Dr John M

cardiac electrophysiologist, cyclist, learner

On PVCs, think anew but think slowly

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Premature ventricular complexes (PVCs) remain a common and vexing problem in cardiology. PVCs deserve attention because they often induce fear in both patient and doctor. In US healthcare, fear is bad. Fear sets the stage for over-treatment.

The approach to the funny-looking beats has not changed much in the last two decades.

That may be changing. Cardiology is beginning to see PVCs in a different way.

First the current approach:

We begin by asking: “What company do the skipped beats keep?”

Old teaching had it that PVCs in the setting of a normal heart were benign. Don’t worry about them. Reassure the patient; remove or decrease irritants (stress, sleep issues and alcohol, for instance); treat symptoms and essentially let time pass. Benign PVCs usually go away.

(I have written about benign PVCs here: Benign PVCs: A heart rhythm doctor’s approach.)

Old teaching also had it that PVCs occurring in the setting of heart disease were not something we did anything about. The abnormal beats were thought to be mere markers of the underlying disease rather than a modifiable condition. For example, in a patient with heart failure who has frequent PVCs, the teaching was to treat the heart failure, and as that improved, so would the PVCs.

In medical speak, we said PVCs in patients with heart disease were a “non-modifiable epi-phenomenon.”

The reason cardiology feels this way about PVCs in the setting of heart disease stems from a large study in the 1990s called the CAST trial. Back then, we thought suppression of PVCs would help patients, especially those who had a heart attack. To most everyone’s surprise at the time, patients with PVCs after a heart attack who were given drugs to suppress the PVCs did indeed have fewer PVCs, but they also had a higher death rate!

Other studies confirmed the notion that drugs for PVCs reduced the number of PVCs, but did not reduce the death rate from heart disease. Hence the non-modifiable thinking.

Ideas in cardiology change slowly. A recent study, and its accompanying editorial, published in the Journal of the American College of Cardiology tempts us to change our thinking about PVCs.

Before I tell you about these writings, it’s best to set out the present-day context in which cardiology sees heart rhythm problems. In 2015, we (generally) favor catheter ablation of rhythm problems over drug suppression. We also benefit from technology that allows us to see both structural and electrical abnormalities of heart muscle more clearly. MRI scans can show small areas of scar and GPS-like maps in the EP laboratory can identify and color-code areas of abnormal electrical properties. It is amazing technology.

In that context, the short story of the new study and editorial is that, in some cases, PVCs may herald the development of heart failure. That wasn’t so important in the past because there was little we could do about them. But now, with the advent of advanced imaging and improved ablation technology, PVCs may be modifiable. This change in thinking also has huge public health implications as millions of Americans have heart failure.

Please note the modifiers in the previous paragraph. PVCs may herald heart failure…in some cases. The study had serious limitations. It could only show weak associations; we cannot say PVCs cause heart failure. Also note that I said PVCs may be modifiable with ablation. We don’t know yet. Yes, most electrophysiologists have done beautiful cases in which we reverse heart failure by burning a PVC focus that was responsible for tens of thousands of daily PVCs. But these are special cases, done in patients with known heart failure due to the PVC.

You know me. I like to take a cautious slow approach to new thinking, especially when it involves exuberance over invasive procedures. I’ve learned over the decades that when cardiologists are exuberant, it is often irrational or premature exuberance.

Here is my cautionary post over at theHeart.org|Medscape Cardiology:

PVCs: Modifiable Risk Factor for Heart Failure . . . Maybe

JMM

Benign PVCs: A heart rhythm doctor’s approach.

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Here is an edited email I received from an athletic colleague:

John,

Quick question….

A 50 year-old male healthy athlete has the new problem of occasional periods of premature beats. He (or she, it doesn’t matter) has visited the doctor and an ECG shows PVCs, or premature ventricular contractions. Otherwise the history, exam, ECG, ECHO and electrolytes are normal.

What’s up with PVCs? Why? Could they be 1) consequence of (chronic) exercise or 2) related in some way to overtraining.

Any thoughts?

PVCs are probably the second most common rhythm problem I see. Atrial arrhythmia, including AF and atrial flutter are the most common.

This image shows PVCs (beats 2, 4, 6 etc) occurring in what we call a bigeminal pattern. Atrial or ventricular beats that appear in an every other beat pattern are referred to as bigeminy. Dr. Fisch called it “boom-boom-pause.”

PVCs

Here are six bullet points on PVCs: (No doubt, if you wanted to be an engineer about it, there would be many more. But then you might indeed get PVCs.)

1. There is an old rule–it’s called the rule of bigeminy. Basically, the long-short intervals of PVCs tend to promote themselves. The point is that PVCs often occur in a bigeminal pattern. It’s not unusual.

2. Understanding PVCs is harder than understanding cyclists. If I had only one adjective for PVCs, I would use capricious. We can’t often find a reason why PVCs come, why they leave, or why they come back.

3. It is worth quantifying facts about the PVCs:

  • Response to exercise: PVCs that mostly occur at times of rest and suppress with exercise are usually benign. PVCs that worsen with exercise may be indicative of a heart under stress, say from a partial blockage of an artery or something else. A heart doctor should evaluate arrhythmia that gets worse with exercise.
  • Quantity of PVCs: A 24-hour-holter monitor tells us how many PVCs occur on a given day. The normal person has about 100,000 heartbeats per day (athletes a few fewer). Patients with more than 20,000 PVCs per day are at risk for developing cardiomyopathy (weak heart). These patients should be referred to an electrophysiologist.

4. In an overwhelming majority of patients, especially those with a structurally normal heart, PVCs are benign. The word benign means the extra beats do not indicate heart disease or predict sudden demise.

5. Mandrola observations: PVCs might indicate training excess. I see this often in athletes. It might happen during a big training block or immediately afterwards. Of course, my theory is that PVCs associate with excess inflammation. The reason I see inflammation as the link is because PVCs often occur in patients who are exposed to stress. The middle-aged person going through a divorce, the doctor embroiled in a lawsuit, the minister who takes care of everyone but himself, the grad student during exams. The theme here is that PVCs tend to cluster at times of high inflammation–be it physical, mental or emotional. But not always.

Recently, a cycling friend told me his PVCs had resolved almost as soon as he stopped training for races. He still rides, fast at times, but doesn’t ‘train.’ (I’m not advocating not racing; it’s just an anecdote.)

6. Ten treatment steps: The first step is to ask what company does the PVC keep? PVCs occurring in patients with a normal heart (by history, exam, ECG and ECHO) are almost always benign.

  • Treatment steps 1-4 are reassurance. It is important to understand the problem, and its benign nature. Removing fear is always a good first step.
  • Steps 5-8 include adjustment of lifestyle, both on a micro and macro style. This gets me back to the 4 legs of the table of health: good food, good exercise, good sleep and good attitude. Cutting back on caffeine and alcohol, looking critically at the dose of exercise, going to bed on time, and smiling are all great strategies for PVCs.
  • Step 9 involves Buddhism. One must know that PVCs are impermanent. Right understanding of PVCs means knowing they will pass.
  • Step 10 involves medicine. I hate when it gets to this step. Beta-blockers are my first choice. These drugs block adrenaline. They sometimes lessen the thudding associated with the irregular beats. Beta-blockers are also good for as-needed use, say for bad days when the PVCs are acting up. And the best part of using beta-blockers: lack of harm. Rarely do I use an anti-arrhythmic drug, like Flecainide or Propafenone or Sotalol.
  • Step 10 (a): Please don’t beat me up on this one. Some patients report benefit from magnesium supplementation. I have found it helpful in my case of atrial premature beats. Let me repeat, I am not promoting supplements. Healthy patients with benign arrhythmia might try taking magnesium, especially at night. Don’t take magnesium if you have kidney disease. And if you take too much, watch out for diarrhea.

Conclusions:

Don’t try too hard to understand PVCs. A basic medical evaluation can exclude significant structural heart disease. Talk to your doctor. Come to a shared decision about what to do.

I am sorry you have them.

JMM

P.S. Please don’t email me or comment with personal medical information. Arrhythmia cannot be treated on the Internet. This post, like all my posts on medical topics, are meant as general guides, not medical advice.