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1.
J Stroke Cerebrovasc Dis ; 28(11): 104308, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31416760

RESUMO

Stroke involving some areas of the cerebral hemisphere, such as insula, amygdala, and lateral hypothalamus, may cause changes in autonomic control of cardiac function. A 58-year-old woman presented to the emergency department for acute onset of left facial-brachial-crural hemiparesis and dysarthria. A brain CT scan showed subacute ischemic lesion with hemorrhagic infarction in right insular-rolandic cortex. Over the next few days ECG showed severe bradycardia with elongation of QTc, significative pauses (5 seconds), runs of nonsustained ventricular tachycardia and torsades de pointes. Drug induced and other several possible causes of elongation of QT and bradycardia such as hypokalemia, a history of heart failure, and structural heart disease were ruled out. The case confirms that insular cortex plays a major role in stroke-induced cardiovascular changes.


Assuntos
Córtex Cerebral/irrigação sanguínea , Sistema de Condução Cardíaco/fisiopatologia , Frequência Cardíaca , Síndrome do QT Longo/etiologia , Acidente Vascular Cerebral/complicações , Torsades de Pointes/etiologia , Potenciais de Ação , Bradicardia/etiologia , Bradicardia/fisiopatologia , Estimulação Cardíaca Artificial , Córtex Cerebral/diagnóstico por imagem , Feminino , Humanos , Síndrome do QT Longo/diagnóstico , Síndrome do QT Longo/fisiopatologia , Síndrome do QT Longo/terapia , Pessoa de Meia-Idade , Marca-Passo Artificial , Acidente Vascular Cerebral/diagnóstico por imagem , Acidente Vascular Cerebral/fisiopatologia , Acidente Vascular Cerebral/terapia , Taquicardia Ventricular/etiologia , Taquicardia Ventricular/fisiopatologia , Torsades de Pointes/diagnóstico , Torsades de Pointes/fisiopatologia , Torsades de Pointes/terapia , Resultado do Tratamento
2.
BMJ Case Rep ; 12(8)2019 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-31451477

RESUMO

Thyroid storm (accelerated hyperthyroidism) is an uncommon life-threatening emergency. The diagnosis is difficult and at times delayed owing to atypical presentation. Early diagnosis is the key to its successful management. We came across a patient who had presentations of acute abdomen but later diagnosed in thyroid storm. Multiorgan involvement leads all resuscitative measures futile and prevented us to salvage the patient.


Assuntos
Dor Abdominal , Hipoglicemia , Enteropatias/diagnóstico , Icterícia , Insuficiência de Múltiplos Órgãos , Crise Tireóidea , Dor Abdominal/diagnóstico , Dor Abdominal/etiologia , Deterioração Clínica , Tratamento Conservador/métodos , Cuidados Críticos/métodos , Diagnóstico Diferencial , Evolução Fatal , Feminino , Humanos , Hipoglicemia/diagnóstico , Hipoglicemia/etiologia , Icterícia/diagnóstico , Icterícia/etiologia , Pessoa de Meia-Idade , Insuficiência de Múltiplos Órgãos/diagnóstico , Insuficiência de Múltiplos Órgãos/etiologia , Insuficiência de Múltiplos Órgãos/terapia , Crise Tireóidea/sangue , Crise Tireóidea/complicações , Crise Tireóidea/diagnóstico , Crise Tireóidea/terapia , Torsades de Pointes/diagnóstico , Torsades de Pointes/etiologia
3.
Int Heart J ; 60(1): 193-198, 2019 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-30518719

RESUMO

Prostate cancer is the most common non-cutaneous malignancy in men and has been steadily rising in an aging society. Medical castration therapy is effective for metastatic prostate cancer, but the proarrhythmic properties have not been reported. We present a 71-year-old Japanese man with metastasis prostate cancer that, during medical castration therapy, had torsades de pointes (TdP) with a QT prolongation and ventricular fibrillation (VF). His QT interval diminished after discontinuing the medical castration, and he developed no further VF recurrences for 15 months. Medical castration is a rare but possible trigger of TdP with QT prolongation and VF.


Assuntos
Castração/efeitos adversos , Neoplasias da Próstata/cirurgia , Torsades de Pointes/etiologia , Fibrilação Ventricular/etiologia , Idoso , Grupo com Ancestrais do Continente Asiático/etnologia , Castração/métodos , Humanos , Síndrome do QT Longo/fisiopatologia , Masculino , Metástase Neoplásica/patologia , Neoplasias da Próstata/patologia , Neoplasias da Próstata/secundário , Torsades de Pointes/fisiopatologia , Fibrilação Ventricular/fisiopatologia
4.
J Pharmacol Sci ; 137(2): 237-240, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29980434

RESUMO

We analyzed torsadogenic and pharmacokinetic profile of E-4031 using chronic atrioventricular block dogs. E-4031 in intravenous doses of 0.03, 0.1 and 0.3 mg/kg over 10 min prolonged QT/QTc, and increased short-term variability of QT in a dose-related manner (n = 4), resulting in onset of torsade de pointes in 1 animal after the middle dose and 4 animals after the high dose, while it attained peak plasma concentrations of 16.5, 60.5 and 182.5 ng/mL at 10 min after their start of administration, respectively (n = 2). These results bridge the gap of information between in vitro proarrhythmia assay and clinical observation in human subjects.


Assuntos
Antiarrítmicos/efeitos adversos , Antiarrítmicos/farmacocinética , Bloqueio Atrioventricular/fisiopatologia , Eletrocardiografia/efeitos dos fármacos , Piperidinas/efeitos adversos , Piperidinas/farmacocinética , Piridinas/efeitos adversos , Piridinas/farmacocinética , Torsades de Pointes/induzido quimicamente , Animais , Antiarrítmicos/administração & dosagem , Bloqueio Atrioventricular/complicações , Doença Crônica , Cães , Relação Dose-Resposta a Droga , Humanos , Infusões Intravenosas , Piperidinas/administração & dosagem , Piridinas/administração & dosagem , Torsades de Pointes/etiologia
6.
J Crit Care ; 46: 151-156, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29929706

RESUMO

PURPOSE: We aimed to investigate the factors that modulate the extent of QTc prolongation and potential arrhythmogenic consequences during mild therapeutic hypothermia (MTH). METHODS: We studied 205 patients after out-of-hospital cardiac arrest (131 underwent MTH). QTc was measured at baseline, 3h, 6h, 12h, 24h (end of hypothermia), 48h and 72h, and ventricular arrhythmias quantified. RESULTS: During MTH, the QTc interval increased progressively peaking at 12h (mean increase 42ms, 95% CI 30-55). There was a strong gender effect (P<0.001) and a significant gender-by-MTH interaction (P=0.004). At 12h, the QTc interval was markedly longer in women as compared with men (mean difference 50ms [95% CI 27-73]. Anoxic brain injury (P=0.002) was also positively associated with QTc prolongation. The risk for ventricular arrhythmic events was not higher with MTH compared with no hypothermia (incidence rate ratio 0.57, 95% CI 0.32-1.02, P=0.06). However, typical cases of Torsade de pointes occurred in association with AV block and LQT2. CONCLUSION: QTc prolongation during MTH is strongly affected by female gender and moderately by concomitant anoxic brain injury. Although the overall risk for ventricular arrhythmias is not greater with MTH, Torsade de pointes may develop when other contributing factors coexist.


Assuntos
Arritmias Cardíacas/etiologia , Hipotermia Induzida/efeitos adversos , Parada Cardíaca Extra-Hospitalar/complicações , Torsades de Pointes/etiologia , Adulto , Idoso , Lesões Encefálicas/complicações , Cuidados Críticos , Eletrocardiografia , Feminino , Ventrículos do Coração/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Ressuscitação , Estudos Retrospectivos , Fatores Sexuais , Fatores de Tempo , Fibrilação Ventricular
7.
Int J Chron Obstruct Pulmon Dis ; 13: 1937-1947, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29942126

RESUMO

Background: A prolonged QT interval is associated with increased risk of Torsade de Pointes and cardiovascular death. The prevalence and clinical relevance of QT prolongation in acute exacerbations of COPD (AECOPD), with high risk for cardiac morbidity and mortality, is currently unclear. Methods: A dual cross-sectional study strategy was therefore designed. A retrospective study evaluated 140 patients with an AECOPD requiring hospitalization, half of which had prolonged QTc on the admission ECG. Univariate and multivariate analyses were conducted to determine associated factors; Kaplan-Meier and Cox regression analyses to assess prognostic significance. A prospective study evaluated 180 pulmonary patients with acute respiratory problems requiring hospitalization, to determine whether a prolonged QTc at admission represents an AECOPD-specific finding and to investigate the change in QTc-duration during hospitalization. Results: Retrospectively, hypokalemia, cardiac troponin T and conductance abnormalities on ECG were significantly and independently associated with QTc prolongation. A prolonged QTc was associated with increased all-cause mortality (HR 2.698 (95% CI 1.032-7.055), p=0.043), however, this association was no longer significant when corrected for age, FEV1 and cardiac troponin T. Prospectively, QTc prolongation was observed in 1/3 of the patients diagnosed with either an AECOPD, lung cancer, pulmonary infection or miscellaneous acute pulmonary disease, and was not more prevalent in AECOPD. The QTc-duration decreased significantly during hospitalization in patients with and without COPD. Conclusion: A prolonged QTc is a marker of underlying cardiovascular disease during an AECOPD. It is not COPD-specific, but a common finding during the acute phase of a pulmonary disease requiring urgent hospital admission.


Assuntos
Progressão da Doença , Hospitalização , Síndrome do QT Longo/fisiopatologia , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Idoso , Análise de Variância , Bélgica , Estudos Transversais , Eletrocardiografia , Feminino , Sistema de Condução Cardíaco/fisiopatologia , Humanos , Hipopotassemia/fisiopatologia , Estimativa de Kaplan-Meier , Síndrome do QT Longo/mortalidade , Masculino , Estudos Prospectivos , Doença Pulmonar Obstrutiva Crônica/complicações , Análise de Regressão , Estudos Retrospectivos , Fatores de Risco , Torsades de Pointes/etiologia , Troponina T/sangue
9.
Pacing Clin Electrophysiol ; 41(4): 414-421, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29405316

RESUMO

Since its initial description by Jervell and Lange-Nielsen in 1957, the congenital long QT syndrome (LQTS) has been the most investigated cardiac ion channelopathy. Although congenital LQTS continues to remain the domain of cardiologists, cardiac electrophysiologists, and specialized centers, the by far more frequent acquired drug-induced LQTS is the domain of all physicians and other members of the health care team who are required to make therapeutic decisions. This report will review the electrophysiological mechanisms of LQTS and torsade de pointes, electrocardiographic characteristics of acquired LQTS, its clinical presentation, management, and future directions in the field.


Assuntos
Síndrome do QT Longo/etiologia , Síndrome do QT Longo/fisiopatologia , Torsades de Pointes/etiologia , Torsades de Pointes/fisiopatologia , Eletrocardiografia , Humanos , Fenótipo
10.
J Cardiovasc Electrophysiol ; 29(3): 471-476, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29314443

RESUMO

AIMS: A significant antiarrhythmic potential of ryanodine receptor inhibition was reported in experimental studies. The aim of the present study was to assess potential antiarrhythmic effects of dantrolene in an experimental whole-heart model of drug-induced long-QT syndrome (LQTS). METHODS: In 12 isolated rabbit hearts, long-QT-2-syndrome was simulated by infusion of erythromycin (300 µM). Twelve rabbit hearts were treated with veratridine (0.5 µM) to mimic long-QT-3-syndrome. RESULTS: Monophasic action potentials and ECG showed a significant prolongation of QT-interval (+71 ms, P < 0.01) and action potential duration (APD, +43 ms, P < 0.01) after infusion of erythromycin as compared with baseline. Similar results were obtained in veratridine-treated hearts (QT-interval: +43 ms, P < 0.01; APD: +36 ms, P < 0.01). Both erythromycin (+36 ms, P < 0.05) and veratridine (+38 ms) significantly increased dispersion of repolarization. Additional infusion of dantrolene (20 µM) did not significantly alter QT-interval and APD but resulted in a significant reduction of dispersion of repolarization (erythromycin group: -33 ms, P < 0.05; veratridine group: -29 ms, P < 0.05). Lowering of potassium concentration resulted in the occurrence of early afterdepolarizations (EAD) and polymorphic ventricular tachycardia (VT) in 9 of 12 erythromycin-treated hearts (175 episodes) and 8 of 12 veratridine-treated hearts (66 episodes). Additional infusion of dantrolene significantly reduced occurrence of polymorphic VT and resulted in occurrence of EAD and polymorphic VT in 1 of 12 erythromycin-treated hearts (18 episodes) and 1 of 12 veratridine-treated hearts (3 episodes). CONCLUSION: Inhibition of the ryanodine receptor by dantrolene significantly reduced occurrence of polymorphic VT in drug-induced LQTS. A significant reduction of spatial dispersion of repolarization represents a major antiarrhythmic mechanism. These results imply that dantrolene may represent a promising antiarrhythmic option in drug-induced LQTS.


Assuntos
Antiarrítmicos/farmacologia , Bloqueadores dos Canais de Cálcio/farmacologia , Dantroleno/farmacologia , Frequência Cardíaca/efeitos dos fármacos , Ventrículos do Coração/efeitos dos fármacos , Síndrome do QT Longo/tratamento farmacológico , Canal de Liberação de Cálcio do Receptor de Rianodina/efeitos dos fármacos , Torsades de Pointes/prevenção & controle , Potenciais de Ação/efeitos dos fármacos , Animais , Modelos Animais de Doenças , Eletrocardiografia , Eritromicina , Ventrículos do Coração/metabolismo , Ventrículos do Coração/fisiopatologia , Preparação de Coração Isolado , Síndrome do QT Longo/induzido quimicamente , Síndrome do QT Longo/metabolismo , Síndrome do QT Longo/fisiopatologia , Coelhos , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Fatores de Tempo , Torsades de Pointes/etiologia , Torsades de Pointes/metabolismo , Torsades de Pointes/fisiopatologia , Veratridina
11.
J Electrocardiol ; 51(1): 111-116, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29037423

RESUMO

A 26-year-old woman, 12 days in postpartum, developed recurrent syncope and cardiac arrest. Her ECG revealed QT-prolongation associated with LQT2-specific T-U wave patterns, T wave alternans, long QT-dependent torsade de pointes (TdP) and ventricular fibrillation (VF). She also had intermittent LBBB (80bpm) on alternate beats and RBBB at sinus tachycardia (113bpm). Family genotyping revealed a novel de novo missense mutation G604C of KCNH2. Propranolol slowed heart rate and further prolonged QT interval (610ms) that caused TdP recurrence. Mexiletine combined with magnesium and potassium supplements prevented TdP/VF recurrence. This patient has remained event-free after 9-month follow-up.


Assuntos
Eletrocardiografia , Síndrome do QT Longo/genética , Mutação de Sentido Incorreto , Antagonistas Adrenérgicos beta/efeitos adversos , Adulto , Feminino , Genótipo , Frequência Cardíaca/efeitos dos fármacos , Heterozigoto , Humanos , Síndrome do QT Longo/complicações , Síndrome do QT Longo/diagnóstico , Síndrome do QT Longo/tratamento farmacológico , Período Pós-Parto , Síncope/etiologia , Torsades de Pointes/etiologia , Fibrilação Ventricular/etiologia
13.
Heart Surg Forum ; 21(6): E507-E512, 2018 12 19.
Artigo em Inglês | MEDLINE | ID: mdl-30604676

RESUMO

Intravenous drug abuse rates in the United States have increased exponentially in recent years. Ohio is one of 5 states with the highest age-adjusted drug overdose death rates, with drug overdose causing 39.1 of every 100,000 deaths. In patients who survive, the associated morbidity poses a significant public health burden. Infective endocarditis, defined as an infection of the endocardium of the heart, is a potentially lethal consequence of bacteremia related to intravenous drug abuse. Methicillin-sensitive Staphylococcus aureus (MSSA) is the most commonly implicated organism and may affect the tricuspid valve. Indications for surgery include failure of medical management, worsening embolization, heart failure, and arrhythmias-typically bradyarrhythmias from infectious extension into the conduction system. Vegetation size and type of infection, such as drug-resistance pattern, fungal infection, and presence of prosthetic material, are becoming known risk factors for complications. Studies have demonstrated that early surgery tends to have a better prognosis than delayed intervention. Established guidelines for right-sided surgery are slowly evolving. Tricuspid valve surgery is becoming more common in these cases, but there is known risk for heart block owing to proximity of the conduction system to the tricuspid valve annulus. If patients develop complete heart block postoperatively, pacemaker placement may be indicated. There may be reluctance to implantation because of the risk of device infection with infective endocarditis. In addition, many may recover conduction as infection and edema resolve. Generally, bradyarrhythmias are well tolerated. However, we present 2 cases of torsades de pointes related to post-tricuspid-valve-replacement bradyarrhythmia. Torsades de pointes is a potentially lethal form of polymorphic ventricular arrhythmia associated with QT interval prolongation. Post-tricuspid-valve- replacement mortality may be secondary to induced lethal ventricular arrhythmias.


Assuntos
Endocardite Bacteriana/complicações , Endocardite Bacteriana/cirurgia , Próteses Valvulares Cardíacas/efeitos adversos , Abuso de Substâncias por Via Intravenosa/complicações , Torsades de Pointes/etiologia , Valva Tricúspide/cirurgia , Adulto , Bacteriemia/complicações , Feminino , Humanos , Complicações Pós-Operatórias
14.
J Clin Psychopharmacol ; 37(5): 540-545, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28817488

RESUMO

PURPOSE/BACKGROUND: Drug-related QTc prolongation has been linked with Torsade de Pointes and sudden cardiac death. The objective of this study was to investigate the impact of starting an additional QTc-prolonging drug on the QTc interval of psychiatric inpatients. METHODS: An observational study was performed between May 2011 and December 2014 in 6 Belgian psychiatric hospitals. Inpatients who were already taking 1 QTc-prolonging drug or more could be included in the study when an additional QTc-prolonging drug was started. Electrocardiograms were performed at baseline and follow-up. Demographic, medical, medication, and laboratory data were collected. A risk score was used to estimate the risk of QTc prolongation based on patient-specific risk factors. A cutoff value of 8 points was set as high risk for QTc prolongation. RESULTS: One hundred fifty-two patients (44.7% women; mean age, 44 [SD, 17] years) were included who received a prescription for an additional QTc-prolonging drug. There was a small but significant difference (P = 0.032) in mean QTc interval between baseline (409.1 [SD, 21.8] milliseconds) and follow-up (411.8 [SD, 21.7] milliseconds). Three patients developed a prolonged QTc interval in the follow-up electrocardiogram (QTc, ≥450 [men]/470 [women] milliseconds); 8 patients had a delta QTc of 30 milliseconds or longer. No cases of torsade de pointes or sudden cardiac death were identified. Fifty-eight patients (38.2%) had a risk score of 8 or higher; these patients had a significantly longer QTc interval at follow-up than did patients with a risk score of lower than 8 (P < 0.001). IMPLICATIONS/CONCLUSIONS: Only a limited number of patients developed a prolonged QTc interval after the start of an additional QTc-prolonging drug. Nevertheless, it is still important to screen for high-risk patients at baseline. A risk score can help to select high-risk patients and to stimulate an appropriate and feasible risk management of QTc prolongation in psychiatry.


Assuntos
Quimioterapia Combinada/efeitos adversos , Eletrocardiografia/efeitos dos fármacos , Síndrome do QT Longo/induzido quimicamente , Síndrome do QT Longo/complicações , Medição de Risco/métodos , Adulto , Bélgica , Morte Súbita Cardíaca/etiologia , Morte Súbita Cardíaca/prevenção & controle , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Torsades de Pointes/induzido quimicamente , Torsades de Pointes/etiologia , Torsades de Pointes/prevenção & controle , Adulto Jovem
15.
Neth J Med ; 75(5): 208-210, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28653942

RESUMO

We report a case of a 48-year-old female patient with newly diagnosed multiple myeloma. She developed recurrent torsade de pointes and required cardiopulmonary resuscitation and defibrillation. Atrial arrhythmias in patients with multiple myeloma and hypercalcaemia have been described, but, to the best of our knowledge, this is the first report of torsade de pointes in this setting.


Assuntos
Hipercalcemia/complicações , Mieloma Múltiplo/complicações , Torsades de Pointes/etiologia , Evolução Fatal , Feminino , Humanos , Pessoa de Meia-Idade
16.
J Electrocardiol ; 50(5): 690-693, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28645448

RESUMO

Takotsubo syndrome is an acute reversible heart failure syndrome triggered by physical or emotional stress, especially in postmenopausal women. Herein, we describe a case of a 31-year-old pacemaker dependent lady who presented with syncope after she was bereaved of her father. Electrocardiogram at admission revealed ventricular paced rhythm at 60/min, prolonged QT interval and frequent runs of torsades de pointes. Transthoracic echocardiogram and left ventriculogram revealed findings typical of Takotsubo syndrome. QT prolongation and torsade de pointes in the context of fixed-rate ventricular pacing imply direct catecholamine toxicity on the ventricular myocardium independent of heart rate.


Assuntos
Marca-Passo Artificial , Síncope/etiologia , Cardiomiopatia de Takotsubo/etiologia , Torsades de Pointes/etiologia , Adulto , Luto , Ecocardiografia , Eletrocardiografia , Feminino , Humanos
17.
Heart ; 103(22): 1821-1829, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28490617

RESUMO

OBJECTIVE: Increasing evidence indicates systemic inflammation as a new potential cause of acquired long QT syndrome (LQTS), via cytokine-mediated changes in cardiomyocyte ion channels. Torsade de pointes (TdP) is a life-threatening polymorphic ventricular tachycardia occurring in patients with LQTS, usually when multiple QT-prolonging factors are simultaneously present. Since classical risk factors cannot fully explain TdP events in a number of patients, we hypothesised that systemic inflammation may represent a currently overlooked risk factor contributing to TdP development in the general population. METHODS: Forty consecutive patients who experienced TdP (TdP cohort) were consecutively enrolled and circulating levels of C-reactive protein (CRP) and proinflammatory cytokines (interleukin-6 (IL-6), tumour necrosis factor alpha (TNFα), interleukin-1 (IL-1)) were compared with patients with active rheumatoid arthritis (RA), comorbidity or healthy controls. An additional 46 patients with different inflammatory conditions (acute infections, n=31; immune-mediated diseases, n=12; others, n=3) and elevated CRP (inflammatory cohort) were prospectively enrolled, and corrected QT (QTc) and cytokine levels were measured during active disease and after a CRP decrease of >75% subsequent to therapy. RESULTS: In the TdP cohort, 80% of patients showed elevated CRP levels (median: ~3 mg/dL), with a definite inflammatory disease identifiable in 18/40 cases (acute infections, n=12; immune-mediated diseases, n=5; others, n=1). In these subjects, IL-6, but not TNFα and IL-1, was ~15-20 times higher than in controls, and comparable to RA patients. In the inflammatory cohort, where QTc prolongation was common (mean values: 456.6±30.9 ms), CRP reduction was associated with IL-6 level decrease and significant QTc shortening (-22.3 ms). CONCLUSION: The data are first to show that systemic inflammation via elevated IL-6 levels may represent a novel QT-prolonging risk factor contributing to TdP occurrence in the presence of other classical risk factors. If confirmed, this could open new avenues in antiarrhythmic therapy.


Assuntos
Mediadores da Inflamação/sangue , Inflamação/complicações , Interleucina-6/sangue , Torsades de Pointes/etiologia , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Proteína C-Reativa/análise , Estudos de Casos e Controles , Eletrocardiografia , Feminino , Humanos , Inflamação/sangue , Inflamação/diagnóstico , Interleucina-1/sangue , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Prospectivos , Fatores de Risco , Torsades de Pointes/sangue , Torsades de Pointes/diagnóstico , Torsades de Pointes/fisiopatologia , Fator de Necrose Tumoral alfa/sangue , Regulação para Cima
18.
Europace ; 19(5): 858-865, 2017 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-28525920

RESUMO

Aims: The chronic complete atrioventricular block (CAVB) dog is highly sensitive for drug-induced torsade de pointes (TdP) arrhythmias. Focal mechanisms have been suggested as trigger for TdP onset; however, its exact mechanism remains unclear. In this study, detailed mapping of the ventricles was performed to assess intraventricular heterogeneity of repolarization in relation to the initiation of TdP. Methods and results: In 8 CAVB animals, 56 needles, each containing 4 electrodes, were inserted in the ventricles. During right ventricular apex pacing (cycle length: 1000-1500 ms), local unipolar electrograms were recorded before and after administration of dofetilide to determine activation and repolarization times (RTs). Maximal RT differences were calculated in the left ventricle (LV) within adjacent electrodes in different orientations (transmural, vertical, and horizontal) and within a square of four needles (cubic dispersion). Dofetilide induced TdP in five out of eight animals. Right ventricle-LV was similar between inducible and non-inducible dogs at baseline (327 ± 30 vs. 345 ± 17 ms) and after dofetilide administration (525 ± 95 vs. 508 ± 15 ms). All measurements of intraventricular dispersion were not different at baseline, but this changed for horizontal (206 ± 20 vs. 142 ± 34 ms) and cubic dispersion (272 ± 29 vs. 176 ± 48 ms) after dofetilide: significantly higher values in inducible animals. Single ectopic beats and the first TdP beat arose consistently from a subendocardially located electrode terminal with the shortest RT in the region with largest RT differences. Conclusion: Chronic complete atrioventricular block dogs susceptible for TdP demonstrate higher RT differences. Torsade de pointes arises from a region with maximal heterogeneity of repolarization suggesting that a minimal gradient is required in order to initiate TdP.


Assuntos
Bloqueio Atrioventricular/complicações , Bloqueio Atrioventricular/fisiopatologia , Mapeamento Potencial de Superfície Corporal/métodos , Modelos Animais de Doenças , Sistema de Condução Cardíaco/fisiopatologia , Torsades de Pointes/etiologia , Torsades de Pointes/fisiopatologia , Animais , Doença Crônica , Cães , Humanos , Especificidade da Espécie
20.
J Electrocardiol ; 50(4): 416-423, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28274542

RESUMO

BACKGROUND: Our primary objective was to determine the adjusted quantitative associations of clinical predictors with QT prolongation, a defining cause of Torsades de Pointes (TdP). METHODS: A retrospective cohort study was performed on consecutive emergency department patients identified by ECG acquisition date, and heart rate corrected QT (QTc) and QRS durations. QTc was modeled as a function of clinical predictors with multiple linear regression. RESULTS: 1010 patients were included. The strongest predictors of QTc and their coefficients were: antidysrhythmic (26.1ms, 95% CI 15.6-36.6) and methadone (43.6ms, 95% CI 28.1-59.2) therapies, and genetic long QT syndrome diagnosis (32.6ms, 95% CI -4.7-70.0). The association of QTc with serum potassium was approximated by a two piecewise linear function that differed by sex. For potassium below 3.9mmol/L, QTc increased by 43.0ms (95% CI 26.2-59.7) and 29.5ms (95% CI 19.1-40.0) for every 1mmol/L decrease in potassium in women and men, respectively. TdP occurred in only 4/686 (0.6%) of patients with QTc≥500 and QRS<120, but mortality during the visit including hospitalization was 8.0%. CONCLUSIONS: QTc duration is highly sensitive to hypokalemia, particularly in women. Methadone prolongs QTc remarkably compared to other non-cardiologic medicines. QTc>500 with normal QRS often signifies profound illness and substantial mortality risk, though not necessarily imminent TdP.


Assuntos
Serviço Hospitalar de Emergência , Hipopotassemia/complicações , Síndrome do QT Longo/etiologia , Metadona/efeitos adversos , Entorpecentes/efeitos adversos , Torsades de Pointes/etiologia , Idoso , Eletrocardiografia , Feminino , Hospitalização , Humanos , Síndrome do QT Longo/mortalidade , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco , Torsades de Pointes/mortalidade
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