An annotated ventricular tachycardia (VT) alarm database: Toward a uniform standard for optimizing automated VT identification in hospitalized patients

Abstract

Background: False ventricular tachycardia (VT) alarms are common during in-hospital electrocardiographic (ECG) monitoring. Prior research shows that the majority of false VT can be attributed to algorithm deficiencies. Purpose:The purpose of this study was: (1) to describe the creation of a VT database annotated by ECG experts and (2) to determine true vs. false VT using a new VT algorithm created by our group. Methods:The VT algorithm was processed in 5320 consecutive ICU patients with 572,574 h of ECG and physiologic monitoring. A search algorithm identified potential VT, defined as: heart rate >100 beats/min, QRSs > 120 ms, and change in QRS morphology in >6 consecutive beats compared to the preceding native rhythm. Seven ECG channels, SpO 2 , and arterial blood pressure waveforms were processed and loaded into a web-based annotation software program. Five PhD-prepared nurse scientists performed the annotations.Results: Of the 5320 ICU patients, 858 (16.13%) had 22,325 VTs. After three levels of iterative annotations, a total of 11,970 (53.62%) were adjudicated as true, 6485 (29.05%) as false, and 3870 (17.33%) were unresolved. The unresolved VTs were concentrated in 17 patients (1.98%). Of the 3870 unresolved VTs, 85.7% (n = 3281) were confounded by ventricular paced rhythm, 10.8% (n = 414) by underlying BBB, and 3.5% (n = 133) had a combination of both. Conclusions:The database described here represents the single largest humanannotated database to date. The database includes consecutive ICU patients, with true, false, and challenging VTs (unresolved) and could serve as a gold standard database to develop and test new VT algorithms.

Ventricular tachycardia and in-hospital mortality in the intensive care unit

“…All available ECG and physiological waveform data were collected using a closed network system that connected all 77 bedside ICU monitors (Solar 8000i Version 5.4 software, GE Healthcare, Milwaukee, WI) via a gateway system. 16 Data were sent to a secure, hospital-approved server maintained by our research laboratory. The following data were collected from each ICU monitor: (1) all available waveforms (ECG, invasive arterial blood pressure [BP], central venous pressure, intracranial pressure, plethysmograph [SpO 2 ]); (2) vital signs (heart rate, noninvasive BP, respiratory rate); (3) alarm settings (crisis, warning, or advisory and message/technical); and (4) audible and inaudible alarms.…”

“…In addition, we used all available ECG waveforms, SpO 2 , and invasive arterial BP waveforms to process the new VT algorithm developed by our group. 16 …”

“…The 7 ECG waveforms, SpO 2 , and invasive arterial BP waveform data were processed with a new VT algorithm created by our group. The new VT algorithm, which was recently published, 16 was designed to decrease false VT by addressing ECG factors identified as primary sources of false VT (ie, motion/noise artifact, bundle branch block [right or left], and/or ventricular paced rhythm). 12 , 13 , 15 , 17 , 18 For example, false VT can occur in patients with wide QRS complexes (ie, bundle branch block or ventricular pacer) when the heart rate exceeds the standard VT criteria of 100 bpm.…”

“…Annotations were performed by 5 PhD prepared nurse scientists who had decades of ICU experience and were highly skilled at interpreting hospital based-ECGs. The annotation protocol was a multitiered, multiexpert, ground truth, manual annotation, with 3-person agreement of VT. 16 Again, our analysis compared patients based on whether they had at least 1 true VT. The same definition of VT as described earlier was used with additional specific criteria as listed in Table 1 .…”

“…The primary aim of this study was to assess the rate of 30-day in-hospital mortality associated with VT alerts generated from bedside ICU ECG monitors, VT events identified via a new algorithm that was developed by our research group, 16 and annotated true VT events.…”