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Cardiac monitoring on the move

Frequent bouts of chest pain were keeping Mona up at night. Once in a while, the pain struck in the daytime, too. As far as she could tell, the episodes, which lasted just a few minutes, weren’t triggered by anything specific.

But at 60, Mona knew she shouldn’t ignore the problem, so she reported it to her doctor. Among the tests he performed was an electrocardiogram (ECG), which charts the heart’s electrical activity on a graph. It didn’t turn up anything abnormal.

To help get to the bottom of the problem, Mona’s doctor recommended 24-hour monitoring. Thanks to a portable version of the ECG, called a Holter monitor, it was possible to do this without disrupting Mona’s daily schedule.

The Holter monitor produces a continuous record of the heart’s electrical activity. Electrodes are attached to the patient’s chest and connected by wires to a paperback-size device that records the heart’s impulses on a tape or computer chip. The device must be worn throughout the test, even during sleep. The recording is then interpreted by the physician or special technicians.

The advantage of “ambulatory monitoring” is that it helps doctors catch episodes of unpredictable and asymptomatic abnormal heart activity and link it to possible triggers, such as stress or physical exertion. To make it easier for doctors to do that, patients usually keep a written diary while being monitored. In it, they note symptoms such as shortness of breath, palpitations and emotions, and any activities they take part in.

What if nothing unusual turns up during round-the-clock monitoring? Patients can use an “event recorder,” a device that can be worn for weeks or months. The recorder is activated only when a symptom occurs, and the resulting ECG is stored for later transmission by phone to the doctor’s office.

In telephone-transmitted electrocardiography, another option, the patient is given a transmitting device and a number to dial when symptoms strike. With this technique, the ECG is sent while the symptom is occurring. But for this method to be effective, the symptoms must last long enough for the patient to make the call.

As for Mona, ambulatory monitoring pointed to a form of angina. Armed with that information, she and her doctor were able to plan her treatment, and Mona could concentrate on helping her heart—instead of worrying about it.