QRS Duration Ms Research Articles

Comparison of PR, QRS, and QT interval measurements by seven ECG interpretation programs

BackgroundElectrocardiograph-generated measurements of PR, QRS, and QT intervals are generally thought to be more precise than manual measurements on paper records. However, the performance of different programs has not been well compared. MethodsRoutinely obtained digital electrocardiograms (ECGs), including over 500 pediatric ECGs, were used to create over 2000 10 s analog ECGs that were replayed through seven commercially available electrocardiographs. The measurements for PR interval, QRS duration, and QT interval made by each program were extracted and compared against each other (using the median of the programs after correction for program bias) and the population mean values. ResultsSmall but significant systematic biases were seen between programs. The smallest and largest variation from the population mean differed by 4.7 ms for PR intervals, 5.8 ms for QRS duration, and 12.4 ms for QT intervals. In pairwise comparison programs showed similar accuracy for most ECGs, with the average absolute errors at the 75th percentile for PR intervals being 4–6 ms from the median, QRS duration 4–8 ms, and QT interval 6–10 ms. However, substantial differences were present in the numbers and extent of large, clinically significant errors (e.g at the 98th percentile), for which programs differed by a factor of two for absolute errors, as well as differences in the mix of overestimations and underestimations. ConclusionsWhen reading digital ECGs, users should be aware that small systematic differences exist between programs and that there may be large clinically important errors in difficult cases.

Enhanced electrocardiographic monitoring of patients with Coronavirus Disease 2019

BackgroundMany of the drugs being used in the treatment of the ongoing pandemic coronavirus disease 2019 (COVID-19) are associated with QT prolongation. Expert guidance supports electrocardiographic (ECG) monitoring to optimize patient safety.ObjectiveThe purpose of this study was to establish an enhanced process for ECG monitoring of patients being treated for COVID-19.MethodsWe created a Situation Background Assessment Recommendation tool identifying the indication for ECGs in patients with COVID-19 and tagged these ECGs to ensure prompt over reading and identification of those with QT prolongation (corrected QT interval > 470 ms for QRS duration ≤ 120 ms; corrected QT interval > 500 ms for QRS duration > 120 ms). This triggered a phone call from the electrophysiology service to the primary team to provide management guidance and a formal consultation if requested.ResultsDuring a 2-week period, we reviewed 2006 ECGs, corresponding to 524 unique patients, of whom 103 (19.7%) met the Situation Background Assessment Recommendation tool–defined criteria for QT prolongation. Compared with those without QT prolongation, these patients were more often in the intensive care unit (60 [58.3%] vs 149 [35.4%]) and more likely to be intubated (32 [31.1%] vs 76 [18.1%]). Fifty patients with QT prolongation (48.5%) had electrolyte abnormalities, 98 (95.1%) were on COVID-19–related QT-prolonging medications, and 62 (60.2%) were on 1–4 additional non-COVID-19–related QT-prolonging drugs. Electrophysiology recommendations were given to limit modifiable risk factors. No patient developed torsades de pointes.ConclusionThis process functioned efficiently, identified a high percentage of patients with QT prolongation, and led to relevant interventions. Arrhythmias were rare. No patient developed torsades de pointes.