PVCs and PACs (Premature Beats)

What is a “premature beat”?

In a normal rhythm, the SA node — the heart’s natural pacemaker — fires at a steady tempo, sending each beat through the heart in order. A premature beat is an extra beat that comes early, from somewhere other than the SA node. It interrupts the sequence and is followed by a brief pause as the heart resets to its usual rhythm.

There are two flavors, named for where the extra beat starts:

• PAC — Premature Atrial Contraction — the extra beat originates in the upper chambers (the atria).
• PVC — Premature Ventricular Contraction — the extra beat originates in the lower chambers (the ventricles).

The label sounds technical but the experience is identical from the patient’s point of view, and the framework for thinking about them is the same.

What patients actually feel

Most patients describe one of three sensations:

• A “skipped beat” — the felt skip is actually the brief pause after the premature beat
• A hard thump in the chest — the felt thump is the normal beat that comes after the pause, which is more forceful because the heart has had a moment longer to fill with blood
• A fluttering in the chest if many extra beats happen close together

Some patients feel nothing at all and only discover their PVCs on a routine ECG or wearable recording.

How common is this?

Very. When monitored for 24 hours, most healthy adults have a handful of PACs or PVCs that day. About 5% have more than 100 PVCs in 24 hours. About 1% have more than 1000. The number going up isn’t, by itself, a sign of disease — it’s a sign you’d notice more.

The mistake is to assume that lots of extra beats automatically means something is wrong. In a heart that’s otherwise structurally normal, ectopy is mostly an annoyance.

When PVCs deserve a closer look

A few situations make us look harder:

• Very high burden — more than 10–15% of all beats are PVCs (over years, this can weaken the heart muscle — “PVC-induced cardiomyopathy”)
• Symptoms out of proportion — the patient is genuinely unable to sleep, eat, work, or function because of the ectopy
• Structural heart disease is present — prior heart attack, cardiomyopathy, severe valve disease, or known reduced ejection fraction
• Family history of sudden cardiac death in a young relative
• Multi-form (multifocal) PVCs — extra beats with different shapes on the ECG, suggesting more than one source
• PVCs that trigger longer rhythms — runs of VT, or PVCs that initiate ventricular fibrillation

These trigger additional testing — echocardiogram, sometimes cardiac MRI, occasionally an EP study.

How we sort it out

The workup for a patient with bothersome PACs or PVCs is usually:

1. A clinical conversation — what you feel, when, how often, what triggers it
2. A 12-lead ECG to characterize the shape of the extra beat — its shape tells us where it’s coming from
3. A 24-hour to 30-day monitor to count beats and measure burden as a percent of total beats
4. An echocardiogram to confirm the underlying heart is structurally normal
5. Cardiac MRI in selected patients — most often when PVCs come from the right ventricle, the patient is young, or there’s a family history concern
6. Blood work — thyroid, electrolytes — these can drive ectopy

In most patients, the workup is reassuring, the echocardiogram is normal, and the conversation shifts to managing symptoms and triggers.

Triggers — the most common ones

Patients can almost always pin a worse pattern of palpitations to one of these:

• Caffeine. Especially energy drinks and pre-workout supplements; ordinary coffee less so. See the caffeine and rhythm page for the dose-by-product detail.
• Alcohol. Often the day after, particularly with sleep loss and dehydration on top.
• Sleep loss — and the fragmented sleep of jet lag, night shifts, or a newborn.
• Stress and adrenaline. Anxiety doesn’t cause PVCs but it does amplify them, and feeling the PVCs amplifies the anxiety in a loop.
• Dehydration.
• Decongestants — pseudoephedrine, phenylephrine. Even one dose can trigger a day’s worth of ectopy.
• Heavy meals late at night.
• High-intensity exercise in some patients; light activity in others paradoxically calms the ectopy.
• Hormonal cycles in some women, particularly perimenopause.

Patients who track their own pattern often work out their triggers within a few weeks. We trust those reports.

When ectopy is benign — the conversation we usually have

If the workup is unremarkable — normal echocardiogram, no inherited risk, no high burden — the conversation usually covers:

• Reassurance. Extra beats are uncomfortable, not dangerous, in a normal heart.
• Trigger control. Cut back on what’s clearly setting it off.
• No automatic medication. Most patients don’t need a daily drug.
• A repeat monitor in a year if the pattern changes.

About 80% of patients with bothersome PACs or PVCs are happy with reassurance, lifestyle changes, and a recheck if things change.

When we treat with medication

If symptoms persist and lifestyle changes haven’t worked, the usual next step is:

• Beta-blocker (metoprolol, propranolol) — calms the adrenaline-driven ectopy, well-tolerated, lowest-risk option
• Calcium channel blocker (diltiazem, verapamil) — alternative when beta-blockers aren’t tolerated
• Flecainide or propafenone — for higher-burden patients in a structurally normal heart
• Sotalol or amiodarone — reserved for selected cases

We start low and go slow. The goal is fewer extra beats, not zero — and almost never at the cost of new side effects.

When ablation makes sense

Catheter ablation of PVCs is a definitive option in select patients:

• High burden (commonly more than 10% of all beats)
• Symptoms despite medication
• PVC-induced reduction in heart function on echo or MRI
• PVCs that come from a single, mappable focus (most commonly the right ventricular outflow tract — these often ablate with very high success)

The procedure is similar to other catheter ablations: vascular access, electrical mapping, then targeted ablation of the site producing the extra beats. Success rates depend on the source: outflow-tract PVCs ablate at 80–90%; deeper or epicardial sources are harder.

When to call us

• You feel the ectopy is constant and intolerable — bring a wearable recording if you have one
• The pattern changes — new fluttering, new dizziness, new chest pain, new fainting
• You feel a “run” of beats lasting more than a few seconds
• You faint or nearly faint — that’s a different evaluation and not “just PVCs”
• You have a family history of sudden cardiac death in a young relative and have never been formally evaluated

For the vast majority of patients with PACs or PVCs, the story ends in reassurance. The job is to make sure that’s the right ending.