Comparison of 5 methods of QT interval measurements on electrocardiograms from a thorough QT/QTc study: effect on assay sensitivity and categorical outliers

Detecting Subclinical Diabetic Cardiac Autonomic Neuropathy by Analyzing Ventricular Repolarization Dynamics

“…In our study, we used the slope intercept method for QT interval detection after applying proper filtering techniques for removing baseline wandering and broadband noise within the ECG. This method of T wave end detection is reported to be more reproducible [40] and used successfully in several QT interval variability studies where correct QT interval detection is critical [20,21]. We prefer this method for QT interval detection in pathology other than the semiautomated template based methods of QT interval detection, where a number of beats are rejected due to absence of normal sinus rhythm ECG and results in less variability of the QT interval, which might contain prognostic information of disease [8].…”

Physical and Psychological Consequences of Left Cardiac Sympathetic Denervation in Long-QT Syndrome and Catecholaminergic Polymorphic Ventricular Tachycardia

“…In case reports and small series, LCSD has been reported to have significantly reduced the occurrence of cardiac events in patients with CPVT. 2,7,[22][23][24][25][26][27] In the largest and most recent series published, 54 symptomatic patients with CPVT underwent LCSD. Although the number of patients who had an incomplete LCSD was small, the authors reported that those who had a complete LCSD were much less likely to have postoperative cardiac events compared with those who had an incomplete denervation (8/47 [17%] versus 5/7 [71%]; P<0.01).…”

Computerized Interpretation of ECGs

“…7 Accurate measurement of the QT interval and its adjustment for rate, sex, and QRS prolongation remains one of the major challenges in electrocardiography. 3,[8][9][10][11][12][13] The matter is of great importance to physicians, drug manufacturers, and regulatory agencies because of the relationship between prolongation of the QT interval and potentially lethal ventricular arrhythmias. 3,[8][9][10][11][12][13] In this respect, the original contribution by Lehman and his colleagues in this issue of Circulation, Arrhythmias and Electrophysiology has particular significance.…”

“…Identification of a prolonged heart rate corrected QT interval (QTc) may identify an individual with an inherited LQTS atrisk for sudden cardiac death because of torsade de point. 3,[7][8][9][10][11][12][13] The QTc also serves as a marker of risk for individuals with a prolonged QT interval, acquired from electrolyte abnormalities or drugs.…”

“…Identification of a prolonged heart rate corrected QT interval (QTc) may identify an individual with an inherited LQTS atrisk for sudden cardiac death because of torsade de point. 3,[7][8][9][10][11][12][13] The QTc also serves as a marker of risk for individuals with a prolonged QT interval, acquired from electrolyte abnormalities or drugs.3,7-13 Specific technical and clinical recommendations for measurement of the QT and QTc intervals on the ECG have been made in a American Heart Association consensus document written to standardize the interpretation of ECGs.3 It is recommended that, in addition to rate, an adjustment for sex and age be incorporated into QTc measurement. As practical clinical limits for considering the QT interval as abnormal, this document recommends that the adjusted QT of 460 ms or longer in women and 450 ms or longer in men be considered a prolonged QT interval, and that QT of 390 ms and shorter be considered a short QT interval.…”