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Riedlova P, Tavandzis S, Kana J, Ostrizkova S, Kramna D, Krajcir L, Kanova T, Lastikova S, Tomaskova H, Roubec J. Changes in the Heart Rate of Sniffer Dogs Trained for Detection of Lung Cancer. Diagnostics (Basel) 2023; 13:2567. [PMID: 37568930 PMCID: PMC10417766 DOI: 10.3390/diagnostics13152567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 07/28/2023] [Accepted: 08/01/2023] [Indexed: 08/13/2023] Open
Abstract
BACKGROUND Lung carcinoma is one of the most common malignancies worldwide. At present, unfortunately, there are no markers that would allow early identification of this tumor in the preclinical or early clinical stage. The use of sniffer dogs has been reported to show some promise in early diagnosis of this type of cancer Aim: This study aimed to evaluate the possibility of utilizing changes in the heart rate of sniffer dogs (which increases when finding a positive sample) in tumor detection. METHODS This double-blinded pilot study included two sniffer dogs. A chest strap was fastened on the dog's chests for heart rate monitoring while they were examining samples and heart rate was recorded. Test parameters (sensitivity, specificity, positive and negative predictive values) were then calculated, evaluating performances based on (i) the dog's indications according to their training and (ii) the changes in their heart rates. RESULTS Calculation according to the dog's indications revealed an overall sensitivity of 95.2% accompanied by a specificity of 81.8%, a PPV of 93.7%, and an NPV of 85.7%, respectively. These results were not significantly different from those evaluated by heart rate; heart rate monitoring was, however, burdened with a relatively high proportion of invalid experiments in which heart rate measurement failed. When the method of calculation was changed from rounds to individual samples, the test parameters further increased. CONCLUSIONS This pilot study confirmed the hypothesis that heart rate increases in trained sniffer dogs when encountering samples from tumor-positive patients but remains unchanged when only negative samples are present. The reliability of results based on heart rate increase is similar to that obtained by a dog's indications and, if the limitation represented by technical issues is overcome, it could serve as a valuable verification method.
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Affiliation(s)
- Petra Riedlova
- Department of Epidemiology and Public Health, Faculty of Medicine, University of Ostrava, 703 00 Ostrava, Czech Republic; (S.O.); (D.K.); (H.T.)
- Centre of Epidemiological Research, Faculty of Medicine, University of Ostrava, 703 00 Ostrava, Czech Republic
- Czech Centre for Signal Animals, 741 01 Novy Jicin, Czech Republic
| | - Spiros Tavandzis
- Czech Centre for Signal Animals, 741 01 Novy Jicin, Czech Republic
- Laboratory of Molecular Biology, Department of Medical Genetics, AGEL Laboratories, 741 01 Novy Jicin, Czech Republic
| | - Josef Kana
- Czech Centre for Signal Animals, 741 01 Novy Jicin, Czech Republic
| | - Silvie Ostrizkova
- Department of Epidemiology and Public Health, Faculty of Medicine, University of Ostrava, 703 00 Ostrava, Czech Republic; (S.O.); (D.K.); (H.T.)
- Centre of Epidemiological Research, Faculty of Medicine, University of Ostrava, 703 00 Ostrava, Czech Republic
| | - Dagmar Kramna
- Department of Epidemiology and Public Health, Faculty of Medicine, University of Ostrava, 703 00 Ostrava, Czech Republic; (S.O.); (D.K.); (H.T.)
- Centre of Epidemiological Research, Faculty of Medicine, University of Ostrava, 703 00 Ostrava, Czech Republic
| | - Libor Krajcir
- Czech Centre for Signal Animals, 741 01 Novy Jicin, Czech Republic
| | - Tereza Kanova
- Czech Centre for Signal Animals, 741 01 Novy Jicin, Czech Republic
| | - Simona Lastikova
- Department of Pneumology and Phthisiology, University Hospital with Polyclinic FDR Banska Bystrica, 975 17 Banska Bystrica, Slovakia
| | - Hana Tomaskova
- Department of Epidemiology and Public Health, Faculty of Medicine, University of Ostrava, 703 00 Ostrava, Czech Republic; (S.O.); (D.K.); (H.T.)
- Centre of Epidemiological Research, Faculty of Medicine, University of Ostrava, 703 00 Ostrava, Czech Republic
| | - Jaromir Roubec
- Department of Pulmonary, Vitkovice Hospital, 703 00 Ostrava, Czech Republic;
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Bidoli EM, Erhard MH, Döring D. Heart rate and heart rate variability in school dogs. Appl Anim Behav Sci 2022. [DOI: 10.1016/j.applanim.2022.105574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Strauss DG, Wu WW, Li Z, Koerner J, Garnett C. Translational Models and Tools to Reduce Clinical Trials and Improve Regulatory Decision Making for QTc and Proarrhythmia Risk (ICH E14/S7B Updates). Clin Pharmacol Ther 2021; 109:319-333. [PMID: 33332579 PMCID: PMC7898549 DOI: 10.1002/cpt.2137] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 12/14/2020] [Indexed: 01/06/2023]
Abstract
After multiple drugs were removed from the market secondary to drug-induced torsade de pointes (TdP) risk, the International Council for Harmonisation (ICH) released guidelines in 2005 that focused on the nonclinical (S7B) and clinical (E14) assessment of surrogate biomarkers for TdP. Recently, Vargas et al. published a pharmaceutical-industry perspective making the case that "double-negative" nonclinical data (negative in vitro hERG and in vivo heart-rate corrected QT (QTc) assays) are associated with such low probability of clinical QTc prolongation and TdP that potentially all double-negative drugs would not need detailed clinical QTc evaluation. Subsequently, the ICH released a new E14/S7B Draft Guideline containing Questions and Answers (Q&As) that defined ways that double-negative nonclinical data could be used to reduce the number of "Thorough QT" (TQT) studies and reach a low-risk determination when a TQT or equivalent could not be performed. We review the Vargas et al. proposal in the context of what was contained in the ICH E14/S7B Draft Guideline and what was proposed by the ICH E14/S7B working group for a "stage 2" of updates (potential expanded roles for nonclinical data and details for assessing TdP risk of QTc-prolonging drugs). Although we do not agree with the exact probability statistics in the Vargas et al. paper because of limitations in the underlying datasets, we show how more modest predictive value of individual assays could still result in low probability for TdP with double-negative findings. Furthermore, we expect that the predictive value of the nonclinical assays will improve with implementation of the new ICH E14/S7B Draft Guideline.
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Affiliation(s)
- David G. Strauss
- Division of Applied Regulatory ScienceOffice of Clinical PharmacologyOffice of Translational SciencesCenter for Drug Evaluation and ResearchUS Food and Drug AdministrationSilver SpringMarylandUSA
| | - Wendy W. Wu
- Division of Applied Regulatory ScienceOffice of Clinical PharmacologyOffice of Translational SciencesCenter for Drug Evaluation and ResearchUS Food and Drug AdministrationSilver SpringMarylandUSA
| | - Zhihua Li
- Division of Applied Regulatory ScienceOffice of Clinical PharmacologyOffice of Translational SciencesCenter for Drug Evaluation and ResearchUS Food and Drug AdministrationSilver SpringMarylandUSA
| | - John Koerner
- Division of Pharm/Tox for Cardiology, Hematology, Endocrinology and NephrologyOffice of Cardiology, Hematology, Endocrinology and NephrologyOffice of New DrugsCenter for Drug Evaluation and ResearchUS Food and Drug AdministrationSilver SpringMarylandUSA
| | - Christine Garnett
- Division of Cardiology and NephrologyOffice of Cardiology, Hematology, Endocrinology and NephrologyOffice of New DrugsCenter for Drug Evaluation and ResearchUS Food and Drug AdministrationSilver SpringMarylandUSA
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Boulay E, Troncy E, Accardi MV, Pugsley MK, Downey AM, Miraucourt L, Huang H, Menard A, Tan W, Dubuc-Mageau M, Sanfacon A, Guerrier M, Authier S. Confounders and Pharmacological Characterization When Using the QT, JTp, and Tpe Intervals in Beagle Dogs. Int J Toxicol 2020; 39:530-541. [PMID: 33063577 DOI: 10.1177/1091581820954865] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
INTRODUCTION Corrected QT (QTc) interval is an essential proarrhythmic risk biomarker, but recent data have identified limitations to its use. The J to T-peak (JTp) interval is an alternative biomarker for evaluating drug-induced proarrhythmic risk. The aim of this study was to evaluate pharmacological effects using spatial magnitude leads and DII electrocardiogram (ECG) leads and common ECG confounders (ie, stress and body temperature changes) on covariate adjusted QT (QTca), covariate adjusted JTp (JTpca), and covariate adjusted T-peak to T-end (Tpeca) intervals. METHODS Beagle dogs were exposed to body hyper- (42 °C) or hypothermic (33 °C) conditions or were administered epinephrine to assess confounding effects on heart rate corrected QTca, JTpca, and Tpeca intervals. Dofetilide (0.1, 0.3, 1.0 mg/kg), ranolazine (100, 140, 200 mg/kg), and verapamil (7, 15, 30, 43, 62.5 mg/kg) were administered to evaluate pharmacological effects. RESULTS Covariate adjusted QT (slope -12.57 ms/°C) and JTpca (-14.79 ms/°C) were negatively correlated with body temperature but Tpeca was minimally affected. Epinephrine was associated with QTca and JTpca shortening, which could be related to undercorrection in the presence of tachycardia, while minimal effects were observed for Tpeca. There were no significant ECG change following ranolazine administration. Verapamil decreased QTca and JTpca intervals and increased Tpeca, whereas dofetilide increased QTca and JTpca intervals but had inconsistent effects on Tpeca. CONCLUSION Results highlight potential confounders on QTc interval, but also on JTpca and Tpeca intervals in nonclinical studies. These potential confounding effects may be relevant to the interpretation of ECG data obtained from nonclinical drug safety studies with Beagle dogs.
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Affiliation(s)
- Emmanuel Boulay
- Charles River Laboratories, Laval, Quebec, Canada.,70354Faculté de médecine vétérinaire, Université de Montréal, Québec, Canada
| | - Eric Troncy
- 70354Faculté de médecine vétérinaire, Université de Montréal, Québec, Canada
| | | | | | | | | | - Hai Huang
- Charles River Laboratories, Laval, Quebec, Canada
| | | | - Wendy Tan
- 70354Faculté de médecine vétérinaire, Université de Montréal, Québec, Canada
| | | | - Audrey Sanfacon
- 70354Faculté de médecine vétérinaire, Université de Montréal, Québec, Canada
| | - Mireille Guerrier
- 70354Faculté de médecine vétérinaire, Université de Montréal, Québec, Canada
| | - Simon Authier
- Charles River Laboratories, Laval, Quebec, Canada.,70354Faculté de médecine vétérinaire, Université de Montréal, Québec, Canada
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Insular cortex lesion and autonomic instability in a herpes simplex virus encephalitis patient. J Neurovirol 2018; 24:649-651. [DOI: 10.1007/s13365-018-0652-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Revised: 03/09/2018] [Accepted: 05/23/2018] [Indexed: 10/28/2022]
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Nagai M, Dote K, Kato M, Oda N, Kunita E. QTc interval in takotsubo cardiomyopathy: How the activation of insular cortex interacts. Clin Cardiol 2018; 41:885. [DOI: 10.1002/clc.22976] [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: 04/27/2018] [Accepted: 05/01/2018] [Indexed: 11/06/2022] Open
Affiliation(s)
- Michiaki Nagai
- Department of Cardiology; Hiroshima City Asa Hospital; Hiroshima Japan
| | - Keigo Dote
- Department of Cardiology; Hiroshima City Asa Hospital; Hiroshima Japan
| | - Masaya Kato
- Department of Cardiology; Hiroshima City Asa Hospital; Hiroshima Japan
| | - Noboru Oda
- Department of Cardiology; Hiroshima City Asa Hospital; Hiroshima Japan
| | - Eiji Kunita
- Department of Cardiology; Hiroshima City Asa Hospital; Hiroshima Japan
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Marocolo M, Silva-Neto JA, Barbosa Neto O. Acute interruption of treatment with nandrolone decanoate is not sufficient to reverse cardiac autonomic dysfunction and ventricular repolarization disturbances in rats. Steroids 2018; 132:12-17. [PMID: 29366731 DOI: 10.1016/j.steroids.2018.01.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 01/10/2018] [Accepted: 01/16/2018] [Indexed: 11/26/2022]
Abstract
Anabolic androgenic steroids are a class of synthetic compounds derived from testosterone, eventually used by athletes, to improve physical performance. However, anabolic steroids can also modify normal cardiovascular function. Thus, we investigated cardiac electrophysiological and autonomic abnormalities in rats, through a electrocardiographic variability protocol during and after interruption of administration of nandrolone decanoate (DECA) anabolic steroid. Twenty male Wistar rats (60-70 days old) received DECA (10 mg. kg-1i.m) once a week or vehicle, during eight weeks. Electrocardiogram was recorded in conscious rats by a noninvasive method, and time and domain analysis of heart rate variability as well as electrocardiogram intervals (QTc / QTd) were performed. Body mass was lower in treated rats compared to control after 4th and 8th weeks, but not at the end of 14th week. QTc and QTd were longer in DECA group compared to control on 4th, 8th, 11th, but equal on 14th week. Cardiac autonomic dysfunction (vagal attenuation) was present on DECA group after 4th week and did not normalize after interruption of treatment. The animals of DECA group showed a correlation between attenuated parasympathetic modulation and increased correct QT interval. Our data allow us to conclude that long-term treatment with DECA impairs autonomic cardiac physiology, predisposing to cardiovascular risk and sudden death, and interruption of administration does not recovery the normality immediately.
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Affiliation(s)
- Moacir Marocolo
- Physiology and Human Performance Research Group, Department of Physiology, Institute of Biological Sciences, Federal University of Juiz de Fora, Juiz de Fora, Brazil.
| | - Julio A Silva-Neto
- "Paes de Carvalho" Laboratory of Biophysics of Heart, Department of Physiology, Federal University of Sergipe, Aracaju, Brazil
| | - Octávio Barbosa Neto
- Department of Sport Sciences, Federal University of Triângulo Mineiro, Uberaba, Brazil
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Improvement of increased cQTd is associated with heart function in patients with ischemic heart failure. JOURNAL OF GERIATRIC CARDIOLOGY : JGC 2018; 15:41-49. [PMID: 29434624 PMCID: PMC5803536 DOI: 10.11909/j.issn.1671-5411.2018.01.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Background Chronic heart failure (CHF) is life-threatening without timely or effective intervention. In this study, we investigated the association between QT dispersion corrected for heart rate (cQTd) and heart function in patients with CHF. Methods From January 2013 to December 2015, we continuously enrolled 240 patients categorized as New York Heart Association functional class (NYHA) III-IV with a left ventricular ejection fraction (LVEF) < 40%. Based on the etiology, the patients were divided into a dilated cardiomyopathy (DCM) group (n = 120) and an ischemic cardiomyopathy (ICM) group (n = 120). Then, based on the cQTd width, the ICM group was divided into two subgroups: a QS group (cQTd ≤ 60 ms, n = 70) and a QL group (cQTd > 60 ms, n = 50). All patients were examined by echocardiography and 12-lead electrocardiography (ECG) at 1, 3, 6, and 12 months after enrollment. Results After one year of optimized medical treatment, patients in both groups showed significant improvement in LVEF and NYHA classification from baseline. However, the cQTd in the ICM group, especially the QL, was significantly shorter than that in the DCM group at each time point. In addition, the cQTd was negatively correlated with LVEF and 6-min walking test and positively correlated with NYHA class in the ICM group. Conclusions The present findings clearly demonstrate that cQTd is a meaningful parameter for assessing heart function in the follow-up of ICM patients.
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Nagai M, Dote K, Kato M, Oda N. The insular cortex and QTc interval in HIV+ and HIV− individuals: Is there an effect of sympathetic nervous system activity? Clin Neurophysiol 2018; 129:336. [DOI: 10.1016/j.clinph.2017.09.119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 09/21/2017] [Indexed: 10/18/2022]
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Nagai M, Dote K, Kato M, Sasaki S, Oda N. Insular cortex and QT correction interval: an effect of hemispheric lateralization? Eur J Neurol 2017. [DOI: 10.1111/ene.13333] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- M. Nagai
- Department of Cardiology; Hiroshima City Asa Hospital; Hiroshima Japan
| | - K. Dote
- Department of Cardiology; Hiroshima City Asa Hospital; Hiroshima Japan
| | - M. Kato
- Department of Cardiology; Hiroshima City Asa Hospital; Hiroshima Japan
| | - S. Sasaki
- Department of Cardiology; Hiroshima City Asa Hospital; Hiroshima Japan
| | - N. Oda
- Department of Cardiology; Hiroshima City Asa Hospital; Hiroshima Japan
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Ware WA, Reina-Doreste Y, Stern JA, Meurs KM. Sudden death associated with QT interval prolongation and KCNQ1 gene mutation in a family of English Springer Spaniels. J Vet Intern Med 2015; 29:561-8. [PMID: 25779927 PMCID: PMC4895492 DOI: 10.1111/jvim.12550] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 12/22/2014] [Accepted: 01/06/2015] [Indexed: 01/04/2023] Open
Abstract
Background A 5‐year‐old, healthy English Springer Spaniel died suddenly 4 months after delivering a litter of 7 puppies. Within 4 months of the dam's death, 3 offspring also died suddenly. Hypothesis Abnormal cardiac repolarization, caused by an inherited long QT syndrome, is thought to be responsible for arrhythmias leading to sudden death in this family. Animals Four remaining dogs from the affected litter and 11 related dogs. Methods Physical examination and resting ECG were done on the littermates and 9 related dogs. Additional tests on some or all littermates included echocardiogram with Doppler, Holter monitoring, and routine serum biochemistry. Blood for DNA sequencing was obtained from all 15 dogs. Results Three of 4 littermates examined, but no other dogs, had prolonged QT intervals with unique T‐wave morphology. DNA sequencing of the KCNQ1 gene identified a heterozygous single base pair mutation, unique to these 3 dogs, which changes a conserved amino acid from threonine to lysine and is predicted to change protein structure. Conclusions and Clinical Importance This family represents the first documentation in dogs of spontaneous familial QT prolongation, which was associated with a KCNQ1 gene mutation and sudden death. Although the final rhythm could not be documented in these dogs, their phenotypic manifestations of QT interval prolongation and abnormal ECG restitution suggested increased risk for sudden arrhythmic death. The KCNQ1 gene mutation identified is speculated to impair the cardiac repolarizing current IKs, similar to KCNQ1 mutations causing long QT syndrome 1 in humans.
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Affiliation(s)
- W A Ware
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA
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Abstract
INTRODUCTION Prolongation of Q-Tc interval is commonly accepted as a surrogate marker for the ability of a drug to cause torsade de pointes. In the present study, safety of olanzapine versus risperidone was compared among a group of patients with schizophrenia to see the frequency of the electrocardiographic alterations induced by those atypical antipsychotics. METHOD Two hundred and sixty-eight female inpatients with schizophrenia entered in one of the two parallel groups to participate in an open study for random assignment to olanzapine (n = 148) or risperidone (n = 120). Standard 12-lead surface electrocardiogram (ECG) was taken from each patient at baseline, before initiation of treatment, and then at the end of management, just before discharge. The parameters that were assessed included heart rate (HR), P-R interval, QRS interval, Q-T interval (corrected = Q-Tc), ventricular activation time (VAT), ST segment, T wave, axis of QRS, and finally, interventricular conduction process. RESULTS A total of 37.83% of cases in the olanzapine group and 30% in the risperidone group showed some Q-Tc changes; 13.51% and 24.32% of the patients in the olanzapine group showed prolongation and shortening of the Q-Tc, respectively, while changes in the risperidone group were restricted to only prolongation of Q-Tc. Comparison of means showed a significant increment in Q-Tc by risperidone (p = 0.02). Also, comparison of proportions in the olanzapine group showed significantly more cases with shortening of Q-Tc versus its prolongation (p = 0.01). No significant alterations with respect to other variables were evident. CONCLUSION Olanzapine and risperidone had comparable potentiality for induction of Q-Tc changes, while production of further miscellaneous alterations in ECG was more observable in the olanzapine group compared with the risperidone group. Also shortening of Q-Tc was specific to olanzapine.
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Affiliation(s)
- Saeed Shoja Shafti
- Associate Professor of Psychiatry, Department of Psychiatry, University of Social Welfare and Rehabilitation Sciences (USWR), Razi Psychiatric Hospital, PO Box 18735-569, Tehran, Iran
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Champeroux P, Martel E, Jude S, Laigot C, Laveissière A, Weyn-Marotte AA, Fowler JSL, Maurin A, Richard S, Babuty D. Power spectral analysis of heart rate variability in cynomolgus monkeys in safety pharmacology studies: comparative study with beagle dogs. J Pharmacol Toxicol Methods 2013; 68:166-74. [PMID: 23435316 DOI: 10.1016/j.vascn.2013.02.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 01/22/2013] [Accepted: 02/05/2013] [Indexed: 11/18/2022]
Abstract
INTRODUCTION Power spectral analysis of heart rate variability is a tool known to provide information of interest on the autonomic control of heart rate in human. However, its use and its conditions of application and interpretation for safety purposes are not well defined for cardiovascular safety pharmacology studies. Likewise, data of power spectral analysis of heart rate variability in cynomolgus monkeys, a species often appropriate for use as second non rodent species in preclinical safety programmes, are not available. This study was designed to evaluate the relevance of this biomarker in this non human primate species, and to compare results with those from beagle dogs under the conditions of safety evaluation studies. METHODS Power spectral analysis of heart rate variability was performed on data collected in both species by telemetry following a standard design for cardiovascular safety pharmacology studies. Various pharmacological agents were tested in order to compare the profile of responses in both species after modifying the autonomic nervous balance. RESULTS Heart rate variability in cynomolgus monkeys is mainly driven by the parasympathetic nervous system as in beagle dogs although vagal tone is less than in dogs. Power spectral analysis of heart rate variability allows detection of interaction with the autonomic nervous system in both species in all investigated situations, i.e. sympatholytic/sympathomimetic and parasympatholytic/parasympathomimetic drug induced effects. However, due to species difference in the autonomic control of heart rate, cynomolgus monkeys are likely to be more sensitive than beagle dogs for assessment of sympatholytic properties. DISCUSSION This study confirms that power spectral analysis of heart rate variability from data derived from ECG recordings in telemetry studies is applicable in cardiovascular safety pharmacology studies and may provide relevant information about possible interaction with the autonomic nervous system when new drug entities are evaluated in either species. However, interspecies differences in autonomic control must be taken into account when interpreting possible drug effects.
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Affiliation(s)
- Pascal Champeroux
- Centre de Recherches Biologiques, CERB, Chemin de Montifault, 18800 Baugy, France.
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Honda M, Komatsu R, Isobe T, Tabo M, Ishikawa T. Involvement of the autonomic nervous system in diurnal variation of corrected QT intervals in common marmosets. J Pharmacol Sci 2013; 121:131-7. [PMID: 23363785 DOI: 10.1254/jphs.12230fp] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
Our previous study has shown that the corrected QT (QTc) interval of the electrocardiogram is longer during the dark period than during the light period in telemetered common marmosets. In the present study, we investigated the involvement of sympathetic and parasympathetic nervous activities in the changes of QTc interval associated with the light-dark cycle.Telemetry transmitters were implanted in six common marmosets to continuously record the electrocardiogram. The QT intervals obtained were corrected for the RR interval by applying individual probabilistic QT-rate correction formulae. Power spectral analysis of heart rate variability was performed to quantify each autonomic nervous function. Changes in QTc intervals and autonomic nervous tones were associated with the light-dark cycle. Parasympathetic nervous activity and QTc intervals significantly increased by approximately 10 ms during the dark period.Atropine, a muscarinic receptor antagonist, suppressed the increased parasympathetic tone and QTc prolongation during the dark period. In contrast, propranolol, a β-adrenoceptor antagonist, decreased the sympathetic activity and increased QTc intervals during the light period. These results suggest that the parasympathetic nerve functions prolong QTc intervals during the dark period, while the sympathetic nerve functions shorten them during the light period in common marmosets.
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Affiliation(s)
- Masaki Honda
- Research Division, Chugai Pharmaceutical Co., Ltd., Komakado, Gotemba City, Shizuoka, Japan.
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Rajput SK, Singh JN, Sharma SS. Evaluation of terfenadine and ketoconazole-induced QT prolongation in conscious telemetered guinea pigs. Pharmacol Rep 2011; 62:683-8. [PMID: 20885008 DOI: 10.1016/s1734-1140(10)70325-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Revised: 01/19/2010] [Indexed: 11/25/2022]
Abstract
Terfenadine and ketoconazole are the most widely used positive reference agents in non-clinical cardiac repolarization safety studies. The aim of the present study was to evaluate the effects of terfenadine, ketoconazole and their combination on QT prolongation using conscious guinea pigs. Conscious telemetered guinea pigs were orally administered terfenadine (50 mg/kg), ketoconazole (200 mg/kg) or a combination of the two, and effects on QT were recorded using a telemetry system. The QT correction was carried out with Bazett's formula to eliminate confounding effect of HR. Neither terfenadine nor ketoconazole produced any effect on the RR and QT intervals, QRS complex or heart rate (HR). However, a combination of terfenadine and ketoconazole significantly prolonged the RR and QT intervals and decreased HR in a time-dependent manner. This study demonstrated that the combination of terfenadine and ketoconazole produces QT prolongation in conscious telemetered guinea pigs.
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Affiliation(s)
- Satyendra K Rajput
- National Centre for Safety Pharmacology, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, S.A.S. Nagar (Mohali)-160 062, Punjab, India
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Abstract
OBJECTIVE Intense emotions are known triggers of sudden cardiac death. However, the effect of typical daily emotion on repolarization has not been examined. We examined whether QT interval changes as a function of typical daily emotion in patients at risk for cardiac events in the context of emotion. METHODS We studied 161 patients (n = 114 females; mean age, 35 years) with the congenital form of the Long QT Syndrome during daily activities. Each day for 3 days, a 12-hour Holter recording was completed. Patients were paged ten times per day at random times and rated the intensity of 16 prespecified emotions during the preceding 5 minutes. Measurements of QT interval and interbeat intervals were synchronized with emotion ratings. RESULTS Low Arousal Positive Affect was associated with significant increases in QT interval corrected for heart rate (using Fridericia's QTc) (p < .001), whereas higher arousal Activated Positive Affect (p < .001) and Activated Negative Affect (p < .01) were associated with significant decreases in QTc. Changes in QTc as a function of daily emotion ranged from 5-ms increases to 11-ms decreases. High-frequency heart rate variability (vagal tone) was positively correlated with QTc (p < .001). The effects of each positive emotion variable on QTc were greater in LQT2 than LQT1 patients (p < .001). CONCLUSION Ventricular repolarization duration (QTc) changes dynamically as a function of daily emotion. These changes are relatively small and do not constitute a risk in themselves. In the context of other risk factors, however, they may contribute to ventricular arrhythmias in vulnerable populations.
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Translational pharmacokinetic-pharmacodynamic modelling; application to cardiovascular safety data for PF-00821385, a novel HIV agent. Br J Clin Pharmacol 2010; 69:336-45. [PMID: 20406218 DOI: 10.1111/j.1365-2125.2009.03594.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
AIM To assess the translation of pharmacokinetic-pharmacodynamic (PK-PD) relationships for heart rate effects of PF-00821385 in dog and man. METHODS Cardiovascular telemetric parameters and concentration data were available for animals receiving active doses (0.5-120 mg kg(-1), n= 4) or vehicle. PF-00821385 was administered to 24 volunteers and pharmacokinetic and vital signs data were collected. PK-PD models were fitted using nonlinear mixed effects. RESULTS Compartmental models with linear absorption and clearance were used to describe pharmacokinetic disposition in animal and man. Diurnal variation in heart and pulse rate was best described with a single cosine function in both dog and man. Canine and human heart rate change were described by a linear model with free drug slope 1.76 bpm microM(-1)[95% confidence interval (CI) 1.17, 2.35] in the dog and 0.76 bpm microM(-1) (95% CI 0.54, 1.14) in man. CONCLUSIONS The preclinical translational of concentration-response has been described and the potential for further interspecies extrapolation and optimization of clinical trial design is addressed.
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Honda M, Komatsu R, Holzgrefe HH, Yamada Y, Isobe T, Kimura K, Itoh T, Tamaoki N, Tabo M. Application of probabilistic analysis for precisely correcting the QT interval for heart rate in telemetered common marmosets. J Pharmacol Toxicol Methods 2010; 61:264-70. [DOI: 10.1016/j.vascn.2010.01.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Revised: 10/28/2009] [Accepted: 01/18/2010] [Indexed: 11/16/2022]
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Champeroux P, Ouillé A, Martel E, Fowler JSL, Maurin A, Jude S, Lala P, Le Guennec JY, Richard S. Interferences of the autonomic nervous system with drug induced QT prolongation: a point to consider in non-clinical safety studies. J Pharmacol Toxicol Methods 2010; 61:251-63. [PMID: 20172034 DOI: 10.1016/j.vascn.2010.02.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Revised: 02/08/2010] [Accepted: 02/10/2010] [Indexed: 02/03/2023]
Abstract
INTRODUCTION QT interval assessment by telemetry has become one of the most useful models in testing strategies adopted for detection of drug induced QT prolongation in non-clinical safety pharmacology studies. This study reports experimental data showing that the autonomic nervous system might influence drug induced QT prolongation. METHODS Animals were instrumented with telemetric transmitters and epicardial ECG leads. Effects on QT interval of reference drugs such as thioridazine and terfenadine were analysed with different approaches, the Holzgrefe's probabilistic method, the QT shift method and an individual analysis of beat-to-beat QT/RR pair distribution visualised as points-cloud. RESULTS Two cases of unexpected absence of QT interval prolongation are reported with thioridazine and terfenadine in conscious beagle dogs under conditions of concomitant tachycardia. The pro-arrhythmic properties of these two molecules were unmasked by co-treatment with sympatholytic agents, atenolol and clonidine respectively suggesting that sympathetic activation and/or parasympathetic withdrawal might impair a drug induced QT prolongation. DISCUSSION The apparent absence of changes in the QT interval due to novel drug candidates should be interpreted cautiously under conditions of concomitant tachycardia or elevated heart rate levels in non-clinical safety studies.
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Affiliation(s)
- Pascal Champeroux
- Centre de Recherches Biologiques, CERB, Chemin de Montifault, 18800 Baugy, France.
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21
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Tabo M, Komatsu R, Isobe T, Honda M, Yamada Y, Kimura K. Accurate detection of drug-induced delayed ventricular repolarization with a suitable correction formula in Langendorff guinea pig heart. J Toxicol Sci 2010; 35:687-98. [DOI: 10.2131/jts.35.687] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Mitsuyasu Tabo
- Safety Assessment Department, Chugai Pharmaceutical Co., Ltd
| | - Ryuichi Komatsu
- Safety Assessment Department, Chugai Pharmaceutical Co., Ltd
| | - Takehito Isobe
- Safety Assessment Department, Chugai Pharmaceutical Co., Ltd
| | - Masaki Honda
- Safety Assessment Department, Chugai Pharmaceutical Co., Ltd
| | - Yuichiro Yamada
- Safety Assessment Department, Chugai Pharmaceutical Co., Ltd
| | - Kazuya Kimura
- Safety Assessment Department, Chugai Pharmaceutical Co., Ltd
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22
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The effects of intravenous ciprofloxacin on the electrocardiogram of healthy dogs. Vet Res Commun 2009; 33:987-90. [PMID: 19728129 DOI: 10.1007/s11259-009-9317-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/25/2009] [Indexed: 10/20/2022]
Abstract
The purpose of this study was to evaluate the electrocardiographic effects of single intravenous dose of ciprofloxacin in dogs. Ten adult cross-breed dogs of both sexes were selected as the sample population. Baseline electrocardiographic values were recorded just before drug administration. Then the dogs received intravenous infusion of ciprofloxacin (10 mg/kg) over the fifteen minutes. The ECGs recorded at 15, 30, 60 and 120 minutes after ciprofloxacin administration. The ECG measurements of heart rate, PR interval, QRS interval, ST segment, T-wave amplitude and QT interval were taken from lead II. There was a small but significant increase in the longest QT intervals over baseline at T₆₀ (P = 0.041). The mean PR intervals, QTc intervals, JT intervals, ST segment, T-wave amplitude did not differ significantly before and after ciprofloxacin except for JT intervals at T₆₀ (P = 0.041). At this measurement point, there was an increased QT interval value of 0.02 second or 9.51% in comparison to the baseline. In Conclusions, Only minor QT intervals changes were observed after ciprofloxacin injection. Despite the occurrence of ECG changes following intravenous ciprofloxacin administration neither dangerous rhythm disturbances nor serious ECG changes were seen in this study.
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Maule S, Rabbia F, Perni V, Tosello F, Bisbocci D, Mulatero P, Veglio F. Prolonged QT interval and reduced heart rate variability in patients with uncomplicated essential hypertension. Hypertens Res 2009; 31:2003-10. [PMID: 19098371 DOI: 10.1291/hypres.31.2003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A prolonged QT interval is a risk factor for ischemic heart disease in hypertensive subjects. Heart rate variability (HRV) is both an index of autonomic function and an important prognostic factor in several diseases. The aim of the present study was to evaluate the relation between a prolonged QT interval and autonomic nervous system function in patients with untreated uncomplicated essential hypertension. Two hundred and fifteen untreated patients with essential hypertension underwent a Holter ECG equipped with software dedicated to HRV and QT analyses. Nine percent of the patients showed a corrected QT (QTc) >or=440 ms. The HRV indexes in the time domain (SDNN, SDNN index, RMSSD, and pNN50) were significantly reduced in the patients with a prolonged QTc compared to those with a normal QTc (SDNN 24 h: 126.4+/-29.9 vs. 143.9+/-35.4 ms, p=0.02; SDNN index [nighttime]: 85.9+/-32.4 vs. 115.5+/-36.7 ms, p=0.0006; RMSSD 24 h: 22.2+/-7.7 vs. 31.2+/-13.0 ms, p=0.0007; pNN50 24 h: 4.4+/-4.9 vs. 9.7+/-8.4%, p=0.0006). The linear correlation analysis between QTc length and HRV parameters showed a significant negative correlation with all the time-domain indexes. Such a correlation was maintained for RMSSD 24 h, pNN50 24 h and SDNN index (nighttime) after correction for gender and age. The present study shows that, even prior to the development of cardiac hypertensive disease, a prolongation of the QTc and a reduced HRV, both markers of cardiovascular risk, coexist in a proportion of patients with untreated essential hypertension. Further studies are warranted to evaluate whether the combination of such markers can identify hypertensive patients at risk for life-threatening arrhythmias and sudden death. (Hypertens Res 2008; 31: 2003-2010).
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Affiliation(s)
- Simona Maule
- Autonomic Unit and Hypertension Unit, Department of Medicine and Experimental Oncology, S. Giovanni Battista Hospital, University of Turin, Turin, Italy.
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Manzo A, Ootaki Y, Ootaki C, Kamohara K, Fukamachi K. Comparative study of heart rate variability between healthy human subjects and healthy dogs, rabbits and calves. Lab Anim 2009; 43:41-5. [DOI: 10.1258/la.2007.007085] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Several studies have been performed to assess heart rate variability (HRV) in several species such as humans, dogs, pigs, calves, rabbits and rats. However, haemodynamic parameters are totally different in each animal, and optimal animal models for studying HRV corresponding to human HRV are still unclear. The purpose of this study was to assess HRV in human subjects and to compare those HRV data with canine, bovine and rabbit HRV data. The heart rate in the human subjects (62.8 ± 7.4 bpm) was significantly lower than that in dogs (124.2 ± 18.8 bpm, P < 0.001), calves (73.4 ± 10.5 bpm, P < 0.05), and rabbits (217.3 ± 21.5 bpm, P < 0.001). The low-frequency waves (LF) (57.9 ± 65.8 ms2/Hz) and high-frequency waves (HF) (33.8 ± 49.1 ms2/Hz) in rabbits were significantly lower than human LF (1216.3 ± 1220.7 ms2/Hz, P < 0.05) and HF (570.9 ± 581.3 ms2/Hz, P < 0.05). Dogs and calves showed similar LF (991.1 ± 646.1 ms2/Hz and 547.0 ± 256.9 ms2/Hz, respectively), HF (702.1 ± 394.1 ms2/Hz and 601.0 ± 666.6 ms2/Hz, respectively) and LF/HF (2.0 ± 1.3 and 2.5 ± 1.9, respectively) when compared with the human data. The present study shows that dogs and calves revealed similar HRV values as those which relate to humans. Large deviation of the HRV values in rabbits compared with humans might be considered when conducting animal studies using those animals to reflect human clinical situations.
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Affiliation(s)
- A Manzo
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Y Ootaki
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - C Ootaki
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - K Kamohara
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - K Fukamachi
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
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Calculation of QT shift in non clinical safety pharmacology studies. J Pharmacol Toxicol Methods 2008; 59:73-85. [PMID: 19135537 DOI: 10.1016/j.vascn.2008.11.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Accepted: 11/18/2008] [Indexed: 11/23/2022]
Abstract
INTRODUCTION Drug-induced QT interval prolongation is a major concern in new drug candidate development. This study presents a method of assessment of drug-induced QT interval prolongation without need for QT correction in conscious Beagle dogs and Cynomolgus monkeys monitored by telemetry. Accuracy and reliability are analysed by comparison with a reference QT correction method (Holzgrefe) from experiments performed with reference substances terfenadine, thioridazine and sotalol. METHODS The QT shift method principle is assessment of any drug-induced QT interval shift directly from the individual QT/RR relationship. The individual QT/RR relationship is built from a treatment-free 24-hour recording period. QT and RR intervals are determined from a beat-to-beat analysis. A probabilistic method is used to define the individual QT/RR relationships. Checks were performed to compare results obtained with the QT shift method and the QT correction methods. The robustness of the QT shift method was tested under various conditions of drug-induced heart rate change (i.e. normal, bradycardia and tachycardia). RESULTS The extent of agreement with the used reference QT correction method, Holzgrefe formula, was excellent (3-4 ms) in both animal species under the various drug induced effects on heart rate. The statistical sensitivity threshold for detection of QT prolongation according to a standard safety pharmacology study design was 7-8 ms. DISCUSSION When combined with the probabilistic determination of individual QT/RR relationships, this simple method provides a direct assessment of a drug-induced effect on QT interval, without any curve fitting or application of correction formula. Despite noticeably different shapes in QT/RR relationships, the QT shift method is applicable to both Beagle dogs and Cynomolgus monkeys. It is likely that the QT shift method will be particularly helpful in problematic cases, enabling detection of drug-induced prolongation of less than 10 ms.
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Tabo M, Hara T, Sone S, Shishido N, Kuramoto S, Nakano K, Onodera H, Kimura K, Kobayashi K. Prediction of drug-induced QT interval prolongation in telemetered common marmosets. J Toxicol Sci 2008; 33:315-25. [PMID: 18670163 DOI: 10.2131/jts.33.315] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Drug-induced QT interval prolongation is a critical issue in development of new chemical entities, so the pharmaceutical industry needs to evaluate risk as early as possible. Common marmosets have been in the limelight in early-stage development due to their small size, which requires only a small amount of test drug. The purpose of this study was to determine the utility of telemetered common marmosets for predicting drug-induced QT interval prolongation. Telemetry transmitters were implanted in common marmosets (male and female), and QT and RR intervals were measured. The QT interval was corrected for the RR interval by applying Bazett's and Fridericia's correction formulas and individual rate correction. Individual correction showed the least slope for the linear regression of corrected QT (QTc) intervals against RR intervals, indicating that it dissociated changes in heart rate most effectively. With the individual correction method, the QT-prolonging drugs (astemizole, dl-sotalol) showed QTc interval prolongations and the non-QT-prolonging drugs (dl-propranolol, nifedipine) did not show QTc interval prolongations. The plasma concentrations of astemizole and dl-sotalol associated with QTc interval prolongations in common marmosets were similar to those in humans, suggesting that the sensitivity of common marmosets would be appropriate for evaluating risk of drug-induced QT interval prolongation. In conclusion, telemetry studies in common marmosets are useful for predicting clinical QT prolonging potential of drugs in early stage development and require only a small amount of test drug.
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Affiliation(s)
- Mitsuyasu Tabo
- Safety Assessment Department, Research Division, Chugai Pharmaceutical Co., Ltd., Shizuoka.
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Li D, Chiang AY, Clawson CA, Main BW, Leishman DJ. Heartbeat dynamics in adrenergic blocker treated conscious beagle dogs. J Pharmacol Toxicol Methods 2008; 58:118-28. [DOI: 10.1016/j.vascn.2008.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2008] [Accepted: 05/02/2008] [Indexed: 10/22/2022]
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Ollerstam A, Visser SAG, Duker G, Forsberg T, Persson AH, Nilsson LB, Björkman JA, Gabrielsson J, Al-Saffar A. Comparison of the QT interval response during sinus and paced rhythm in conscious and anesthetized beagle dogs. J Pharmacol Toxicol Methods 2007; 56:131-44. [PMID: 17689270 DOI: 10.1016/j.vascn.2007.05.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2007] [Accepted: 03/28/2007] [Indexed: 11/20/2022]
Abstract
INTRODUCTION The aim of the present study was to compare sensitivity in detecting the drug-induced QT interval prolongation in three dog models: conscious telemetered at sinus rhythm and conscious and anesthetized dogs during atrial pacing. The test substances used represent different chemical classes with different pharmacological and pharmacokinetic profiles. METHOD Dofetilide and moxifloxacin were tested in all models, whereas cisapride and terfenadine were tested in the conscious telemetered and paced models. All substances were given as two consecutive 1.5-h intravenous infusions (infusions 1 and 2). The individual concentration-time courses of dofetilide, moxifloxacin, and cisapride were linked to the drug-induced effects on the QT interval and described with a pharmacokinetic-pharmacodynamic model to obtain an estimate of the unbound plasma concentrations at steady state that give a 10- and 20-ms drug-induced QT interval prolongation (CE10ms and CE20ms). RESULTS In the conscious telemetered, conscious paced, and anesthetized dog models, the mean CE10ms values were 1.4, 4.0, and 2.5 nM for dofetilide and 1300, 1800, and 12,200 nM for moxifloxacin. For cisapride, the CE10ms values were 8.0 and 4.4 nM in the conscious telemetered and conscious paced dog models. The drug-induced QT interval prolongation during the last 30 min of infusions 1 and 2 was comparable in the conscious models, but smaller in the anesthetized dog model. Terfenadine displayed a marked delay in onset of response, which could only be detected by the extended ECG recording. DISCUSSION All dog models investigated detected QT interval prolongation after administration of the investigated test substances with similar sensitivity, except for a lower sensitivity in the anesthetized dogs following moxifloxacin administration. The conscious telemetered dog model was favorable, mainly due to the extended continuous ECG recording, which facilitated detection and quantification of delayed temporal differences between systemic exposure and drug-induced QT interval prolongation.
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Affiliation(s)
- Anna Ollerstam
- Safety Pharmacology, AstraZeneca R&D Södertälje, SE-151 85 Södertälje, Sweden.
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Abstract
There are consistent differences in cardiovascular state between acute illness in malaria and recovery that prolong the electrocardiographic QT interval and have been misinterpreted as resulting from antimalarial cardiotoxicity. Of the different classes of antimalarial drugs, only the quinolines, and structurally related antimalarial drugs, have clinically significant cardiovascular effects. Drugs in this class can exacerbate malaria-associated orthostatic hypotension and several have been shown to delay ventricular depolarisation slightly (class 1c effect), resulting in widening of the QRS complex, but only quinidine and halofantrine have clinically significant effects on ventricular repolarisation (class 3 effect). Both drugs cause potentially dangerous QT prolongation, and halofantrine has been associated with sudden death. The parenteral quinoline formulations (chloroquine, quinine, and quinidine) are predictably hypotensive when injected rapidly, and cardiovascular collapse can occur with self-poisoning. Transiently hypotensive plasma concentrations of chloroquine can occur when doses of 5 mg base/kg or more are given by intramuscular or subcutaneous injection. At currently recommended doses, other antimalarial drugs do not have clinically significant cardiac effects. More information on amodiaquine, primaquine, and the newer structurally related compounds is needed.
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Affiliation(s)
- Nicholas J White
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
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Shiotani M, Harada T, Abe J, Hamada Y, Horii I. Methodological validation of an existing telemetry system for QT evaluation in conscious guinea pigs. J Pharmacol Toxicol Methods 2006; 55:27-34. [PMID: 16831559 DOI: 10.1016/j.vascn.2006.04.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2006] [Accepted: 04/18/2006] [Indexed: 11/16/2022]
Abstract
INTRODUCTION Guinea pigs are suitable for in vivo QT assessment of newly discovered drugs at the pre-clinical stage because of the ease with which these animals can be handled, the lower amount of compound required for testing, and the similarity of the ion channels between the guinea pig heart and the human. Our purpose was to provide detailed methodological information on an existing telemetry recording system for use in evaluating QT interval prolongation in guinea pigs. METHODS Hartley guinea pigs weighing 400-700 g were used to investigate the appropriate configuration of electrodes to record defined T-waves and the influence of the surgical implantation of a transmitter on the QT interval, as well as to determine the appropriate formula for QT correction. In addition, the validity of using telemetry-monitored guinea pigs was tested by using compounds with (positive references) or without (vehicles) a QT-prolonging effect. RESULTS A lead with the negative pole placed between the scapulas and the positive pole positioned close to the sternum was found to be the most appropriate to obtain well-defined T-waves. The period for recovery from transmitter implantation was estimated to be at least 1 week. The best-fit formula for our telemetry guinea pig model was a modified Bazett's formula. QTc was prolonged significantly in guinea pigs given positive references, and the QTc was unaffected when the animals were given vehicles. DISCUSSION We believe that the information provided herein will be a quite helpful guide for researchers to evaluate the QT interval reliably and reproducibly in this telemetry guinea pig model.
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Affiliation(s)
- Motohiro Shiotani
- Worldwide Safety Sciences, Pfizer Global Research and Development, Nagoya Laboratories, Pfizer Japan Inc. 5-2 Taketoyo, Aichi 470-2393, Japan.
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