A transtelephonic system for evaluation of implanted cardiac pacemakers has been developed. Over a 12-month period, 134 units were tested. Of the 28 pacemaker replacements, 26 were due to battery failure and were predicted. All 26 patients were electively admitted for pacemaker replacement. Catheter electrode failure occurred in two patients and was diagnosed via the transtelephonic system. This system provides a method for prolonging life expectancy of permanent cardiac pacemakers as well as drastically reducing emergency admissions for unpredicted failure.
Pennock RS, Dreifus LS, Morse DP, Watanabe Y. Cardiac Pacemaker Function. JAMA. 1972;222(11):1379–1382. doi:10.1001/jama.1972.03210110021006