creators_name: Lanjewar, Pallavi creators_name: Pathak, Vaishali creators_name: Lokhandwala, Yash editors_name: Singh, Balbir editors_name: Lokhandwala, Yash editors_name: Francis, Johnson editors_name: Gupta, Anup type: journalp datestamp: 2005-04-14 lastmod: 2011-03-11 08:55:53 metadata_visibility: show title: Issues in QT interval measurement ispublished: pub subjects: ipej full_text_status: public keywords: QT interval measurement abstract: The QT interval, apart from clinical implications is crucial for safety assessment of new drugs under development. A QTc prolongation of even 10 msec in a study group is a warning signal for a new drug. There are various issues involved in the measurement of the QT interval especially regarding the ending of the T wave and different morphological pattern of T-U complex. The other issue is significant spontaneous variability in the QT interval, resulting in spurious QT prolongation and unnecessary concern. To minimize all these confounding factors, all clinical trials for assessing QT interval prolongation should be randomized and double blinded with appropriate control groups including placebo. ECG measurements should be done by trained readers with electronic calipers at ECG core Lab. ECGs should be compared with multiple baseline values with multiple, time-matched on-treatment values. date: 2004-10 date_type: published publication: Indian Pacing and Electrophysiology Journal volume: 4 number: 4 publisher: Indian Pacing and Electrophysiology Group pagerange: 156-161 refereed: TRUE referencetext: 1. 1. Kautzener J. QT interval measurements : Card Electrophysiolol Rev 2002 Sep;6(3): 273-7 2. Lazzara R.Antiarrhythmic drugs and torsade de pointes.Eur Heart J 14 (suppl H):88,1993 3. Masatoshi Hassimoto, DVM. Accurate Evaluation of QT Interval in conscious Rhesus Monkeys by use of Holter ECG.J of Electro cardiology Vol, 35 No 4 2002; 333-342 4. Denes P. The importance of derived 12-lead Electrocardiography in the Interpretation of Arrhythmias detected by Holter recording. Am Heart J. 1992 Oct; 124(4):905-11. 5. Kowey KR, Kocovic DZ. Ambulatory Electrocardiographic Recording. Circulation 2003;108:e31-e33) 6. Ng J, Sahakian AV, Swiryn S. Accelerometer-based Body- position sensing for Ambulatory Electrocardiographic Monitoring. Biomed Instrum Technol. 2003 Sep- Oct; 37(5): 338-46. 7. Shiner Z, Baharav A, Akselrod S. Detection of different Recumbent Body positions from the Electrocardiogram. Med Biol Eng Comput. 2003 Mar; 41(2):206-10. 8. Jones AY, Kam C, Lai KW, Lee HY, Chow HT, Lau SF, Wong LM, He J. Changes in Heart rate and R-wave Amplitude with Posture. Chin J Physiol 2003 Jun 30; 46(2):63-9 9. Bethge KP, Gonska BD: Long-term electrocardiography: value and reliability of various systems. Z Kardiol. 1985 Oct; 74(10):567-79. 10. Sarapa N, Morganroth J, Couderc JP, Francom SF, Darpo B, Fleishaker JC, McEnroe JD, Chen WT, Zareba W, Moss AJ. Electrocardiographic identification of drug-induced QT prolongation: assessment by different recording and measurement methods. Ann Noninvasive Electrocardiol. 2004 Jan; 9(1):48-57. 11. Zhou SH, Wong S, Rautaharju PM, Karnik N, Calhoun HP. Should the JT rather than the QT interval be used to Detect Prolongation of Ventricular Repolarization? An Assessment in Normal Conduction and in Ventricular Conduction Defects. J Electrocardiol 1992; 25: Suppl: 131-6 12. Das G. QT interval and Repolarization Time in Patients with Intraventricular Conduction Delay. J Electrocardiol. 1990 Jan;23(1):49-52. 13. Crow RS, Hannan PJ, Folsom AR. Prognostic Significance of Corrected QT and corrected JT interval for incident Coronary Heart Disease in a general population sample stratified by presence or absence of wide QRS complex: the ARIC Study with 13 years of follow-up Circulation. 2003 Oct 21; 108(16):1985-9. Epub 2003 Sep 29. 14. Moss AJ. The QT interval and torsade de pointes.Drug Safety 1999; 21(1):5-10. citation: Lanjewar, Pallavi and Pathak, Vaishali and Lokhandwala, Yash (2004) Issues in QT interval measurement. [Journal (Paginated)] document_url: http://cogprints.org/4178/1/yash3.pdf