What are some of the causes of Premature Ventricular Contractions (PVCs)?

I seem to be getting a lot of questions about rhythm problems. As a heart surgeon, my perspective of this condition is very different from others doctors.

I often dealt with acute rhythm problems during or immediately after surgery, and was also one of the early surgeons in the US involved with the treatment of survivors of Sudden Cardiac Death Syndrome (more about this later). As such I did a number of procedures where the inside of the left ventricle was "mapped", identifying abnormal electrical pathways than I then treated with stripping and freezing those areas (cryo-ablation and resection). Although very successful in my hands, this operation was later eclipsed by the Implantable Defibrillator, a procedure I pioneered in my region of the country. So here it goes:

Causes of PVCs include:

  • A variety of underlying cardiac conditions, including coronary artery disease, cardiomyopathy, mitral valve prolapse, etc.
  • Abnormal levels of "electrolytes" (minerals) in the blood. Decreased potassium and/or magnesium are the most common associated abnormalities of electrolytes. Both may be caused by the use of diuretics (water pills), among other reasons.
  • There are unusual congenital (familial) causes of ventricular arrhythmias.
  • Abnormal conditions such as increased thyroid hormones, and others.
  • Toxins, including alcohol.
  • Stimulants including Caffeine, Nicotine, Cocaine and some over-the-counter medications and herbal/natural formulations contain important stimulants.
  • Infection, inflammation or degeneration of the heart muscle.
  • Infections at other sites in the body.
  • They are often worse with lack of sleep, or stress.

A number of these conditions occasionally played a role in my patients, and the first thing to do was to control the rhythm if it affected blood pressure etc. while simultaneously correct abnormalities found, especially in electrolytes, pH and ventilation. It also depended to a degree whether the underlying condition was corrected by the surgery (not always possible), and often required working closely with cardiologists. Heart surgery includes a lot more than just operating!

Dr T


Hi Mary,

It is unlikely his meds have anything to do with the PVCs. The Beta Blockers reduces their frequency but not eliminate them. However, any time a change occurs it should be checked with a re-evaluation. That may include blood tests, an EKG, Holter monitor and/or a cardiac (stress) echo if indicated. PVCs sometimes are a marker for underlying heart disease, and previous negative tests  don't exclude future problems.

You can check here whether you are at risk. If your heart function is otherwise normal, most often PVCs  are completely benign. If necessary, Beta Blockers can be used to decrease the number of PVCs to a more tolerable level.

My advice: ask his doctors for a stress echocardiogram to make sure his bypasses are working and there is no evidence of recurrent heart disease.

Hope this helps,

Dr T

Hi Mary,

CABG is not a cure for coronary artery disease: the atherosclerosis disease that caused the blockages is still present. If successful, the operation will restore the blood flow to the heart back to normal, but that is all (even if essential). The same applies to stents. That said, a CABG is often extremely successful. I have a neighbor whom I operated in 1988, who is still doing great all these years later! The same is usually not true about stenting.

Diet, exercise (heart healthy living in general) and drugs such as Statins  may help prevent progression of disease, but don't believe the stories about regression of the blockages. Even if true, to be effective it would take another lifetime for it to happen.

An echocardiogram only shows the heart function at the time of the study. If not done as part of a stress test, there will be no information about it during exercise: it may be perfectly normal, or show areas that don't work well. Therefore I'd recommend a stress test at one or two year intervals after bypass surgery.

I have mixed feelings about the continued use of statins if his cholesterol is now normal. The potential of a protective effect needs to be weighed against the potential complications.

Statins are commonly used to treat  high cholesterol and minimize the major risk factors for cardiovascular disease and in particular, the risk of developing coronary artery disease. Studies have shown there is no clear evidence of any significant harm caused by statin prescription, but - particularly at higher doses - they are sometimes associated with side effects that include

Hope this helps,

Dr T

Post new comment

The content of this field is kept private and will not be shown publicly.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Allowed HTML tags: <a> <em> <strong> <cite> <code> <ul> <ol> <li> <dl> <dt> <dd>
  • Lines and paragraphs break automatically.

More information about formatting options

This question is for testing whether you are a human visitor and to prevent automated spam submissions.
6 + 3 =
Solve this simple math problem and enter the result. E.g. for 1+3, enter 4.
By submitting this form, you accept the Mollom privacy policy.