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A short P-wave duration is associated with incident heart failure in the elderly: a 15 years follow-up cohort study. J Geriatr Cardiol 2022; 19:643-650. [PMID: 36284675 PMCID: PMC9548055 DOI: 10.11909/j.issn.1671-5411.2022.09.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Early identification of patients at risk of congestive heart failure (HF) may alter their poor prognosis. The aim was therefore to test whether simple electrocardiographic variables, the P-wave and PR-interval, could predict incident HF. METHODS The PIVUS (Prospective Investigation of the Vasculature in Uppsala Seniors) study (1016 individuals all aged 70 years, 50% women) was used to identify predictors of HF. Subjects with prevalent HF, QRS duration ≥ 130 ms, atrial tachyarrhythmias, implanted pacemaker/defibrillator, second- and third-degree atrioventricular block or delta waves at baseline were excluded. Cox proportional hazard analysis was used to relate the PR interval, P-wave duration (Pdur) and amplitude (Pamp), measured in lead V1, to incident HF. Adjustment was performed for gender, RR-interval, beta-blocking agents, systolic blood pressure, body mass index and smoking. RESULTS Out of 836 subjects at risk, 107 subjects were diagnosed with HF during a follow-up of 15 years. In the multivariate analysis, there was a strong U-shaped correlation between Pdur in lead V1 and incident HF (P = 0.0001) which was significant for a Pdur < 60 ms [HR = 2.75; 95% CI: 1.87-4.06, at Pdur 40 ms] but not for prolonged Pdur. There was no significant relationship between incident HF and the PR-interval or the Pamp. A Pdur < 60 ms improved discrimination by 3.7% when added to the traditional risk factors including sex, RR-interval, beta-blocking agents, systolic blood pressure, BMI and smoking (P = 0.048). CONCLUSIONS A short Pdur, an easily measured parameter on the ECG, may potentially be a useful marker of future HF, enabling its early detection and prevention, thus improving outcomes.
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Ostrowska B, Lind L, Sciaraffia E, Blomström-Lundqvist C. Short P-Wave Duration Is Associated with Incident Atrial Fibrillation. Int Heart J 2022; 63:700-707. [PMID: 35831146 DOI: 10.1536/ihj.21-797] [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] [Indexed: 11/18/2022]
Abstract
Atrial fibrillation (AF) is common and increases the risk for stroke and heart failure (HF). The early identification of patients at risk may prevent the development of AF and improve prognosis. This study, therefore, aimed to test the effect of the association between P-wave and PR-interval on the ECG and incident AF.The PIVUS (Prospective Investigation of the Vasculature in Uppsala Seniors) study (1016 individuals all aged 70 years; 50% women) was used to identify whether the ECG variables P-wave duration (Pdur) and PR-duration in lead V1 were related to new-onset AF. Exclusion criteria were prevalent AF, QRS-duration ≥ 130 milliseconds (msec), atrial tachyarrhythmias and implanted pacemaker/defibrillator. Cox proportional-hazards models were used for analyses. Adjustments were made for gender, RR-interval, beta-blocking agents, systolic blood pressure, body mass index, and smoking.Of 877 subjects at risk, 189 individuals developed AF during a 15-year follow-up. There was a U-shaped relationship between the Pdur and incident AF (P = 0.017) following multiple adjustment. Values below 60 msec were significantly associated with incident AF, with a hazard ratio of 1.55 (95% confidence interval 1.15-2.09) for a Pdur ≤ 42 msec. There was no significant relationship between incident AF and the PR-interval.A short Pdur derived from the ECG in V1 may be a useful marker for new-onset AF, enabling the early identification of at-risk patients.
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Affiliation(s)
| | - Lars Lind
- Department of Medical Sciences, Uppsala University
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Meiser K, Jordaan P, Latypova S, Darpo B. Comparing QT interval variability of semiautomated and high-precision ECG methodologies in seven thorough QT studies-implications for the power of studies intended for definitive evaluation of a drug's QT effect. Ann Noninvasive Electrocardiol 2016; 22. [PMID: 27995684 DOI: 10.1111/anec.12416] [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] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND In studies of drug effects on electrocardiographic parameters, the level of precision in measuring QTc interval changes will influence a study's ability to detect small effects. METHODS Variability data from investigational, placebo and moxifloxacin treatments from seven thorough QT studies performed by the same sponsor were analyzed with the objective to compare the performance of two commonly used approaches for ECG interval measurements: semiautomated (SA) and the high-precision QT (HPQT) analysis. Five studies were crossover and two parallel. Harmonized procedures were implemented to ensure similar experimental conditions across studies. ECG replicates were extracted serially from continuous 12-lead recordings at predefined time points from subjects supinely resting. The variability estimates were based on the time-point analysis of change-from-baseline QTcF as the dependent variable for the standard primary analysis of previous thorough QT studies. The residual variances were extracted for each study and ECG technique. RESULTS High-precision QT resulted in a substantial reduction in ∆QTc variability as compared to SA. A reduction in residual variability or approximately 50% was achieved in both crossover and parallel studies, both for the active comparison (drug vs. placebo) and for assay sensitivity (moxifloxacin vs. placebo) data. CONCLUSIONS High-precision QT technique significantly reduces QT interval variability and thereby the number of subjects needed to exclude small effects in QT studies. Based on this assessment, the sample size required to exclude a QTc effect >10 ms with 90% power is reduced from 35 with SA to 18 with HPQT, if a 3 ms underlying drug effect is assumed.
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Affiliation(s)
| | | | | | - Borje Darpo
- iCardiac Technologies, Inc., Rochester, NY, USA.,Karolinska Institutet, Division of Cardiovascular Medicine, Department of Clinical Sciences, Danderyd's Hospital, Stockholm, Sweden
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Evaluation of the Effect of Selumetinib on Cardiac Repolarization: A Randomized, Placebo- and Positive-controlled Crossover QT/QTc Study in Healthy Subjects. Clin Ther 2016; 38:2555-2566. [DOI: 10.1016/j.clinthera.2016.10.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 10/03/2016] [Accepted: 10/10/2016] [Indexed: 11/20/2022]
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Ferber G, Zhou M, Dota C, Garnett C, Keirns J, Malik M, Stockbridge N, Darpo B. Can Bias Evaluation Provide Protection Against False-Negative Results in QT Studies Without a Positive Control Using Exposure-Response Analysis? J Clin Pharmacol 2016; 57:85-95. [DOI: 10.1002/jcph.779] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Revised: 06/02/2016] [Accepted: 06/02/2016] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | - Christine Garnett
- Division of Cardiovascular and Renal Products; Center for Drug Evaluation and Research; US Food and Drug Administration; Silver Spring MD USA
| | - James Keirns
- Clinical Pharmacology & Exploratory Development; Astellas Pharma Global Development, Inc; Northbrook IL USA
| | - Marek Malik
- St Paul's Cardiac Electrophysiology; University of London, and Imperial College; London UK
| | - Norman Stockbridge
- Division of Cardiovascular and Renal Products; Center for Drug Evaluation and Research; US Food and Drug Administration; Silver Spring MD USA
| | - Borje Darpo
- iCardiac Technologies; Inc; Rochester NY USA
- Karolinska Institutet; Division of Cardiovascular Medicine; Department of Clinical Sciences; Danderyd's Hospital; Stockholm Sweden
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Johansson S, Löfberg B, Aunes M, Lunde H, Frison L, Edvardsson N, Cullberg M. In Silico Predictions and In Vivo Results of Drug-Drug Interactions by Ketoconazole and Verapamil on AZD1305, a Combined Ion Channel Blocker and a Sensitive CYP3A4 Substrate. Clin Pharmacol Drug Dev 2016; 5:364-73. [DOI: 10.1002/cpdd.250] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 12/18/2015] [Accepted: 01/04/2016] [Indexed: 11/07/2022]
Affiliation(s)
| | | | | | | | | | - Nils Edvardsson
- Sahlgrenska Academy at Sahlgrenska University Hospital; Göteborg Sweden
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Gottfridsson C, Carlson G, Lappalainen J, Sostek M. Evaluation of the effect of Naloxegol on cardiac repolarization: a randomized, placebo- and positive-controlled crossover thorough QT/QTc study in healthy volunteers. Clin Ther 2013; 35:1876-83. [PMID: 24238792 DOI: 10.1016/j.clinthera.2013.09.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 09/03/2013] [Accepted: 09/21/2013] [Indexed: 01/08/2023]
Abstract
BACKGROUND Opioid-induced constipation (OIC) is a common adverse effect associated with opioid use. Naloxegol is a PEGylated derivative of naloxone in clinical development as a once-daily oral treatment of OIC. OBJECTIVES A thorough QT/QTc study was conducted, according to International Conference on Harmonisation E14 guidelines, to characterize the effect of naloxegol on cardiac repolarization. METHODS In this randomized, positive- and placebo-controlled crossover study, healthy men received a single dose of naloxegol 25 mg (therapeutic dose), naloxegol 150 mg (supratherapeutic dose), moxifloxacin 400 mg (positive control), or placebo in 1 of 4 sequences (Williams Latin square design). The washout time between treatment periods was at least 5 days. Digital 12-lead ECGs were recorded at baseline and at 10 time points over 24 hours after dosing in each treatment period. QT intervals were corrected for heart rate using the Fridericia formula (QTcF) and the Bazett formula (QTcB). RESULTS A total of 52 subjects were enrolled (mean age, 28 years), and 45 received all 4 treatments. The placebo-corrected, baseline-adjusted, mean increases in QTcF with naloxegol 25 and 150 mg were both <5 msec at each time point, and all upper limits of the 2-sided 90% CI were <10 msec. Similar findings were observed using QTcB; the upper limits of the 2-sided 90% CI were <10 msec at all time points after dosing with naloxegol 25 or 150 mg. With moxifloxacin 400 mg, mean QTcF was increased by a maximum of 11.1 msec (90% CI, 9.3-12.9 msec), supporting assay sensitivity. CONCLUSION Naloxegol at 25 and 150 mg was not associated with QT/QTc interval prolongation in these healthy men, and at the proposed therapeutic dose of 25 mg/d, naloxegol is not expected to have a clinically relevant effect on cardiac repolarization in patients with OIC. ClinicalTrials.gov identifier: NCT01325415.
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Affiliation(s)
| | | | | | - Mark Sostek
- AstraZeneca Pharmaceuticals, Wilmington, Delaware.
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Geller JC, Egstrup K, Kulakowski P, Rosenqvist M, Jansson MA, Berggren A, Edvardsson N, Sager P, Crijns HJ. Rapid Conversion of Persistent Atrial Fibrillation to Sinus Rhythm by Intravenous AZD7009. J Clin Pharmacol 2013; 49:312-22. [DOI: 10.1177/0091270008329549] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Abrahamsson C, Dota C, Skallefell B, Carlsson L, Frison L, Berggren A, Edvardsson N, Duker G. Assessment of ventricular repolarization variability with the DeltaT50 method improves identification of patients with congenital long QT syndromes. Ann Noninvasive Electrocardiol 2012; 18:240-50. [PMID: 23714082 DOI: 10.1111/anec.12016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
BACKGROUND We analyzed ventricular repolarization variability in genotyped long QT syndrome (LQTS) patients and in healthy volunteers (HV). METHOD The deltaT50, that is, the temporal variability of ventricular repolarization at 50% of the T-wave downslope, was analyzed every 15th minute on 175 and 390 Holter electrocardiogram (ECG) recordings from HV and genotyped LQTS patients, respectively. The average deltaT50 and QTcF were calculated in each subject. RESULTS DeltaT50 was 2.26 ± 0.71 ms (mean ± SD) in the HV and 5.74 ± 2.30 ms in the LQTS population (P < 0.0001). The sensitivity and specificity of QTcF (cutoff value 450 ms) to discriminate between the LQTS patients and the HV were 51.5% and 98.9%, and for deltaT50 (cutoff value 3 ms) 93.9% and 88.6%, respectively. The combination of both variables improved the diagnosis of the LQTS patients even further. Subgroups of LQTS patients at higher risk of cardiac events (with LQTS3, JLN, QTc > 500 ms or symptoms) had higher deltaT50 than subgroups at lower risk (with LQTS1, QTc < 450 ms or without symptoms). The variation in deltaT50 between day and night was concordant with the risk of symptoms; patients with LQTS1 had higher deltaT50 in the daytime and patients with LQTS3 had higher deltaT50 during the night. CONCLUSION DeltaT50 more accurately distinguished between LQTS patients and HV than QTcF and was higher in LQTS patients with a higher risk of cardiac events. DeltaT50 can be used together with QTcF to improve the diagnosis in patients with the LQTS phenotype and tentatively also be of value for risk assessment in such patients.
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Abrahamsson C, Dota C, Skallefell B, Carlsson L, Halawani D, Frison L, Berggren A, Edvardsson N, Duker G. DeltaT50--a new method to assess temporal ventricular repolarization variability. J Electrocardiol 2011; 44:477.e1-9. [PMID: 21704223 DOI: 10.1016/j.jelectrocard.2011.04.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Indexed: 11/19/2022]
Abstract
BACKGROUND Increased beat-to-beat variability in cardiac repolarization time is a tentative risk marker of drug-induced torsades de pointes. We developed a new, automatic method based on the temporal variability of the T-wave down slope to assess this variability. METHOD AND RESULTS Leads V(1) to V(6) of resting electrocardiograms were recorded in 42 healthy subjects (18-68 years, 22 men). The temporal variability at 50% of the T-wave down slope, deltaT50 (1.5 ± 0.41 milliseconds; range, 0.86-2.66 milliseconds), was measured with an accuracy of 1 millisecond on at least 9 pairs of electrocardiogram complexes with a signal-to-noise ratio more than 10 and changes in the R-R interval less than 150 milliseconds. The correlation between repeated measurements of deltaT50 was high. DeltaT50 was measured without corrections for age, sex, heart rate, T-wave amplitude, signal-to-noise ratio, R-R variability, and QTcF because none of these factors explained more than 4% of the within-subject deltaT50 variability. CONCLUSION The beat-to-beat repolarization variability was measured with high fidelity with the deltaT50 method and was a robust measure in healthy volunteers.
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Affiliation(s)
- Christina Abrahamsson
- AstraZeneca R&D, Mölndal and Sahlgrenska Academy at Sahlgrenska University Hospital, Göteborg, Sweden.
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Carlson GF, Tou CKP, Parikh S, Birmingham BK, Butler K. Evaluation of the effect of dapagliflozin on cardiac repolarization: a thorough QT/QTc study. Diabetes Ther 2011; 2:123-32. [PMID: 22127822 PMCID: PMC3173598 DOI: 10.1007/s13300-011-0003-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Indexed: 01/10/2023] Open
Abstract
INTRODUCTION Dapagliflozin is a first-in-class sodium-glucose transporter 2 (SGLT2) inhibitor under investigation for the treatment of type 2 diabetes mellitus. A thorough QTc study was conducted, according to International Conference on Harmonization E14 guidelines, to characterize the effect of dapagliflozin on cardiac repolarization. METHODS The present study was a double-blind, four-period, placebo-controlled crossover study at a single-center inpatient clinical pharmacology unit. The study enrolled 50 healthy men who were randomized to receive sequences of single doses of dapagliflozin 150 mg, dapagliflozin 20 mg, moxifloxacin 400 mg, and placebo. The sequences were randomized based on the Williams design for a cross-over study to reduce the "carryover" effects from drug-to-drug even with sufficient washout periods. Digital 12-lead electrocardiograms were recorded at nine time points over 24 hours in each period. QT intervals were corrected for heart rate using a study-specific correction factor (QTcX) and Fridericia's formula. RESULTS For dapagliflozin, the upper bound of the one-sided 95% confidence interval (CI) for time-matched, placebo-subtracted, baseline adjusted QTc intervals (ΔΔQTc) was <10 ms. ΔΔQTc was independent of dapagliflozin concentrations. No QTc thresholds >450 ms or QTc increases >30 ms were observed. Moxifloxacin increased the mean QTcX interval by 7.7 ms (lower bound 90% CI, 6.2 ms) over 1-4 hours after dosing, confirming assay sensitivity. CONCLUSION Dapagliflozin, at supratherapeutic doses, does not have a clinically significant effect on the QT interval in healthy subjects.
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Affiliation(s)
- Glenn F Carlson
- AstraZeneca LP, 1800 Concord Pike, PO Box 1543, Wilmington, DE, 19850-5437, USA,
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Gosse P, Coulon P, Papaioannou G, Litalien J, Lemetayer P. Atrioventricular conduction in the hypertensive patient: influence of aging, pulse pressure, and arterial stiffness. Rejuvenation Res 2011; 14:405-10. [PMID: 21599452 DOI: 10.1089/rej.2010.1152] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Atrioventricular (AV) conduction time (PR interval) lengthens with age. Hypertension is often presented as an accelerated aging of the heart and arteries. The principal marker of arterial aging is an increase in arterial stiffness and pulse pressure. We were interested to find out whether parameters of blood pressure and arterial stiffness were related to the PR interval and whether they influenced its long-term progression. We examined factors linked to the PR interval at baseline in a cohort of untreated hypertensive patients including office and 24-hr blood pressure and arterial stiffness (QKD(100-60)). Long-term evolution of the PR interval and related factors were obtained during follow-up of this population. Baseline data were obtained in 1,034 untreated hypertensive patients. At baseline, four variables emerged as significantly and independently correlated with PR interval: Gender, age, weight, and heart rate. During follow-up (137 ± 78 months), 328 of these patients were re-examined. In this group, PR increased from 159 ± 20 to 167 ± 25 msec (p<0.001), a mean alteration of 8 ± 19 msec. This change was correlated with the baseline 24 hr PP (r=0.17, p=0.004) and with the duration of follow-up (r=0.13, p=0.02). In the group with baseline evaluation of arterial stiffness (n=141), QKD(100-60) was correlated with the change in PR interval (r= -0.33, p<0.0001) along with the duration of follow-up (r=0.22, p=0.005). This study shows a link between baseline increased pulse pressure or arterial stiffness with the prolongation of the PR interval with aging. Because this link was observed during follow-up, it is possible that increased arterial stiffness favors the increase in the PR interval with age.
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Affiliation(s)
- Philippe Gosse
- Hypertension Unit, Hopital Saint André, University Hospital of Bordeaux, 1 rue Jean Burguet, Bordeaux, France.
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An automated method for detection of layer activation order in information processing pathway of rat barrel cortex under mechanical whisker stimulation. J Neurosci Methods 2010; 196:141-50. [PMID: 21145917 DOI: 10.1016/j.jneumeth.2010.11.024] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Revised: 11/26/2010] [Accepted: 11/28/2010] [Indexed: 11/22/2022]
Abstract
Rodents perform object localization, texture and shape discrimination very precisely through whisking. During whisking, microcircuits in corresponding barrel columns get activated to segregate and integrate tactile information through the information processing pathway. Sensory signals are projected through the brainstem and thalamus to the corresponding 'barrel columns' where different cortical layers are activated during signal projection. Therefore, having precise information about the layer activation order is desirable to better understand this signal processing pathway. This work proposes an automated, computationally efficient and easy to implement method to determine the cortical layer activation from intracortically recorded local field potentials (LFPs) and derived current source density (CSD) profiles: 1. Barrel cortex LFPs are represented by a template of four subsequent events: small positive/negative (E1) → large negative (E2) → slow positive (E3)→ slow long negative (E4). The method exploits the layer specific characteristics of LFPs to obtain latencies of the individual events (E1–E4), then taking the latency of E2 for calculating the layer activation order. 2. The corresponding CSD profile is calculated from the LFPs and the first sink’s peak is considered as a reference point to calculate latencies and evaluate the layer activation order. Other reference points require manual calculation. Similar results of layer activation sequence are found using LFPs and CSDs. Extensive tests on LFPs recorded using standard borosilicate micropipettes demonstrated the method's workability. An interpretation of layer activation order and CSD profiles on the basis of a simplified interacortical barrel column architecture is also provided.
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Tjäderborn M, Aunes-Jansson M, Samuelsson E, Frison L, Johansson S, Berggren A, Edvardsson N. Prediction of drug-related morphological changes of the T wave. SCAND CARDIOVASC J 2010; 44:215-22. [PMID: 20429697 DOI: 10.3109/14017431003789892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVES To describe the characteristics of patients presenting with morphological T wave changes that lead to measurement difficulties, and to identify possible predictors of such changes at baseline and early after start of treatment. DESIGN ECGs from 145 patients receiving a combined potassium and sodium channel blocking agent for conversion of atrial fibrillation (AF), underwent semiautomatic analysis in a digitalized high-precision analysis program. In 15 patients, one or more ECGs were identified as difficult to interpret due to morphological T wave changes. They were compared with the 130 patients without such changes. RESULTS A history of cardiac failure (p=0.027), a smaller left atrial area (p=0.010) and a longer QT(tang) minus QT(top) interval (p<0.001) at baseline was significantly more frequent as compared to the controls. Identified patients also had somewhat longer baseline QT interval duration (median QT(cB) 432 vs. 408 ms, N.S.) and a larger proportion of them were females (47% vs. 27%, N.S.). After start of infusion the QT(cB) became significantly longer in identified patients than in controls (p=0.012). CONCLUSIONS Independent predictors of subsequent morphological changes were found at baseline and shortly after start of treatment, and may be of use to identify individuals with a reduced repolarization reserve.
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Dota CD, Edvardsson N, Skallefell B, Fager G. PC-Based ECG waveform recognition-validation of novel software against a reference ECG database. Ann Noninvasive Electrocardiol 2009; 14 Suppl 1:S42-7. [PMID: 19143742 DOI: 10.1111/j.1542-474x.2008.00263.x] [Citation(s) in RCA: 7] [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 PC-based ECG measurements must cope with normal as well as pathological ECGs in a reliable manner. EClysis, a software for ECG measurements was tested against reference values from the Common Standards for Quantitative Electrocardiography (CSE) database. METHODS Digital ECGs (12 leads, 500 Hz) were recorded by the CSE project. Data Set 3 contains reference values for 125 ECGs (33 normal and 92 pathological). Median values of measurements by 11 computer programs and by five cardiologists, respectively, refer to the earliest P and QRS onsets and to the latest P, QRS, and T offsets in any lead of a selected (index) beat. EClysis automatically measured all ECGs, without user interference. RESULTS The PQRST points were correctly detected but in two ECGs with AV block II-III. The software was not designed to detect atrial activity in atrial fibrillation (n = 9) and flutter (n = 1). In one case of atrial fibrillation, atrial activity interfered with positioning of QRS and T offsets. Regression coefficients between EClysis and CSE (software-generated and human) were above 0.95 (P < 0.0001). The confidence intervals were 95% for the slope and the intercept of the regression lines. CONCLUSIONS The PC-based detection and analysis of PQRST points showed a high level of agreement with the CSE database reference values.
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Pollard CE, Valentin JP, Hammond TG. Strategies to reduce the risk of drug-induced QT interval prolongation: a pharmaceutical company perspective. Br J Pharmacol 2008; 154:1538-43. [PMID: 18500356 DOI: 10.1038/bjp.2008.203] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Drug-induced prolongation of the QT interval is having a significant impact on the ability of the pharmaceutical industry to develop new drugs. The development implications for a compound causing a significant effect in the 'Thorough QT/QTc Study' -- as defined in the clinical regulatory guidance (ICH E14) -- are substantial. In view of this, and the fact that QT interval prolongation is linked to direct inhibition of the hERG channel, in the early stages of drug discovery the focus is on testing for and screening out hERG activity. This has led to understanding of how to produce low potency hERG blockers whilst retaining desirable properties. Despite this, a number of factors mean that when an integrated risk assessment is generated towards the end of the discovery phase (by conducting at least an in vivo QT assessment) a QT interval prolongation risk is still often apparent; inhibition of hERG channel trafficking and partitioning into cardiac tissue are just two confounding factors. However, emerging information suggests that hERG safety margins have high predictive value and that when hERG and in vivo non-clinical data are combined, their predictive value to man, whilst not perfect, is >80%. Although understanding the anomalies is important and is being addressed, of greater importance is developing a better understanding of TdP, with the aim of being able to predict TdP rather than using an imperfect surrogate marker (QT interval prolongation). Without an understanding of how to predict TdP risk, high-benefit drugs for serious indications may never be marketed.
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Affiliation(s)
- C E Pollard
- AstraZeneca R&D Alderley Park, Safety Assessment UK, Macclesfield, Cheshire, UK.
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Darpo B, Nebout T, Sager PT. Clinical evaluation of QT/QTc prolongation and proarrhythmic potential for nonantiarrhythmic drugs: the International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use E14 guideline. J Clin Pharmacol 2006; 46:498-507. [PMID: 16638733 DOI: 10.1177/0091270006286436] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Proarrhythmias due to drug-induced QT prolongation are the second most common cause for drug withdrawal and have caused increasing concern. Two new International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) guidelines were recently endorsed in which nonclinical (S7B) and clinical (E14) methodologies are discussed and guidance is given to the industry. This commentary describes the key components of the E14 document, the impact of nonclinical testing on the clinical program, the thorough QT study, and the impact of its result on late-stage development. The studies described in S7B and E14 will contribute to a better understanding of the link between nonclinical assays and QT prolongation in humans. Differences in interpretation among individual regulators in the major regions with respect to measures proposed in the E14 guideline might impact regional regulatory decisions. These differences include the value of nonclinical assays for the subsequent clinical testing and how predictive a negative thorough QT study result is for proarrhythmic risk in patients.
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Darpo B, Agin M, Kazierad DJ, Layton G, Muirhead G, Gray P, Jorkasky DK. Man versus machine: is there an optimal method for QT measurements in thorough QT studies? J Clin Pharmacol 2006; 46:598-612. [PMID: 16707406 DOI: 10.1177/0091270006286900] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Electrocardiographic (ECG) recordings from 3 placebo-controlled thorough QT healthy volunteer studies were used to compare QT intervals obtained by manual measurement with those generated by ECG machines. The effect of the positive control was compared to placebo at each time point for data obtained from both sources. Both manual and automated techniques consistently demonstrated statistically significant prolongation of QTcF with the positive controls. The proportion of outlier values was small for both methods. The pairwise comparison between manual and automated uncorrected QT intervals demonstrated clear differences, with intervals derived from one machine on average 16 to 19 milliseconds shorter and from the other 7 milliseconds longer than the manually measured QT intervals, but these differences disappeared when analyzing QT change from baseline. Both manual and automated, commercially available QT algorithms demonstrated small statistically significant effects on the QTc interval induced by positive controls.
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Affiliation(s)
- Borje Darpo
- MSc, Clinical Statistics, Clinical R and D, Pfizer Global Research and Development, Ramsgate Road, Sandwich, Kent, CT13 9NJ, United Kingdom
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Sager PT, Nebout T, Darpo B. ICH E14: A New Regulatory Guidance on the Clinical Evaluation of QT/QTc Internal Prolongation and Proarrhythmic Potential for Non-antiarrhythmic Drugs. ACTA ACUST UNITED AC 2005. [DOI: 10.1177/009286150503900407] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Azie NE, Adams G, Darpo B, Francom SF, Polasek EC, Wisser JM, Fleishaker JC. Comparing methods of measurement for detecting drug-induced changes in the QT interval: implications for thoroughly conducted ECG studies. Ann Noninvasive Electrocardiol 2004; 9:166-74. [PMID: 15084215 PMCID: PMC6932408 DOI: 10.1111/j.1542-474x.2004.92542.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: 11/30/2022] Open
Abstract
BACKGROUND The aim of this study was to compare the reproducibility and sensitivity of four commonly used methods for QT interval assessment when applied to ECG data obtained after infusion of ibutilide. METHODS Four methods were compared: (1) 12-lead simultaneous ECG (12-SIM), (2) lead II ECG (LEAD II), both measured on a digitizing board, (3) 3-LEAD ECG using a manual tangential method, and (4) a computer-based, proprietary algorithm, 12SL trade mark ECG Analysis software (AUT). QT intervals were measured in 10 healthy volunteers at multiple time points during 24 hours at baseline and after single intravenous doses of ibutilide 0.25 and 0.5 mg. Changes in QT interval from baseline were calculated and compared across ECG methods, using Bland-Altman plots. Variability was studied using a mixed linear model. RESULTS Baseline QT values differed between methods (range 376-395 ms), mainly based on the number of leads incorporated into the measurement, with LEAD II and 3-LEAD providing the shortest intervals. The 3-LEAD generated the largest QT change from baseline, whereas LEAD II and 12-SIM generated essentially identical result within narrow limits of agreement (0.4 ms mean difference, 95% confidence interval +/- 20.5 ms). Variability with AUT (standard deviation 15.8 ms for within-subject values) was clearly larger than with 3-LEAD, LEAD II, and 12-SIM (9.6, 10.0, and 11.3 ms). CONCLUSION This study demonstrated significant differences among four commonly used methods for QT interval measurement after pharmacological prolongation of cardiac repolarization. Observed large differences in variability of measurements will have a substantial impact on the sample size required to detect QT prolongation in the range that is currently advised in regulatory guidance.
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Affiliation(s)
| | - Gregory Adams
- Clinical Pharmacology, Pfizer Ltd., Kalamazoo, MI, USA
| | - Borje Darpo
- Clinical Pharmacology, Pfizer Ltd., High Wycombe, UK and Department of Cardiology, Karolinska Hospital, Stockholm, Sweden
| | | | | | - Joy M. Wisser
- Clinical Pharmacology, Pfizer Ltd., Kalamazoo, MI, USA
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