Premature Atrial Contractions (PACs) Predict A-Fib

PACs Predict A-Fib

by Steve S. Ryan, PhD

Revised 1/9/20

PACs

Premature Atrial Contractions (PACs) are generally considered benign. Everybody gets them, not just people with A-Fib. PACs occur when electrically-active tissue in the heart decides to fire off (depolarize) before it has received the signal from the normal pacemaker of the heart, the sinus node.

PACs come from one of the atria (upper chambers of the heart). PACs generate an early beat (ventricular depolarization). They are often referred to as “extra beats” or “skipped beats”. They can cause palpitations and an irregular pulse, but in general they are benign. PACs become more common as we age. PACs (and PVCs) increase with age—from about one per hour in those 50 to 55 years old to 2.6 per hour among those 70 and older.

But PACs Often Precede or Forewarn of an A-Fib Attack

However, studies indicate that PACs often precede or forewarn of an A-Fib attack. A-Fibbers seem to have more problems with these extra beats than normal people. An important study from Dr. Boon-Hor Chong and others from China shows that frequent PACs (more than 100 beats/day) actually predict who will develop A-Fib.

The top quartile (107 patients) with more than 100 beats/day were considered to have frequent PACs. (Some patients in this top quartile had much higher rates of PACs than 100 beats/day. The mean number of PACs was 533.5.)

There were no significant differences in gender, diabetes, hypertension or coronary artery disease. But patients with frequent PACs were older and more likely to be smokers. Frequent PACs predicted that someone in the 6.1-year follow-up would develop A-Fib.

Frequent PACs also predicted who would develop ischemic stroke, congestive heart failure, and death. (Other predictors were age, male gender, hypertension, diabetes, and coronary artery disease, as previous studies have demonstrated.) More patients with frequent PACs developed congestive heart failure or died.

Editor’s Comments:

This study is a major medical breakthrough for A-Fib patients. A-Fib is often not diagnosed till it is too late, till complications such as ischemic stroke, congestive heart failure, and death occur. Up to 25% of patients were first diagnosed with A-Fib only at the time they had a stroke. But now we have a documented method of predicting who is more likely to develop A-Fib. (We previously knew that older people and people with coronary artery disease were more prone to develop A-Fib.)

A catheter ablation, in addition to removing A-Fib producing spots in the heart, can also map and ablate areas producing PACs/PVCs.

It’s relatively easy for doctors, using today’s sophisticated and low effort monitoring devices, to determine if someone has a lot of PACs/PVCs. It should become part of a routine physical exam when one turns 50 to monitor for frequent PACs/PVCs. Then preventive measures can be taken such as natural remedies like magnesium, or anticoagulants, devices to close off the Left Atrial Appendage where 90%-95% of A-Fib strokes come from, antiarrhythmic meds, ”Pill-In-The-Pocket” therapies, or a catheter ablation.

A catheter ablation, in addition to removing A-Fib producing spots in the heart, can also map and ablate areas producing PACs/PVCs. Frequent PACs can be as damaging and troublesome as A-Fib. Ablations are done not just to fix A-Fib, but also  for the sole purpose of freeing someone from frequent PACs. They are an option patients with frequent PACs should be aware of.

But one question this study didn’t fully address is how often someone with frequent PACs develops A-Fib (and other heart problems). Frequent PACs is a definite predictor. But how many people or what proportion of people with frequent PACs will definitely develop A-Fib? If you have frequent PACs, what are the odds that you will develop A-Fib, or how soon will you go into A-Fib? (The editor has written Dr. Chong and asked him this question.)

If you have frequent PACs, you shouldn’t try to play the odds and hope you don’t develop A-Fib. Instead you should face the reality that you are on the road to developing A-Fib and act accordingly. Talk with your doctor about what you should do, what preventive measures you can take.

(A special thanks to David Young for calling attention to this research and pointing out its importance for A-Fib patients.)

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Last updated: Friday, February 21, 2020

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