Medical Edge Newspaper Column

People With Pacemakers Have Few Restraints
On Activities

Aug. 21, 2006
DEAR MAYO CLINIC:
I need some good, honest information about whether it's safe to use power tools -- chainsaws or jackhammers, for example -- when I have a new aortic valve and pacemaker for my heart. -- Prairie View, Ill.

ANSWER:
Assuming that you are past the one- to two-month recovery period following surgery for the valve and pacemaker, and assuming as well that neither the chain saw nor jackhammer are heavy-duty industrial models with very high electrical currents, these and similar devices are generally safe for you to use.

In the weeks following surgery, patients are advised against lifting heavy objects or subjecting themselves to strenuous exertion. But once that period is over, they are largely without restriction. Short of participating in professional-level contact sports such as wrestling or football, which can sometimes result in severe trauma, a person with a new heart valve or pacemaker is free to pursue the same range of physical activities as people without these implanted devices.

The only issue for a person with an artificial valve (as opposed to a biological valve derived from a pig or cadaver) has to do with taking warfarin (Coumadin). Warfarin is an anticoagulant that prevents potential stroke-causing blood clots from forming on the valve's metallic surfaces that open and close to regulate blood flow through the heart. With the bloodstream thus "thinned," clotting takes a little longer than normal and an injury might result in heavier-than-normal bleeding. Patients, duly informed about this heightened risk, must decide for themselves whether or not to participate in certain activities.

Pacemakers, which generate electrical pulses to pace an otherwise slow or irregular heartbeat, are potentially vulnerable to the electromagnetic or electromechanical fields created by electrical equipment. While a strong enough field could temporarily inhibit or shut off a pacemaker, fields produced by the modest-sized machines that a hobbyist tends to use are unlikely to cause such interference. To be on the safe side, however, discuss using the machine with a caregiver prior to trying it out.

Ironically, significant threats to pacemakers may be found in the hospital environment. Magnetic resonance imaging machines, for example, can disrupt a patient's pacemaker. (MRI is considered contraindicated for patients with such implanted devices.) Medical staff are also trained to monitor patients carefully for adverse effects during exposure to other equipment that produces strong fields.

Modern ("rate-responsive") pacemakers, which are set not at a single rate but adjust depending on activity levels, may be sensitive to mechanical vibration caused by machines. They might incorrectly sense such movement as coming from your body and increase the heart rate accordingly. This is not a dangerous situation, just an inappropriate one in which your environment -- rather than your actual physical activity -- is driving the pacemaker.

Simply being exposed to the vibration of a dentist's drill, for instance, can prompt a pacemaker to heighten the heart rate slightly. But then again, people without pacemakers could have a similar (and similarly harmless) reaction under the same circumstances.

-- David L. Hayes, M.D., Cardiovascular Diseases, Mayo Clinic, Rochester, Minn.