Two automatic QT algorithms compared with manual measurement in identification of long QT syndrome
2010 (English)In: Journal of Electrocardiology, ISSN 0022-0736, E-ISSN 1532-8430, Vol. 43, no 1, 25-30 p.Article in journal (Refereed) Published
BACKGROUND: Long QT syndrome (LQTS) is an inherited disorder that increases the risk of syncope and malignant ventricular arrhythmias, which may result in sudden death.
METHODS: We compared manual measurement by 4 observers (QT(manual)) and 3 computerized measurements for QT interval accuracy in the diagnosis of LQTS: 1. QT measured from the vector magnitude calculated from the 3 averaged orthogonal leads X, Y, and Z (QTVCG) and classified using the same predefined QTc cut-points for classification of QT prolongation as in manual measurements; 2. QT measured by a 12-lead electrocardiogram (ECG) program (QTECG) and subsequently classified using the same cut-points as in (1) above; 3. The same QT value as in (2) above, automatically classified by a 12-lead ECG program with thresholds for QT prolongation adjusted for age and sex (QTinterpret). The population consisted of 94 genetically confirmed carriers of KCNQ1 (LQT1) and KCNH2 (LQT2) mutations and a combined control group of 28 genetically confirmed noncarriers and 66 unrelated healthy volunteers.
RESULTS: QT(VCG) provided the best combination of sensitivity (89%) and specificity (90%) in diagnosing LQTS, with 0.948 as the area under the receiver operating characteristic curve. The evaluation of QT measurement by the 4 observers revealed a high interreader variability, and only 1 of 4 observers showed acceptable level of agreement in LQTS mutation carrier identification (kappa coefficient >0.75).
CONCLUSION: Automatic QT measurement by the Mida1000/CoroNet system (Ortivus AB, Danderyd, Sweden) is an accurate, efficient, and easily applied method for initial screening for LQTS.
Place, publisher, year, edition, pages
2010. Vol. 43, no 1, 25-30 p.
Long QT syndrome, QT interval, Automatic measurement, Vectorcardiography, Mutation analysis
Cardiac and Cardiovascular Systems
IdentifiersURN: urn:nbn:se:umu:diva-32965DOI: 10.1016/j.jelectrocard.2009.09.008PubMedID: 20005993OAI: oai:DiVA.org:umu-32965DiVA: diva2:306858