The fact that more than 30 percent of American households no longer have landlines might have some unintended consequences in healthcare.

As the Wall Street Journal reports, implanted defibrillators may be wireless devices, but the in-home base stations the heart monitors transmit data to still need landlines to relay information to the device makers. The manufacturers, notably Medtronic and St. Jude Medical, make readings available to doctors via company-run portals.

Perhaps more importantly, some leading-edge cardiologists like the University of Southern California's Dr. Leslie Saxon are actually monitoring the safety of implanted defibrillators. This can't happen today without the vital telephone connection.

According to the Journal, only 60 percent of Dr. Westby Fisher's defibrillator patients plug in the base stations the NorthShore University HealthSystem (Evanston, Ill.) cardiac electrophysiologist sends home with them. "The technology has not evolved to being able to use someone's cell phone," Fisher laments.

While there are cellular options for some cardiac monitoring base stations, the Journal says there is no additional cost for landline-based transmitters to access phone lines. Cellular adaptors, on the other hand, need wireless service, an expense that may get passed on to patients.

Cellular-enabled technology for heart monitors isn't fully developed, either. Boston Scientific reportedly is awaiting Food and Drug Administration approval for a fully mobile implantable monitor, and the FDA has rejected a standalone device developed by CardioMEMS. (St. Jude Medical holds a minority stake in CardioMEMS, plus an option to acquire the rest of the company.)

Other issues are holding back the move to fully wireless implantables, too. Device makers must team up with cellular carriers for service, something the medical device industry historically has not had to do to collect lucrative monitoring data. After all, that's where the money is.

"What we're doing now is recognizing that we're putting computers into patients' bodies, and there is so much value in the data," Elizabeth Hoff, general manager of cardiac connected care at Medtronic, tells the Journal. "Our strategy is to exploit the data," she says.