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1.
Int Heart J ; 61(5): 927-935, 2020 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-32879263

RESUMO

We prospectively collected device and heart rate data through remote monitoring (RM) of patients with an implantable cardioverter defibrillator (ICD). The objective was to identify the predictors of lethal arrhythmic events (VT/VF).Thirty-three patients (mean age: 50 years) with ICDs [with functionality of heart rate variability (HRV) analysis] were divided into two groups [VT/VF (+), VT/VF (-) ]. Clinical, device (ventricular lead impedance; amplitude of ventricular electrogram), and HRV data were compared between the two groups. The NN interval-index (SDNNi) was calculated for every 5 minutes, and the mean, maximum, minimum, and standard deviation of SDNNi during the 24-hour period were used.During the observation period of 13 ± 10 months, 10 patients experienced VT/VF events. Total mean, max, and min SDNNi were higher in the VT/VF (+) than the VT/VF (-) group (132.9 ± 9.3 versus 93.5 ± 6.1, P = 0.0013; 214.6 ± 10.6 versus 167.0 ± 7.0, P = 0.0007; 71.2 ± 7.5 versus 43.9 ± 4.9, P = 0.0047). On logistic regression analysis, a total mean SDNNi of 100.1, max SDNNi of 185.0 and min SDNNi of 52.0 as cut-off values for prediction of a VT/VF event demonstrated significant receiver operating characteristic (ROC) curves (AUC = 0.86, P = 0.0007; AUC = 0.84, P = 0.0005; AUC = 0.78, P = 0.0030). The max ΔSDNNi, i.e., difference from baseline SDNNi, and min ΔSDNNi in 7 and 28 days preceding VT/VF events were significant predictors of VT/VF events.Time-domain HRV analysis through a RM system may help identify patients at high risk of lethal arrhythmic events; in addition, it may help predict the occurrence of lethal arrhythmic events in specific cases.


Assuntos
Morte Súbita Cardíaca/prevenção & controle , Desfibriladores Implantáveis , Frequência Cardíaca , Taquicardia Ventricular/epidemiologia , Fibrilação Ventricular/epidemiologia , Adulto , Idoso , Síndrome de Brugada/fisiopatologia , Cardiomiopatias/fisiopatologia , Feminino , Humanos , Síndrome do QT Longo/fisiopatologia , Masculino , Pessoa de Meia-Idade , Isquemia Miocárdica/fisiopatologia , Tecnologia de Sensoriamento Remoto , Taquicardia Ventricular/fisiopatologia , Fibrilação Ventricular/fisiopatologia
2.
J Investig Med High Impact Case Rep ; 8: 2324709620948407, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32762368

RESUMO

Recent reports have suggested an increased risk of QT prolongation and subsequent life-threatening ventricular arrhythmias, particularly torsade de pointes, in patients with coronavirus disease-2019 (COVID-19) treated with hydroxychloroquine and azithromycin. In this article, we report the case of a 75-year-old female with a baseline prolonged QT interval in whom the COVID-19 illness resulted in further remarkable QT prolongation (>700 ms), precipitating recurrent self-terminating episodes of torsade de pointes that necessitated temporary cardiac pacing. Despite the correction of hypoxemia and the absence of reversible factors, such as adverse medication effects, electrolyte derangements, and usage of hydroxychloroquine/azithromycin, the QT interval remained persistently prolonged compared with the baseline with subsequent degeneration into ventricular tachycardia and death. Thus, we highlight that COVID-19 illness itself can potentially lead to further prolongation of QT interval and unmask fatal ventricular arrhythmias in patients who have a prolonged QT and low repolarization reserve at baseline.


Assuntos
Betacoronavirus , Infecções por Coronavirus/fisiopatologia , Síndrome do QT Longo/fisiopatologia , Pneumonia Viral/fisiopatologia , Taquicardia Ventricular/fisiopatologia , Idoso , Azitromicina/uso terapêutico , Infecções por Coronavirus/complicações , Infecções por Coronavirus/dietoterapia , Infecções por Coronavirus/tratamento farmacológico , Infecções por Coronavirus/metabolismo , Evolução Fatal , Feminino , Humanos , Hidroxicloroquina/uso terapêutico , Síndrome do QT Longo/tratamento farmacológico , Pandemias , Pneumonia Viral/complicações , Pneumonia Viral/dietoterapia , Taquicardia Ventricular/etiologia
3.
Anaesth Crit Care Pain Med ; 39(3): 393-394, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32562808
4.
J Cardiovasc Magn Reson ; 22(1): 32, 2020 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-32389126

RESUMO

BACKGROUND: Data on the usefulness of cardiovascular magnetic resonance (CMR) imaging for clinical decision making in patients with an implanted cardioverter defibrillator (ICD) are scarce. The present study determined the impact of CMR imaging on diagnostic stratification and treatment decisions in ICD patients presenting with electrical instability or progressive heart failure symptoms. METHODS: 212 consecutive ICD patients underwent 1.5 T CMR combining diagnostic imaging modules tailored to the individual clinical indication (ventricular function assessment, myocardial tissue characterization, adenosine stress-perfusion, 3D-contrast-enhanced angiography); four CMR examinations (4/212, 2%) were excluded due to non-diagnostic CMR image quality. The resultant change in diagnosis or clinical management was determined in the overall population and compared between ICD patients for primary (115/208, 55%) or secondary prevention (93/208, 45%). Referral indication consisted of documented ventricular tachycardia, inadequate device therapy or progressive heart failure symptoms. RESULTS: Overall, CMR imaging data changed diagnosis in 40% (83/208) with a significant difference between primary versus secondary prevention ICD patients (37/115, 32% versus 46/93, 49%, respectively; p = 0.01). The information gain from CMR led to an overall change in treatment in 21% (43/208) with a similar distribution in primary versus secondary prevention ICD patients (25/115,22% versus 18/93,19%, p = 0.67). The effect on treatment change was highest in patients initially scheduled for ventricular tachycardia ablation procedure (18/141, 13%) with revision of the treatment plan to medical therapy or coronary revascularization. CONCLUSIONS: CMR imaging in ICD patients presenting with electrical instability or worsening heart failure symptoms provided diagnostic or management-changing information in a considerable proportion (40% and 21%, respectively).


Assuntos
Morte Súbita Cardíaca/prevenção & controle , Desfibriladores Implantáveis , Cardioversão Elétrica/instrumentação , Insuficiência Cardíaca/terapia , Imagem Cinética por Ressonância Magnética , Taquicardia Ventricular/terapia , Idoso , Ablação por Cateter , Tomada de Decisão Clínica , Progressão da Doença , Feminino , Insuficiência Cardíaca/diagnóstico por imagem , Insuficiência Cardíaca/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Prevenção Primária , Prevenção Secundária , Taquicardia Ventricular/diagnóstico por imagem , Taquicardia Ventricular/fisiopatologia , Fatores de Tempo , Resultado do Tratamento , Função Ventricular Esquerda
5.
PLoS One ; 15(5): e0232529, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32357163

RESUMO

Electrical defibrillation is a well-established treatment for cardiac dysrhythmias. Studies have suggested that shock-induced spatial sawtooth patterns and virtual electrodes are responsible for defibrillation efficacy. We hypothesize that high-frequency shocks enhance defibrillation efficacy by generating temporal sawtooth patterns and using rapid virtual electrodes synchronized with shock frequency. High-speed optical mapping was performed on isolated rat hearts at 2000 frames/s. Two defibrillation electrodes were placed on opposite sides of the ventricles. An S1-S2 pacing protocol was used to induce ventricular tachyarrhythmia (VTA). High-frequency shocks of equal energy but varying frequencies of 125-1000 Hz were used to evaluate VTA vulnerability and defibrillation success rate. The 1000-Hz shock had the highest VTA induction rate in the shorter S1-S2 intervals (50 and 100 ms) and the highest VTA defibrillation rate (70%) among all frequencies. Temporal sawtooth patterns and synchronous shock-induced virtual electrode responses could be observed with frequencies of up to 1000 Hz. The improved defibrillation outcome with high-frequency shocks suggests a lower energy requirement than that of low-frequency shocks for successful ventricular defibrillation.


Assuntos
Cardioversão Elétrica/métodos , Taquicardia Ventricular/terapia , Fibrilação Ventricular/terapia , Animais , Modelos Animais de Doenças , Eletrodos , Fenômenos Eletrofisiológicos , Feminino , Ventrículos do Coração/fisiopatologia , Técnicas In Vitro , Modelos Cardiovasculares , Ratos , Ratos Sprague-Dawley , Taquicardia Ventricular/fisiopatologia , Interface Usuário-Computador , Fibrilação Ventricular/fisiopatologia , Função Ventricular , Imagens com Corantes Sensíveis à Voltagem/instrumentação , Imagens com Corantes Sensíveis à Voltagem/métodos
8.
Rev. chil. cardiol ; 39(1): 55-65, abr. 2020. tab, graf
Artigo em Espanhol | LILACS | ID: biblio-1115451

RESUMO

El diagnóstico electrocardiográfico correcto de la causa de una taquicardia de complejo QRS ancho (TCA) es fundamental, ya que tanto el manejo, como el pronóstico del paciente, es diferente según su etiología, y define el estudio que debemos realizar. Numerosos criterios y algoritmos han sido descritos para diferenciar el origen de estas taquicardias. Sin embargo, muchos de estos son complejos y difíciles de aplicar para el médico menos experimentado. Esto es particularmente importante en los servicios de emergencia, donde se necesita una definición rápida que permita un manejo agudo apropiado. En la presente revisión analizamos los diferentes mecanismos de las TCA y los principales criterios diagnósticos en el ECG, reforzando, especialmente, aquellos de aplicación rápida y de alto rendimiento diagnóstico.


The correct electrocardiographic diagnosis of the cause of a wide QRS complex tachycardia (WCT) is essential since both management and prognosis of the patient. The correct electrocardiographic diagnosis of the cause of a wide QRS complex tachycardia (WCT) is essential since both management and prognosis is different according to its etiology and defines the study that we should perform. Numerous criteria and algorithms have been described to differentiate the origin of these tachycardias. However, many of these are complex and difficult to apply to the less experienced doctor. This is particularly important in emergency rooms, where a rapid definition is needed to allow proper therapy. In this review we analyze the different mechanisms of WCT and the main EKG diagnostic criteria, emphasizing those which can be applied rapidly and have high diagnostic value.


Assuntos
Humanos , Taquicardia Ventricular/diagnóstico , Taquicardia/diagnóstico , Taquicardia/fisiopatologia , Algoritmos , Taquicardia Supraventricular/diagnóstico , Taquicardia Supraventricular/fisiopatologia , Síndromes de Pré-Excitação , Bloqueio de Ramo , Taquicardia Ventricular/fisiopatologia , Diagnóstico Diferencial , Eletrocardiografia
10.
Circ Arrhythm Electrophysiol ; 13(4): e007792, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32191131

RESUMO

BACKGROUND: Characterizing myocardial conduction velocity (CV) in patients with ischemic cardiomyopathy (ICM) and ventricular tachycardia (VT) is important for understanding the patient-specific proarrhythmic substrate of VTs and therapeutic planning. The objective of this study is to accurately assess the relation between CV and myocardial fibrosis density on late gadolinium-enhanced cardiac magnetic resonance imaging (LGE-CMR) in patients with ICM. METHODS: We enrolled 6 patients with ICM undergoing VT ablation and 5 with structurally normal left ventricles (controls) undergoing premature ventricular contraction or VT ablation. All patients underwent LGE-CMR and electroanatomic mapping (EAM) in sinus rhythm (2960 electroanatomic mapping points analyzed). We estimated CV from electroanatomic mapping local activation time using the triangulation method that provides an accurate estimate of CV as it accounts for the direction of wavefront propagation. We evaluated the association between LGE-CMR intensity and CV with multilevel linear mixed models. RESULTS: Median CV in patients with ICM and controls was 0.41 m/s and 0.65 m/s, respectively. In patients with ICM, CV in areas with no visible fibrosis was 0.81 m/s (95% CI, 0.59-1.12 m/s). For each 25% increase in normalized LGE intensity, CV decreased by 1.34-fold (95% CI, 1.25-1.43). Dense scar areas have, on average, 1.97- to 2.66-fold slower CV compared with areas without dense scar. Ablation lesions that terminated VTs were localized in areas of slow conduction on CV maps. CONCLUSIONS: CV is inversely associated with LGE-CMR fibrosis density in patients with ICM. Noninvasive derivation of CV maps from LGE-CMR is feasible. Integration of noninvasive CV maps with electroanatomic mapping during substrate mapping has the potential to improve procedural planning and outcomes. Visual Overview: A visual overview is available for this article.


Assuntos
Técnicas Eletrofisiológicas Cardíacas , Frequência Cardíaca , Imagem por Ressonância Magnética , Infarto do Miocárdio/diagnóstico por imagem , Miocárdio/patologia , Taquicardia Ventricular/diagnóstico , Função Ventricular , Potenciais de Ação , Idoso , Ablação por Cateter , Tomada de Decisão Clínica , Feminino , Fibrose , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/patologia , Infarto do Miocárdio/fisiopatologia , Valor Preditivo dos Testes , Sistema de Registros , Estudos Retrospectivos , Fatores de Risco , Taquicardia Ventricular/fisiopatologia , Taquicardia Ventricular/cirurgia , Fatores de Tempo , Remodelação Ventricular
11.
PLoS One ; 15(3): e0230214, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32168323

RESUMO

Several pathological conditions introduce spatial variations in the electrical properties of cardiac tissue. These variations occur as localized or distributed gradients in ion-channel functionality over extended tissue media. Electrical waves, propagating through such affected tissue, demonstrate distortions, depending on the nature of the ionic gradient in the diseased substrate. If the degree of distortion is large, reentrant activity may develop, in the form of rotating spiral (2d) and scroll (3d) waves of electrical activity. These reentrant waves are associated with the occurrence of lethal cardiac rhythm disorders, known as arrhythmias, such as ventricular tachycardia (VT) and ventricular fibrillation (VF), which are believed to be common precursors of sudden cardiac arrest. By using state-of-the-art mathematical models for generic, and ionically-realistic (human) cardiac tissue, we study the detrimental effects of these ionic gradients on electrical wave propagation. We propose a possible mechanism for the development of instabilities in reentrant wave patterns, in the presence of ionic gradients in cardiac tissue, which may explain how one type of arrhythmia (VT) can degenerate into another (VF). Our proposed mechanism entails anisotropic reduction in the wavelength of the excitation waves because of anisotropic variation in its electrical properties, in particular the action potential duration (APD). We find that the variation in the APD, which we induce by varying ion-channel conductances, imposes a spatial variation in the spiral- or scroll-wave frequency ω. Such gradients in ω induce anisotropic shortening of wavelength of the spiral or scroll arms and eventually leads to instabilitites.


Assuntos
Coração/fisiopatologia , Taquicardia Ventricular/fisiopatologia , Fibrilação Ventricular/fisiopatologia , Potenciais de Ação/fisiologia , Anisotropia , Simulação por Computador , Morte Súbita Cardíaca/patologia , Eletricidade , Eletrofisiologia/métodos , Humanos , Modelos Cardiovasculares
13.
Circ Arrhythm Electrophysiol ; 13(3): e007471, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32063070

RESUMO

BACKGROUND: Risk stratification in catecholaminergic polymorphic ventricular tachycardia remains ill defined. Heart rate recovery (HRR) immediately after exercise is regulated by autonomic reflexes, particularly vagal tone, and may be associated with symptoms and ventricular arrhythmias in patients with catecholaminergic polymorphic ventricular tachycardia. Our objective was to evaluate whether HRR after maximal exercise on the exercise stress test (EST) is associated with symptoms and ventricular arrhythmias. METHODS: In this retrospective observational study, we included patients ≤65 years of age with an EST without antiarrhythmic drugs who attained at least 80% of their age- and sex-predicted maximal HR. HRR in the recovery phase was calculated as the difference in heart rate (HR) at maximal exercise and at 1 minute in the recovery phase (ΔHRR1'). RESULTS: We included 187 patients (median age, 36 years; 68 [36%] symptomatic before diagnosis). Pre-EST HR and maximal HR were equal among symptomatic and asymptomatic patients. Patients who were symptomatic before diagnosis had a greater ΔHRR1' after maximal exercise (43 [interquartile range, 25-58] versus 25 [interquartile range, 19-34] beats/min; P<0.001). Corrected for age, sex, and relatedness, patients in the upper tertile for ΔHRR1' had an odds ratio of 3.4 (95% CI, 1.6-7.4) of being symptomatic before diagnosis (P<0.001). In addition, ΔHRR1' was higher in patients with complex ventricular arrhythmias at EST off antiarrhythmic drugs (33 [interquartile range, 22-48] versus 27 [interquartile range, 20-36] beats/min; P=0.01). After diagnosis, patients with a ΔHRR1' in the upper tertile of its distribution had significantly more arrhythmic events as compared with patients in the other tertiles (P=0.045). CONCLUSIONS: Catecholaminergic polymorphic ventricular tachycardia patients with a larger HRR following exercise are more likely to be symptomatic and have complex ventricular arrhythmias during the first EST off antiarrhythmic drug.


Assuntos
Exercício Físico/fisiologia , Frequência Cardíaca/fisiologia , Recuperação de Função Fisiológica/fisiologia , Taquicardia Ventricular/fisiopatologia , Adulto , Eletrocardiografia , Teste de Esforço , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Taquicardia Ventricular/diagnóstico , Nervo Vago/fisiopatologia , Adulto Jovem
14.
Am J Cardiol ; 125(8): 1137-1141, 2020 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-32093953

RESUMO

We examined the baseline characteristics, rates of implantable cardioverter defibrillator implantation, and long-term all-cause mortality for survivors of in-hospital (IHSCA) versus out-of-hospital (OHSCA) sudden cardiac arrest (SCA). A total of 1,433 SCA survivors (807 IHSCA and 626 OHSCA) from 2002 to 2012 were followed through February 2017. Baseline characteristics and potential triggers of SCA, including significant electrolyte and metabolic abnormalities and acute myocardial infarction and ischemia, were collected. Adjusted survival analyses were performed using a multivariate Cox model. The presence of SCA triggers was similar between IHSCA and OHSCA patients (39% vs 35%, p = 0.3), but OHSCA was more likely associated with cardiac ischemia and drug abuse, whereas IHSCA was more associated with new antiarrhythmic drugs (p <0.05). OHSCA survivors were more likely to receive an implantable cardioverter defibrillator (38% vs 18%, p <0.001). Over a median follow-up of 3.6 years, 674 (47%) patients died. After adjusting for unbalanced baseline characteristics, survival was similar between IHSCA and OHSCA survivors (hazard ratio 1.1, 95% confidence interval 0.9 to 1.3, p = 0.4). In conclusion, survivors of IHSCA and OHSCA differed in baseline characteristic, potential SCA triggers, and treatment interventions but their adjusted survival was comparable.


Assuntos
Mortalidade , Isquemia Miocárdica/fisiopatologia , Parada Cardíaca Extra-Hospitalar/fisiopatologia , Taquicardia Ventricular/fisiopatologia , Fibrilação Ventricular/fisiopatologia , Desequilíbrio Hidroeletrolítico/fisiopatologia , Fatores Etários , Idoso , Antiarrítmicos/efeitos adversos , Fibrilação Atrial/epidemiologia , Causas de Morte , Comorbidade , Desfibriladores Implantáveis , Eletrocardiografia , Feminino , Parada Cardíaca/epidemiologia , Parada Cardíaca/etiologia , Parada Cardíaca/fisiopatologia , Parada Cardíaca/terapia , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Infarto do Miocárdio/complicações , Infarto do Miocárdio/metabolismo , Infarto do Miocárdio/fisiopatologia , Isquemia Miocárdica/complicações , Isquemia Miocárdica/metabolismo , Parada Cardíaca Extra-Hospitalar/epidemiologia , Parada Cardíaca Extra-Hospitalar/etiologia , Parada Cardíaca Extra-Hospitalar/terapia , Prognóstico , Modelos de Riscos Proporcionais , Insuficiência Renal Crônica/epidemiologia , Volume Sistólico , Transtornos Relacionados ao Uso de Substâncias/complicações , Sobreviventes , Taquicardia Ventricular/etiologia , Fibrilação Ventricular/etiologia , Desequilíbrio Hidroeletrolítico/complicações , Desequilíbrio Hidroeletrolítico/metabolismo
15.
Circ Arrhythm Electrophysiol ; 13(2): e007377, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31934784

RESUMO

BACKGROUND: ECG imaging (ECGI) has been used to guide treatment of ventricular ectopy and arrhythmias. However, the accuracy of ECGI in localizing the origin of arrhythmias during catheter ablation of ventricular tachycardia (VT) in structurally abnormal hearts remains to be fully validated. METHODS: During catheter ablation of VT, simultaneous mapping was performed using electroanatomical mapping (CARTO, Biosense-Webster) and ECGI (CardioInsight, Medtronic) in 18 patients. Sites of entrainment, pace-mapping, and termination during ablation were used to define the VT site of origin (SoO). Distance between SoO and the site of earliest activation on ECGI were measured using co-registered geometries from both systems. The accuracy of ECGI versus a 12-lead surface ECG algorithm was compared. RESULTS: A total of 29 VTs were available for comparison. Distance between SoO and sites of earliest activation in ECGI was 22.6, 13.9 to 36.2 mm (median, first to third quartile). ECGI mapped VT sites of origin onto the correct AHA segment with higher accuracy than a validated 12-lead ECG algorithm (83.3% versus 38.9%; P=0.015). CONCLUSIONS: This simultaneous assessment demonstrates that CardioInsight localizes VT circuits with sufficient accuracy to provide a region of interest for targeting mapping for ablation. Resolution is not sufficient to guide discrete radiofrequency lesion delivery via catheter ablation without concomitant use of an electroanatomical mapping system but may be sufficient for segmental ablation with radiotherapy.


Assuntos
Ablação por Cateter , Eletrocardiografia/métodos , Taquicardia Ventricular/fisiopatologia , Taquicardia Ventricular/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Algoritmos , Mapeamento Epicárdico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
17.
Artigo em Inglês | MEDLINE | ID: mdl-31922881

RESUMO

Ventricular fibrillation (VF) during acute myocardial infarction (AMI) is an important contributor to sudden cardiac death. Large animal models are widely used to study AMI-induced arrhythmia, but the mode of AMI induction ranges from thoracotomy and surgical ligation of a coronary vessel (open chest) to minimally invasive techniques, including balloon occlusion (closed chest). How the choice of induction affects arrhythmia development is unclear. The aim of this study was to compare an open-chest and a closed-chest model with regard to hemodynamics, electrophysiology, and arrhythmia development. Forty-two female Danish Landrace pigs (20 open chest, 22 closed chest) were anesthetized, and occlusion of the mid-left anterior descending coronary artery was performed for 60 min. Opening the chest reduced blood pressure and cardiac output (Δ -22 mmHg, Δ -1.5 L/min from baseline, both P < 0.001 intragroup). Heart rate decreased with opening of the chest but increased with balloon placement (P < 0.001). AMI-induced ST elevation was lower in the open-chest group (P < 0.001). Premature ventricular contractions occurred in two distinct phases (0-15 and 15-40 min), the latter of which was delayed in the open-chest group (P = 0.005). VF occurred in 7 out of 20 and 12 out of 22 pigs in the open-chest and closed-chest groups, respectively (P = 0.337), with longer time-to-VF in the open-chest group (23.4 ± 1.2 min in open chest and 17.8 ± 1.4 min in closed chest; P = 0.007). In summary, opening the chest altered hemodynamic parameters and delayed the onset of ventricular arrhythmias. Hence, in the search for mechanisms and novel treatments of AMI-induced arrhythmia, caution should be taken when choosing between or comparing the results from these two models.NEW & NOTEWORTHY We demonstrated pronounced differences in hemodynamic parameters and time course of ventricular arrhythmias in regard to mode of infarct induction. Inducing myocardial infarction by thoracotomy and subsequent ligation decreased blood pressure and cardiac output and delayed the onset of ventricular arrhythmia, whereas balloon occlusion resulted in higher heart rates during infarct.


Assuntos
Arritmias Cardíacas/fisiopatologia , Eletrocardiografia , Coração/fisiopatologia , Hemodinâmica , Infarto do Miocárdio/fisiopatologia , Potenciais de Ação/fisiologia , Animais , Vasos Coronários/fisiopatologia , Modelos Animais de Doenças , Técnicas Eletrofisiológicas Cardíacas , Feminino , Contração Miocárdica , Suínos , Taquicardia Ventricular/fisiopatologia , Complexos Ventriculares Prematuros/fisiopatologia
18.
Life Sci ; 241: 117119, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31794771

RESUMO

AIM: Mechanoelectric feedback (MEF) was related to malignant arrhythmias in heart failure (HF). Desmin is a cytoskeleton protein and could be involved in MEF as a mechanoelectrical transducer. In this study, we will discuss the role of desmin alterations in mechanical electrical feedback in heart failure and its mechanisms. METHODS: We used both an in vivo rat model and an in vitro cardiomyocyte model to address this issue. For the in vivo experiments, we establish a sham group, an HF group, streptomycin (SM) group, and an MDL-28170 group. The occurrence of ventricular arrhythmias (VA) was recorded in each group. For the in vitro cardiomyocyte model, we established an NC group, a si-desmin group, and a si-desmin + NBD IKK group. The expression of desmin, IKKß, p-IKKß, IKBα, p-NF-κB, and SERCA2 were detected in both in vivo and in vitro experiments. The content of Ca2+ in cytoplasm and sarcoplasmic were detected by confocal imaging in vitro experiments. RESULTS: An increased number of VAs were found in the HF group. SM and MDL-28170 can reduce desmin breakdown and the number of VAs in heart failure. The knockdown of desmin in the cardiomyocyte can activate the NF-κB pathway, decrease the level of SERCA2, and result in abnormal distribution of Ca2+. While treatment with NF-κB inhibitor can elevate the level of SERCA2 and alleviate the abnormal distribution of Ca2+. SIGNIFICANCE: Overall, desmin may participate in MEF through the NF-κB pathway. This study provides a potential therapeutic target for VA in HF.


Assuntos
Cálcio/metabolismo , Desmina/metabolismo , Insuficiência Cardíaca/etiologia , NF-kappa B/metabolismo , Animais , Calpaína/metabolismo , Células Cultivadas , Desmina/genética , Dipeptídeos/farmacologia , Modelos Animais de Doenças , Eletrocardiografia , Retroalimentação Fisiológica , Técnicas de Silenciamento de Genes , Masculino , Miócitos Cardíacos , NF-kappa B/genética , Ratos Sprague-Dawley , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/genética , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismo , Taquicardia Ventricular/complicações , Taquicardia Ventricular/fisiopatologia
19.
J Cardiovasc Pharmacol Ther ; 25(1): 65-71, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31242756

RESUMO

Ranolazine has been found to prevent ventricular arrhythmias (VAs) during acute myocardial infarction (AMI). This study aimed to investigate its efficacy on VAs induced several days post-MI. For this purpose, 13 anesthetized rabbits underwent coronary artery ligation. Ten of these animals that survived AMI were reanesthetized 3 to 7 days later for electrophysiologic testing. An endocardial monophasic action potential combination catheter was placed in the right ventricle for simultaneous pacing and recording. Monophasic action potential duration, ventricular effective refractory period (VERP), and VAs induced by programmed stimulation were assessed. Measurements were performed during control pacing, and following an intravenous infusion of either a low-dose ranolazine (2.4 mg/kg, R1) or a higher dose ranolazine (4.8 mg/kg cumulative dose, R2). During control stimulation, 2 animals developed primary ventricular fibrillation (VF), 6 sustained ventricular tachycardia (sVT), and 2 nonsustained VT (nsVT). R1 did not prevent the appearance of VAs in any of the experiments; in contrast, it aggravated nsVT into sVT and complicated sVT termination in 2 of 6 animals. Sustained ventricular tachycardia cycle length and VERP were only slightly decreased after R1 (112 ± 5 vs 110 ± 6 ms and 101 ± 11 vs 98 ± 10 ms, respectively). R2 suppressed inducibility of control nsVT, VF, and sVT in 2 animals. In 4 animals with still inducible sVT, R2 significantly prolonged VT cycle length by 150 ± 23 ms (P < .01), and VERP by 120 ± 7 ms (P < .001) versus control. In conclusion, R2 exerted antiarrhythmic efficacy against subacute-MI VAs, whereas R1 rather aggravated than prevented these arrhythmias. Ventricular effective refractory period prolongation could partially explain the antiarrhythmic action of R2 in this rabbit model.


Assuntos
Antiarrítmicos/administração & dosagem , Infarto do Miocárdio/tratamento farmacológico , Ranolazina/administração & dosagem , Taquicardia Ventricular/prevenção & controle , Fibrilação Ventricular/prevenção & controle , Potenciais de Ação/efeitos dos fármacos , Animais , Antiarrítmicos/toxicidade , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Feminino , Frequência Cardíaca/efeitos dos fármacos , Masculino , Infarto do Miocárdio/complicações , Infarto do Miocárdio/fisiopatologia , Coelhos , Ranolazina/toxicidade , Período Refratário Eletrofisiológico , Taquicardia Ventricular/etiologia , Taquicardia Ventricular/fisiopatologia , Fatores de Tempo , Fibrilação Ventricular/etiologia , Fibrilação Ventricular/fisiopatologia
20.
Am J Med ; 133(7): 857-864, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-31883773

RESUMO

BACKGROUND: Milrinone infusion is one of a few select "non-device" therapies for patients with New York Heart Association (NYHA) class IV, stage D heart failure, which has been associated with an increase in ventricular tachyarrhythmia and atrial fibrillation. Milrinone improves hemodynamics and provides symptomatic relief. Many patients with end-stage heart failure die from cardiac pump failure, and the impact of ventricular tachyarrhythmia and atrial fibrillation on their mortality is unclear. METHODS: This is a retrospective study of 98 consecutive patients receiving outpatient milrinone in a single center from 2008 to 2016. The primary endpoint of the study was overall survival on milrinone. Secondary endpoints were incidence of post-milrinone implantable cardioverter defibrillator (ICD) shocks and development of ventricular tachyarrhythmia or atrial fibrillation. RESULTS: Median survival was 581 ± 96 days with no difference between those with prior ventricular tachyarrhythmia and those without at 1 month (92% vs 97%, P = 0.34), 6 months (67% vs 73%, P = 0.75), and 12 months (67% vs 61%, P = 0.88). Seven out of 12 (58%) patients with prior ventricular tachyarrhythmia had ICD shocks, as compared to 5 out of 78 (6.4%) (P <0.001). Thirty-five patients had atrial fibrillation prior to starting milrinone, which decreased to 72% (P <0.05) by the third follow-up time period (7-9 months). Amiodarone use was protective against new onset atrial fibrillation. CONCLUSIONS: Patients with stage D heart failure with a history of ventricular tachyarrhythmia have similar survival on outpatient milrinone compared to those without. However, those with prior ventricular tachyarrhythmia received more ICD shocks for more ventricular tachyarrhythmias. Milrinone remains a viable therapy for patients with stage D heart failure with limited therapeutic options.


Assuntos
Fibrilação Atrial/complicações , Desfibriladores Implantáveis , Insuficiência Cardíaca/terapia , Milrinona/administração & dosagem , Taquicardia Ventricular/complicações , Idoso , Fibrilação Atrial/fisiopatologia , Fibrilação Atrial/terapia , Cardiotônicos/administração & dosagem , Relação Dose-Resposta a Droga , Feminino , Insuficiência Cardíaca/etiologia , Insuficiência Cardíaca/mortalidade , Humanos , Infusões Intravenosas , Masculino , Estudos Retrospectivos , Taxa de Sobrevida/tendências , Taquicardia Ventricular/fisiopatologia , Taquicardia Ventricular/terapia
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