Evaluation and detection of pathological tachycardias in infants somet
imes is difficult. Noninvasive recording of the infant's ECG at the ti
me of symptoms forms the mainstay of diagnosis, although invasive elec
trophysiological testing may be required. Accurate rhythm diagnosis is
central to successful treatment. The advent of high capacity ambulato
ry memory monitoring makes it possible to record ECG signals, as well
as apnea data. We present two cases of infant tachycardia studied by m
emory monitor. These devices yield good quality ECG signals and may pr
ovide information regarding a particular rhythm disturbance.