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1.
Ann Rehabil Med ; 2024 Oct 11.
Artículo en Inglés | MEDLINE | ID: mdl-39389785

RESUMEN

Objective: To investigate the impact of body mass index (BMI) and exercise habits on readmission rates among older patients with heart failure. Methods: Ninety-seven older patients admitted for heart failure (median age: 81 years; 57.7% male) were included in the study. Patients were categorized into four groups based on the presence or absence of lower BMI and/or the absence of exercise habits. Lower BMI was defined as BMI<20.3 kg/m2 at discharge and exercise habits were defined as engaging in 30 or more minutes of moderate or vigorous exercise at least once a week. The primary outcome was all-cause readmission during the 1-year follow-up period. Results: The patients were distributed across four groups: lower BMI/non-exerciser (n=24, 24.7%), lower BMI/exerciser (n=22, 22.7%), non-lower BMI/non-exerciser (n=21, 21.6%), and non-lower BMI/exerciser (n=30, 30.9%). Forty-six patients (47.4%) experienced readmission during the 1-year follow-up period. In a cox proportional hazard analysis, non-lower BMI/exerciser remained an independent prognostic factor even after adjusting for confounding factors (non-lower BMI/exerciser vs. lower BMI/non-exerciser: hazard ratio, 0.26; 95% confidence interval, 0.08-0.83; p=0.022). Conclusion: The coexistence of non-lower BMI and regular exercise habits may reduce readmission during the 1-year in older patients with heart failure. Therefore, it is imperative to conduct appropriate nutritional assessments for patients with lower BMI at discharge. Additionally, promoting and monitoring sustained physical activity after discharge is crucial for older patients with heart failure.

3.
Tokai J Exp Clin Med ; 47(4): 162-164, 2022 Dec 20.
Artículo en Inglés | MEDLINE | ID: mdl-36420546

RESUMEN

We present the autopsy procedure and findings of severe coronavirus disease 2019 (COVID-19) pneumonia in an 85-year-old man. The patient required intubation immediately after admission for severe COVID-19 pneumonia. He had severe hypoxia that did not improve despite treatment with remdesivir, corticosteroids, and appropriate mechanical ventilation. On day 13, the patient developed sudden hypercapnia. His renal dysfunction subsequently worsened and became associated with hyperkalemia, and he passed away on day 15. An autopsy was performed to clarify the cause of the hypercapnic hypoxia. None of the medical personnel involved in the autopsy developed symptoms of COVID-19. Histologic examination showed various stages of diffuse alveolar damage throughout the lungs, with intra-alveolar hemorrhage in the upper zones. Microscopic examination of the kidneys revealed acute tubular necrosis. There was no significant systemic thrombosis. The autopsy findings were consistent with those typical of COVID-19.


Asunto(s)
COVID-19 , Enfermedades Pulmonares , Neumonía , Masculino , Humanos , Anciano de 80 o más Años , Autopsia , Hospitales Municipales , Enfermedades Pulmonares/patología , Hipoxia/complicaciones
5.
Int Heart J ; 55(5): 409-15, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25088583

RESUMEN

The association between the urinary albumin-to-creatinine ratio (UACR) and target lesion revascularization (TLR) is unknown in patients who are implanted with drug-eluting stents (DESs) or bare metal stents (BMSs) for the treatment of coronary artery disease. Of 231 Japanese patients who were implanted with DESs and/or BMSs during percutaneous coronary intervention (PCI) between July 2009 and January 2011, 118 underwent follow-up coronary angiography at 6 to 9 months after PCI; 103 were negative for qualitative tests for urine protein: 32 (31.0%)/103 patients underwent TLR for severe in-stent restenosis (ISR) and 71 did not. On the next day after admission to the hospital, first-morning-void spot urine samples were collected to calculate UACR based on urinalysis results. Pearson's product-moment correlation coefficients indicated positive associations of UACR with late loss as assessed by quantitative coronary analysis in the overall cohort, (r = +0.515, P < 0.0001), the DES subgroup (r = +0.443, P < 0.0001), and the BMS subgroup (r = +0.652, P < 0.0001). The incidence of multivessel lesions was significantly higher (P < 0.05) in the TLR group. UACR was significantly higher (P < 0.01) in the TLR group (23.88 ± 31.8 mg/gCr) than in the control group (6.29 ± 7.46 mg/gCr). Multivariate logistic regression analysis revealed UACR (odds ratio: 1.07; 95% confidence interval: 1.02-1.12; P < 0.01) to be associated with TLR. UACR was suggested to be a potential predictor of TLR required for severe ISR after PCI with coronary stents.


Asunto(s)
Albuminuria/orina , Enfermedad de la Arteria Coronaria/orina , Reestenosis Coronaria/diagnóstico , Creatina/orina , Intervención Coronaria Percutánea , Anciano , Albuminuria/diagnóstico , Albuminuria/etiología , Angiografía Coronaria , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Enfermedad de la Arteria Coronaria/cirugía , Reestenosis Coronaria/epidemiología , Reestenosis Coronaria/orina , Femenino , Estudios de Seguimiento , Humanos , Japón/epidemiología , Masculino , Valor Predictivo de las Pruebas , Pronóstico , Estudios Retrospectivos , Stents , Factores de Tiempo , Urinálisis
6.
Int Heart J ; 53(5): 276-81, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-23038087

RESUMEN

Although the clinical benefits of implantable cardioverter-defibrillators (ICDs) have been demonstrated, inappropriate therapies (IATs) cannot be completely avoided even with the most advanced devices. Recently, IATs are considered to decrease the ventricular function and prognosis of a patient. The aim of this study was to investigate the predictors of IAT with parameters during cardiopulmonary exercise stress test (CPX). Sixty consecutive ICD patients underwent symptom-limited CPX, and were divided into IAT (+) and IAT (-) groups. During and after CPX, ECG and hemodynamic parameters of systemic blood pressure, heart rate, and maximal O2 consumption (max VO2) were evaluated every minute. In selected patients, sympathetic and parasympathetic activities were evaluated with analyses of heart rate variability (HRV). No significant differences were observed in clinical background parameters. In the CPX parameters, only the maximal heart rate exhibited a significant difference between the IAT (+) group and the IAT (-) group (154.8 ± 5.9 versus 137.9 ± 4.2 beats per minute, P = 0.032), and LF/HF was higher during the recovery phase 4 minutes after peak exercise in the former group (4.5 ± 1.0 versus 2.4 ± 0.9, P = 0.021). In ICD patients, IAT can be predicted using simple parameters of increased sympathetic activity such as increased maximal heart rate and increased LF/HF ratio during and after the exercise stress test.


Asunto(s)
Enfermedades Cardiovasculares/terapia , Desfibriladores Implantables , Prueba de Esfuerzo , Frecuencia Cardíaca/fisiología , Enfermedades Cardiovasculares/fisiopatología , Contraindicaciones , Electrocardiografía , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Estudios Retrospectivos
7.
Circ J ; 75(3): 662-71, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21187656

RESUMEN

BACKGROUND: Electrical and structural remodeling, characterized by prolonged action potential duration (APD), Kv4.2 downregulation and cellular infiltration were studied in rat experimental autoimmune myocarditis (EAM). Because the reactive oxygen species (ROS) has been speculated to play a role in the promotion of such remodeling, the effect of N-acetylcysteine (NAC) on the progression of ventricular remodeling was evaluated. METHODS AND RESULTS: Six-week-old Lewis rats were immunized with porcine cardiac myosin. On Days 10-11 after the immunization, NAC (0, 1, 10, or 100mg) was injected intraperitoneally to EAM and control rats. On Day 14, the electrophysiological parameters were evaluated and the expression levels of the mRNA were examined by quantitative real-time reverse-transcription polymerase chain reaction (RT-PCR).The EAM rats exhibited a typical acute myocarditis with prolonged APD and reduced Kv4.2 expression as previously reported. The myocarditis and electrical changes were significantly suppressed by NAC-treatment in a dose-dependent manner (P<0.05). In rats with 100mg NAC, the myocarditis was almost totally negated although the mortality increased. In rats with 1mg NAC, the suppression of myocarditis was not obvious, but APD prolongation and Kv4.2 reduction was attenuated (P<0.05). CONCLUSIONS: The NAC treatment suppressed ventricular remodeling in the EAM rats. This may indicate the role of oxidative stress in causing remodeling and myocarditis itself in the acute phase of myocarditis.


Asunto(s)
Acetilcisteína/farmacología , Enfermedades Autoinmunes/fisiopatología , Progresión de la Enfermedad , Miocarditis/fisiopatología , Remodelación Ventricular/efectos de los fármacos , Acetilcisteína/administración & dosificación , Acetilcisteína/uso terapéutico , Enfermedad Aguda , Animales , Enfermedades Autoinmunes/tratamiento farmacológico , Enfermedades Autoinmunes/metabolismo , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Depuradores de Radicales Libres/administración & dosificación , Depuradores de Radicales Libres/farmacología , Depuradores de Radicales Libres/uso terapéutico , Inyecciones Intraperitoneales , Miocarditis/tratamiento farmacológico , Miocarditis/metabolismo , Estrés Oxidativo/efectos de los fármacos , Estrés Oxidativo/fisiología , Ratas , Ratas Endogámicas Lew , Especies Reactivas de Oxígeno/metabolismo , Remodelación Ventricular/fisiología
8.
Circ J ; 72(2): 268-73, 2008 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-18219165

RESUMEN

BACKGROUND: Ventricular tachyarrhythmias (VT/VF) are 1 of the most important factors determining the prognosis of patients with heart failure (HF). Although priority is given to implantable cardioverter defibrillator (ICD) therapy for the prevention of sudden cardiac death, electrophysiologic-study (EPS)-guided preventive therapy could be important for reducing the number of cardiac events. METHODS AND RESULTS: Of 864 patients with a history of HF, an EPS was performed in 168 and 121 had inducible VT/VF. Under the basic therapy of an ICD, additional catheter ablation was attempted for 95 of 124 monomorphic VT foci in 74 patients, and 78 of the VT were successfully ablated. The prognoses were compared among 5 patient groups with different results for the EPS and catheter ablation: (1) success group (n=43), (2) failure group (n=15), (3) not attempted group (n=16), (4) VF group (n=47), and (5) no inducible VT/VF group. During a follow-up period of 31+/-22 months, the incidence of VT/VF was lower in the success and no inducible VT/VF groups than in the other groups (p=0.0018), although a significant difference was not observed for the total deaths. CONCLUSION: EPS-guided preventive therapy using an ICD and catheter ablation can be useful, at least for the reduction of arrhythmic events in patients with HF.


Asunto(s)
Ablación por Catéter , Desfibriladores Implantables , Técnicas Electrofisiológicas Cardíacas , Insuficiencia Cardíaca/fisiopatología , Insuficiencia Cardíaca/terapia , Taquicardia Ventricular/prevención & control , Taquicardia Ventricular/fisiopatología , Anciano , Electrocardiografía , Femenino , Insuficiencia Cardíaca/mortalidad , Humanos , Masculino , Persona de Mediana Edad , Taquicardia Ventricular/mortalidad
9.
Int Heart J ; 48(2): 155-63, 2007 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-17409581

RESUMEN

BACKGROUND: Ventricular tachyarrhythmia is one of the most important factors determining the prognosis of patients with heart failure and sudden death can be observed even during stable therapy controlling clinical heart failure. In this study, the usefulness of electrophysiologic study (EPS) for the prediction of a future arrhythmic event was evaluated in patients with heart failure. METHODS AND RESULTS: The patient population consisted of 474 patients with a history of clinical heart failure but without an episode of spontaneous sustained ventricular tachycardia or fibrillation (VT/VF). A Holter ECG was performed in all patients, and 177 of the 474 patients underwent EPS because of a recording of nonsustained VT (NSVT, > 5 beats). When sustained VT/VF was inducible in EPS, the patient was assigned to implantation of a defibrillation device. The patients were divided into 3 groups, ie, 1) no NSVT (n = 297), 2) NSVT + no inducible VT/VF (n = 134), and 3) NSVT + inducible VT/VF (n = 43), and were followed-up for > 12 months. All patients were followed-up under standard therapy for heart failure. There were no significant differences in basic clinical characteristics and therapies among the 3 groups. During the follow-up period of 32 +/- 18 months, 56/474 patients suffered a VT/VF episode, ie, 21/297 in no NSVT, 14/134 in NSVT + no inducible VT/VF, and 21/43 in NSVT + inducible VT/VF patients (P = 0.032). All patients were rescued from sudden death among patients with an implanted defibrillator, but 11 patients without a defibrillator died. CONCLUSION: In patients with heart failure, future arrhythmic events could be predicted by EPS and Holter ECG. EPS-guided risk stratification seems to be useful in managing patients with heart failure.


Asunto(s)
Muerte Súbita Cardíaca/etiología , Electrocardiografía Ambulatoria , Técnicas Electrofisiológicas Cardíacas , Insuficiencia Cardíaca/complicaciones , Taquicardia Ventricular/etiología , Fibrilación Ventricular/etiología , Adulto , Anciano , Muerte Súbita Cardíaca/prevención & control , Desfibriladores Implantables , Femenino , Insuficiencia Cardíaca/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Medición de Riesgo/métodos , Taquicardia Ventricular/prevención & control , Fibrilación Ventricular/prevención & control
10.
Int Heart J ; 47(2): 229-36, 2006 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-16607050

RESUMEN

The natural history of asymptomatic individuals with a Brugada-type electrocardiogram (ECG) is still controversial. In this study, we evaluated ventricular fibrillation (VF) inducibility in Brugada-type ECG patients and compared it with other risk factors to clarify the significance of these data on their prognosis. The study population consisted of 38 patients who presented with a typical ST-segment elevation in the precordial leads and underwent an electrophysiological study (EPS). The patients were divided into 3 groups; group A: patients with spontaneous ventricular fibrillation (VF) (n = 5), group B: patients without clinical VF but with inducible VF in EPS (n = 16), and group C: patients with neither clinical nor inducible VF (n = 17). The clinical features, diagnostic results, and prognosis were compared among these groups. During the follow-up period of 26 +/- 19 months, 2/5 (group A), 1/16 (group B), and 0/17 (group C) patients suffered fatal arrhythmic events. None of the clinical features showed any significant difference, although the incidence of positive results in a drug challenge test was higher in groups A and B than in group C (P < 0.05). On the other hand, VF inducibility was higher in patients with positive results in the drug challenge test than in patients with negative results (59% versus 13%; P < 0.05). No VF episodes were observed in patients without VF induction, although one was observed in 1 of 16 patients with VF induction in asymptomatic Brugada syndrome. The drug challenge test appears to be useful for predicting VF inducibility even though it is a noninvasive test.


Asunto(s)
Bloqueo de Rama/complicaciones , Electrocardiografía , Corazón/diagnóstico por imagen , Fibrilación Ventricular/diagnóstico , 3-Yodobencilguanidina , Acetilcolina , Bloqueo de Rama/diagnóstico , Angiografía Coronaria , Estenosis Coronaria/fisiopatología , Electrofisiología , Femenino , Estudios de Seguimiento , Humanos , Radioisótopos de Yodo , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Pronóstico , Cintigrafía , Radiofármacos , Síndrome , Fibrilación Ventricular/etiología
11.
Circ J ; 70(5): 605-9, 2006 May.
Artículo en Inglés | MEDLINE | ID: mdl-16636498

RESUMEN

BACKGROUND: Inflammatory cytokines have been reported to contribute to the progression of cardiac remodeling in various heart diseases and a remarkable prolongation of the monophasic action potential duration and reductions in the expression of Kv4.2 and K+ channel-interacting protein-2 (KChIP-2) in a rat autoimmune myocarditis model have been documented. In this study, the effect of tumor necrosis factor-alpha (TNF-alpha) on cultured cardiomyocytes was evaluated, focusing on the change in the voltage-gated outward K+ current and expression of related molecules. METHODS AND RESULTS: Cardiomyocytes isolated from 1-day-old Lewis rats were cultured for 72 h and treated with TNF-alpha (50 ng/ml) for an additional 48 h. The myocytes treated with TNF-alpha showed a 22% reduction in the peak K+ current, which consisted of a transient outward K+ current (Ito) and 1.4-fold enhancement of the cell-capacitance in comparison with the control. Among the cardiac ion channel related molecules evaluated in this study, Kv4.2 and KChIP-2 mRNA exhibited remarkable reductions (p < 0.05). CONCLUSIONS: Treatment with TNF-alpha induced reductions in Ito as well as cellular hypertrophy in neonatal cultured myocytes, which indicates that TNF-alpha might play a role in promoting electrical remodeling of cardiomyocytes under inflammatory conditions.


Asunto(s)
Proteínas de Interacción con los Canales Kv/efectos de los fármacos , Miocitos Cardíacos/metabolismo , Canales de Potasio con Entrada de Voltaje/efectos de los fármacos , Potasio/metabolismo , Canales de Potasio Shal/efectos de los fármacos , Factor de Necrosis Tumoral alfa/farmacología , Potenciales de Acción , Animales , Animales Recién Nacidos , Células Cultivadas , Modelos Animales de Enfermedad , Regulación hacia Abajo/efectos de los fármacos , Regulación hacia Abajo/genética , Cardiopatías/patología , Cardiopatías/fisiopatología , Hipertrofia/inducido químicamente , Hipertrofia/patología , Proteínas de Interacción con los Canales Kv/genética , Miocarditis/inmunología , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/patología , Canales de Potasio con Entrada de Voltaje/genética , ARN Mensajero/análisis , Ratas , Ratas Endogámicas Lew , Canales de Potasio Shal/genética
12.
Circ J ; 70(3): 268-72, 2006 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-16501291

RESUMEN

BACKGROUND: Although electrophysiologic study (EPS) is one of the most reliable methods for selecting preventive therapy for patients with sustained ventricular tachycardia (VT), VT may recur during EPS-guided effective therapy; therefore, the importance of implantable cardioverter-defibrillator (ICD) has been emphasized. In this study, the prognoses of VT patients were evaluated to clarify the importance of EPS-guided therapy for the secondary prevention of VT. METHODS AND RESULTS: The study population consisted of 99 consecutive patients with a history of sustained VT, which was inducible in EPS. The VT induction protocol used 1-3 extrastimuli and rapid ventricular pacing at 2 right ventricular sites and included additional isoproterenol infusion. ICD implantation was applied to all patients with an episode of hemodynamically unstable VT, regardless of the result of preventive therapy. For preventive therapy, an antiarrhythmic drug and/or catheter ablation were selected, and they were defined as being effective in the EPS-guided therapy when the induction of VT was completely prevented. When no therapy was effective for prevention, an antiarrhythmic drug was prescribed under ICD implantation. During the follow-up period of 19+/-20 months, VT recurred in 17 of 32 patients (53%) in the ineffective group and in 10 of 67 patients (15%) in the effective group (p=0.0001). The therapies used in the effective group were class I antiarrhythmic drug in 9, class III in 15, and catheter ablation in 35 patients. Between the patients with and without VT recurrence, there were no significant differences in the left ventricular ejection fraction and the maximum number of repetitive ventricular responses that remained in VT induction in EPS. CONCLUSIONS: Although VT may recur in up to 15% of patients with EPS-guided effective therapy, the recurrence rate was significantly reduced in comparison to that in the ineffective group. EPS-guided therapy may be useful to reduce the clinical recurrence of VT, as well as the action of ICD.


Asunto(s)
Técnicas Electrofisiológicas Cardíacas/métodos , Técnicas Electrofisiológicas Cardíacas/estadística & datos numéricos , Taquicardia Ventricular/prevención & control , Taquicardia Ventricular/terapia , Adulto , Anciano , Amiodarona/uso terapéutico , Antiarrítmicos/uso terapéutico , Arritmias Cardíacas/fisiopatología , Arritmias Cardíacas/terapia , Ablación por Catéter/métodos , Desfibriladores Implantables , Femenino , Hemodinámica/efectos de los fármacos , Hemodinámica/fisiología , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Prevención Secundaria , Taquicardia Ventricular/fisiopatología , Fibrilación Ventricular/fisiopatología , Fibrilación Ventricular/prevención & control , Fibrilación Ventricular/terapia , Función Ventricular/efectos de los fármacos , Función Ventricular/fisiología
13.
Circ J ; 70(2): 169-73, 2006 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-16434810

RESUMEN

BACKGROUND: Little is known about the shortening of atrial refractoriness as a result of electrical remodeling in atrial fibrillation (AF) in clinical cases, especially in terms of long-term follow-up, because of a lack of noninvasive testing methods. METHODS AND RESULTS: The present study population comprised 38 consecutive patients with persistent AF (PAF, >1 month). Before and after the follow-up period of 1-14 months, surface ECGs were recorded for analysis. In each case, the fibrillation wave was purified by subtracting the QRS-T complex template and then power spectral analysis was performed. The mean fibrillation cycle length (FCL) and FCL coefficient of variation (FCL-CV) were determined from peak power frequency in 20 epochs in each recording. The change in FCL (FCL) was calculated by subtracting the baseline FCL from the FCL after the follow-up period. To correct for the difference in the follow-up period, DeltaFCL was divided by the follow-up period in each case. In 38 cases, mean FCL decreased from 160+/-20 ms to 151+/-19 ms (p<0.05), and the FCL-CV also decreased from 15+/-9% to 12+/-5% (p<0.05). The corrected DeltaFCL was -2.4+/-7.6 (ms/month) and there was a significant negative correlation between corrected DeltaFCL and baseline FCL (p<0.01). CONCLUSION: Shortening of the FCL during a relatively long-term follow-up period was observed in patients with PAF.


Asunto(s)
Fibrilación Atrial/fisiopatología , Electrocardiografía , Electrocardiografía/métodos , Femenino , Estudios de Seguimiento , Humanos , Masculino
14.
Circ J ; 70(2): 206-13, 2006 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-16434817

RESUMEN

Background The effect of bepridil, a multichannel blocker, on atrial electrical remodeling was evaluated in a canine rapid atrial stimulation model. Methods and Results In 10 beagle dogs, the right atrial appendage (RAA) was paced at 400 beats/min for 2 weeks. The atrial electrophysiological parameters, including effective refractory period (AERP), were evaluated at three atrial sites: RAA, the right atrium close to the inferior vena cava (IVC) and the left atrium (LA), during the time course of rapid pacing. Five of the dogs were given bepridil (10 mg . kg (-1) . day(-1) po). In the control group, AERP was significantly shortened at all atrial sites and the AERP shortening (DeltaAERP) was larger for the RAA and LA than at the IVC site (p<0.05). In the bepridil group, DeltaAERP was smaller than that of the controls at all atrial sites, and the AERP started to return slowly to the pre-pacing level in the second week, regardless of the continuation of rapid pacing. Conclusions In a canine rapid atrial stimulation model, bepridil suppressed AERP shortening. Bepridil might have a reverse electrical remodeling effect, at least for AERP shortening, because it showed slow recovery of AERP in the subacute phase of rapid atrial pacing. (Circ J 2006; 70: 206 - 213).


Asunto(s)
Bepridil/farmacología , Bloqueadores de los Canales de Calcio/farmacología , Sistema de Conducción Cardíaco/fisiopatología , Modelos Cardiovasculares , Contracción Miocárdica/efectos de los fármacos , Animales , Perros , Atrios Cardíacos/fisiopatología
15.
J Cardiovasc Pharmacol ; 44(6): 639-44, 2004 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-15550781

RESUMEN

OBJECTIVES: Although we have previously shown that mexiletine might protect myocardium during acute ischemia, the precise mechanism was unclear. In the present study, the mechanism of this effect was examined by using selective K-ATP channel blockers in closed-chest acute ischemia model in rabbits. METHODS: In 40 rabbits, the large left ventricular branch (LLVB) of the left coronary artery was occluded for 30 minutes by inserting a catheter bead (varphi0.5-0.7 x 1.5 mm) through the left carotid artery and was then reperfused. The rabbits were divided into the following 5 groups: (1) control group (n = 8); (2) mexiletine (Mex) group (n = 8, continuous infusion of Mex 24 mg/kg/h); (3) Mex + 5-hydroxydecanoate (5HD) group (n = 8, preadministration of 5HD, 5 mg/kg, followed by Mex infusion); (4) Mex + HMR1098 (selective sarcolemmal K-ATP channel blocker) group (n = 8, preadministration of HMR1098, 3 mg/kg, followed by Mex infusion); and (5) pilsicainide (Pil) group (n = 8, continuous infusion of Pil 18 mg/kg/h). The incidence of ventricular arrhythmia, hemodynamics, left ventricular ejection fraction (LVEF), and infarction size were evaluated and compared among the 5 groups. RESULTS: The incidence of ventricular arrhythmia was lower in groups treated with Mex than the control. The hemodynamics did not show significant differences among the 5 groups. Although the LVEF at 30 minutes after reperfusion was lower in the Mex group (41 +/- 3%, P < 0.001) than the control group (48 +/- 3%), the LVEF at 360 minutes after reperfusion had recovered and became higher in the Mex group (62 +/- 3%, P < 0.001) than the control group (55 +/- 3%). The infarction size was smaller in the Mex group (30 +/- 5%, P = 0.028) than the control group (51 +/- 8%). These effects of Mex were negated by HMR1098 but not by 5HD and were larger than the effects of Pil. CONCLUSIONS: Mex showed improvement in the LVEF in the later phase after reperfusion as well as a reduction in ventricular arrhythmia. The cardioprotective effect of Mex was considered to appear through its action on the sarcolemmal K-ATP channel.


Asunto(s)
Antiarrítmicos/uso terapéutico , Lidocaína/análogos & derivados , Mexiletine/uso terapéutico , Isquemia Miocárdica/tratamiento farmacológico , Isquemia Miocárdica/patología , Miocardio/patología , Canales de Potasio/efectos de los fármacos , Sarcolema/metabolismo , Transportadoras de Casetes de Unión a ATP , Enfermedad Aguda , Animales , Modelos Animales de Enfermedad , Electrocardiografía/efectos de los fármacos , Hemodinámica/efectos de los fármacos , Canales KATP , Lidocaína/farmacología , Infarto del Miocardio/patología , Daño por Reperfusión Miocárdica/tratamiento farmacológico , Daño por Reperfusión Miocárdica/patología , Canales de Potasio/agonistas , Canales de Potasio de Rectificación Interna , Conejos , Sarcolema/efectos de los fármacos , Bloqueadores de los Canales de Sodio/farmacología , Volumen Sistólico/efectos de los fármacos , Función Ventricular Izquierda/efectos de los fármacos
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