Ablação com mapeamento eletroanatômico de taquicardia ventricular recorrente refratária a terapia medicamentosa na cardiomiopatia dilatada isquêmica em portador de cardiodesfibrilador multissítio / Ablation with electroanatomic mapping of refractory recurrent ventricular tachycardia to drug therapy in ischemic dilated cardiomyopathy in patients carrying a multisite cardiac defibrillator

As arritmias ventriculares em portadores de cardiomiopatia isquêmica estão diretamente relacionadas ao aumento da morbimortalidade, sendo sua recorrência associada a pior prognóstico. A despeito da otimização do tratamento medicamentoso, muitos são os pacientes refratários, e, nesse contexto, a ablação por adiofrequência torna-se uma importante alternativa terapêutica diante da refratariedade ao tratamento convencional. O mapeamento eletroanatômico permite visualização das áreas de fibrose e dos istmos de condução, aumentando as taxas de sucesso desse procedimento

Ventricular arrhythmias in ischemic cardiomyopathy patients are directly related to increased morbidity and mortality, and recurrence is associated to a worse prognosis. Despite the optimization of drug therapy, many patients are refractory to conventional therapy and in this context, radiofrequency ablation becomes an important therapeutic alternative. Electroanatomic mapping allows the visualization of fibrosis and isthmus conduction areas, increasing the success rates of this procedure

Value of the Qrs-T Angle in Predicting the Induction of Ventricular Tachyarrhythmias in Patients with Chagas Disease / Valor do Ângulo Qrs-T na Predição de Indução de Taquiarritmias Ventriculares em Pacientes Chagásicos

Background: The QRS-T angle correlates with prognosis in patients with heart failure and coronary artery disease, reflected by an increase in mortality proportional to an increase in the difference between the axes of the QRS complex and T wave in the frontal plane. The value of this correlation in patients with Chagas heart disease is currently unknown. Objective: Determine the correlation of the QRS-T angle and the risk of induction of ventricular tachycardia / ventricular fibrillation (VT / VF) during electrophysiological study (EPS) in patients with Chagas disease. Methods: Case-control study at a tertiary center. Patients without induction of VT / VF on EPS were used as controls. The QRS-T angle was categorized as normal (0-105º), borderline (105-135º) or abnormal (135-180º). Differences between groups for continuous variables were analyzed with the t test or Mann-Whitney test, and for categorical variables with Fisher's exact test. P values < 0.05 were considered significant. Results: Of 116 patients undergoing EPS, 37.9% were excluded due to incomplete information / inactive records or due to the impossibility to correctly calculate the QRS-T angle (presence of left bundle branch block and atrial fibrillation). Of 72 patients included in the study, 31 induced VT / VF on EPS. Of these, the QRS-T angle was normal in 41.9%, borderline in 12.9% and abnormal in 45.2%. Among patients without induction of VT / VF on EPS, the QRS-T angle was normal in 63.4%, borderline in 14.6% and abnormal in 17.1% (p = 0.04). When compared with patients with normal QRS-T angle, those with abnormal angle had a fourfold higher risk of inducing ventricular tachycardia / ventricular fibrillation on EPS [odds ratio (OR) 4; confidence interval (CI) 1.298-12.325; p = 0.028]. After adjustment for other variables such as age, ejection fraction (EF) and QRS size, there was a trend for the abnormal QRS-T angle to identify patients with ...

Fundamento: O ângulo QRS-T mostra correlação com prognóstico em pacientes com insuficiência cardíaca e doença coronariana, traduzido por um aumento na mortalidade proporcional ao aumento na diferença entre os eixos do complexo QRS e da onda T no plano frontal. Até hoje, nenhuma informação a este respeito foi obtida em pacientes com cardiopatia chagásica. Objetivo: Correlacionar o ângulo QRS-T com a indução de taquicardia ventricular / fibrilação ventricular (TV / FV) em chagásicos durante estudo eletrofisiológico (EEF). Métodos: Estudo caso-controle em centro terciário. Pacientes sem indução de TV / FV ao EEF foram utilizados como controles. O ângulo QRS-T foi categorizado como normal (0-105º), limítrofe (105-135º) e anormal (135-180º). As diferenças entre os grupos foram analisadas pelo teste t ou teste de Mann-Whitney para variáveis contínuas, e teste exato de Fisher ou qui-quadrado para variáveis categóricas. Valores de p < 0,05 foram considerados significativos. Resultados: De 116 pacientes submetidos ao EEF, 37,9% foram excluídos por estarem com dados incompletos / prontuários inativos ou pela impossibilidade de se calcular corretamente o ângulo QRS-T (presença de bloqueio de ramo esquerdo e fibrilação atrial). De 72 pacientes incluídos, 31 induziram TV / FV ao EEF. Destes, o ângulo QRS-T se encontrava normal em 41,9%, limítrofe em 12,9% e anormal em 45,2%. No grupo de pacientes sem indução de TV / FV, o ângulo QRS-T se encontrava normal em 63,4%, limítrofe em 14,6% e anormal em 17,1% (p = 0,04). Quando comparados aos pacientes com ângulo QRS-T normal, o risco de indução de TV / FV nos pacientes com ângulo anormal foi quatro vezes maior [odds ratio (OR) 4; intervalo de confiança ...

The development of ventricular fibrillation due to etomidate for anesthetic induction: a very rare side effect, case report / Desenvolvimento de fibrilação ventricular por causa de etomidato para indução anestésica: um efeito colateral muito raro, relato de caso / Desarrollo de fibrilación ventricular debido al etomidato para la inducción anestésica: un efecto colateral muy raro, relato de caso

Background and objectives: Ventricular fibrillation occurring in a patient can result in unexpected complications. Here, our aim is to present a case of ventricular fibrillation occurring immediately after anesthesia induction with etomidate administration. Case report: A fifty-six-year-old female patient with a pre-diagnosis of gallstones was admitted to the operating room for laparoscopic cholecystectomy. The induction was performed by etomidate with a bolus dose of 0.3 mg/kg. Severe and fast adduction appeared in the patient's arms immediately after induction. A tachycardia with wide QRS and ventricular rate 188 beat/min was detected on the monitor. The rhythm turned to VF during the preparation of cardioversion. Immediately we performed defibrillation to the patient. Sinus rhythm was obtained. It was decided to postpone the operation due to the patient's unstable condition. Conclusion: In addition to other known side effects of etomidate, very rarely, ventricular tachycardia and fibrillation can be also seen. To the best of our knowledge, this is the first case regarding etomidate causing VF in the literature. .

Justificativa e objetivos: A ocorrência de fibrilação ventricular em um paciente pode resultar em complicações inesperadas. Nosso objetivo é apresentar um caso de fibrilação ventricular que ocorreu após a indução anestésica com administração de etomidato. Relato de caso: Paciente do sexo feminino, 56 anos, com pré-diagnóstico de cálculos biliares, foi admitida na sala de cirurgia para colecistectomia laparoscópica. A anestesia foi induzida com a administração de etomidato com uma dose em bolus de 0,3 mg/kg. A paciente apresentou uma grave e rápida adução dos braços logo após a indução. Taquicardia com QRS largo e frequência ventricular de 188 bpm foram detectadas no monitor. O ritmo converteu-se em fibrilação ventricular (FV) durante a preparação para a cardioversão. A paciente foi imediatamente submetida a desfibrilação. O ritmo sinusal foi obtido. Decidimos adiar a cirurgia por causa da condição de instabilidade da paciente. Conclusão: Além dos efeitos secundários conhecidos de etomidato, taquicardia ventricular e fibrilação, embora muito raramente, também podem ser observadas. Até onde sabemos, esse é o primeiro caso na literatura de FV causado por etomidato. .

Justificación y objetivos: La aparición de fibrilación ventricular en un paciente puede originar complicaciones inesperadas. Nuestro objetivo es presentar un caso de fibrilación ventricular que ocurrió después de la inducción anestésica con administración de etomidato. Caso clínico: Paciente del sexo femenino, 56 años, con prediagnóstico de cálculos biliares que entró en quirófano para colecistectomía laparoscópica. La inducción de la anestesia fue realizada con administración de etomidato con una dosis en bolo de 0,3 mg/kg. La paciente presentó una grave y rápida aducción de los brazos inmediatamente después de la inducción. En el monitor se detectó taquicardia con QRS ancho y frecuencia ventricular de 188lpm. El ritmo se convirtió en fibrilación ventricular durante la preparación para la cardioversión. La pacientefue inmediatamente sometida a la desfibrilación. Se logró el ritmo sinusal. Decidimos postergar la cirugía debido a la condición de inestabilidad del paciente. Conclusión: Además de los efectos secundarios conocidos del etomidato también se pueden observar taquicardia ventricular y fibrilación (aunque sea algo muy raro). Hasta donde sabemos, este es el primer caso de fibrilación ventricular causado por etomidato en la literatura. .

Arritmias ventriculares e hipertrofia ventricular esquerda na cardiomiopatia hipertrófica / Ventricular arrhythmias and left ventricular hypertrophy in hypertrophic cardiomyopathy

FUNDAMENTO: Na Cardiomiopatia Hipertrófica (CMH), o grau de Hipertrofia Ventricular Esquerda (HVE) poderia influenciar o desenvolvimento de arritmias ventriculares. OBJETIVO: Analisar, na CMH, a associação entre a ocorrência de arritmias ventriculares no eletrocardiograma-Holter (ECG-Holter) e o grau de HVE determinado ao ecocardiograma pela espessura parietal máxima (EPM) e Índice de Massa (IM). MÉTODOS: Cinquenta e quatro pacientes consecutivos com CMH realizaram ECG-Holter de 24 horas e ecocardiograma para avaliação do grau de HVE através da EPM e IM. Foram estabelecidos dois níveis para a ocorrência de arritmias ventriculares: I - extrassístoles isoladas ou pareadas e II - Taquicardia Ventricular Não Sustentada (TVNS). RESULTADOS: Nos 13 pacientes (24%) com TVNS (nível II), houve maior frequência de EPM do ventrículo esquerdo (VE) > 21 mm (n = 10, 77%; 25 ± 4 mm) e IMVE > 144 g/m² (n = 10, 77%; 200 ± 30 g/m²), em relação àqueles que apresentavam apenas arritmia extrassistólica (nível I) (n = 41, 76%), em que essas medidas foram identificadas em, respectivamente, 37% (n = 15, 23 ± 1 mm), p = 0,023, e 39% (n = 16, 192 ± 53 g/m²) dos casos, p = 0,026. Os citados valores de corte foram determinados por curva ROC com intervalo de confiança de 95%. O registro de TVNS foi mais comum em pacientes com EPMVE > 21 mm e IMVE > 144 g/m² (8 de 13; 62%), do que naqueles com uma (4 de 13; 31%) ou nenhuma (1 de 13; 8%) variável ecocardiográfica acima dos valores de corte, p = 0,04. CONCLUSÃO: A ocorrência de arritmias ventriculares no Holter associou-se, na CMH, ao grau de HVE, avaliado pelo ecocardiograma através da respectiva EPM e IM.

BACKGROUND: In hypertrophic cardiomyopathy (HCM), the degree of left ventricular hypertrophy (LVH) could influence the development of ventricular arrhythmias. OBJECTIVE: In HCM, analyze the association between the occurrence of ventricular arrhythmias determined by Holter electrocardiogram (ECG-Holter) and the degree of LVH determined by maximum wall thickness (MWT) in echocardiography and body mass index (BMI). METHODS: Fifty-four consecutive patients with HCM underwent 24-hour ECG-Holter and echocardiography for assessment of level of LVH through MWT and BMI. Two levels were established for the occurrence of Ventricular Arrhythmias: I - alone or paired extrasystoles and II - Non- Sustained Ventricular Tachycardia (NSVT). RESULTS: In 13 patients (24%) with NSVT (level II), there was a higher frequency of MWT of the left ventricle (LV) > 21 mm (n = 10, 77%, 25 ± 4 mm) and LLLV = 144 g/m² (n = 10, 77%, 200 ± 30 g/m²), in comparison with those presenting with extrasystole arrhythmias (level I) (n = 41, 76%), in which these measures were identified in, respectively, 37 % (n= 15, 23 ± 1 mm), p = 0.023, and 39% (n = 16, 192 ± 53 g / m²) of the cases (p = 0.026). The cut-off values mentioned were determined by the ROC curve with a confidence interval of 95%. NSVT was more common in patients with MWTLV > 21 mm and LLLV > 144 g/m² (8 of 13, 62%) than in those with (4 of 13, 31%) or without (1 of 13; 8%) echocardiographic variables above cut-off values (p = 0.04). CONCLUSION: In HCM, occurrence of ventricular arrhythmias by Holter was associated with the degree of LVH assessed by echocardiography through MWT and BMI.

Cardiac herniation following completion pneumonectomy for bronchiectasis.

Sporadic reports on cardiac herniation are available in the literature; most of them had followed intrapericardial pneumonectomies for malignant pulmonary tumors. We present an uncommon event of heart herniation after a completion pneumonectomy indicated for chronic bronchiectasis. A 35-year-old male patient was operated for left completion pneumonectomy. A 6 cm Χ 4 cm area of adherent pericardium near the obtuse margin of heart was removed during surgery. During head-end elevation of the bed in postoperative intensive care unit, patient got accidentally tilted to the left side, which resulted in ventricular fibrillation. Chest cavity was re-opened for cardiopulmonary resuscitation. Left ventricle was found herniating through the pericardial deficiency into the left-thoracic cavity with the cardiac apex touching chest wall. During surgical re-exploration, the pericardial deficiency was closed with a synthetic Dacron patch. Hemodynamic condition remained stable in the immediate postoperative period. Patients had infection of the left thoracic cavity after 5 weeks, for which he was subjected to thoracoplasty and omentopexy. Prompt recognition with timely intervention is life saving from cardiac herniation. Strategy of closing the pericardial defect after pneumonectomy should be followed routinely, irrespective of the indication for pneumonectomy.

Procedimiento de Bentall en la enfermedad aneurismática de la aorta ascendente: mortalidad hospitalaria / Bentall procedure in ascending aortic aneurysm: hospital mortality

Introducción: La enfermedad aneurismática de la aorta ascendente (EAAA) se caracteriza por su baja frecuencia, comportamiento heterogéneo, riesgo de rotura y disección, que conllevan elevada mortalidad, por lo que la cirugía electiva es fundamental. Se han desarrollado diversos procedimientos quirúrgicos, considerándose la técnica de Bentall el estándar de referencia. Se describe la mortalidad hospitalaria de la EAAA tratada quirúrgicamente mediante el procedimiento de Bentall. Material y métodos: Estudio descriptivo en el que se incluyeron 23 pacientes con EAAA operados entre el 1 de marzo de 2005 y el 30 de septiembre de 2008; la información fue obtenida de los expedientes clínicos. Resultados: Los 23 pacientes correspondieron a 1.2 % de las cirugías efectuadas. Edad media de 46 años (rango 16 a 74), sexo masculino 83 %. Etiología: degeneración inespecífica de la capa media con implicación valvular 43 %, aorta bivalva 22 %, síndrome de Marfán, de Turner y aneurismas posestenóticos, 9 % cada uno. Enfermedad de Takayasu y espondilitis anquilosante, 4 % cada uno. Enfermedad cardiaca asociada en seis (26 %): coartación aórtica (2), cardiopatía isquémica (1), comunicación interauricular (1), insuficiencia mitral severa (1) y rodete subaórtico (1). Procedimientos realizados: cirugía de Bentall 20 (87 %), aortoplastia con prótesis valvular tres (13 %). Complicaciones: sangrado anormal con reintervención 17 %, neumonía nosocomial 13 %, arritmias 13 %, choque séptico 9 %. Mortalidad tres (13 %): choque séptico y fibrilación ventricular. Conclusiones: La mortalidad hospitalaria para la cirugía de Bentall fue semejante a la registrada en otros centros especializados. Los eventos relacionados con la patología aórtica, técnica quirúrgica, prótesis valvular aórtica y la disfunción ventricular izquierda, obligan a realizar estudios de seguimiento a largo plazo.

BACKGROUND: Ascending aortic aneurysm disease (AAAD) shows a low frequency, heterogeneous behavior, high risk of rupture, dissection and mortality, making elective surgery necessary. Several procedures have been developed, and the Bentall technique is considered as the reference standard. The objective was to describe the hospital mortality of AAAD surgically treated using the Bentall procedure. METHODS: We carried out a descriptive study. Included were 23 patients with AAAD who were operated on between March 1, 2005 and September 30, 2008 at our hospital. Data were obtained from clinical files, and descriptive statistics were selected for analysis. RESULTS: The study population was comprised of 23 patients with an average age of 46 years; 83% were males. Etiology was nonspecific degeneration of the middle layer with valve implication in 43%, bivalve aorta in 22%, Marfan syndrome, Turner's syndrome and poststenotic aneurysms each represented 9%, and Takayasu disease and ankylosing spondylitis 4% each. Associated heart disease was reported in six (26%) patients as follows: aortic coarctation (2), ischemic cardiopathy (1), atrial septal defect (1), severe mitral insufficiency (1) and subaortic membrane (1). Procedures carried out were Bentall surgery in 20 (87%) patients and aortoplasty with valve prosthesis in three (13%) patients. Complications reported were abnormal bleeding with mediastinal exploration (17%), nosocomial pneumonia (13%), arrhythmia (13%), and septic shock (9%). Mortality was reported in three (13%) patients due to septic shock and ventricular fibrillation. CONCLUSIONS: Surgical mortality with the Bentall procedure is similar to published results by other specialized centers. Events related to the basic aortic pathology, surgical technique, aortic valve prosthesis and left ventricular dysfunction encourage longterm studies with follow-up.

Incidence of ventricular arrhythmias, brady-arrhythmias and sudden cardiac death in Sudanese patients with acute myocardial infarction

Ventricular arrhythmias [VAS], including ventricular tachycardia [VT], ventricular fibrillation [VF] and Brady-arrhythmias, are life-threatening complications of acute myocardial infarction [MI]. To study the incidence of ventricular arrhythmias, brady-arrhythmias and Sudden Cardiac Death [SCD] in Sudanese patients with acute MI. This is a prospective cross sectional, hospital based study, conducted at Elshaab Teaching Hospital Khartoum Sudan. One Hundred Sudanese patients with acute MI were enrolled in the study in the period between August 2006 and December 2006. A questionnaire was constructed in sections to address the different aspect of the study group. ECG Monitor was used to confirm the complication in every patient. Of the study group forty seven [47%] patients were 55-65 years old, twenty eight [28%] were more than 65 years old and twenty five [25%] were less than 55 years old. Sixty nine [69%] were males. Twenty patients [20%] developed complications [ventricular arrhythmias [VAS], Brady-arrhythmias and SCD]. The incidence of ventricular arrhythmias, brady-arrhythmias and sudden cardiac death following acute myocardial infarction were significantly high in Sudanese patients. The increased incidence is even in all age groups. DM, smoking and past history of IHD are the commonest associated risk factors. Thrombolysis is under used and had no significant impact

WPW and preexcitation syndromes.

Wolff-Parkinson-White syndrome is a disorder characterized by presence of an accessory pathway which predisposes patients to tachyarrhythmias and sudden death. Among patients with WPW syndrome, atrioventricular reentrant tachycardia (AVRT) is the most common arrhythmia, accounting for 95% of re-entrant tachycardias. It has been estimated that one-third of patients with WPW syndrome have atrial fibrillation (AF). AF is a potentially life-threatening arrhythmia. If an accessory pathway has a short anterograde refractory period, then rapid repetitive conduction to the ventricles during AF can result in a rapid ventricular response with subsequent degeneration to ventricular fibrillation (VF). The accessory pathway may be located anywhere along the atrioventricular valve Most of the patients are young and do not have structural heart disease hence it is important to risk stratify these patients so as to prevent the sudden death. Management of asymptomatic patients with WPW syndrome has always remained controversial Catheter ablation of accessory pathways has become an established mode of therapy for symptomatic patients and asymptomatic patients employed in high-risk professions.

Continuous arteriovenous haemofiltration to regulate hyperkalaemia during renal transplantation: a case report.

Progressive hyperkalaemia is common in end stage renal disease patients waiting for renal transplantation. Ventricular tachycardia and ventricular fibrillation due to hyperkalaemia are life-threatening complications in these patients. In live and related renal transplant, after induction and anaesthesia, ventricular fibrillation and pulmonary oedema occurred. After immediate resuscitation by defibrillation and intravenous injection of adrenaline, the patient was put on continuous femoral arteriovenous haemofiltration (CAVH). This improved his pulmonary oedema, controlled hyperkalaemia and surgery could be completed uninterruptedly. After anaesthetising live and related kidney donor for nephrectomy, since it is not prudent to stop recipient surgery because of unforeseen complication, the authors wish to recommend CAVH as an alternative method to prevent life threatening cardiac complication of hyperkalaemia.

Ressonância magnética em paciente portadora de marcapasso / Magnetic resonance imaging in a patient with pacemaker

Mulher de 24 anos, portadora de marcapasso dupla câmara, com hipertensão intracraniana e perda visual progressiva, e vários exames de tomografia de crânio inconclusivos. Foi submetida à Ressonância Magnética, mesmo sendo este método diagnóstico uma contra-indicação absoluta em portadores de marcapasso.

Casi muerte súbita recuperada tras fibrilación ventricular / Near sudden death recovered to ventricular fibrillation

El síndrome de bloqueo de rama derecha, elevación del segmento ST en las derivaciones V1 a V3 y muerte súbita es una nueva entidad (distinta de otros síndromes, como el síndrome del QT largo o la displasia ventricular derecha), que está determinada por anomalías genéticas que afectan al canal de sodio y se denomina síndrome de Brugada. El único tratamiento que podemos ofrecer a estos pacientes actualmente es un desfibrilador implantable

Clinical predictors of in -hospital sustained ventricular tachyarrhythmias following coronary artery bypass grafting

Sustained ventricular tachyarrhythmias [VT] such as monomorphic or polymorphic ventricular tachycardia and ventricular fibrillation represent the most dreadful arrhythmic events that can complicate the postoperative course of coronary artery bypass grafting [CABG]. The perioperative factors that are potentially associated with the onset of post-CAGB sustained VT have not been deeply investigated. Hence, the aim of our paper was to identify which perioperative variables predict post-CABG VT occurrence. One hundred fifty-two consectivity patients who underwent CABG surgery at our institution between September and December 1997 comprised the study population. Post-CABG VT occurred in 13 [8.5%] out of 152 patients [6 cases of monomorphic ventricular tachycardia and 7 cases of ventricular fibrillation]. Using university analysis, VT patients were compared with those who remained in sinus rhythm [SR]. VT patients were significantly younger [54.8 +/- 6.6 vs. 60.1 +/- 8.8, p=0.038], had more severe coronary artery disease [CAD] [NO. of diseased vessels 2.92 +/- 0.3 vs 2.45 +/- 0.7, p=0.023], had a higher incidence of three-vessel CAD [91.7% vs 57.3%, p=0.043], and received a greater number of CABG[s] [% of patients teceiving three or more CABG[s] 76.9% vs. 38.8%, p=0.018]. VT patients were found to developed intra-or operative myocardial infarction more frequently [total CK> 1000 76.9% vs. 38%, p=0.016; and MB-CK> normal range 72.7% vs 30.7%, p=0.014], had a higher incidence of electrolyte derangement [84.6% vs 45.6%, p=0.017] and more severe hemodynamic impairment [need of IABP 23% vs 2.9%, p=0.009]. At multivariate analysis, total CK> 1000, postoperative electrolyte imbalance, the need of three or more CABG[s] and use of IABP were found to be independent correlates for VT. Post-CABG VT seem to be related to the pre-existence of severe underlying coronary artery disease and to triggering factors such as acute ischemia, electrolyte disorders, and a sudden hemodynamic impairment that might precipitate the onset of VT

Hipokalemia crónica, tetraplejía y coma / Chronic hypokalemia, quadriplegia and coma

Hemos observado la evolución de una paciente de 36 años con menopausia precoz, hipokalemia crónica, grave y persistente, con episodios de astenia, adinamia, hipotonía muscular y arreflexia osteotendinosa y, en su mayor grado de expresión, con kalemia de 0,9 mEq/L, tetraplejía, coma y una arritmia ventricular severa tipo torsades de pointes. Durante su internación se pensaron en numerosas etiologías sospechando, en primer término, en un síndrome de Bartter debido al cuadro de hipokalemia normotensiva. Las cifras de aldosterona y angiotensina I en rangos normales nos hicieron abandonar el diagnóstico por el cual fue medicada en forma sucesiva con indometacina, enalapril, acetazolamida y amiloride. Con este último fármaco y el aumento de las dosis orales de potasio, la paciente normalizó su kalemia, recuperó sus potencialidades psicofísicas y se le dio el alta para su estudio por consultorio externo. Los diagnósticos diferenciales se detallan en los cuadros correspondientes. Los repetidos balances positivos de potasio nos hicieron sospechar en un cuadro clínico aún no determinado de desplazamiento del K+ del LEC al LIC. Destacamos la importancia semiológica por su infrecuencia, sus implicancias reales y potenciales, además de la recuperación con amiloride y aumento de la ingestión de potasio

Antagonizing the hydroxyl ion free radical (HO.) does not abolish reperfusion ventricular fibrillation in anesthetized dogs

1. The hypothesis that the hydroxyl ion free radical, HO; derived from O2 plays a pivotal role in the development of reperfusion ventricular fibrillation was tested in 63 anesthetized mongrel dogs of either sex weighing 14 +/- 7 kg submitted to 90-min coronary occlusion followed by 60-min reperfusion. 2. OH. was blocked by the iron chelator deferoxamine (DF, 500 mg) and by dimethylthiourea (DMTU, 500 mg/kg), a HO. scavenger both given iv over 30 min before reperfusion. 3. The frequency of reperfusion ventricular fibrillation was similar in all animals, i.e., 7/27 (26 per cent ) control dogs, 7/23 (30 per cent ) DF-treated dogs and 3/13 (23 per cent ) DMTU-treated dogs. Arterial pressure, heart rate and double product were not significantly different among the three groups during occlusion or reperfusion. The hemodynamic variables were also similar among dogs that fibrillated and those that did not. Likewise, extent of ischemic areas and necrosis was similar among the three experimental groups, with the control values being 34 +/- 4 per cent and 14 +/- 5 per cent , respectively. 4. We conclude that OH. does not play a major role in the induction of reperfusion ventricular fibrillation in the anesthetized dog with ischemia/necrosis