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1.
Artículo en Inglés | MEDLINE | ID: mdl-39082327

RESUMEN

INTRODUCTION: Early-onset atrial fibrillation (AF) has already been observed in approximately 2% of patients with genetically proven long QT syndrome (LQTS). This frequency is higher than population-based estimates of early-onset AF. However, the concomitant expression of AF in LQTS is likely underestimated. The purpose of this study was to examine the clinical presentation, genetic background, and outcomes of a cohort of patients with LQTS and early-onset AF referred to a single tertiary center. METHODS: Twenty-seven patients diagnosed with congenital LQTS were included in the study based on the documentation of early-onset (age ≤50 years) clinical or subclinical AF episodes in all available medical records, including standard electrocardiograms, wearable monitor or cardiac implantable electronic devices. RESULTS: Seventeen patients experienced clinical AF during the follow-up period. Subclinical AF was detected in 10 patients through insertable or wearable cardiac monitors. In our series, the mean heart rate during AF episodes was found to be relatively low despite the patients' young age and the low or minimal effective doses of beta-blockers used for QTc interval control. All patients exhibiting LQTS and early-onset AF were genotype positive, carrying mutations in the KCNQ1 (66%), KCNH2, KCNE1, and SCN5A genes. Notably, most of these patients carried the same p.(R231C) mutation in the KCNQ1 gene (59%) and were from the same families, suggesting concurrent expression of familial AF and LQTS. CONCLUSION: LQTS patients are prone to developing clinical and subclinical AF, even at a younger age. The occurrence of early-onset AF in the LQTS population could be more frequent than previously assumed. AF should be considered as a potential dysrhythmia related to LQTS. Our study emphasizes the importance of carefully researching clinical and/or subclinical episodes of AF through strict heart rhythm monitoring in the LQTS population.

2.
Int J Toxicol ; 43(4): 357-367, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38477622

RESUMEN

In silico modeling offers an opportunity to supplement and accelerate cardiac safety testing. With in silico modeling, computational simulation methods are used to predict electrophysiological interactions and pharmacological effects of novel drugs on critical physiological processes. The O'Hara-Rudy's model was developed to predict the response to different ion channel inhibition levels on cardiac action potential duration (APD) which is known to directly correlate with the QT interval. APD data at 30% 60% and 90% inhibition were derived from the model to delineate possible ventricular arrhythmia scenarios and the marginal contribution of each ion channel to the model. Action potential values were calculated for epicardial, myocardial, and endocardial cells, with action potential curve modeling. This study assessed cardiac ion channel inhibition data combinations to consider when undertaking in silico modeling of proarrhythmic effects as stipulated in the Comprehensive in Vitro Proarrhythmia Assay (CiPA). As expected, our data highlight the importance of the delayed rectifier potassium channel (IKr) as the most impactful channel for APD prolongation. The impact of the transient outward potassium channel (Ito) inhibition on APD was minimal while the inward rectifier (IK1) and slow component of the delayed rectifier potassium channel (IKs) also had limited APD effects. In contrast, the contribution of fast sodium channel (INa) and/or L-type calcium channel (ICa) inhibition resulted in substantial APD alterations supporting the pharmacological relevance of in silico modeling using input from a limited number of cardiac ion channels including IKr, INa, and ICa, at least at an early stage of drug development.


Asunto(s)
Potenciales de Acción , Simulación por Computador , Canales Iónicos , Miocitos Cardíacos , Potenciales de Acción/efectos de los fármacos , Humanos , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/metabolismo , Canales Iónicos/efectos de los fármacos , Canales Iónicos/metabolismo , Canales Iónicos/fisiología , Arritmias Cardíacas/inducido químicamente , Arritmias Cardíacas/fisiopatología
3.
Biochem Biophys Res Commun ; 655: 82-89, 2023 05 07.
Artículo en Inglés | MEDLINE | ID: mdl-36933311

RESUMEN

BACKGROUND: Torsade de pointes is a potentially lethal polymorphic ventricular tachyarrhythmia that can occur in the setting of long QT syndrome (LQTS). LQTS is multi-hit in nature and multiple factors combine their effects leading to increased arrhythmic risk. While hypokalemia and multiple medications are accounted for in LQTS, the arrhythmogenic role of systemic inflammation is increasingly recognized but often overlooked. We tested the hypothesis that the inflammatory cytokine interleukin(IL)-6 will significantly increase the incidence of arrhythmia when combined with other pro-arrhythmic conditions (hypokalemia and the psychotropic medication, quetiapine). METHODS: Guinea pigs were injected intraperitoneally with IL-6/soluble IL-6 receptor and QT changes were measured in vivo. Subsequently, hearts were cannulated via Langendorff perfusion for ex vivo optical mapping measurements of action potential duration (APD90) and arrhythmia inducibility. Computer simulations (MATLAB) were performed to investigate IKr inhibition at varying IL-6 and quetiapine concentrations. RESULTS: IL-6 prolonged QTc in vivo guinea pigs from 306.74 ± 7.19 ms to 332.60 ± 8.75 ms (n = 8, p = .0021). Optical mapping on isolated hearts demonstrated APD prolongation in IL-6- vs saline groups (3Hz APD90:179.67 ± 2.47 ms vs 153.5 ± 7.86 ms, p = .0357). When hypokalemia was introduced, the APD90 increased to 195.8 ± 5.02 ms[IL-6] and 174.57 ± 10.7 ms[saline] (p = .2797), and when quetiapine was added to hypokalemia to 207.67 ± 3.03 ms[IL-6] and 191.37 ± 9.49 ms[saline] (p = .2449). After the addition of hypokalemia ± quetiapine, arrhythmia was induced in 75% of IL-6-treated hearts (n = 8), while in none of the control hearts (n = 6). Computer simulations demonstrated spontaneous depolarizations at ∼83% aggregate IKr inhibition. CONCLUSIONS: Our experimental observations strongly suggest that controlling inflammation, specifically IL-6, could be a viable and important route for reducing QT prolongation and arrhythmia incidence in the clinical setting.


Asunto(s)
Hipopotasemia , Síndrome de QT Prolongado , Torsades de Pointes , Animales , Cobayas , Torsades de Pointes/inducido químicamente , Citocinas , Fumarato de Quetiapina , Interleucina-6 , Arritmias Cardíacas , Síndrome de QT Prolongado/inducido químicamente , Inflamación/complicaciones , Electrocardiografía
4.
Br J Clin Pharmacol ; 89(4): 1386-1392, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-36346345

RESUMEN

AIMS: Few studies have investigated linezolid (LZD)-associated cardiotoxicity. This study explored the potential association between LZD and QT interval prolongation. METHODS: Adverse event reports of QT interval prolongation associated with LZD from the Food and Drug Administration Adverse Event Reporting System from January 2013 to December 2021 were analysed and the reporting odds ratio (ROR) with 95% confidence intervals were calculated. RESULTS: A total of 6738 adverse event reports of LZD as the primary and secondary suspected drug were obtained from the database, including 192 reports with electrocardiogram QT prolonged (QTp), and the ROR value was 26.1 (95% CI = 22.6-30.2). There were 8 reports of long QT syndrome, ROR 14.2 (95% CI = 7.1-28.5); 5 reports of torsade de pointes, ROR 3.2 (95% CI = 1.3-7.6); and 5 reports of ventricular tachycardia, ROR 1.9 (95% CI = 0.8-4.5). Subgroup analysis revealed that patients with tuberculosis treated with LZD had a higher reporting rate among all QTp reports, exhibiting an odds ratio of 330.0 (95% CI = 223.1-488.1). The odds ratios of QTp associated with LZD treatments in patients with and without tuberculosis were 4.2 (95% CI = 3.4-5.3) and 1.2 (95% CI = 0.8-1.6), respectively. CONCLUSION: The study showed an association between LZD and QT interval prolongation. In the report on patients with tuberculosis, the incidence of QTp was higher when treated with LZD.


Asunto(s)
Síndrome de QT Prolongado , Torsades de Pointes , Estados Unidos/epidemiología , Humanos , Linezolid/efectos adversos , Farmacovigilancia , United States Food and Drug Administration , Síndrome de QT Prolongado/inducido químicamente , Síndrome de QT Prolongado/epidemiología
5.
Br J Clin Pharmacol ; 89(7): 2272-2282, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-36823349

RESUMEN

AIMS: Patients with solid tumours were treated with the anti-PD-1 antibody dostarlimab in the Phase I GARNET trial. This study aimed to examine dostarlimab's effect on corrected QT (QTc) interval and the systemic concentration-QTc interval relationship. METHODS: In GARNET Part 2B, patients received 500 mg dostarlimab every 3 weeks (Q3W) for four cycles, then 1000 mg Q6W. Triplicate 12-lead ECGs were recorded and time-matched pharmacokinetic (PK) samples collected at screening, on Day 1 of Cycles 1, 4, 5, 8, 12 (pre-dose and 0.5 h after infusion end), and at treatment end. Concentration-change from baseline QTcF (ΔQTcF) analysis using a linear mixed effects model, summary statistics, incidence of clinically noteworthy ECG values and rhythm abnormalities were evaluated. RESULTS: A total of 377 patients were considered for evaluation (n = 15 excluded from concentration-ΔQTcF). There was a non-significant concentration-ΔQTcF relationship (0.001589 ms/µg/mL; P = .5906). Mean ΔQTcF increase was <6 ms (upper-bound two-sided 90% confidence interval [CI], <10 ms at all post-dose timepoints). Highest geometric mean concentration was 414.1 µg/mL (Cycle 5 Day 1, 0.5 h) with predicted mean ∆QTcF of 3.064 ms (upper-bound two-sided 90% CI: 5.071). Mean QTcF prolongation (all concentrations) was 2.4 ms. QTcF prolongation ≥500 ms occurred in five patients (1.3%); 51 (13.6%) and nine patients (2.4%) had ΔQTcF ≥30 ms and ≥60 ms, respectively. Ten patients (2.7%) reported rhythm abnormalities. No U-wave abnormalities, torsades de pointes, ventricular tachycardia or ventricular fibrillation/flutter were observed. CONCLUSIONS: Dostarlimab does not cause clinically significant QTcF prolongation exceeding the regulatory concern threshold.


Asunto(s)
Síndrome de QT Prolongado , Neoplasias , Humanos , Anticuerpos Monoclonales/efectos adversos , Neoplasias/tratamiento farmacológico , Neoplasias/inducido químicamente , Anticuerpos Monoclonales Humanizados/efectos adversos , Electrocardiografía , Síndrome de QT Prolongado/inducido químicamente , Síndrome de QT Prolongado/epidemiología , Frecuencia Cardíaca
6.
Eur Arch Psychiatry Clin Neurosci ; 273(1): 65-74, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-35217913

RESUMEN

Dear Doctor Letters (DDLs, Direct Healthcare Professional Communications) from 2011 provided guidance regarding QTc-prolonging effects with risk of torsade de pointes during treatment with citalopram and escitalopram. This study examines the DDLs' effects on prescription behavior. Data from 8842 inpatients treated with citalopram or escitalopram with a primary diagnosis of major depressive disorder (MDD) were derived from a European pharmacovigilance study (Arzneimittelsicherheit in der Psychiatrie, AMSP) from 2001 to 2017. It was examined to what extent new maximum doses were adhered to and newly contraindicated combinations with QTc-prolonging drugs were avoided. In addition, the prescriptions of psychotropic drugs before and after DDLs were compared in all 43,480 inpatients with MDD in the data set. The proportion of patients dosed above the new limit decreased from 8 to 1% in patients ≤ 65 years and from 46 to 23% in patients > 65 years old for citalopram versus 14-5% and 47-31% for escitalopram. Combinations of es-/citalopram with other QTc-prolonging psychotropic drugs reduced only insignificantly (from 35.9 to 30.9%). However, the proportion of patients with doses of quetiapine > 150 mg/day substantially decreased within the combinations of quetiapine and es-/citalopram (from 53 to 35%). After the DDLs, prescription of citalopram decreased and of sertraline increased. The DDLs' recommendations were not entirely adhered to, particularly in the elderly and concerning combination treatments. This might partly be due to therapeutic requirements of the included population. Official warnings should consider clinical needs.


Asunto(s)
Trastorno Depresivo Mayor , Síndrome de QT Prolongado , Humanos , Anciano , Citalopram/efectos adversos , Escitalopram , Fumarato de Quetiapina , Trastorno Depresivo Mayor/inducido químicamente , Síndrome de QT Prolongado/inducido químicamente , Psicotrópicos
7.
Circulation ; 144(10): 823-839, 2021 09 07.
Artículo en Inglés | MEDLINE | ID: mdl-34491774

RESUMEN

Polymorphic ventricular tachyarrhythmias are highly lethal arrhythmias. Several types of polymorphic ventricular tachycardia have similar electrocardiographic characteristics but have different modes of therapy. In fact, medications considered the treatment of choice for one form of polymorphic ventricular tachycardia, are contraindicated for the other. Yet confusion about terminology, and thus diagnosis and therapy, continues. We present an in-depth review of the different forms of polymorphic ventricular tachycardia and propose a practical step-by-step approach for distinguishing these malignant arrhythmias.


Asunto(s)
Tratamiento de Urgencia , Síndrome de QT Prolongado/diagnóstico , Taquicardia Ventricular/fisiopatología , Taquicardia Ventricular/terapia , Arritmias Cardíacas/fisiopatología , Electrocardiografía/métodos , Humanos , Síndrome de QT Prolongado/fisiopatología , Taquicardia Ventricular/diagnóstico
8.
J Cardiovasc Electrophysiol ; 33(7): 1592-1595, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35488741

RESUMEN

We report a 28-year-old female patient with congenital type 2 long QT syndrome (LQTS) in which mexiletine shortened corrected QT interval (QTc) and effectively prevented refractory Torsade de Pointes (TdP) and ventricular fibrillation (VF). She developed TdP and VF, and was subsequently diagnosed with congenital type 2 LQTS. She had refractory TdP and VF every day despite medical therapy including ß-blocker. They were completely suppressed after the initiation of mexiletine with shorting of QTc interval.


Asunto(s)
Síndrome de QT Prolongado , Torsades de Pointes , Adulto , Arritmias Cardíacas , Proteínas de Unión al ADN , Electrocardiografía , Femenino , Humanos , Síndrome de QT Prolongado/complicaciones , Síndrome de QT Prolongado/diagnóstico , Síndrome de QT Prolongado/tratamiento farmacológico , Mexiletine/uso terapéutico , Torsades de Pointes/diagnóstico , Torsades de Pointes/etiología , Fibrilación Ventricular/diagnóstico , Fibrilación Ventricular/etiología , Fibrilación Ventricular/prevención & control
9.
J Pharmacol Sci ; 150(2): 67-73, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-36055753

RESUMEN

We analyzed role of cardiac α1-adrenoreceptors for the torsadogenic action of IKr blocker nifekalant in isoflurane-anesthetized atrioventricular block rabbits. Bradycardia was induced by atrioventricular node ablation, and the ventricle was electrically driven at a constant rate of 60 beats/min throughout the experiments to prevent rate-dependent modification by the IKr blocker in ventricular repolarization phase. Nifekalant (3 mg/kg per 10 min, n = 5) prolonged the duration of monophasic action potential (MAP90) by +178 ± 43 ms, increased the short-term variability of repolarization (STV) to 4.2 ± 1.2 ms, and induced torsade de pointes (TdP) in 1 animal. In the presence of methoxamine (n = 5), nifekalant prolonged the MAP90 by +328 ± 32 ms, increased the STV to 8.0 ± 1.0 ms, and induced TdP in 2 animals. In the presence of prazosin and methoxamine (n = 5), nifekalant prolonged the MAP90 by +267 ± 22 ms, increased the STV to 9.2 ± 3.6 ms, and induced no TdP. These results suggest that cardiac α1-adrenoreceptor activation by methoxamine essentially sensitizes the rabbit heart to nifekalant-induced QT interval prolongation, leading to the onset of TdP.


Asunto(s)
Bloqueo Atrioventricular , Síndrome de QT Prolongado , Torsades de Pointes , Potenciales de Acción , Animales , Antiarrítmicos/farmacología , Bloqueo Atrioventricular/inducido químicamente , Electrocardiografía , Síndrome de QT Prolongado/inducido químicamente , Metoxamina/efectos adversos , Pirimidinonas , Conejos , Torsades de Pointes/inducido químicamente
10.
Ann Noninvasive Electrocardiol ; 27(4): e12939, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35146844

RESUMEN

Hypoparathyroidism predisposes patients to hypocalcemia. Patients with hypoparathyroidism are thus at risk of electrocardiographic abnormalities, including T-wave alternans. T-wave alternans is poorly understood and lacks uniform diagnostic criteria. Its presence suggests myocardial electrical instability, and it has become an important sign for identifying patients at high risk of malignant arrhythmias and sudden cardiac death. We report a rare case of T-wave alternans with torsade de pointes due to hypocalcemia. The etiology of T-wave alternans may easily be overlooked. It should thus be thoroughly investigated to avoid misdiagnosis and poor outcomes.


Asunto(s)
Hipocalcemia , Hipoparatiroidismo , Torsades de Pointes , Arritmias Cardíacas/complicaciones , Electrocardiografía/efectos adversos , Humanos , Hipocalcemia/complicaciones , Hipocalcemia/diagnóstico , Hipoparatiroidismo/complicaciones , Hipoparatiroidismo/diagnóstico , Torsades de Pointes/complicaciones , Torsades de Pointes/diagnóstico
11.
Ann Noninvasive Electrocardiol ; 27(4): e12936, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35322503

RESUMEN

Drug-induced QT prolongation, primarily antiarrhythmic drugs, is a common cause of torsade de pointes (TdP). Although there have been previous reports of drug-induced TdP in patients, it has not been well documented when caused by citalopram during the pacemaker battery-depletion phase. To improve delirium recognition, we report a case of citalopram-induced TdP during the pacemaker battery-depletion phase. An 84-year-old Chinese female was brought to the hospital presenting recurrent syncope. She lost consciousness and was admitted after her syncope TdP was documented. Her pacemaker was inspected and found to be operating in an extremely ineffective manner. Although she had prolonged QT interval after the pacemaker was replaced, she did not suffer another syncope attack, and ECG monitoring revealed no cardiac arrhythmia or TdP. During her admission, she was treated with citalopram for depression. Citalopram was discontinued when the QT interval shortened progressively. In this study, we described a case of citalopram-induced TdP during the depletion phase of a pacemaker battery. This case should serve as a cautionary lesson to clinicians to avoid using citalopram during the pacemaker battery-depletion phase.


Asunto(s)
Síndrome de QT Prolongado , Marcapaso Artificial , Torsades de Pointes , Anciano de 80 o más Años , Citalopram/efectos adversos , Proteínas de Unión al ADN , Electrocardiografía , Femenino , Humanos , Síndrome de QT Prolongado/complicaciones , Marcapaso Artificial/efectos adversos , Síncope/inducido químicamente , Síncope/terapia , Torsades de Pointes/inducido químicamente , Torsades de Pointes/diagnóstico , Torsades de Pointes/terapia
12.
Ann Noninvasive Electrocardiol ; 27(1): e12888, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34547155

RESUMEN

BACKGROUND: TdP is a form of polymorphic ventricular tachycardia which develops in the setting of a prolonged QT interval. There are limited data describing risk factors, treatment, and outcomes of this potentially fatal arrhythmia. OBJECTIVE: Our goals were as follows: (1) to validate cases presenting with Torsade de Pointes (TdP), (2) to identify modifiable risk factors, and (3) to describe the management strategies used for TdP and its prognosis in a real-world healthcare setting. METHODS: Case-control study (with 2:1 matching on age, sex, and race/ethnicity) nested within the Genetic Epidemiology Research on Aging (GERA) cohort. Follow-up of the cohort for case ascertainment was between January 01, 2005 and December 31, 2018. RESULTS: A total of 56 cases of TdP were confirmed (incidence rate = 3.6 per 100,000 persons/years). The average (SD) age of the TdP cases was 74 (13) years, 55 percent were female, and 16 percent were non-white. The independent predictors of TdP were potassium concentration <3.6 mEq/L (OR = 10.6), prior history of atrial fibrillation/flutter (OR = 6.2), QTc >480 ms (OR = 4.4) and prior history of coronary artery disease (OR = 2.6). Exposure to furosemide and amiodarone was significantly greater in cases than in controls. The most common treatment for TdP was IV magnesium (78.6%) and IV potassium repletion (73.2%). The in-hospital and 1-year mortality rates for TdP cases were 10.7% and 25.0% percent, respectively. CONCLUSIONS: These findings may inform quantitative multivariate risk indices for the prediction of TdP and could guide practitioners on which patients may qualify for continuous ECG monitoring and/or electrolyte replacement therapy.


Asunto(s)
Prestación Integrada de Atención de Salud , Síndrome de QT Prolongado , Torsades de Pointes , Anciano , Estudios de Casos y Controles , Electrocardiografía , Femenino , Humanos , Torsades de Pointes/diagnóstico , Torsades de Pointes/epidemiología
13.
Eur Heart J ; 42(38): 3915-3928, 2021 10 07.
Artículo en Inglés | MEDLINE | ID: mdl-34370839

RESUMEN

AIMS: With the explosion of anticancer drugs, an emerging concern is the risk for drug-induced sudden death (SD) via ventricular arrhythmias (VA). METHODS AND RESULTS: We used the international pharmacovigilance database VigiBase (n = 18 441 659 reports) to compare drug-induced long QT (diLQT, n = 18 123) and VA (n = 29 193) including torsade de pointes (TdP, n = 8163) reporting for 663 anticancer drugs vs. all other drugs until 01/01/2019. The analysis used the 95% lower-end credibility interval of the information component (IC025), an indicator for disproportionate Bayesian reporting; significant when IC025 >0. There were 2301 reports (13.8% fatal) for 40 anticancer drugs significantly associated with diLQT (with 27 also associated with VA or SD) and 9 drugs associated with VA without diLQT. Half of these (46.9%, 23/49) were associated with SD. Most (41%, 20/49) were kinase inhibitors, 8% (4/49) were hormonal therapies, 6% (3/49) were immunotherapies, 24% (12/49) were cytotoxics, and 20% (10/49) were miscellaneous. In VigiBase, reports of diLQT, TdP, or VA increased from 580 in the period 1967-83 to 15 070 in 2014-18 with the proportion related to anticancer drugs increasing from 0.9% (5/580) to 14.0% (2115/15 070) (P < 0.0001). Concordance between these VigiBase signals and data concerning diLQT and VA/TdP identified in CredibleMeds or US Food and Drug Administration (FDA) labels was moderate (κ = 0.47 and 0.40, P < 0.0001). Twenty-three drugs represent new signals, while 24 flagged by CredibleMeds or FDA had no signal in VigiBase. A three-level SD risk stratification relying on isolated long QT (low risk), associated with VA without SD (moderate risk), and VA with SD (high risk) is proposed. CONCLUSION: This list of liable anticancer drugs may prove useful for physicians and regulatory authorities to re-evaluate cardiac monitoring requirements. CLINICAL TRIAL REGISTRATION: NCT03530215.


Asunto(s)
Antineoplásicos , Síndrome de QT Prolongado , Torsades de Pointes , Sistemas de Registro de Reacción Adversa a Medicamentos , Antineoplásicos/efectos adversos , Teorema de Bayes , Humanos , Farmacovigilancia , Torsades de Pointes/inducido químicamente , Torsades de Pointes/epidemiología , Organización Mundial de la Salud
14.
Eur Heart J ; 42(38): 3965-3975, 2021 10 07.
Artículo en Inglés | MEDLINE | ID: mdl-33693589

RESUMEN

AIMS: Distinctive types of polymorphic ventricular tachycardia (VT) respond differently to different forms of therapy. We therefore performed the present study to define the electrocardiographic characteristics of different forms of polymorphic VT. METHODS AND RESULTS: We studied 190 patients for whom the onset of 305 polymorphic VT events was available. The study group included 87 patients with coronary artery disease who had spontaneous polymorphic VT triggered by short-coupled extrasystoles in the absence of myocardial ischaemia. This group included 32 patients who had a long QT interval but nevertheless had their polymorphic VT triggered by ectopic beats with short coupling interval, a subcategory termed 'pseudo-torsade de pointes] (TdP). For comparison, we included 50 patients who had ventricular fibrillation (VF) during acute myocardial infarction ('ischaemic VF' group) and 53 patients with drug-induced TdP ('true TdP' group). The QT of patients with pseudo-TdP was (by definition) longer than that of patients with polymorphic VT and normal QT (QTc 491.4 ± 25.2 ms vs. 447.3 ± 55.6 ms, P < 0.001). However, their QT was significantly shorter than that of patients with true TdP (QTc 564.6 ± 75.6 ms, P < 0.001). Importantly, the coupling interval of the ectopic beat triggering the arrhythmia was just as short during pseudo-TdP as during polymorphic VT with normal QT (359.1 ± 38.1 ms vs. 356.6 ± 39.4 ms, P = 0.467) but was much shorter than during true TdP (581.2 ± 95.3 ms, P < 0.001). CONCLUSIONS: The coupling interval helps discriminate between polymorphic VT that occurs despite a long QT interval (pseudo-TdP) and polymorphic arrhythmias striking because of a long QT (true TdP).


Asunto(s)
Síndrome de QT Prolongado , Taquicardia Ventricular , Torsades de Pointes , Diagnóstico Diferencial , Electrocardiografía , Humanos , Síndrome de QT Prolongado/diagnóstico , Taquicardia Ventricular/diagnóstico , Torsades de Pointes/diagnóstico , Torsades de Pointes/etiología , Fibrilación Ventricular/diagnóstico , Fibrilación Ventricular/etiología
15.
Indian Pacing Electrophysiol J ; 22(5): 254-257, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35870802

RESUMEN

Torsade de Pointes (TdP) can be triggered by a pacing spike on the T-wave, due to pacemaker undersensing. However, it is not widely known that this phenomenon can occur even during pacemaker implantation. An 84-year-old woman underwent pacemaker implantation for the treatment of a complete atrioventricular block with dyspnea. During the procedure, immediately following ventricular lead insertion and before torque wrench tightening, TdP was observed. Ventricular pacing was initiated by inserting the lead into the header of the generator; however, sensing remained unstable. T-waves associated with undersensed PVCs and ventricular pacing occurred simultaneously, resulting in a spike on the T-wave and TdP.

16.
J Neural Transm (Vienna) ; 128(2): 243-252, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33417009

RESUMEN

At least 170 approved drugs are linked to QT prolongation, which can lead to serious adverse drug reactions (ADRs), such as Torsade de Pointes (TdP). The aim of this study was to analyze the prevalence and type of pharmacodynamic drug-drug interactions (DDIs) between QT-prolonging drugs in psychiatry. The present retrospective analysis used data from a large pharmacovigilance study, conducted in 10 psychiatric hospitals in Germany. Patients medication lists were screened for QT-prolonging drugs, classified according to the Arizona Center for Education and Research on Therapeutics (AZCERT). In total, 27,396 patient cases (46% female) with a mean (± standard deviation) age of 47 ± 18 years were included in the study. Altogether, 83% of the cases received at least one and up to eight QT-prolonging drugs at the same time. Combination of drugs with a known or possible risk for TdP (according to the AZCERT) was detected in 13,670 cases (50%). Most frequently prescribed psychotropic high-risk drugs (n = 48,995) were the antipsychotics pipamperone (n = 6202), quetiapine (n = 5718), prothipendyl (n = 4298), and risperidone (n = 4265). The replacement of high-risk drugs such as tricyclic antidepressants, levomepromazine, melperone, and promethazine with more tolerable drugs could avoid 11% of QT-prolonging drugs and increase the tolerability of psychopharmacological treatment. More than 80% of psychiatric patients receive at least one QT-prolonging drug during their hospital stay, and almost 50% of these drugs are combined in clinical practice. For the prevention of cardiac ADRs, the physician should evaluate the risk for QT prolongation for each drug and patient-specific risk factors before prescribing these drugs or drug combinations.


Asunto(s)
Síndrome de QT Prolongado , Preparaciones Farmacéuticas , Torsades de Pointes , Interacciones Farmacológicas , Femenino , Humanos , Recién Nacido , Síndrome de QT Prolongado/inducido químicamente , Síndrome de QT Prolongado/epidemiología , Masculino , Estudios Retrospectivos , Factores de Riesgo , Torsades de Pointes/inducido químicamente
17.
Europace ; 23(6): 828-836, 2021 06 07.
Artículo en Inglés | MEDLINE | ID: mdl-33200170

RESUMEN

Plenty of non-cardiovascular drugs alter cardiac electrophysiology and may ultimately lead to life-threatening arrhythmias. In clinical practice, measuring the QT interval as a marker for the repolarization period is the most common tool to assess the electrophysiologic safety of drugs. However, the sole measurement of the QT interval may be insufficient to determine the proarrhythmic risk of non-cardiovascular agents. Several other markers are considered in pre-clinical safety testing to determine potential harm on cardiac electrophysiology. Besides measuring typical electrophysiologic parameters such as repolarization duration, whole-heart models allow the determination of potential predictors for proarrhythmia. Spatial and temporal heterogeneity as well as changes of shape of the action potential can be easily assessed. In addition, provocation manoeuvers (either by electrolyte imbalances or programmed pacing protocols) may induce sustained arrhythmias and thereby determine ventricular vulnerability to arrhythmias. Compared with the human heart, the rabbit heart possesses a similar distribution of ion currents that govern cardiac repolarization, resulting in a rectangular action potential configuration in both species. In addition, similar biophysical properties of rabbit and human cardiac ion channels lead to a comparable pharmacologic response in human and rabbit hearts. Of note, arrhythmia patterns resemble in both species due to the similar effective size of human and rabbit hearts. Thus, the rabbit heart is particularly suitable for testing the electrophysiologic safety of drugs. Several experimental setups have been developed for studying cardiac electrophysiology in rabbits, ranging from single cell to tissue preparations, whole-heart setups, and in vivo models.


Asunto(s)
Síndrome de QT Prolongado , Torsades de Pointes , Potenciales de Acción , Animales , Arritmias Cardíacas/inducido químicamente , Arritmias Cardíacas/diagnóstico , Electrocardiografía , Corazón , Frecuencia Cardíaca , Conejos
18.
Eur J Clin Pharmacol ; 77(10): 1513-1521, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-33938974

RESUMEN

PURPOSE: To analyze the cases of torsade de pointes (TdP) and related symptoms reported in association with chloroquine (CQ), hydroxychloroquine (HCQ), and azithromycin (AZT) to the World Health Organization (WHO) global database of individual case safety reports (ICSRs) for drug monitoring (VigiBase) using qualitative and quantitative pharmacovigilance approaches. METHODS: The main characteristics of the ICSRs reporting TdP with CQ, HCQ, and AZT have been summarized. Co-reported drugs with risk to cause QT prolongation have been described. Reporting odds ratios (RORs) as a measure of disproportionality for reported TdP and individual drugs have been calculated. RESULTS: One hundred seventy ICSRs reporting TdP in association with the drugs of interest were identified (CQ: 11, HCQ: 31, CQ + HCQ: 1, HCQ + AZT: 27, AZT: 100). From these, 41 (24.3%) were received during the pandemic period (December 2019 to February 2021). The median age of the patients was 63, 53, and 63 years old for CQ, HCQ, and AZT, respectively. Reports included concomitant use of other QT-prolonging drugs (CQ 25.0%, HCQ 71.2%, AZT 64.6%). A proportion of the cases were fatal (CQ 25.0%, HCQ 8.6%, AZT 16.1%). Increased disproportionality has been found for the individual drugs and TdP: CQ (ROR: 7.41, 95% confidence interval (CI): 3.82, 12.96), HCQ (ROR: 8.49, 95% CI: 6.57, 10.98), azithromycin (ROR: 8.06, 95% CI: 6.76, 9.61). Disproportionality was also found for other related symptoms, Standardized MedDRA Query for torsade de pointes/QT prolongation (narrow): CQ (ROR: 11.95, 95% CI: 10.04-14.22); HCQ (ROR: 20.43, 95% CI: 19.13, 21.83), AZT (ROR: 7.78, 95% CI: 7.26, 8.34). CONCLUSIONS: The prescription of CQ, HCQ, and AZT should be restricted to therapeutic indications with established positive benefit/risk profile. Doctors and patients should be aware of this potential adverse reaction especially when several risk factors are present.


Asunto(s)
Azitromicina/efectos adversos , Cloroquina/efectos adversos , Hidroxicloroquina/efectos adversos , Torsades de Pointes/inducido químicamente , Adulto , Anciano , Azitromicina/administración & dosificación , Cloroquina/administración & dosificación , Quimioterapia Combinada , Femenino , Humanos , Hidroxicloroquina/administración & dosificación , Masculino , Persona de Mediana Edad , Farmacovigilancia , Estudios Retrospectivos
19.
Biol Pharm Bull ; 44(11): 1796-1799, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34719656

RESUMEN

Torsadogenic effects of ivabradine, an inhibitor of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, were assessed in an in vivo proarrhythmia model of acute atrioventricular block rabbit. Ivabradine at 0.01, 0.1, and 1 mg/kg was intravenously administered to isoflurane-anesthetized rabbits (n = 5) in the stable idioventricular rhythm. Ivabradine at 0.01 and 0.1 mg/kg hardly affected the atrial and ventricular automaticity, QT interval, or the monophasic action potential duration of the ventricle. Additionally administred ivabradine at 1 mg/kg decreased the atrial and ventricular rate significantly but increased the QT interval and duration of the monophasic action potential. Meanwhile, torsade de pointes arrhythmias were detected in 1 out of 5 animals and in 2 out of 5 animals after the administration of 0.1 and 1 mg/kg, respectively. Importantly, torsade de pointes arrhythmias could be observed only in 2 rabbits showing more potent suppressive effects on ventricular automaticity. These results suggest that the torsadogenic potential of ivabradine may become evident when its expected bradycardic action appears more excessively.


Asunto(s)
Bloqueo Atrioventricular/tratamiento farmacológico , Fármacos Cardiovasculares/efectos adversos , Canales Regulados por Nucleótidos Cíclicos Activados por Hiperpolarización/antagonistas & inhibidores , Ivabradina/efectos adversos , Torsades de Pointes/inducido químicamente , Animales , Fármacos Cardiovasculares/farmacología , Fármacos Cardiovasculares/uso terapéutico , Modelos Animales de Enfermedad , Electrocardiografía , Frecuencia Cardíaca/efectos de los fármacos , Hemodinámica , Ivabradina/farmacología , Ivabradina/uso terapéutico , Masculino , Conejos
20.
Heart Vessels ; 36(7): 1088-1097, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33763729

RESUMEN

To characterize in vivo anti-atrial fibrillatory potential and pharmacological safety profile of ranolazine having INa,L plus IKr inhibitory actions in comparison with those of clinically available anti-atrial fibrillatory drugs; namely, dronedarone, amiodarone, bepridil and dl-sotalol in our previous studies, ranolazine dihydrochloride in sub-therapeutic (0.3 mg/kg) and supra-therapeutic (3 mg/kg) doses was intravenously infused over 10 min to the halothane-anesthetized dogs (n = 5). The low dose increased the heart rate, cardiac output and atrioventricular conduction velocity possibly via vasodilator action-induced, reflex-mediated increase of adrenergic tone. Meanwhile, the high dose decreased the heart rate, ventricular contraction, cardiac output and mean blood pressure, indicating that drug-induced direct actions may exceed the reflex-mediated compensation. In addition, it prolonged the atrial and ventricular effective refractory periods, of which potency and selectivity for the former were less great compared with those of the clinically-available drugs. Moreover, it did not alter the ventricular early repolarization period in vivo, but prolonged the late repolarization with minimal risk for re-entrant arrhythmias. These in vivo findings of ranolazine suggest that INa,L suppression may attenuate IKr inhibition-associated prolongation of early repolarization in the presence of reflex-mediated increase of adrenergic tone. Thus, ranolazine alone may be less promising as an anti-atrial fibrillatory drug, but its potential risk for inducing torsade de pointes will be small. These information can be used as a guide to predict the utility and adverse effects of anti-atrial fibrillatory drugs having multi-channel modulatory action.


Asunto(s)
Anestesia por Inhalación/métodos , Fibrilación Atrial/tratamiento farmacológico , Halotano/farmacología , Atrios Cardíacos/fisiopatología , Sistema de Conducción Cardíaco/efectos de los fármacos , Frecuencia Cardíaca/efectos de los fármacos , Ranolazina/administración & dosificación , Potenciales de Acción/efectos de los fármacos , Anestésicos por Inhalación/farmacología , Animales , Fibrilación Atrial/fisiopatología , Gasto Cardíaco/efectos de los fármacos , Modelos Animales de Enfermedad , Perros , Relación Dosis-Respuesta a Droga , Electrocardiografía/efectos de los fármacos , Femenino , Atrios Cardíacos/efectos de los fármacos , Sistema de Conducción Cardíaco/fisiopatología , Infusiones Intravenosas , Bloqueadores de los Canales de Sodio/administración & dosificación
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