Hi.. Voluntary breathing disturbances can also cause alterations in the heart rate. So if the monitoring did not show positive signs of arrhythmia's then you may not really be having the condition.. The breathing disturbances may be due to stress and other psychogenic cause.. Do not bother on this.. Regular sleep and adequate diet habits with a bit of relaxing measures that include meditation and yoga may help.. If the problems persists or its disturbing daily activities, seek professional help.. You are free to take an opinion from a cardiologist..