BACKGROUND: Patients with long QT syndrome (LQTS) have inadequate shortening of the QT interval in response to the sudden heart rate accelerations provoked by standing-a phenomenon of diagnostic value. We now validate our original observations in a cohort twice as large. We also describe that this abnormal QT-interval response persists as the heart rate acceleration returns to baseline. OBJECTIVES: To describe a novel observation, termed "QT stunning" and to validate previous observations regarding the "QT-stretching" phenomenon in patients with LQTS by using our recently described "standing test." METHODS: The electrocardiograms of 108 patients with LQTS and 112 healthy subjects were recorded in the supine position. Subjects were then instructed to stand up quickly and remain standing for 5 minutes during continuous electrocardiographic recording. The corrected QT interval was measured at baseline (QTc(base)), when heart rate acceleration without appropriate QT-interval shortening leads to maximal QT stretching (QTc(stretch)) and upon return of heart rate to baseline (QTc(return)). RESULTS: QTc(stretch) lengthened significantly more in patients with LQTS (103 ± 80 ms vs 66 ± 40 ms in controls; P <.001) and so did QTc(return) (28 ± 48 ms for patients with LQTS vs -3 ± 32 ms for controls; P <.001). Using a sensitivity cutoff of 90%, the specificity for diagnosing LQTS was 74% for QTc(base), 84% for QTc(return), and 87% for QTc(stretch). CONCLUSIONS: The present study extends our previous findings on the abnormal response of the QT interval in response to standing in patients with LQTS. Our study also shows that this abnormal response persists even after the heart rate slows back to baseline.
BACKGROUND:Patients with long QT syndrome (LQTS) have inadequate shortening of the QT interval in response to the sudden heart rate accelerations provoked by standing-a phenomenon of diagnostic value. We now validate our original observations in a cohort twice as large. We also describe that this abnormal QT-interval response persists as the heart rate acceleration returns to baseline. OBJECTIVES: To describe a novel observation, termed "QT stunning" and to validate previous observations regarding the "QT-stretching" phenomenon in patients with LQTS by using our recently described "standing test." METHODS: The electrocardiograms of 108 patients with LQTS and 112 healthy subjects were recorded in the supine position. Subjects were then instructed to stand up quickly and remain standing for 5 minutes during continuous electrocardiographic recording. The corrected QT interval was measured at baseline (QTc(base)), when heart rate acceleration without appropriate QT-interval shortening leads to maximal QT stretching (QTc(stretch)) and upon return of heart rate to baseline (QTc(return)). RESULTS:QTc(stretch) lengthened significantly more in patients with LQTS (103 ± 80 ms vs 66 ± 40 ms in controls; P <.001) and so did QTc(return) (28 ± 48 ms for patients with LQTS vs -3 ± 32 ms for controls; P <.001). Using a sensitivity cutoff of 90%, the specificity for diagnosing LQTS was 74% for QTc(base), 84% for QTc(return), and 87% for QTc(stretch). CONCLUSIONS: The present study extends our previous findings on the abnormal response of the QT interval in response to standing in patients with LQTS. Our study also shows that this abnormal response persists even after the heart rate slows back to baseline.
Authors: Anthony A Fossa; Meijian Zhou; Nuala Brennan; Patrick Round; John Ford Journal: Ann Noninvasive Electrocardiol Date: 2013-09-09 Impact factor: 1.468
Authors: Martin K Stiles; Arthur A M Wilde; Dominic J Abrams; Michael J Ackerman; Christine M Albert; Elijah R Behr; Sumeet S Chugh; Martina C Cornel; Karen Gardner; Jodie Ingles; Cynthia A James; Jyh-Ming Jimmy Juang; Stefan Kääb; Elizabeth S Kaufman; Andrew D Krahn; Steven A Lubitz; Heather MacLeod; Carlos A Morillo; Koonlawee Nademanee; Vincent Probst; Elizabeth V Saarel; Luciana Sacilotto; Christopher Semsarian; Mary N Sheppard; Wataru Shimizu; Jonathan R Skinner; Jacob Tfelt-Hansen; Dao Wu Wang Journal: Heart Rhythm Date: 2020-10-19 Impact factor: 6.343
Authors: Martin K Stiles; Arthur A M Wilde; Dominic J Abrams; Michael J Ackerman; Christine M Albert; Elijah R Behr; Sumeet S Chugh; Martina C Cornel; Karen Gardner; Jodie Ingles; Cynthia A James; Jyh-Ming Jimmy Juang; Stefan Kääb; Elizabeth S Kaufman; Andrew D Krahn; Steven A Lubitz; Heather MacLeod; Carlos A Morillo; Koonlawee Nademanee; Vincent Probst; Elizabeth V Saarel; Luciana Sacilotto; Christopher Semsarian; Mary N Sheppard; Wataru Shimizu; Jonathan R Skinner; Jacob Tfelt-Hansen; Dao Wu Wang Journal: J Arrhythm Date: 2021-04-08
Authors: Arja S Vink; Ben J M Hermans; Joana Pimenta; Puck J Peltenburg; Luc H P M Filippini; Nynke Hofman; Sally-Ann B Clur; Nico A Blom; Arthur A M Wilde; Tammo Delhaas; Pieter G Postema Journal: Heart Rhythm O2 Date: 2021-03-13
Authors: Lee L Eckhardt; Elizabeth S Kaufman; Michael J Ackerman; Peter F Aziz; Elijah R Behr; Marina Cerrone; Mina K Chung; Michael J Cutler; Susan P Etheridge; Andrew D Krahn; Steven A Lubitz; Marco V Perez; Silvia G Priori; Jason D Roberts; Dan M Roden; Eric Schulze-Bahr; Peter J Schwartz; Wataru Shimizu; M Benjamin Shoemaker; Raymond W Sy; Jeffrey A Towbin; Sami Viskin; Arthur A M Wilde; Wojciech Zareba Journal: Circ Arrhythm Electrophysiol Date: 2021-07-09