1
|
Yoshinaga M, Ninomiya Y, Tanaka Y, Fukuyama M, Kato K, Ohno S, Horie M, Ogata H. Holter Electrocardiographic Approach to Predicting Outcomes of Pediatric Patients With Long QT Syndrome. Circ J 2024; 88:1176-1184. [PMID: 38044147 DOI: 10.1253/circj.cj-23-0409] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
BACKGROUND This study was performed to clarify the clinical findings of pediatric patients diagnosed with long QT syndrome (LQTS) through electrocardiographic screening programs and to predict their outcome using Holter electrocardiographic approaches.Methods and Results: This retrospective study included pediatric patients with a Schwartz score of ≥3.5 who visited the National Hospital Organization Kagoshima Medical Center between April 2005 and March 2019. Resting 12-lead and Holter electrocardiograms were recorded at every visit. The maximum resting QTc and maximum Holter QTc values among all recordings were used for statistical analyses. To test the prognostic value of QTc for the appearance of cardiac events after the first hospital visit, receiver operating characteristic curves were used to calculate the area under the curve (AUC). Among 207 patients, 181 (87%) were diagnosed through screening programs. The prevalence of cardiac events after the first hospital visit was 4% (8/207). Among QTc at diagnosis, maximum resting QTc, and maximum Holter QTc, only maximum Holter QTc value was a predictor (P=0.02) of cardiac events after the hospital visit in multivariate regression analysis. The AUC of the maximum Holter QTc was significantly superior to that of maximum resting QTc. CONCLUSIONS The maximum Holter QTc value can be used to predict the appearance of symptoms in pediatric patients with LQTS.
Collapse
Affiliation(s)
- Masao Yoshinaga
- Department of Pediatrics, National Hospital Organization Kagoshima Medical Center
- Orange Medical and Welfare Center for Severe Motor and Intellectual Disabilities
| | - Yumiko Ninomiya
- Department of Pediatrics, National Hospital Organization Kagoshima Medical Center
| | - Yuji Tanaka
- Department of Pediatrics, National Hospital Organization Kagoshima Medical Center
| | - Megumi Fukuyama
- Department of Cardiovascular Medicine, Shiga University of Medical Science
| | - Koichi Kato
- Department of Cardiovascular Medicine, Shiga University of Medical Science
| | - Seiko Ohno
- Department of Bioscience and Genetics, National Cerebral and Cardiovascular Center
| | - Minoru Horie
- Department of Cardiovascular Medicine, Shiga University of Medical Science
| | | |
Collapse
|
2
|
Koponen M, Marjamaa A, Väänänen H, Tuiskula AM, Kontula K, Swan H, Viitasalo M. Effects of beta-blockers on ventricular repolarization documented by 24-h electrocardiography in long-QT syndrome type 2. Heart Rhythm 2022; 19:1491-1498. [PMID: 35525424 DOI: 10.1016/j.hrthm.2022.04.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 04/11/2022] [Accepted: 04/27/2022] [Indexed: 11/04/2022]
Abstract
BACKGROUND Long QT syndrome (LQTS) is an inherited arrhythmia disorder characterized by ventricular repolarization abnormalities and a risk of sudden cardiac death. The electrophysiological components generating the high risk of arrhythmias in LQTS are prolonged repolarization, increased dispersion of repolarization, and early afterdepolarizations, which are clinically estimated as QT interval, T-wave peak to end (TPE) interval, and T2/T1-wave amplitude ratio, respectively. In experimental LQTS type 2 (LQT2) models, beta-blockers decrease dispersion of repolarization and prevent early afterdepolarizations. In clinical studies among LQT2 patients beta-blockers are more effective against exercise-induced than arousal-induced cardiac events. OBJECTIVES AND METHODS The aim of the study was to investigate the effects of beta-blocker therapy on QT and TPE intervals, and maximal T2/T1-wave amplitude ratios recorded by 24-h electrocardiograms (ECG) among 25 LQT2 patients. RESULTS Beta-blocker therapy decreased the maximal T2/T1-wave amplitude ratio from 2.9±1.1 to 1.8±0.7 (p<0.001), but did not change pause-induced T2/T1-wave amplitude ratio. Under medication abrupt maximal TPE intervals were shorter at heart rates of 75 beats/min or over, and maximal QT intervals were shorter at a heart rate of 100 beats/min. CONCLUSIONS Beta-blockers stabilize ventricular repolarization in LQT2 by reducing electrocardiographic early afterdepolarizations, and by reducing abrupt prolongation of electrocardiographic dispersion of repolarization and ventricular repolarization duration at elevated heart rates. The effect of beta-blockers on pause-induced electrocardiographic early afterdepolarizations is weak. The findings provide electrocardiographic explanation for the protective effects of beta-blockers against exercise-induced cardiac events in LQT2.
Collapse
Affiliation(s)
- Mikael Koponen
- Heart and Lung Center, Helsinki University Hospital, Helsinki, Finland.
| | - Annukka Marjamaa
- Heart and Lung Center, Helsinki University Hospital, Helsinki, Finland
| | - Heikki Väänänen
- Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland
| | - Annukka M Tuiskula
- Department of Medicine, Helsinki University Hospital and University of Helsinki, Helsinki, Finland; HUS Diagnostic Center, Laboratory of Genetics, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Kimmo Kontula
- Department of Medicine, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Heikki Swan
- Heart and Lung Center, Helsinki University Hospital, Helsinki, Finland
| | - Matti Viitasalo
- Heart and Lung Center, Helsinki University Hospital, Helsinki, Finland
| |
Collapse
|
3
|
Yodogawa K, Aiba T, Sumitomo N, Yamamoto T, Murata H, Iwasaki YK, Kokubo Y, Shimizu W. Differential diagnosis between LQT1 and LQT2 by QT/RR relationships using 24-hour Holter monitoring: A multicenter cross-sectional study. Ann Noninvasive Electrocardiol 2021; 26:e12878. [PMID: 34245193 PMCID: PMC8411756 DOI: 10.1111/anec.12878] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 05/16/2021] [Accepted: 06/29/2021] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND The clinical course and therapeutic strategies in the congenital long QT syndrome (LQTS) are genotype-specific. However, accurate estimation of LQTS genotype is often difficult from the standard 12-lead ECG. OBJECTIVES This study aims to evaluate the utility of QT/RR slope analysis by the 24-hour Holter monitoring for differential diagnosis of LQTS genotype between LQT1 and LQT2. METHODS This cross-sectional study enrolled 54 genetically identified LQTS patients (29 LQT1 and 25 LQT2) recruited from three medical institutions. The QT-apex (QTa) interval and the QT-end (QTe) interval at each 15-second were plotted against the RR intervals, and the linear regression (QTa/RR and QTe/RR slopes, respectively) was calculated from the entire 24-hour and separately during the day or night-time periods of the Holter recordings. RESULTS The QTe/RR and QTa/RR slopes at the entire 24-hour were significantly steeper in LQT2 compared to those in LQT1 patients (0.262 ± 0.063 vs. 0.204 ± 0.055, p = .0007; 0.233 ± 0.052 vs. 0.181 ± 0.040, p = .0002, respectively). The QTe interval was significantly longer, and QTe/RR and QTa/RR slopes at daytime were significantly steeper in LQT2 than in LQT1 patients. The receiver operating curve analysis revealed that the QTa/RR slope of 0.211 at the entire 24-hour Holter was the best cutoff value for differential diagnosis between LQT1 and LQT2 (sensitivity: 80.0%, specificity: 75.0%, and area under curve: 0.804 [95%CI = 0.68-0.93]). CONCLUSION The continuous 24-hour QT/RR analysis using the Holter monitoring may be useful to predict the genotype of congenital LQTS, particularly for LQT1 and LQT2.
Collapse
Affiliation(s)
- Kenji Yodogawa
- Department of Cardiovascular Medicine, Nippon Medical School, Tokyo, Japan
| | - Takeshi Aiba
- Department of Advanced Arrhythmia and Translational Medical Science, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Naotaka Sumitomo
- Department of Pediatric Cardiology, Saitama Medical University International Medical Center, Saitama, Japan
| | - Teppei Yamamoto
- Department of Cardiovascular Medicine, Nippon Medical School, Tokyo, Japan
| | - Hiroshige Murata
- Department of Cardiovascular Medicine, Nippon Medical School, Tokyo, Japan
| | - Yu-Ki Iwasaki
- Department of Cardiovascular Medicine, Nippon Medical School, Tokyo, Japan
| | - Yoshihiro Kokubo
- Department of Preventive Cardiology, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Wataru Shimizu
- Department of Cardiovascular Medicine, Nippon Medical School, Tokyo, Japan
| |
Collapse
|
4
|
Niimi N, Yuki K, Zaleski K. Long QT Syndrome and Perioperative Torsades de Pointes: What the Anesthesiologist Should Know. J Cardiothorac Vasc Anesth 2020; 36:286-302. [PMID: 33495078 DOI: 10.1053/j.jvca.2020.12.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 11/16/2020] [Accepted: 12/07/2020] [Indexed: 02/08/2023]
Affiliation(s)
- Naoko Niimi
- Department of Anesthesiology, Juntendo University, Tokyo, Japan.
| | - Koichi Yuki
- Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Boston, MA; Department of Anesthesia, Harvard Medical School, Boston, MA
| | - Katherine Zaleski
- Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Boston, MA; Department of Anesthesia, Harvard Medical School, Boston, MA
| |
Collapse
|
5
|
Jalanko M, Väänänen H, Tarkiainen M, Sipola P, Jääskeläinen P, Lauerma K, Laitinen T, Laitinen T, Laine M, Heliö T, Kuusisto J, Viitasalo M. Fibrosis and wall thickness affect ventricular repolarization dynamics in hypertrophic cardiomyopathy. Ann Noninvasive Electrocardiol 2018; 23:e12582. [PMID: 29974557 DOI: 10.1111/anec.12582] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 05/11/2018] [Accepted: 06/06/2018] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Hypertrophic cardiomyopathy (HCM) is characterized by ventricular repolarization abnormalities and risk of ventricular arrhythmias. Our aim was to study the association between the phenotype and ventricular repolarization dynamics in HCM patients. METHODS HCM patients with either the MYBPC3-Q1061X or TPM1-D175N mutation (n = 46) and control subjects without mutation and hypertrophy (n = 35) were studied with 24-hr ambulatory ECG recordings by measuring time intervals of rate-adapted QT (QTe), maximal QT, and T-wave apex to wave end (TPE) intervals and the QTe/RR slope. Findings were correlated to specified echocardiographic and cardiac magnetic resonance imaging (CMRI) findings. RESULTS Rate-adapted QTe interval was progressively longer in HCM patients with decreasing heart rates compared to control subjects (p = 0.020). The degree of hypertrophy correlated with measured QTe values. HCM patients with maximal wall thickness higher than the mean (20.6 mm) had longer maximum QTe and median TPE intervals compared to control subjects and HCM patients with milder hypertrophy (p < 0.001 and p = 0.014, respectively). HCM patients with late gadolinium enhancement (LGE) on CMRI had steeper QTe/RR slopes compared to HCM patients without LGE and control subjects (p = 0.044 and p = 0.001, respectively). LGE was an independent predictor of QTe/RR slope (p = 0.023, B = 0.043). CONCLUSION Dynamics of ventricular repolarization in HCM are affected by hypertrophy and fibrosis. LGE may confer an independent effect on QT dynamics which may increase the arrhythmogenic potential in HCM.
Collapse
Affiliation(s)
- Mikko Jalanko
- Department of Cardiology, Heart and Lung Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Heikki Väänänen
- Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland
| | - Mika Tarkiainen
- Department of Radiology, Kuopio University Hospital, Kuopio, Finland
| | - Petri Sipola
- Department of Radiology, Kuopio University Hospital, Kuopio, Finland
| | | | - Kirsi Lauerma
- Department of Radiology, Helsinki University Hospital, Helsinki, Finland
| | - Tiina Laitinen
- Department of Clinical Physiology, Kuopio University Hospital, Kuopio, Finland
| | - Tomi Laitinen
- Department of Clinical Physiology, Kuopio University Hospital, Kuopio, Finland
| | - Mika Laine
- Department of Cardiology, Heart and Lung Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Tiina Heliö
- Department of Cardiology, Heart and Lung Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Johanna Kuusisto
- Centre for Medicine and Clinical Research, University of Eastern Finland and Kuopio University Hospital, Kuopio, Finland
| | - Matti Viitasalo
- Department of Cardiology, Heart and Lung Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| |
Collapse
|
6
|
Ogawa Y, Tanaka T, Kido S. Maximum QTc on Holter electrocardiography in children. Pediatr Int 2018; 60:507-512. [PMID: 29575607 DOI: 10.1111/ped.13556] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 02/24/2018] [Accepted: 03/09/2018] [Indexed: 11/28/2022]
Abstract
BACKGROUND Corrected QT interval (QTc) on electrocardiography (ECG) at rest and after exercise in a short daytime recording period may be insufficient for the diagnosis and management of long QT syndrome (LQTS), especially for LQTS type 2 and 3. Therefore, examination of QTc on Holter ECG is important. We designed a method of analyzing QTc on Holter ECG that can be performed in daily clinical practice by combining automatic and manual measurements. METHODS We reviewed the charts of healthy children (n = 210) and LQTS patients (n = 35) aged <16 years and analyzed QTc at rest and after exercise, and the maximum QTc on Holter ECG. RESULTS The QTc (Fridericia's correction) of most controls and LQTS patients reached the maximum at night or early in the morning. QTc differed according to sex and age. In the control group, QTc on ECG of all three types tended to lengthen with age. QTc after exercise was slightly longer than QTc at rest, and the maximum QTc on Holter ECG was much longer than both, reaching >450 ms in boys and 500 ms in girls. In most LQTS type 1 patients, QTc after exercise and that on Holter ECG tended to be long. In most LQTS type 2 and 3 patients, QTc at rest and that after exercise was long, and that on Holter ECG tended to be much longer. CONCLUSIONS The present method of analyzing QTc on Holter ECG, in which automatic and manual measurements are combined, is practical and may be useful for diagnosis and risk stratification of LQTS.
Collapse
Affiliation(s)
- Yoshiharu Ogawa
- Division of Cardiology, Hyogo Prefectural Kobe Children's Hospital, Kobe, Hyogo, Japan
| | - Toshikatsu Tanaka
- Division of Cardiology, Hyogo Prefectural Kobe Children's Hospital, Kobe, Hyogo, Japan
| | - Sachiko Kido
- Division of Cardiology, Hyogo Prefectural Kobe Children's Hospital, Kobe, Hyogo, Japan
| |
Collapse
|
7
|
Abstract
OBJECTIVE Menopausal hot flushes are associated with elevated activity of the sympathetic nervous system and may be related to increased risk for cardiovascular events. Sympathetic activation may trigger severe arrhythmias by modulating cardiac repolarization. The aim of this study was to evaluate the impact of hot flushes on cardiac repolarization in postmenopausal women with and without hot flushes. METHODS We assessed 150 recently postmenopausal healthy women-72 with hot flushes and 78 without hot flushes. They underwent 24-hour electrocardiographic recording, comprising a total of over 10,000,000 QT-interval measurements. The cardiac repolarization was assessed by measuring QT-intervals, heat rate dependence of QT-end intervals, and T-waves. RESULTS The maximal QT-end interval was shorter in women with hot flushes compared with those without hot flushes (481 ± 64 ms vs 493 ± 50 ms; P = 0.046). There were no differences between the rate dependence of QT-end intervals and T-wave measures between the groups. During the night-time hot flush period, we detected a steeper rate-dependence of QT-end intervals and a longer maximal T-peak-T-end interval (117 ± 54 ms vs 111 ± 56 ms; P < 0.001) compared with the control period. CONCLUSIONS Women with hot flushes did not have clinically significant differences in ambulatory cardiac repolarization measurements compared with asymptomatic women. However, a sudden sympathetic surge occurring during the night-time hot flush may have direct effects on cardiac repolarization.
Collapse
|
8
|
Follansbee CW, Beerman L, Arora G. Automated QT analysis on Holter monitors in pediatric patients can differentiate long QT syndrome from controls. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2018; 41:50-56. [DOI: 10.1111/pace.13244] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 10/26/2017] [Accepted: 11/26/2017] [Indexed: 12/31/2022]
Affiliation(s)
| | - Lee Beerman
- Division of Pediatric Cardiology; Children's Hospital of Pittsburgh of UPMC; Pittsburgh PA USA
| | - Gaurav Arora
- Division of Pediatric Cardiology; Children's Hospital of Pittsburgh of UPMC; Pittsburgh PA USA
| |
Collapse
|
9
|
Vasomotor hot flashes and cardiac repolarization: a randomized placebo-controlled trial of postmenopausal hormone therapy. Menopause 2017; 24:1386-1391. [PMID: 28697043 DOI: 10.1097/gme.0000000000000932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The aim of the study was to compare the effects of different hormone therapies on cardiac repolarization in recently postmenopausal women with and without hot flashes. METHODS We recruited 150 healthy women: 72 with and 78 without hot flashes. They were randomized and treated for 6 months with transdermal estradiol (1 mg/day), oral estradiol (OE) alone (2 mg/day) or combined with medroxyprogesterone acetate (MPA; 5 mg/day), or placebo. Cardiac repolarization was assessed by measuring QT intervals, rate-dependence of QT-end interval, and T waves from 24-hour electrocardiographic recording before and during hormone therapy, comprising a total of over 20 million QT-interval measurements. RESULTS Hot flashes were accompanied with shortened median T-peak - T-end interval (at RR interval of 700, 800, and 900 ms; P = 0.040, 0.020, and 0.032; η = 0.35, 0.39, and 0.37; respectively) during the use of OE but not transdermal estradiol. In contrast, the addition of MPA to OE lengthened the maximal QT-end (at RR interval of 500 ms, P = 0.016, η = 0.27) and the maximal T-peak - T-end interval (at RR interval of 500 and 600 ms; P = 0.016 and 0.032; η = 0.25 and 0.22, respectively). These effects were not seen in women without hot flashes. CONCLUSIONS Hot flashes predict beneficial shortening in cardiac repolarization during OE, but not if MPA is combined with OE. These data may provide one explanation for MPA-related cardiac hazards in epidemiological studies.
Collapse
|
10
|
Sugrue A, Noseworthy PA, Kremen V, Bos JM, Qiang B, Rohatgi RK, Sapir Y, Attia ZI, Brady P, Asirvatham SJ, Friedman PA, Ackerman MJ. Identification of Concealed and Manifest Long QT Syndrome Using a Novel T Wave Analysis Program. Circ Arrhythm Electrophysiol 2016; 9:CIRCEP.115.003830. [DOI: 10.1161/circep.115.003830] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 06/03/2016] [Indexed: 11/16/2022]
Abstract
Background—
Congenital long QT syndrome (LQTS) is characterized by QT prolongation. However, the QT interval itself is insufficient for diagnosis, unless the corrected QT interval is repeatedly ≥500 ms without an acquired explanation. Further, the majority of LQTS patients have a corrected QT interval below this threshold, and a significant minority has normal resting corrected QT interval values. Here, we aimed to develop and validate a novel, quantitative T wave morphological analysis program to differentiate LQTS patients from healthy controls.
Methods and Results—
We analyzed a genotyped cohort of 420 patients (22±16 years, 43% male) with either LQT1 (61%) or LQT2 (39%). ECG analysis was conducted using a novel, proprietary T wave analysis program that quantitates subtle changes in T wave morphology. The top 3 discriminating features in each ECG lead were determined and the lead with the best discrimination selected. Classification was performed using a linear discriminant classifier and validated on an untouched cohort. The top 3 features were Tpeak–Tend interval, T wave left slope, and T wave center of gravity
x
axis (last 25% of the T wave). Lead V6 had the best discrimination. It could distinguish 86.8% of LQTS patients from healthy controls. Moreover, it distinguished 83.33% of patients with concealed LQTS from controls, despite having essentially identical resting corrected QT interval values.
Conclusions—
T wave quantitative analysis on the 12-lead surface ECG provides an effective, novel tool to distinguish patients with either LQT1/LQT2 from healthy matched controls. It can provide guidance while mutation-specific genetic testing is in motion for family members.
Collapse
Affiliation(s)
- Alan Sugrue
- From the Division of Internal Medicine (A.S.), Division of Cardiovascular Diseases (P.A.N., V.K., B.Q., R.K.R., Z.I.A., P.B., S.J.A., P.A.F., M.J.A.), Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology (J.M.B., S.J.A., M.J.A.), Mayo Clinic, Rochester, MN; Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Czech Republic (V.K.); Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel (Y.S
| | - Peter A. Noseworthy
- From the Division of Internal Medicine (A.S.), Division of Cardiovascular Diseases (P.A.N., V.K., B.Q., R.K.R., Z.I.A., P.B., S.J.A., P.A.F., M.J.A.), Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology (J.M.B., S.J.A., M.J.A.), Mayo Clinic, Rochester, MN; Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Czech Republic (V.K.); Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel (Y.S
| | - Vaclav Kremen
- From the Division of Internal Medicine (A.S.), Division of Cardiovascular Diseases (P.A.N., V.K., B.Q., R.K.R., Z.I.A., P.B., S.J.A., P.A.F., M.J.A.), Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology (J.M.B., S.J.A., M.J.A.), Mayo Clinic, Rochester, MN; Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Czech Republic (V.K.); Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel (Y.S
| | - J. Martijn Bos
- From the Division of Internal Medicine (A.S.), Division of Cardiovascular Diseases (P.A.N., V.K., B.Q., R.K.R., Z.I.A., P.B., S.J.A., P.A.F., M.J.A.), Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology (J.M.B., S.J.A., M.J.A.), Mayo Clinic, Rochester, MN; Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Czech Republic (V.K.); Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel (Y.S
| | - Bo Qiang
- From the Division of Internal Medicine (A.S.), Division of Cardiovascular Diseases (P.A.N., V.K., B.Q., R.K.R., Z.I.A., P.B., S.J.A., P.A.F., M.J.A.), Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology (J.M.B., S.J.A., M.J.A.), Mayo Clinic, Rochester, MN; Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Czech Republic (V.K.); Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel (Y.S
| | - Ram K. Rohatgi
- From the Division of Internal Medicine (A.S.), Division of Cardiovascular Diseases (P.A.N., V.K., B.Q., R.K.R., Z.I.A., P.B., S.J.A., P.A.F., M.J.A.), Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology (J.M.B., S.J.A., M.J.A.), Mayo Clinic, Rochester, MN; Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Czech Republic (V.K.); Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel (Y.S
| | - Yehu Sapir
- From the Division of Internal Medicine (A.S.), Division of Cardiovascular Diseases (P.A.N., V.K., B.Q., R.K.R., Z.I.A., P.B., S.J.A., P.A.F., M.J.A.), Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology (J.M.B., S.J.A., M.J.A.), Mayo Clinic, Rochester, MN; Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Czech Republic (V.K.); Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel (Y.S
| | - Zachi I. Attia
- From the Division of Internal Medicine (A.S.), Division of Cardiovascular Diseases (P.A.N., V.K., B.Q., R.K.R., Z.I.A., P.B., S.J.A., P.A.F., M.J.A.), Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology (J.M.B., S.J.A., M.J.A.), Mayo Clinic, Rochester, MN; Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Czech Republic (V.K.); Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel (Y.S
| | - Peter Brady
- From the Division of Internal Medicine (A.S.), Division of Cardiovascular Diseases (P.A.N., V.K., B.Q., R.K.R., Z.I.A., P.B., S.J.A., P.A.F., M.J.A.), Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology (J.M.B., S.J.A., M.J.A.), Mayo Clinic, Rochester, MN; Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Czech Republic (V.K.); Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel (Y.S
| | - Samuel J. Asirvatham
- From the Division of Internal Medicine (A.S.), Division of Cardiovascular Diseases (P.A.N., V.K., B.Q., R.K.R., Z.I.A., P.B., S.J.A., P.A.F., M.J.A.), Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology (J.M.B., S.J.A., M.J.A.), Mayo Clinic, Rochester, MN; Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Czech Republic (V.K.); Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel (Y.S
| | - Paul A. Friedman
- From the Division of Internal Medicine (A.S.), Division of Cardiovascular Diseases (P.A.N., V.K., B.Q., R.K.R., Z.I.A., P.B., S.J.A., P.A.F., M.J.A.), Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology (J.M.B., S.J.A., M.J.A.), Mayo Clinic, Rochester, MN; Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Czech Republic (V.K.); Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel (Y.S
| | - Michael J. Ackerman
- From the Division of Internal Medicine (A.S.), Division of Cardiovascular Diseases (P.A.N., V.K., B.Q., R.K.R., Z.I.A., P.B., S.J.A., P.A.F., M.J.A.), Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology (J.M.B., S.J.A., M.J.A.), Mayo Clinic, Rochester, MN; Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Czech Republic (V.K.); Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel (Y.S
| |
Collapse
|
11
|
Yamaguchi Y, Mizumaki K, Hata Y, Sakamoto T, Nakatani Y, Kataoka N, Ichida F, Inoue H, Nishida N. Latent pathogenicity of the G38S polymorphism of KCNE1 K + channel modulator. Heart Vessels 2016; 32:186-192. [PMID: 27255646 DOI: 10.1007/s00380-016-0859-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 05/27/2016] [Indexed: 01/08/2023]
Abstract
KCNE1 encodes a modulator of KCNQ1 and KCNH2 channels. Although KCNE1(G38S), a single-nucleotide polymorphism (SNP) causing a G38S substitution in KCNE1, is found frequently, whether and how this SNP causes long QT syndrome (LQTS) remains unclear. We evaluated rate-dependent repolarization dynamics using Holter electrocardiogram (ECG) to assess the pathogenicity of KCNE1(G38S). Forty-five patients exhibiting long QT intervals, as assessed by their baseline ECGs, and 16 control subjects were enrolled. KCNE1(G38S) carriers were identified using genome sequencing. LQTS patients were classified into LQT1 or LQT2 using genetic analysis or epinephrine test. QT-RR relations were determined using 24-h Holter ECG recordings. Among the 15 patients (33.3 %) with KCNE1(G38S), four patients without any mutations or amino acid changes in other major cardiac ion channels were categorized as KCNE1(G38S) carriers. In the QT-RR regression lines, the QT-RR slope was greater in the KCNE1(G38S) carriers and the LQT2 patients (0.215 ± 0.021 and 0.207 ± 0.032, respectively) than in the LQT1 patients (0.163 ± 0.014, P < 0.05) and the control subjects (0.135 ± 0.025, P < 0.001). The calculated QT intervals at an RR interval of 1200 ms were longer in the KCNE1(G38S) carriers and LQT1 and LQT2 patients than in the control subjects. Patients with KCNE1(G38S) had a rate-dependent repolarization abnormality similar to patients with LQT2 and, therefore, may have a potential risk to develop lethal arrhythmias.
Collapse
Affiliation(s)
- Yoshiaki Yamaguchi
- Second Department of Internal Medicine, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Koichi Mizumaki
- Clinical Research and Ethics Center, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan.
| | - Yukiko Hata
- Department of Legal Medicine, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Tamotsu Sakamoto
- Second Department of Internal Medicine, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Yosuke Nakatani
- Second Department of Internal Medicine, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Naoya Kataoka
- Second Department of Internal Medicine, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Fukiko Ichida
- Department of Pediatrics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Hiroshi Inoue
- Second Department of Internal Medicine, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Naoki Nishida
- Department of Legal Medicine, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| |
Collapse
|
12
|
Yamaguchi Y, Mizumaki K, Hata Y, Inoue H. Abnormal repolarization dynamics in a patient with KCNE1(G38S) who presented with torsades de pointes. J Electrocardiol 2015; 49:94-8. [PMID: 26520166 DOI: 10.1016/j.jelectrocard.2015.10.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Indexed: 11/29/2022]
Abstract
Risk of G38S, major KCNE1 polymorphism [KCNE1(G38S)], for long QT syndrome (LQTS) remains unclear. A 72-year-old woman was admitted with recurrent torsades de pointes (TdP). She had remarkable QT prolongation (corrected QT interval 568 ms) under conditions of hypokalemia and hypomagnesemia. After correction of this electrolytic imbalance, TdP was suppressed and metoprolol was started. The QT-RR slope in 24-hour Holter electrocardiogram was steep and this enhanced bradycardia-dependent QT prolongation was similar to that in LQTS. She carried KCNE1(G38S). Patients with KCNE1(G38S) could have similar potential risk of ventricular arrhythmia as with LQTS. Analysis of QT-RR relationship could also evaluate the latent arrhythmogenicity of KCNE1(G38S).
Collapse
Affiliation(s)
- Yoshiaki Yamaguchi
- Second Department of Internal Medicine, Graduate School of Medicine, University of Toyama, Toyama, Japan
| | - Koichi Mizumaki
- Clinical Research and Ethics Center, University of Toyama, Toyama, Japan.
| | - Yukiko Hata
- Legal Medicine, University of Toyama, Toyama, Japan
| | - Hiroshi Inoue
- Second Department of Internal Medicine, Graduate School of Medicine, University of Toyama, Toyama, Japan
| |
Collapse
|
13
|
Esperer HD, Bajer M, Hahn J, Braun-Dullaeus RC, Said SM. Effects of dronedarone on ventricular repolarization and repolarization dynamics in patients with preserved left ventricular systolic function. Int J Cardiol 2015; 185:119-21. [DOI: 10.1016/j.ijcard.2015.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 03/01/2015] [Indexed: 10/23/2022]
|
14
|
Hekkala AM, Väänänen H, Swan H, Viitasalo M, Toivonen L. T-wave morphology after epinephrine bolus may reveal silent long QT syndrome mutation carriers. J Electrocardiol 2012; 45:368-372. [PMID: 22560601 DOI: 10.1016/j.jelectrocard.2012.04.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Indexed: 10/28/2022]
Abstract
BACKGROUND Long QT syndrome (LQTS) gene mutation carriers with indeterminate electrocardiogram frequently escape clinical diagnosis. We assessed the use of epinephrine bolus injection in revealing T-wave abnormalities. METHODS We recruited 30 genotyped asymptomatic LQTS gene carriers with nondiagnostic QT interval and 15 controls. Electrocardiogram was recorded with body surface potential mapping after an intravenous epinephrine bolus. T-wave morphology was determined as normal, biphasic, inverted, bifid, or combined pattern. RESULTS Long QT syndrome carriers and healthy controls had different T-wave profiles (P = .027). Of controls, 12 (80%) of 15 had no change or biphasic appearance, whereas only 10 (33%) of 30 of LQTS carriers had so. Bifid or combined pattern occurred in 15 (50%) of 30 in LQTS and in 6 (60%) of 10 in the LQT3 subgroup but only in 1 (7%) of 15 of healthy. CONCLUSIONS Modification of ventricular repolarization with low-dose epinephrine injection helps to distinguish silent LQTS mutation carriers. This concerns also the LQT3 subtype, which may escape tests.
Collapse
Affiliation(s)
- Anna-Mari Hekkala
- Helsinki University Central Hospital, Department of Cardiology, Helsinki, Finland.
| | - Heikki Väänänen
- Aalto University, Department of Biomedical Engineering and Computational Science, Espoo, Finland
| | - Heikki Swan
- Helsinki University Central Hospital, Department of Cardiology, Helsinki, Finland
| | - Matti Viitasalo
- Helsinki University Central Hospital, Department of Cardiology, Helsinki, Finland
| | - Lauri Toivonen
- Helsinki University Central Hospital, Department of Cardiology, Helsinki, Finland
| |
Collapse
|
15
|
Hekkala AM, Swan H, Viitasalo M, Väänänen H, Toivonen L. Epinephrine bolus test in detecting long QT syndrome mutation carriers with indeterminable electrocardiographic phenotype. Ann Noninvasive Electrocardiol 2011; 16:172-9. [PMID: 21496168 DOI: 10.1111/j.1542-474x.2011.00426.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND In long QT syndrome (LQTS), prolonged and heterogeneous ventricular repolarization predisposes to serious arrhythmias. We examined how QT intervals are modified by epinephrine bolus in mutation carriers of three major LQTS subtypes with indefinite QT interval. METHODS Genotyped, asymptomatic subjects with LQTS type 1 (LQT1; n = 10; four different KCNQ1 mutations), type 2 (LQT2; n = 10; three different HERG mutations), and type 3 (LQT3; n = 10; four different SCN5A mutations), and healthy volunteers (n = 15) were examined. Electrocardiogram was recorded with body surface potential mapping system. After an epinephrine 0.04 μg/kg bolus QT end, QT apex, and T-wave peak-to-end (Tpe) intervals were determined automatically as average of 12 precordial leads. Standard deviation (SD) of the 12 channels was calculated. RESULTS Heart rate increased 26 ± 10 bpm with epinephrine bolus, and similarly in all groups. QT end interval lengthened, and QT apex interval shortened in LQTS and normals, leading to lengthening of Tpe interval. However, the lengthening in Tpe was larger in LQTS than in normals (mean 32 vs 18 ms; P < 0.05) and SD of QT apex increased more in LQTS than in normals (mean 23 vs 7 ms; P < 0.01). The increase in Tpe was most pronounced in LQT2, and in SD of QT apex in LQT1 and LQT2. CONCLUSIONS Abrupt adrenergic stimulation with a moderate dose of exogenous epinephrine affects ventricular repolarization in genotype-specific fashion facilitating distinction from normals. This delicate modification may help in diagnosing electrocardiographically silent mutation carriers when screening LQTS family members.
Collapse
Affiliation(s)
- Anna-Mari Hekkala
- Helsinki University Hospital, Department of Cardiology, Helsinki, Finland.
| | | | | | | | | |
Collapse
|
16
|
Haapalahti P, Viitasalo M, Perhonen M, Väänänen H, Mäkijärvi M, Swan H, Toivonen L. Comparison of QT peak and QT end interval responses to autonomic adaptation in asymptomatic LQT1 mutation carriers. Clin Physiol Funct Imaging 2010; 31:209-14. [PMID: 21138517 PMCID: PMC3121965 DOI: 10.1111/j.1475-097x.2010.01002.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Background LQT1 subtype of long QT syndrome is characterized by defective IKs, which is intrinsically stronger in the epicardium than in the midmyocardial region. Electrocardiographic QT peak and QT end intervals may reflect complete repolarization of epicardium and midmyocardial region of the ventricular wall, respectively. Repolarization abnormalities in LQT1 carriers may therefore be more easily detected in the QT peak intervals. Methods Asymptomatic KCNQ1 mutation carriers (LQT1, n = 9) and unaffected healthy controls (n = 8) were studied during Valsalva manoeuvre, mental stress, handgrip and supine exercise. Global QT peak and QT end intervals derived from 25 simultaneous electrocardiographic leads were measured beat to beat with an automated method. Results In unaffected subjects, the percentage shortening of QT peak was greater than that of QT end during mental stress and during the recovery phases of Valsalva and supine exercise. In LQT1 carriers, the percentage shortening of the intervals was similar. At the beginning of Valsalva strain under abrupt endogenous sympathetic activation, QT peak shortened in LQT1 but not in control patients yielding increased electrocardiographic transmural dispersion of repolarization in LQT1. Conclusions In asymptomatic KCNQ1 mutation carriers, repolarization abnormalities are more evident in the QT peak than in the QT end interval during adrenergic adaptation, possibly related to transmural differences in the degree of IKs block.
Collapse
Affiliation(s)
- Petri Haapalahti
- Department of Cardiology, Laboratory of Clinical Physiology, Helsinki University Hospital, Helsinki, Finland.
| | | | | | | | | | | | | |
Collapse
|
17
|
Järvenpää J, Oikarinen L, Korhonen P, Väänänen H, Toivonen L, Viitasalo M. Dynamic QT/RR relationship in post-myocardial infarction patients with and without cardiac arrest. SCAND CARDIOVASC J 2010; 44:352-8. [PMID: 21070120 DOI: 10.3109/14017431.2010.490950] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVES Changes in QT interval dynamicity may be associated with susceptibility to ventricular fibrillation (VF) after myocardial infarction (MI). We tested the hypothesis that dynamic QT/RR relationship might differ between post-MI patients with and without a history of VF. We also evaluated the influence of negative T-waves on the assessment of QT/RR relationship. DESIGN We reviewed Holter recordings from 37 post-MI patients resuscitated from VF not associated with new MI (VF group) and 30 patients after MI without known sustained ventricular arrhythmias (control group). With an automated computerized program, we measured QT interval dynamicity as the mean QT/RR slope and as the maximal QT/RR slope determined at stable heart rates. RESULTS The mean QT/RR slope was 0.20 ± 0.08 in control group and 0.15 ± 0.09 in VF group (p=0.01) whereas corresponding maximal QT/RR slope values were 0.42 ± 0.20 and 0.33 ± 0.18 (p=0.01), respectively. Thirteen control patients (43%) and 22 VF patients (59%) showed only negative or both positive and negative T-waves (p=0.45). Mean QT/RR slope values were similar irrespective of T-wave polarity whereas maximal QT/RR slopes were steeper in cases with both positive and negative T-waves. Cases showing T-waves of both positive and negative polarity exhibited greatest intersubject variability of both QT/RR slope values. CONCLUSIONS Lower mean QT/RR slope may be associated with a risk of VF after MI. A detailed assessment and definition of differing T-wave polarities is essential in evaluating the QT/RR relation in post-MI patients.
Collapse
Affiliation(s)
- Jere Järvenpää
- Department of Cardiology, Helsinki University Central Hospital, Helsinki, Finland.
| | | | | | | | | | | |
Collapse
|
18
|
Hekkala AM, Viitasalo M, Vaananen H, Swan H, Toivonen L. Abnormal repolarization dynamics revealed in exercise test in long QT syndrome mutation carriers with normal resting QT interval. Europace 2010; 12:1296-301. [DOI: 10.1093/europace/euq184] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
19
|
Haapalahti P, Viitasalo M, Kaartinen M, Väänänen H, Oikarinen L, Heliö T, Toivonen L. Electrocardiographic ventricular repolarization during cardiovascular autonomic function testing in patients with arrhythmogenic right ventricular cardiomyopathy. SCAND CARDIOVASC J 2009; 42:375-82. [DOI: 10.1080/14017430802192337] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
20
|
Anttonen O, Väänänen H, Junttila J, Huikuri HV, Viitasalo M. Electrocardiographic transmural dispersion of repolarization in patients with inherited short QT syndrome. Ann Noninvasive Electrocardiol 2008; 13:295-300. [PMID: 18713331 DOI: 10.1111/j.1542-474x.2008.00234.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Short QT syndrome (SQTS) carries an increased risk for sudden cardiac death. However, only a short QT interval does not express the risk of ventricular arrhythmias. Thus, additional evaluation of the repolarization abnormality in SQTS patients is essential. In experimental models of SQTS, increased transmural dispersion of repolarization (TDR) and its electrocardiographic counterpart T-wave peak to T-wave end interval (TPE) appeared critical for induction of polymorphic ventricular tachycardia (PMVT). In a clinical study with acquired long QT syndrome patients, TPE/QT ratio > 0.28 indicated arrhythmia risk. We hypothesized that the TPE/QT ratio would be greater in SQTS patients than in control subjects. METHODS AND RESULTS We compared the behavior of the electrocardiographic TDR in three seriously symptomatic SQTS patients of unknown genotype presenting baseline QTc values < 320 ms and in nine healthy age-matched control subjects. We determined QT and TPE intervals as well as TPE/QT ratio from 24-hour ECG recordings using a computer-assisted program. Diurnal average of TPE/QT ratio was 0.28 +/- 0.03 in SQTS patients and 0.21 +/- 0.02 in control subjects (P = 0.01). SQTS patients had also lesser capacity to change TPE intervals from steady-state conditions to abrupt maximal values than control subjects. CONCLUSION SQTS patients have increased and autonomically uncontrolled electrocardiographic TDR. According to experimental SQTS models, the present results may in part explain increased vulnerability of SQTS patients to ventricular arrhythmias.
Collapse
Affiliation(s)
- Olli Anttonen
- Department of Medicine, Päijät-Häme Central Hospital, Lahti, Finland.
| | | | | | | | | |
Collapse
|
21
|
Brunner M, Peng X, Liu GX, Ren XQ, Ziv O, Choi BR, Mathur R, Hajjiri M, Odening KE, Steinberg E, Folco EJ, Pringa E, Centracchio J, Macharzina RR, Donahay T, Schofield L, Rana N, Kirk M, Mitchell GF, Poppas A, Zehender M, Koren G. Mechanisms of cardiac arrhythmias and sudden death in transgenic rabbits with long QT syndrome. J Clin Invest 2008; 118:2246-59. [PMID: 18464931 DOI: 10.1172/jci33578] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2007] [Accepted: 03/19/2008] [Indexed: 11/17/2022] Open
Abstract
Long QT syndrome (LQTS) is a heritable disease associated with ECG QT interval prolongation, ventricular tachycardia, and sudden cardiac death in young patients. Among genotyped individuals, mutations in genes encoding repolarizing K+ channels (LQT1:KCNQ1; LQT2:KCNH2) are present in approximately 90% of affected individuals. Expression of pore mutants of the human genes KCNQ1 (KvLQT1-Y315S) and KCNH2 (HERG-G628S) in the rabbit heart produced transgenic rabbits with a long QT phenotype. Prolongations of QT intervals and action potential durations were due to the elimination of IKs and IKr currents in cardiomyocytes. LQT2 rabbits showed a high incidence of spontaneous sudden cardiac death (>50% at 1 year) due to polymorphic ventricular tachycardia. Optical mapping revealed increased spatial dispersion of repolarization underlying the arrhythmias. Both transgenes caused downregulation of the remaining complementary IKr and IKs without affecting the steady state levels of the native polypeptides. Thus, the elimination of 1 repolarizing current was associated with downregulation of the reciprocal repolarizing current rather than with the compensatory upregulation observed previously in LQTS mouse models. This suggests that mutant KvLQT1 and HERG interacted with the reciprocal wild-type alpha subunits of rabbit ERG and KvLQT1, respectively. These results have implications for understanding the nature and heterogeneity of cardiac arrhythmias and sudden cardiac death.
Collapse
Affiliation(s)
- Michael Brunner
- Innere Medizin III-Kardiologie und Angiologie, Universitätsklinikum Freiburg, Freiburg, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
U-waves and T-wave peak to T-wave end intervals in patients with catecholaminergic polymorphic ventricular tachycardia, effects of beta-blockers. Heart Rhythm 2008; 5:1382-8. [PMID: 18929323 DOI: 10.1016/j.hrthm.2008.06.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Accepted: 06/10/2008] [Indexed: 11/22/2022]
Abstract
BACKGROUND Catecholaminergic polymorphic ventricular tachycardia (CPVT) is characterized by risk of polymorphic ventricular tachycardia (pVT) and sudden death during stress. Experimental CPVT models show that delayed afterdepolarization (DAD)-induced triggered activity is the initiating mechanism of pVT, whereas an increase in transmural dispersion of repolarization (TDR) controls degeneration of pVT to ventricular fibrillation. U-wave and T-wave peak to T-wave end interval (TPE) are regarded as electrocardiographic counterparts of DAD and TDR, respectively. OBJECTIVE We tested hypotheses that patients with CPVT might show abnormal U-waves and TPE intervals and that beta-blockers could suppress appearance of these repolarization abnormalities. METHODS We reviewed Holter recordings from 19 CPVT patients with a RyR2 mutation (P2328S or V4653F) and from 19 healthy unaffected subjects to record U-waves and TPE intervals as well as to measure beta-blockers' effects on ventricular repolarization by use of an automated computerized program. RESULTS The maximal U-wave to T-wave amplitude ratio was 0.8 +/- 0.6 in CPVT patients and 0.4 +/- 0.3 in unaffected subjects (P = .009). Patients with most ventricular extrasystoles had a higher U-wave to T-wave amplitude ratio than those with fewest extrasystoles. Treatment with beta-blockers decreased U-wave amplitude at high heart rates. CPVT patients had longer TPE intervals than unaffected subjects at high heart rates, and beta-blocker treatment shortened their TPE intervals. CONCLUSION Present data support the hypothesis that U-waves associate with the DAD-triggered extrasystolic activity in CPVT patients. Patients with a RyR2 mutation show increased TPE at high heart rates. Beta-blocker treatment suppresses observed repolarization abnormalities in CPVT patients.
Collapse
|
23
|
Xhaët O, Argacha JF, Pathak A, Gujic M, Houssiere A, Najem B, Degaute JP, Van de Borne P. Sympathoexcitation increases the QT/RR slope in healthy men: differential effects of hypoxia, dobutamine, and phenylephrine. J Cardiovasc Electrophysiol 2007; 19:178-84. [PMID: 18081764 DOI: 10.1111/j.1540-8167.2007.01039.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
INTRODUCTION Dynamic ventricular repolarization assessed by QT/RR slopes studies the effects of modifications in cardiac repolarization independently of variations in RR interval (RR). The effects of changes in sympathetic and vagal activity on the QT/RR slope are controversial. We tested the hypothesis that sympathoexcitation is an important determinant of the QT/RR slope. METHODS AND RESULTS We compared the effects of a reflex sympathetic activation in response to hypoxia, to the direct effects of the infusion of the beta-adrenergic agent dobutamine, on the QTa (apex) and QTe (end)/RR slopes. Dobutamine was titrated to obtain similar increases in cardiac output than with hypoxia. Cardiac vagal activity was estimated by rMSSD and pNN50. In a second group of healthy subjects, we assessed the effect of a reflex cardiac vagal activation in response to phenylephrine infusion on the same variables. We observed a similar increase in QTa and QTe slopes during hypoxia and dobutamine (both P < 0.017 vs. normoxia), despite divergent changes in cardiac vagal activity, as rMSSD and pNN50 decreased with hypoxia compared to normoxia (P < 0.001) but increased during dobutamine infusion compared to hypoxia (P < 0.017). In contrast, these slopes did not change during the rises in rMSSD and pNN50 elicited by phenylephrine (P > 0.7). CONCLUSION Beta-adrenergic stimulation induces comparable increases in the QT/RR slopes than hypoxia, but in the presence of a larger cardiac vagal activity. Vagal cardiac activation by phenylephrine does not change the QT slopes. This reveals that the sympathetic system is an important determinant of QT/RR dynamicity in healthy men.
Collapse
Affiliation(s)
- Olivier Xhaët
- Department of Cardiology, Erasme University Hospital, Brussels, Belgium.
| | | | | | | | | | | | | | | |
Collapse
|
24
|
Järvenpää J, Oikarinen L, Korhonen P, Väänänen H, Toivonen L, Viitasalo M. Changing capacity of electrocardiographic ventricular repolarization in post-myocardial infarction patients with and without nonfatal cardiac arrest. Am J Cardiol 2007; 99:295-9. [PMID: 17261385 DOI: 10.1016/j.amjcard.2006.08.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2006] [Revised: 08/21/2006] [Accepted: 08/21/2006] [Indexed: 11/22/2022]
Abstract
Prolonged and labile ventricular repolarization and decreased heart rate variability may be associated with susceptibility to ventricular fibrillation (VF) after myocardial infarction (MI). The response of ventricular repolarization related to abrupt heart rate changes may also be associated with arrhythmia vulnerability. We investigated whether diurnal maximal values or changing capacities of QT and T-wave peak to T-wave end (TPE) intervals are different in patients after MI with and without a history of VF. With an automated computerized program, Holter recordings from 29 patients after MI resuscitated from VF not associated with new MI (VF group) and 27 patients after MI without clinical ventricular arrhythmias (control group) were analyzed. Maximal QT and maximal TPE intervals were shorter in the VF group than in the control group. Patients with VF exhibited smaller capacity to change QT and TPE intervals, with differences between study groups being greatest at heart rates from 60 to 75 beats/min (p = 0.002 and 0.01, respectively). Capacity to change QT and TPE intervals correlated with vagally mediated measurements of heart rate variability (r from 0.35 to 0.46, p from 0.01 to <0.001, respectively). In conclusion, long maximal QT interval may not be the key factor exposing patients after MI to VF. Impaired capacity to change QT and TPE intervals seems to be associated with risk of VF after MI.
Collapse
Affiliation(s)
- Jere Järvenpää
- Department of Cardiology, Helsinki University Central Hospital, Helsinki, Finland.
| | | | | | | | | | | |
Collapse
|
25
|
Hekkala AM, Väänänen H, Swan H, Oikarinen L, Viitasalo M, Toivonen L. Reproducibility of computerized measurements of QT interval from multiple leads at rest and during exercise. Ann Noninvasive Electrocardiol 2007; 11:318-26. [PMID: 17040280 PMCID: PMC6932062 DOI: 10.1111/j.1542-474x.2006.00124.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Accurate measurement of the QT interval is important for diagnosing long QT syndrome (LQTS), and in research on determinants of ventricular repolarization time. We tested automatic analysis of QT intervals from multiple ECG leads on chest. METHODS Eleven healthy volunteers and 10 genotyped LQTS patients were tested at rest and during exercise with a bicycle ergometer twice 1-31 months apart. Electrocardiograms were recorded with the body surface potential mapping system, and 12 precordial channels were selected for analysis. Averaged QT peak and QT end intervals were determined with an automated algorithm, and the difference QT end minus QT peak (Tp-e) was calculated. Repeatability was assessed by coefficient of variation (CV) between measurements. RESULTS Within one test at rest the QT end intervals were highly repeatable with CV 0.6%. In repeated tests CV was 4.4% for QT end interval and 3.5% when the QT interval was corrected for heart rate. In exercise test at specified heart rates, mean CV was 3.0% for QT end and 2.9% for QT peak interval. The CV of Tp-e interval was 10.2% at rest, and 9.3% in exercise test. Reproducibility was comparable between healthy subjects and LQTS patients. CONCLUSIONS The BSPM system with automated analysis produced accurate and highly repeatable QT interval measurements. Reproducibility was adequate also over prolonged time periods both at rest and in exercise stress test. The method can be applied in studying duration of ventricular repolarization time in different physiologic and pharmacologic interventions.
Collapse
Affiliation(s)
- Anna-Mari Hekkala
- Helsinki University Hospital, Department of Cardiology, Helsinki, Finland.
| | | | | | | | | | | |
Collapse
|
26
|
Haapalahti P, Viitasalo M, Perhonen M, Mäkijärvi M, Väänänen H, Oikarinen L, Hekkala AM, Salorinne Y, Swan H, Toivonen L. Ventricular Repolarization and Heart Rate Responses During Cardiovascular Autonomic Function Testing in LQT1 Subtype of Long QT Syndrome. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2006; 29:1122-9. [PMID: 17038145 DOI: 10.1111/j.1540-8159.2006.00506.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND In the most prevalent LQT1 form of inherited long QT syndrome symptoms often occur during abrupt physical or emotional stress. Sympathetic stimulation aggravates repolarization abnormalities in experimental LQT1 models. We hypothesized that autonomic function tests might reveal the abnormal repolarization in asymptomatic LQT1 patients. METHODS We measured heart rates (HRs) and QT intervals in nine asymptomatic carriers of a C-terminal KCNQ1 mutation and 8 unaffected healthy subjects using an approach of global QT values derived from 28 simultaneous electrocardiographic leads on beat-to-beat base during Valsalva maneuver, mental stress, sustained handgrip, and light supine exercise. RESULTS LQT1 patients exhibited impaired shortening of both QTpeak and QTend intervals during autonomic interventions but exaggerated lengthening of the intervals--a QT overshoot--during the recovery phases. The number of tests with a QT overshoot was 2.4 +/- 1.7 in LQT1 patients and 0.8 +/- 0.7 in unaffected subjects (P = 0.02). Valsalva strain prolonged T wave peak to T wave end interval (TPE) in LQT1 but not in unaffected patients. LQT1 patients showed diminished HR acceleration in response to adrenergic challenge whereas HR responses to vagal stimuli were similar in both groups. CONCLUSIONS Standard cardiovascular autonomic provocations induce a QT interval overshoot during recovery in asymptomatic KCNQ1 mutation carriers. Valsalva maneuver causes an exaggerated fluctuation of QT and TPE intervals partly explaining the occurrence of cardiac events during abrupt bursts of autonomic activity in LQT1 patients.
Collapse
Affiliation(s)
- Petri Haapalahti
- Department of Cardiology, Helsinki University Hospital, Helsinki, Finland.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Viitasalo M, Oikarinen L, Swan H, Väänänen H, Järvenpää J, Hietanen H, Karjalainen J, Toivonen L. Effects of beta-blocker therapy on ventricular repolarization documented by 24-h electrocardiography in patients with type 1 long-QT syndrome. J Am Coll Cardiol 2006; 48:747-53. [PMID: 16904544 DOI: 10.1016/j.jacc.2006.04.084] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2006] [Revised: 04/06/2006] [Accepted: 04/23/2006] [Indexed: 11/28/2022]
Abstract
OBJECTIVES We tested the hypothesis that in long-QT syndrome (LQT) type 1 (LQT1), beta-blocker therapy may decrease both the diurnal maximal T-wave peak to T-wave end interval (TPE) and the maximal ratio between late and early T-wave peak amplitude (T2/T1 ratio), which are electrocardiographic counterparts of transmural dispersion of repolarization (TDR) and early afterdepolarizations (EA), respectively. BACKGROUND Ventricular repolarization duration and increased TDR and EAs are the three electrophysiological components generating the high risk of ventricular arrhythmias and sudden death in the inherited LQT. In the most prevalent LQT1 form of LQT, treatment with beta-blockers reduces serious arrhythmia events dramatically without a known influence on QT interval duration. In experimental LQT1 models, beta-blockers decrease TDR and prevent EAs. METHODS We reviewed 24-h electrocardiographic recordings obtained before and during the treatment with beta-blockers from 24 genotyped LQT1 patients to record maximal TPE intervals and T2/T1 ratios as well as maximal and rate-adapted QT intervals using a computer-assisted program. RESULTS Treatment with beta-blockers decreased the maximal diurnal T2/T1 amplitude ratio from 3.0+/- 1.0 to 2.2 +/- 0.6 (p = 0.002). Beta-blockers also decreased both maximal TPE intervals and abrupt maximal QT intervals at heart rates higher than 85 beats/min, whereas QT intervals measured at steady-state conditions remained unchanged. CONCLUSIONS Prevention of abrupt increases of electrocardiographic TDR, EA, and ventricular repolarization duration at elevated heart rates may explain the favorable clinical effects of beta-blockers in LQT1.
Collapse
Affiliation(s)
- Matti Viitasalo
- Department of Cardiology, Helsinki University Central Hospital, Helsinki, Finland.
| | | | | | | | | | | | | | | |
Collapse
|
28
|
Viitasalo M, Oikarinen L, Swan H, Glatter KA, Väänänen H, Fodstad H, Chiamvimonvat N, Kontula K, Toivonen L, Scheinman MM. Ratio of late to early T-wave peak amplitude in 24-h electrocardiographic recordings as indicator of symptom history in patients with long-QT Syndrome types 1 and 2. J Am Coll Cardiol 2005; 47:112-20. [PMID: 16386673 DOI: 10.1016/j.jacc.2005.07.068] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2005] [Revised: 07/14/2005] [Accepted: 07/25/2005] [Indexed: 10/25/2022]
Abstract
UNLABELLED We reviewed 24-h electrocardiographic recordings from 214 genotyped subjects--97 with long-QT syndrome type 1 (LQT1), 62 with LQT2, and 55 unaffected--to record maximal diurnal amplitude ratios between late and early T-wave peaks. Maximal amplitude ratios between late and early T-wave peaks were higher in symptomatic than in asymptomatic patients both in LQT1 (3.2 +/- 1.0 vs. 2.3 +/- 0.8; p < 0.001) and in LQT2 patients (2.6 +/- 1.0 vs. 1.7 +/- 0.5; p < 0.001). The maximal amplitude ratio between late and early T-wave peaks was independently associated with symptom history in both LQT1 and LQT2 patients. OBJECTIVES We tested the hypothesis that in long-QT syndrome types 1 (LQT1) and 2 (LQT2), the diurnal maximal ratio between late and early T-wave peak amplitudes correlates with a history of symptoms better than QT interval durations. BACKGROUND Genotype and phenotype studies have delineated clinical profiles of the most prevalent LQT1 and LQT2 subtypes of inherited LQT, but prediction of arrhythmia risk remains uncertain, the baseline QTc interval being the best predictor. In experimental long-QT syndrome models, the ratio between late and early T-wave peak amplitude predicts onset of torsade de pointes. METHODS We reviewed 24-h electrocardiographic recordings from 214 genotyped subjects--97 with LQT1, 62 with LQT2, and 55 unaffected-to record maximal amplitude ratios between late and early T-wave peaks by use of a computer-assisted program. RESULTS Maximal amplitude ratios between late and early T-wave peaks were higher in symptomatic than in asymptomatic patients both in LQT1 (3.2 +/- 1.0 vs. 2.3 +/- 0.8; p < 0.001) and LQT2 patients (2.6 +/- 1.0 vs. 1.7 +/- 0.5; p < 0.001). Although the QTc interval also was longer in symptomatic patients, only the maximal amplitude ratio between late and early T-wave peaks was independently associated with symptoms in both LQT1 and LQT2 patients. CONCLUSIONS Maximal diurnal ratio between late and early T-wave peak amplitude improves noninvasive risk assessment both in LQT1 and LQT2 syndromes. We propose this new indicator in clinical evaluation of arrhythmia risk in LQT1 and LQT2.
Collapse
Affiliation(s)
- Matti Viitasalo
- Department of Cardiology, Helsinki University Central Hospital, Helsinki, Finland.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Nemec J, Buncová M, Bůlková V, Hejlik J, Winter B, Shen WK, Ackerman MJ. Heart rate dependence of the QT interval duration: differences among congenital long QT syndrome subtypes. J Cardiovasc Electrophysiol 2004; 15:550-6. [PMID: 15149424 DOI: 10.1046/j.1540-8167.2004.03096.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
INTRODUCTION The heart rate dependence of QT interval duration is abnormal in patients with congenital long QT syndrome. Patients with LQT1 have a defective I(Ks) current, a major determinant of QT response to heart rate. METHODS AND RESULTS We studied the heart rate dependence of QT interval duration in different long QT syndrome genotypes and control subjects using computerized QT measurements obtained from Holter recordings. The dependence of QT duration on heart rate is steeper in long QT syndrome than in control subjects (0.347 +/- 0.263 vs 0.162 +/- 0.083 at heart rate 100 beats/min; P < 0.05). In addition, QT interval is significantly longer in LQT2 and LQT3 than in LQT1 patients at slow (533 +/- 23 ms vs 468 +/- 30 ms at heart rate 60 beats/min; P < 0.0001) but not at rapid heart rate. The heart rate dependence of QT interval is steeper in LQT2 and LQT3 than in LQT1 (0.623 +/- 0.245 vs 0.19 +/- 0.079 at heart rate 100 beats/min; P < 0.05). For a given heart rate, the QT intervals vary more in LQT2 and LQT3 than in LQT1 patients (25.98 +/- 11.18 ms vs 14.39 +/- 1.55 ms; P < 0.01). CONCLUSION Individual long QT syndrome genotypes differ with respect to QT interval dependence on heart rate. These differences may relate to the propensity of LQT2 and LQT3 patients to develop arrhythmias during bradycardia.
Collapse
|
30
|
Viitasalo M, Oikarinen L, Swan H, Väänänen H, Glatter K, Laitinen PJ, Kontula K, Barron HV, Toivonen L, Scheinman MM. Ambulatory electrocardiographic evidence of transmural dispersion of repolarization in patients with long-QT syndrome type 1 and 2. Circulation 2002; 106:2473-8. [PMID: 12417545 DOI: 10.1161/01.cir.0000036369.16112.7d] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Transmural dispersion of repolarization (TDR) may be related to the genesis of torsade de pointes (TdP) in patients with the long-QT (LQT) syndrome. Experimentally, LQT2 models show increased TDR compared with LQT1, and beta-adrenergic stimulation increases TDR in both models. Clinically, LQT1 patients experience symptoms at elevated heart rates, but LQT2 patients do so at lower rates. The interval from T-wave peak to T-wave end (TPE interval) is the clinical counterpart of TDR. We explored the relationship of TPE interval to heart rate and to the presence of symptoms in patients with LQT1 and LQT2. METHODS AND RESULTS We reviewed Holter recordings from 90 genotyped subjects, 31 with LQT1, 28 with LQT2, and 31 from unaffected family members, to record TPE intervals by use of an automated computerized program. The median TPE interval was greater in LQT2 (112+/-5 ms) than LQT1 (91+/-2 ms) or unaffected (86+/-3 ms) patients (P<0.001 for all group comparisons), and the maximal TPE values differed as well. LQT1 patients showed abrupt increases in TPE values at RR intervals from 600 to 900 ms, but LQT2 patients did so at RR intervals from 600 to 1400 ms (longest RR studied). Asymptomatic and symptomatic patients showed similar TDRs. CONCLUSIONS TDR is greater in LQT2 than in LQT1 patients. LQT1 patients showed a capacity to increase TDR at elevated heart rates, but LQT2 patients did so at a much wider rate range. The magnitude of TDR is not related to a history of TdP.
Collapse
Affiliation(s)
- Matti Viitasalo
- Department of Medicine, Cardiac Electrophysiology, University of California, San Francisco, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|