When a Prince William County man fell unconscious last week because his automated heart pump was malfunctioning, the county's fire and rescue team knew exactly how to fix the problem.

The device's alarm was blaring, and the paramedics zeroed in immediately: The battery was low. The emergency paramedics had just been trained on how to work the left ventricular assist device (LVAD), a mechanism that is usually the province of hospital trauma staff members, not local rescue workers.

"It could have been a loose connection, a clogged filter, a problem with the system controller, but they were able to get another form of electricity," said Barbara Brown, the assistant chief of the Dale City Volunteer Fire Department who helped train some of the paramedics who responded that day. "It could have been a worse situation if they didn't know what they were dealing with. These devices are starting to make their way out into the community, and now it's time to be proactive."

The heart's left ventricle pumps blood out to the body. An LVAD is a battery-operated, mechanical pump device that is surgically implanted but has its power source outside the patient. The devices are being more frequently prescribed to patients, elevating the need for local paramedics to be trained to work them, according to hospital and emergency rescue officials.

Patients with LVADs, typically people waiting for a heart transplant who until recently were confined to a hospital during their wait, are now more mobile since the FDA approved them as portable in the late 1990s. Two years ago, the FDA approved the devices for another segment of the population that is ineligible for heart transplants and must use them for the rest of their lives.

Although only a few people in Northern Virginia have LVADs, out-of-state traffic coming through the Interstate 95 corridor makes the need for training among "pre-hospital providers" more pressing, Brown said. Patients and their caretakers -- medical professionals, relatives or friends -- are also trained on how to troubleshoot and fix the machines, but they have difficulty acting under stress.

Since the spring, Brown, who is also a flight paramedic for MedSTAR Transport based at the Washington Hospital Center, has been training Dale City's volunteer fire and rescue workers as well as the salaried county emergency staff in how to operate and fix the devices.

But the rescue workers in Prince William County and a handful in Fairfax County who are trained are not enough, said Tonya Kraus, the artificial heart coordinator at Inova Fairfax Hospital. Last week, she said she e-mailed her colleagues at the Washington Hospital Center and Johns Hopkins Hospital asking them to brainstorm on ways to improve regional training among EMS responders.

With newer models being rolled out continuously, Leslie Sweet, a clinical research coordinator at Washington Hospital Center, said training should not just occur once, but continuously.

"What they need to be able to do is set up a system to maintain proficiency, even though the frequency of the use may be sporadic," Sweet said. "The more groups that get involved, the better."

Angela Goodwin-Slater, 37, a paramedic for the Dale City Volunteer Fire Department, said she had heard about the device a couple of years ago and soon began asking for training.

"The biggest roadblock was getting the training," Goodwin-Slater said. "The device is visually intimidating . . . but the way Chief Brown broke it down to us, it's not difficult to understand."