BACKGROUND: Nearly 40% of patients with long QT syndrome (LQTS) can have a nondiagnostic QTc at rest. Treadmill and cycle exercise stress testing are used in the diagnostic evaluation of LQTS. OBJECTIVE: The purpose of this study was to determine the diagnostic significance of peak exercise and recovery phase QTc values during treadmill stress testing in LQTS. METHODS: An Institutional Review Board-approved, retrospective analysis was performed on the treadmill stress tests in 243 patients including 82 LQT1, 55 LQT2, 18 LQT3, and 88 genotype-negative patients dismissed as normal. Blinded to genotype, QTc was calculated at rest, peak exercise, and 1, 2, 3, 4, and 5 minutes of recovery. RESULTS: Compared with those dismissed as normal, the average QTc was greater at all scored stages in LQT1 and LQT3 patients and at all stages in LQT2 patients except peak exercise and 1 minute of recovery (P < .01). Either an absolute QTc ≥ 460 ms during the recovery phase or a maladaptive, paradoxical increase in QTc, defined as QTc recovery--QTc baseline ≥ 30 ms (ΔQTc), distinguished patients with either manifest or concealed LQT1 from all other subsets (P < .0001). The presence of beta-blockers did not blunt these abnormal repolarization profiles. CONCLUSION: Treadmill stress testing can unmask patients with concealed LQTS, particularly LQT1, with good diagnostic accuracy.
BACKGROUND: Nearly 40% of patients with long QT syndrome (LQTS) can have a nondiagnostic QTc at rest. Treadmill and cycle exercise stress testing are used in the diagnostic evaluation of LQTS. OBJECTIVE: The purpose of this study was to determine the diagnostic significance of peak exercise and recovery phase QTc values during treadmill stress testing in LQTS. METHODS: An Institutional Review Board-approved, retrospective analysis was performed on the treadmill stress tests in 243 patients including 82 LQT1, 55 LQT2, 18 LQT3, and 88 genotype-negative patients dismissed as normal. Blinded to genotype, QTc was calculated at rest, peak exercise, and 1, 2, 3, 4, and 5 minutes of recovery. RESULTS: Compared with those dismissed as normal, the average QTc was greater at all scored stages in LQT1 and LQT3patients and at all stages in LQT2patients except peak exercise and 1 minute of recovery (P < .01). Either an absolute QTc ≥ 460 ms during the recovery phase or a maladaptive, paradoxical increase in QTc, defined as QTc recovery--QTc baseline ≥ 30 ms (ΔQTc), distinguished patients with either manifest or concealed LQT1 from all other subsets (P < .0001). The presence of beta-blockers did not blunt these abnormal repolarization profiles. CONCLUSION: Treadmill stress testing can unmask patients with concealed LQTS, particularly LQT1, with good diagnostic accuracy.
Authors: Arnon Adler; Christian van der Werf; Pieter G Postema; Raphael Rosso; Zahir A Bhuiyan; Jonathan M Kalman; Jitendra K Vohra; Milton E Guevara-Valdivia; Manlio F Marquez; Amir Halkin; Jesaia Benhorin; Charles Antzelevitch; Arthur A M Wilde; Sami Viskin Journal: Heart Rhythm Date: 2012-01-31 Impact factor: 6.343
Authors: Josef Halamek; Jean-Philippe Couderc; Pavel Jurak; Vlastimil Vondra; Wojciech Zareba; Ivo Viscor; Pavel Leinveber Journal: Ann Noninvasive Electrocardiol Date: 2012-08-13 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