Validation of Displayed Electrocardiographic Rhythms at the Central Monitoring Station

Abstract

Scenario: The monitor technician made an overhead announcement to the intensive care unit (ICU) staff “bed check room 10” after seeing what appeared to be ventricular tachycardia (VT) in lead V1 at the central monitoring station (see box below). The ECG below was automatically printed from the central monitoring station following an alarm for “VTach.” The alarm occurred in a 72-year-old man admitted to the medical/surgical ICU for sepsis.False alarm caused by artifact mimicking VT in lead V1 at twice the actual heart rate. Sinus rhythm at a rate of 88 beats per minute. Possible ST-segment depression in inferior leads II and III, but wandering baseline is present.Although lead V1 shows a wide complex tachycardia suggestive of VT, the other simultaneously recorded leads show normal sinus rhythm. Note that the pulse waveform of the oxygen saturation (Spo2) is normal, indicating that the arterial pressure waveform did not change during this false alarm and the oxygen saturation is 99%. The respiratory waveform is unchanged as well. Of note, algorithms used in bedside ECG monitors often do not use all available leads for arrhythmia detection; hence, false alarms can occur. In addition, central monitoring stations typically display only 1 or 2 selected ECG leads, thus one may observe, as in this case, what appears to be VT on the central monitoring station. Verification of arrhythmias by examining all of the available leads should be standard protocol.The nurse should assess the patient immediately to ensure that no acute changes or symptoms are apparent. In addition, the nurse should check the patient’s chest to verify that lead V1 is in the correct location (4th intercostal space, right sternal border) and ensure that nothing is causing the artifact (ie, other devices, lead wires). The ST segments are consistently flattened in leads II and III. Because the T wave is also inverted in these leads, ischemia should be ruled out. Obtain a clean standard 12-lead ECG to verify that these T-wave changes are valid, and compare that ECG with a prior 12-lead ECG to determine if these changes are new.