The significance of Respiratory artifact (RA) in the ECG - Dr. Littmann

I.  Characteristics of respiratory artifact

1. Repetitive microoscillations, best seen in the inferolateral leads; rarely seen in leads I and V1
2. Occasionally, the microoscillations are preceded by what look like P waves - the presence of pseudo-P waves may mimic atrial dissociation
3. The RA corresponds to the inspiratory phase of the respiratory cycle
4. Duration of the RA corresponds to duration of the inspiratory phase of respiration

 
II.  The clinical significance of respiratory artifact

1. The presence of RA always indicates increased work of breathing, respiratory distress
2. It allows precise measurement and tracking of the respiratory rate - count the number of RAs in the 10-sec 12-lead ECG and multiply it by 6; measure 1 or more respiratory cycles in mm and divide it into 1,500 or its multiples
3. 44% of pts with RA required ventilation support; 28% required intubation, mechanical ventilation
4. Successful treatment of the underlying condition resulted in a decreased rate or elimination of RA

 
III.  Respiratory artifact can aid in the recognition of sleep-disordered breathing

1. Central sleep apnea is characterized by

                a. marked sinus deceleration or AV block followed by
                b. an abrupt increase in heart rate and the
                c. simultaneous appearance of very fast RA

1. Obstructive sleep apnea is characterized by

                a. profound sinus bradycardia with
                b. simultaneously occurring very long respiratory (snoring) artifact followed by
                c. a sudden increase in the heart rate and resolution of the RA

1. Cheyne-Stokes breathing is characterized by

                 a. periodic, cyclic clustering of RA
                 b. the onset of most periods which contain the RAs show the characteristics of central sleep apnea
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