Slight rate acceleration in permanent rechargeable nickel-cadmium pacemakers: a possible marker of battery failure.

Thirty-seven rechargeable pacemakers were implanted in 33 patients between 1972 and 1976. Average follow-up has been 4.9 years. Six patients have had these pacers for an average of 7.8 years. Slight rate acceleration of 3 to 5 beats per minute was demonstrated in 46% of the units; rate acceleration to greater than 80 beats per minute was present in three pacemakers, two of which failed within three months. Although rechargeable pacemakers have performed well, frequent surveillance or replacement is warranted if the pacing rate increases to greater than 80 beats per minute.