication causes side effects or is not a good option
During this minimally invasive procedure, an electrophysiologist guides thin catheters into the heart, locates the source of the PVCs and treats the small area producing the abnormal electrical signals.
Hamon says UI Health Care has a success rate above 90% after one ablation for appropriately selected patients with PVCs. However, ablation is not necessary or practical for everyone. The PVCs need to occur often enough during the procedure for the electrophysiology team to locate their source.
Specialized electrophysiology care for extra heartbeats
UI Health Care has a comprehensive team of cardiac electrophysiologists with experience studying, diagnosing, and treating PVCs, PACs, and other arrhythmias.
Patients have access to:
- Advanced heart rhythm monitoring
- Echocardiography and cardiac MRI
- Specialized imaging for rare underlying conditions
- Multiple electrophysiology labs
- Advanced cardiac mapping systems
- Several types of ablation technology
“We have access to the highest technologies and a very experienced team for the initial assessment,” Hamon says. “When we decide to go with an ablation, we have access to the latest technology and a broad spectrum of mapping systems.”
This range of expertise is especially valuable when premature beats arise from a hard-to-reach part of the heart or testing suggests that another condition may be contributing to the rhythm changes.
