BACKGROUND: Mexiletine is often used for medical therapy in LQT3 patients, however, the usefulness of mexiletine infusion test for LQT3 patients has not been reported. The aim of this study was to evaluate the usefulness of mexiletine infusion test for detecting LQT3 patients. METHODS AND RESULTS: We analyzed response in 12-lead electrocardiogram parameters measured in II or V5 to i.v. mexiletine infusion (2 mg/kg) during sinus rhythm among 31 genotype-positive LQT patients (29 ± 18 years, 12 male). Change in QTc interval after mexiletine was compared between LQT3 (n=15, 24 ± 21 years, 9 male) and other LQT patients (4 LQT1 and 12 LQT2; 34 ± 14 years, 3 male). Baseline RR, QT, and QTc interval were not different between the 2 groups (981 ± 182 vs. 1,023 ± 192 ms; 550 ± 94 vs. 524 ± 75 ms; 556 ± 66 vs. 520 ± 62 ms, respectively). While QTc interval was shortened with mexiletine in both groups (P<0.0001 vs. baseline), degree of QTc shortening (∆QTc) was significantly larger in LQT3 than in LQT1/LQT2 patients (99 ± 39 vs. 48 ± 32 ms; P=0.0004). The sensitivity, specificity and predictive accuracy of mexiletine infusion test for differentiating LQT3 from LQT1/LQT2 were 86.7%, 81.3% and 81.3%, respectively, and the optimal cut-off for ∆QTc was 69 ms on receiver operating characteristic analysis. No pro-arrhythmic event was observed. CONCLUSIONS: Pronounced shortening of QT interval with mexiletine may facilitate genetic testing in patients with LQT3 syndrome.
BACKGROUND:Mexiletine is often used for medical therapy in LQT3patients, however, the usefulness of mexiletine infusion test for LQT3patients has not been reported. The aim of this study was to evaluate the usefulness of mexiletine infusion test for detecting LQT3patients. METHODS AND RESULTS: We analyzed response in 12-lead electrocardiogram parameters measured in II or V5 to i.v. mexiletine infusion (2 mg/kg) during sinus rhythm among 31 genotype-positive LQT patients (29 ± 18 years, 12 male). Change in QTc interval after mexiletine was compared between LQT3 (n=15, 24 ± 21 years, 9 male) and other LQT patients (4 LQT1 and 12 LQT2; 34 ± 14 years, 3 male). Baseline RR, QT, and QTc interval were not different between the 2 groups (981 ± 182 vs. 1,023 ± 192 ms; 550 ± 94 vs. 524 ± 75 ms; 556 ± 66 vs. 520 ± 62 ms, respectively). While QTc interval was shortened with mexiletine in both groups (P<0.0001 vs. baseline), degree of QTc shortening (∆QTc) was significantly larger in LQT3 than in LQT1/LQT2patients (99 ± 39 vs. 48 ± 32 ms; P=0.0004). The sensitivity, specificity and predictive accuracy of mexiletine infusion test for differentiating LQT3 from LQT1/LQT2 were 86.7%, 81.3% and 81.3%, respectively, and the optimal cut-off for ∆QTc was 69 ms on receiver operating characteristic analysis. No pro-arrhythmic event was observed. CONCLUSIONS: Pronounced shortening of QT interval with mexiletine may facilitate genetic testing in patients with LQT3 syndrome.
Authors: Rou-Mu Hu; David J Tester; Ryan Li; Tianyu Sun; Blaise Z Peterson; Michael J Ackerman; Jonathan C Makielski; Bi-Hua Tan Journal: Channels (Austin) Date: 2018 Impact factor: 2.581
Authors: Arthur A M Wilde; Christopher Semsarian; Manlio F Márquez; Alireza Sepehri Shamloo; Michael J Ackerman; Euan A Ashley; Back Sternick Eduardo; Héctor Barajas-Martinez; Elijah R Behr; Connie R Bezzina; Jeroen Breckpot; Philippe Charron; Priya Chockalingam; Lia Crotti; Michael H Gollob; Steven Lubitz; Naomasa Makita; Seiko Ohno; Martín Ortiz-Genga; Luciana Sacilotto; Eric Schulze-Bahr; Wataru Shimizu; Nona Sotoodehnia; Rafik Tadros; James S Ware; David S Winlaw; Elizabeth S Kaufman; Takeshi Aiba; Andreas Bollmann; Jong-Il Choi; Aarti Dalal; Francisco Darrieux; John Giudicessi; Mariana Guerchicoff; Kui Hong; Andrew D Krahn; Ciorsti Mac Intyre; Judith A Mackall; Lluís Mont; Carlo Napolitano; Pablo Ochoa Juan; Petr Peichl; Alexandre C Pereira; Peter J Schwartz; Jon Skinner; Christoph Stellbrink; Jacob Tfelt-Hansen; Thomas Deneke Journal: J Arrhythm Date: 2022-05-31
Authors: Arthur A M Wilde; Christopher Semsarian; Manlio F Márquez; Alireza Sepehri Shamloo; Michael J Ackerman; Euan A Ashley; Eduardo Back Sternick; Héctor Barajas-Martinez; Elijah R Behr; Connie R Bezzina; Jeroen Breckpot; Philippe Charron; Priya Chockalingam; Lia Crotti; Michael H Gollob; Steven Lubitz; Naomasa Makita; Seiko Ohno; Martín Ortiz-Genga; Luciana Sacilotto; Eric Schulze-Bahr; Wataru Shimizu; Nona Sotoodehnia; Rafik Tadros; James S Ware; David S Winlaw; Elizabeth S Kaufman; Takeshi Aiba; Andreas Bollmann; Jong Il Choi; Aarti Dalal; Francisco Darrieux; John Giudicessi; Mariana Guerchicoff; Kui Hong; Andrew D Krahn; Ciorsti MacIntyre; Judith A Mackall; Lluís Mont; Carlo Napolitano; Juan Pablo Ochoa; Petr Peichl; Alexandre C Pereira; Peter J Schwartz; Jon Skinner; Christoph Stellbrink; Jacob Tfelt-Hansen; Thomas Deneke Journal: Europace Date: 2022-09-01 Impact factor: 5.486
Authors: Gang Li; Ryan L Woltz; Cheng-Yu Wang; Lu Ren; Pei-Xin He; Shan-Dong Yu; Xue-Qin Liu; Vladimir Yarov-Yarovoy; Dan Hu; Nipavan Chiamvimonvat; Lin Wu Journal: Front Pharmacol Date: 2020-08-04 Impact factor: 5.810
Authors: Ivan Gando; Chiara Campana; Reina Bianca Tan; Frank Cecchin; Eric A Sobie; William A Coetzee Journal: J Mol Cell Cardiol Date: 2020-04-24 Impact factor: 5.000