Yuko Y Inoue1, Takeshi Aiba1, Hiro Kawata1, Tomoko Sakaguchi2, Wataru Mitsuma3, Hiroshi Morita4, Takashi Noda1, Hiroshi Takaki1, Keiko Toyohara5, Yoshiaki Kanaya6, Toshiyuki Itoi7, Takeshi Mitsuhashi8, Naokata Sumitomo9, Yongkeun Cho10, Satoshi Yasuda1, Shiro Kamakura1, Kengo Kusano1, Yoshihiro Miyamoto11, Minoru Horie2, Wataru Shimizu1,12. 1. Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, 5-7-1 Fujishiro-dai, Suita, Osaka, Japan. 2. Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Setatsukinowacho, Otsu, Shiga, Japan. 3. Department of Cardiovascular Biology and Medicine, Niigata University Graduate School of Medical and Dental Sciences, 757 Ichibancho, Asahimachidori, Chuo-ku, Niigata, Niigata, Japan. 4. Department of Cardiovascular Therapeutics, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, 2-5-1 Shikatacho, Kita, Okayama, Okayama, Japan. 5. Department of Pediatric Cardiology, Tokyo Women's Medical University, 8-1 Kawadacho, Shinjuku, Tokyo, Japan. 6. Department of Pediatrics, Oita Prefectural Hospital, 476 Bunyo, Oita, Oita, Japan. 7. Department of Pediatrics, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, Kajii-cho, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, Kyoto, Japan. 8. Division of Cardiovascular Medicine, Department of Medicine, Saitama Medical Center Jichi Medical University, 1-847 Amanuma, Omiya-ku, Saitama, Saitama, Japan. 9. Department of Pediatric Cardiology, Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka, Saitama, Japan. 10. Department of Cardiology, Kyungpook National University Hospital, Daegu, 130 Dongdeok-ro, Jung-gu, Daegu, Republic of Korea. 11. Department of Preventive Cardiology, National Cerebral and Cardiovascular Center, 5-7-1 Fujishiro-dai, Suita, Osaka, Japan. 12. Department of Cardiovascular Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, Japan.
Abstract
Aims: Andersen-Tawil Syndrome (ATS) and catecholaminergic polymorphic ventricular tachycardia (CPVT) are both inherited arrhythmic disorders characterized by bidirectional ventricular tachycardia (VT). The aim of this study was to evaluate the diagnostic value of exercise stress tests for differentiating between ATS and CPVT. Methods and results: We included 26 ATS patients with KCNJ2 mutations from 22 families and 25 CPVT patients with RyR2 mutations from 22 families. We compared the clinical and electrocardiographic (ECG) characteristics, responses of ventricular arrhythmias (VAs) to exercise testing, and the morphology of VAs between ATS and CPVT patients. Ventricular arrhythmias were more frequently observed at baseline in ATS patients compared with CPVT patients [the ratio of ventricular premature beats (VPBs)/sinus: 0.83 ± 1.87 vs. 0.06 ± 0.30, P = 0.01]. At peak exercise, VAs were suppressed in ATS patients, whereas they were increased in CPVT patients (0.14 ± 0.40 vs. 1.94 ± 2.71, P < 0.001). Twelve-lead ECG showed that all 25 VPBs and 15 (94%) of 16 bidirectional VTs were right bundle branch block (RBBB) morphology in ATS patients, whereas 19 (86%) of 22 VPBs had left bundle branch block (LBBB), and 12 (71%) of 17 bidirectional VT had LBBB and RBBB morphologies in CPVT patients. Conclusion: In patients with ATS, VAs with RBBB morphology were frequently observed at baseline and suppressed at peak exercise. In contrast, exercise provoked VAs with mainly LBBB morphology in patients with CPVT. In adjunct to clinical and baseline ECG assessments, exercise testing might be useful for making the diagnosis of ATS vs. CPVT, both characterized by bidirectional VT.
Aims: Andersen-Tawil Syndrome (ATS) and catecholaminergic polymorphic ventricular tachycardia (CPVT) are both inherited arrhythmic disorders characterized by bidirectional ventricular tachycardia (VT). The aim of this study was to evaluate the diagnostic value of exercise stress tests for differentiating between ATS and CPVT. Methods and results: We included 26 ATS patients with KCNJ2 mutations from 22 families and 25 CPVT patients with RyR2 mutations from 22 families. We compared the clinical and electrocardiographic (ECG) characteristics, responses of ventricular arrhythmias (VAs) to exercise testing, and the morphology of VAs between ATS and CPVT patients. Ventricular arrhythmias were more frequently observed at baseline in ATS patients compared with CPVT patients [the ratio of ventricular premature beats (VPBs)/sinus: 0.83 ± 1.87 vs. 0.06 ± 0.30, P = 0.01]. At peak exercise, VAs were suppressed in ATS patients, whereas they were increased in CPVT patients (0.14 ± 0.40 vs. 1.94 ± 2.71, P < 0.001). Twelve-lead ECG showed that all 25 VPBs and 15 (94%) of 16 bidirectional VTs were right bundle branch block (RBBB) morphology in ATS patients, whereas 19 (86%) of 22 VPBs had left bundle branch block (LBBB), and 12 (71%) of 17 bidirectional VT had LBBB and RBBB morphologies in CPVT patients. Conclusion: In patients with ATS, VAs with RBBB morphology were frequently observed at baseline and suppressed at peak exercise. In contrast, exercise provoked VAs with mainly LBBB morphology in patients with CPVT. In adjunct to clinical and baseline ECG assessments, exercise testing might be useful for making the diagnosis of ATS vs. CPVT, both characterized by bidirectional VT.