RESUMO
AIM: The association between cranial ultrasound (CUS) or magnetic resonance imaging (MRI) lesions and neonatal Group B streptococcal (GBS) meningitis outcome has not been studied in detail. METHODS: This retrospective study assessed CUS, cranial MRI and neurodevelopmental outcome in 50 neonates with GBS meningitis admitted to three neonatal intensive care units in the Netherlands between 1992 and 2014. Death, cognitive outcome and motor outcome below -1 SD were considered as adverse outcomes. RESULTS: CUS was available in all and MRIs in 31 infants (62%) with 28 CUS (56%) and 27 MRIs (87%) being abnormal. MRI lesions were multifocal (n = 10, 37%), bilateral (n = 22; 82%) and extensive (n = 11; 41%). A total of 10 died in the neonatal period. Median age at assessment was 24 months. Among survivors, abnormal cognitive outcome and motor outcome were seen in 23 and 20 patients, respectively. Abnormal CUS [odds ratio (OR) 5.3, p = 0.017], extensive bilateral deep grey lesions (OR 6.7, p = 0.035) and white matter lesions (OR 14.0, p = 0.039) correlated with abnormal motor outcome. Extensive bilateral deep grey matter lesions correlated with abnormal cognitive outcome (OR 8.1, p = 0.029). CONCLUSION: Abnormal CUS and the most severely affected MRIs were associated with poor neurodevelopmental outcome in neonatal GBS meningitis.
Assuntos
Encéfalo/diagnóstico por imagem , Desenvolvimento Infantil/fisiologia , Meningites Bacterianas/diagnóstico por imagem , Infecções Estreptocócicas/diagnóstico por imagem , Streptococcus agalactiae , Cognição , Feminino , Humanos , Lactente , Recém-Nascido , Imageamento por Ressonância Magnética , Masculino , Meningites Bacterianas/fisiopatologia , Meningites Bacterianas/psicologia , Destreza Motora , Estudos Retrospectivos , Infecções Estreptocócicas/fisiopatologia , Infecções Estreptocócicas/psicologia , UltrassonografiaRESUMO
UNLABELLED: This case report presents a rare cause of progressive hypotonia due to a congenital bony defect of the atlas in a 2-month-old girl. The patient was initially referred to the paediatric department with feeding problems. Within days after admission she developed progressive hypotonia and showed decreased reflexes of the upper extremities. Magnetic resonance imaging showed compressive myelopathy at the level of vertebra C1. After laminectomy of the C1-vertebra the neurological symptoms resolved. CONCLUSION: Most anomalies of the vertebras are asymptomatic. Only symptomatic anomalies with compression and neurological symptoms need surgery.
Assuntos
Atlas Cervical/patologia , Hipotonia Muscular/etiologia , Compressão da Medula Espinal/complicações , Estenose Espinal/complicações , Extremidade Superior/patologia , Fatores Etários , Atlas Cervical/cirurgia , Descompressão Cirúrgica , Progressão da Doença , Feminino , Humanos , Lactente , Imageamento por Ressonância Magnética , Hipotonia Muscular/patologia , Hipotonia Muscular/cirurgia , Fatores de Risco , Compressão da Medula Espinal/diagnóstico , Compressão da Medula Espinal/cirurgia , Estenose Espinal/diagnóstico , Estenose Espinal/cirurgiaRESUMO
BACKGROUND: Mechanical ventilation (MV) induces an inflammatory response in healthy lungs. The resulting pro-inflammatory state is a risk factor for ventilator-induced lung injury and peripheral organ dysfunction. Isoflurane is known to have protective immunological effects on different organ systems. We tested the hypothesis that the MV-induced inflammatory response in healthy lungs is reduced by isoflurane. METHODS: Healthy C57BL6 mice (n=34) were mechanically ventilated (tidal volume, 8 ml/kg; positive end-expiratory pressure, 4 cmH(2)O; and fraction of inspired oxygen, 0.4) for 4 h under general anesthesia using a mix of ketamine, medetomidine and atropine (KMA). Animals were divided into four groups: (1) Unventilated control group; (2) MV group using KMA anesthesia; (3) MV group using KMA with 0.25 MAC isoflurane; (4) MV group using KMA with 0.75 MAC isoflurane. Cytokine levels were measured in lung homogenate and plasma. Leukocytes were counted in lung tissue. RESULTS: Lung homogenates: MV increased pro-inflammatory cytokines. In mice receiving KMA+ isoflurane 0.75 MAC, no significant increase in interleukin (IL)-1beta was found compared with non-ventilated control mice. PLASMA: MV induced a systemic pro-inflammatory response. In mice anesthetized with KMA+ isoflurane (both 0.25 and 0.75 MAC), no significant increase in tumor necrosis factor (TNF)-alpha was found compared with non-ventilated control mice. CONCLUSIONS: The present study is the first to show that isoflurane attenuates the pulmonary IL-1beta and systemic TNF-alpha response following MV in healthy mice.
Assuntos
Anestésicos Inalatórios/farmacologia , Interleucina-1beta/metabolismo , Isoflurano/farmacologia , Pulmão/metabolismo , Respiração Artificial , Fator de Necrose Tumoral alfa/metabolismo , Animais , Atropina/farmacologia , Pressão Sanguínea/efeitos dos fármacos , Antagonistas de Aminoácidos Excitatórios/farmacologia , Hipnóticos e Sedativos/farmacologia , Ketamina/farmacologia , Contagem de Leucócitos , Pulmão/efeitos dos fármacos , Masculino , Medetomidina/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Antagonistas Muscarínicos/farmacologia , Pneumonia/patologiaRESUMO
UNLABELLED: A case report is presented of a rapidly growing congenital nasopharyngeal teratoma (epignathus) in a preterm infant, leading to severe upper airway obstruction. Prenatal diagnosis by ultrasonography did not reveal the condition because the tumour masses were initially small and there was no polyhydramnios. Epignathus is a rare cause of upper airway obstruction of the newborn that can grow rapidly in the neonatal period and should be treated surgically. CONCLUSION: Epignathus is a rare cause of upper airway obstruction of the newborn that can grow rapidly in the neonatal period.
Assuntos
Obstrução das Vias Respiratórias/etiologia , Doenças do Prematuro/diagnóstico , Neoplasias Nasofaríngeas/congênito , Nasofaringe/patologia , Teratoma/congênito , Diagnóstico Diferencial , Feminino , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Imageamento por Ressonância Magnética , Neoplasias Nasofaríngeas/complicações , Neoplasias Nasofaríngeas/diagnóstico , Nasofaringe/diagnóstico por imagem , Teratoma/complicações , Teratoma/diagnóstico , UltrassonografiaRESUMO
AIM: In pyridoxine dependent epilepsy (PDE), patients usually present with neonatal seizures. A small subgroup is characterized by late-onset beyond 2 months of age. We aim to analyze the observation of relatively good cognitive outcome in this subgroup of late-onset PDE patients. METHODS: We retrospectively analyzed data from four metabolically and genetically confirmed late-onset patients with PDE due to antiquitin (ALDH7A1) deficiency. Data were analyzed regarding ALDH7A1 mutations, alpha-Aminoadipic semialdehyde (α-AASA) and pipecolic acid (PA) levels, medication during pregnancy, delivery, treatment delay, amount of seizures, pyridoxine dose, adjuvant therapy and findings on brain MRI. RESULTS: Results showed that three patients had relatively good outcome (IQ 80-97), while one patient did not undergo formal testing and was considered mildly delayed. We were unable to find a clear association between the above-mentioned variables and cognitive outcome, although a less severe genotype may be present in three patients, and maternal medication could be accountable for better outcome in two patients. INTERPRETATION: We suggest that favorable outcome in late onset PDE might be explained by a combination of factors. A yet unknown protective factor, different genetic variations, functional variation and secondarily variation in treatment regimens and absence of neonatal seizure induced brain damage.
Assuntos
Idade de Início , Epilepsia/complicações , Deficiência Intelectual/genética , Aldeído Desidrogenase/genética , Epilepsia/genética , Feminino , Genótipo , Humanos , Lactente , Deficiência Intelectual/epidemiologia , Inteligência/genética , Imageamento por Ressonância Magnética , Masculino , Mutação , Piridoxina/uso terapêutico , Estudos RetrospectivosRESUMO
At the Máxima Medisch Centrum in Veldhoven, The Netherlands, neonatal sepsis caused by invasive Streptococcus pneumoniae infection was diagnosed in 5 neonates between 1996 and 2004. This infection is relatively rare and its clinical features are variable, but often particularly severe and fulminant as was the case in 2 of the 5 children, one of whom died and the other was left with serious psychomotor retardation. The other 3 recovered fully. The child who died and one of the children who recovered are described in some detail. They were both prematurely born neonates, a girl and a boy, who presented almost immediately after birth with an early-onset sepsis caused by S. pneumoniae. In both cases neonatal cultures as well as maternal vaginal swabs were positive for S. pneumoniae growth. 2 different patients had other risk factors for peripartal infection. Neonatal pneumococcal infections are most likely transmitted trough the maternal vaginal tract. Maternal vaginal colonization is rare (0.11%), but associated with a high risk of transmission to the newborn. Asymptomatic neonatal colonization was not observed. In light of the likelihood of a high rate of transmission and subsequent infection, peripartal prophylactic antibiotic treatment is advised for all mothers with proven vaginal S. pneumoniae colonization. If this is not given or is not effective, then in contrast with the policy on patients with group B streptococcal colonization, prophylactic antibiotic treatment is advocated for all neonates born to colonized mothers. Amoxicillin is the preferred treatment. In areas of increasing macrolide resistance, erythromycin should only be advised in cases of penicillin allergy.
Assuntos
Transmissão Vertical de Doenças Infecciosas/prevenção & controle , Infecções Pneumocócicas/prevenção & controle , Infecções Pneumocócicas/transmissão , Complicações Infecciosas na Gravidez/prevenção & controle , Vagina/microbiologia , Adulto , Antibioticoprofilaxia , Feminino , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Masculino , Gravidez , Complicações Infecciosas na Gravidez/microbiologia , Índice de Gravidade de Doença , Streptococcus pneumoniae/efeitos dos fármacos , Streptococcus pneumoniae/isolamento & purificaçãoRESUMO
BACKGROUND: Mechanical ventilation is known to induce and aggravate lung injury. One of the underlying mechanisms is biotrauma, an inflammatory response in which cytokines play a crucial role. OBJECTIVE: To review the literature on the role of cytokines in ventilator-induced lung injury (VILI) and multiple organ dysfunction syndrome (MODS). MATERIAL AND METHODS: 57 English written, peer-reviewed articles on cytokines in in-vitro settings (n=5), ex-vivo models (n=9) in-vitro models (n=19) and clinical trials (n=24). RESULTS: Mechanical ventilation (MV) can induce cytokine upregulation in both healthy and injured lungs. The underlying mechanisms include alveolar cellular responses to stretch with subsequent decompartimentalisation due to concomitant cellular barrier damage. The cytokines involved are interleukin (IL)-8 and CXC chemokines, and probably IL-6, IL-1beta and tumour necrosis factor (TNF)-alpha. Cytokines are important for signalling between inflammatory cells and recruiting leucocytes to the lung. There is strong circumstantial evidence that the release of cytokines into the systemic circulation contributes to the pathogenesis of MODS. Multiple studies demonstrate the relation between elevated proinflammatory cytokine concentrations and mortality. CONCLUSION: Cytokines are likely to play a role in the various interrelated processes that lead to VILI and other MV-related complications, such as MODS and possibly ventilatorassociated pneumonia. Cytokines are good surrogate endpoints in exploring the pathogenesis and pathophysiology of VILI in both experimental and clinical studies.
Assuntos
Citocinas/imunologia , Lesão Pulmonar , Pulmão/imunologia , Ventiladores Mecânicos/efeitos adversos , Animais , Humanos , Insuficiência de Múltiplos Órgãos/etiologia , Síndrome de Resposta Inflamatória Sistêmica/etiologiaAssuntos
Doenças do Prematuro/etiologia , Intubação Intratraqueal/efeitos adversos , Pneumopericárdio/etiologia , Respiração Artificial/efeitos adversos , Evolução Fatal , Feminino , Parada Cardíaca/etiologia , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Doenças do Prematuro/diagnóstico , Pneumopericárdio/diagnósticoRESUMO
Haemophilia A is usually a genetic deficiency of coagulation factor VIII (F VIII). The development of antibodies against F VIII is a well known and frequent complication in the treatment of haemophilia A. Rarely, a F VIII inhibitor arises spontaneously, causing a condition which is known as acquired haemophilia A. We describe a patient with acquired haemophilia A and pemphigus, who presented with spontaneous haematomas of the extremities. Laboratory tests showed an activated partial thromboplastin time (aPTT) of 71 s (normal: 26-36 s), a F VIII concentration of 9% (normal: 60-140%), and a F VIII inhibitor-activity of 7.5 Bethesda Units/ml (B.U./ml, normal: 0). The haematomas disappeared within a few days and the laboratory tests normalized within 6 weeks, after administration of a booster of oral corticosteroids. One and a half years after the corticosteroids were stopped, both the clinical and the laboratory course of the patient has been uneventful. As far as we know, the combination of acquired haemophilia A and pemphigus has been reported in the literature only three times before. The diagnosis acquired haemophilia A should be considered in a patient presenting with a newly arisen haemorrhagic diathesis.
Assuntos
Hemofilia A/complicações , Pênfigo/complicações , Idoso , Fator VIII/metabolismo , Seguimentos , Glucocorticoides/uso terapêutico , Hematoma/tratamento farmacológico , Hematoma/etiologia , Hemofilia A/sangue , Hemofilia A/tratamento farmacológico , Humanos , Perna (Membro)/irrigação sanguínea , Masculino , Pênfigo/sangue , Pênfigo/tratamento farmacológico , Prednisona/uso terapêuticoRESUMO
During operation for a right inguinal hernia, a baby boy aged 3 months was discovered to have internal female genitalia. Biopsies were taken from the gonads and blood was sent for karyotyping. The biopsies showed normal testicular tissue and the karyotyping result was 46XY, so the diagnosis of persistent Müllerian duct syndrome (PMDS) was made. Recovery was uneventful. At the age of 2 he underwent bilateral orchidopexy. PMDS is a rare disorder of the MIF synthesis or receptor. Patients present with cryptorchism, inguinal herniation of Müllerian structures, or problems related to the abnormal urinary tract, such as infection or stone formation. In cryptorchism, orchidopexy and life-long palpatory follow-up are advised. If urological symptoms occur, surgical removal of the Müllerian remnants may be considered. The prognosis for fertility is poor.
Assuntos
Criptorquidismo , Glicoproteínas/genética , Hérnia Inguinal , Ductos Paramesonéfricos/patologia , Hormônios Testiculares/genética , Hormônio Antimülleriano , Criptorquidismo/genética , Criptorquidismo/patologia , Criptorquidismo/cirurgia , Fertilidade , Genitália/anormalidades , Inibidores do Crescimento/genética , Hérnia Inguinal/genética , Hérnia Inguinal/patologia , Hérnia Inguinal/cirurgia , Humanos , Lactente , Masculino , Ductos Paramesonéfricos/cirurgia , Síndrome , Hormônios Testiculares/sangueRESUMO
Oropharyngeal lymphatic malformations usually present with a mass either at birth or in the first 2 years of life. Rarely, lymphatic malformations present with extremely progressive respiratory problems shortly after birth, and usually occur in cases which have remained undetected in the absence of antenatal ultrasound. We report the case of a newborn that required tracheostomy and gastrostomy due to a rapidly expansive lymphatic malformation. MRI showed multilocular microcystic lymphatic malformation. Intralesional bleomycin injections proved to be successful in this patient. A short review of epidemiology, clinical manifestation and treatment is given.
Assuntos
Anormalidades Linfáticas/diagnóstico , Boca , Doença Aguda , Feminino , Humanos , Recém-NascidoRESUMO
A 6-year-old girl without any medical history experienced a drowning incident for a duration of 2 min, according to witnesses. This was followed by cardiopulmonary resuscitation, during which the automatic external defibrillator (AED) detected a shockable rhythm and subsequently delivered a single electroshock. At the time of admission, her medical history was unclear, and as her chest had been wet, it was not clear if the AED had been capable of correctly analysing the rhythm. The AED printout, however, revealed ventricular fibrillation (VF), which proved to be a primary cardiac cause at the time of the incident. This case report confirms the assumption that the AED can adequately perform rhythm analysis on children and convert VF into sinus rhythm. Moreover, the AED printout can provide information about the rhythm that is necessary for the diagnosis of an underlying cardiac disease.
Assuntos
Reanimação Cardiopulmonar/métodos , Desfibriladores , Afogamento , Fibrilação Ventricular/diagnóstico , Fibrilação Ventricular/terapia , Criança , Eletrocardiografia , Feminino , HumanosRESUMO
Persistent Müllerian Duct Syndrome (PMDS) is a rare disorder of the anti-mullerian hormone (AMH) synthesis or receptor, which due to the visual contrast of normal masculine external genitalia and female internal genitalia can raise confusion, sometimes during surgery for cryptorchidism or hernia inguinalis. For an acute and accurate analysis of such a situation a thorough knowledge of gonadal embryology is mandatory. The diagnosis is made on finding Müllerian structures in an individual with complete virilization without signs of hypocortisolism or exposition to maternal androgens during foetal life. Karyotyping and gonadal biopsy provide additional information to confirm the diagnosis. As the risk of malignant transformation is not clear, orchidopexy is advised in patients with cryptorchidism, with lifelong palpatory follow-up. In case of urologic symptoms, surgical removal of the Müllerian remnants can be considered, with careful attention for the vulnerable ductus deferens. Despite optimal treatment the prognosis regarding fertility remain uncertain.
Assuntos
Transtornos do Desenvolvimento Sexual/diagnóstico , Ductos Paramesonéfricos/anormalidades , Hormônio Antimülleriano/metabolismo , Criptorquidismo/diagnóstico , Diagnóstico Diferencial , Transtornos do Desenvolvimento Sexual/fisiopatologia , Hérnia Inguinal/diagnóstico , Humanos , Lactente , Recém-Nascido , Masculino , Doenças Raras , SíndromeRESUMO
UNLABELLED: The amplitude-integrated electroencephalogram (aEEG) is a useful tool to assess brain function after perinatal asphyxia in term infants. We report a full-term newborn with moderate perinatal asphyxia, who accidentally received an overdose of morphine (5000 microg/kg). The overdose of morphine resulted in a clear and immediate change of aEEG background activity from a continuous (C) to discontinuous (DC) background pattern. After administration of naloxone, the background activity restored immediately to continuous background pattern. The aEEG was used to monitor the stepwise reduction in continuous naloxone infusion. CONCLUSION: An overdose of morphine leads to clear and immediate changes in aEEG which restore after naloxone treatment. The aEEG can be used to monitor naloxone infusion.
Assuntos
Analgésicos Opioides/intoxicação , Eletroencefalografia , Morfina/intoxicação , Naloxona/uso terapêutico , Antagonistas de Entorpecentes/uso terapêutico , Encéfalo/efeitos dos fármacos , Overdose de Drogas/diagnóstico , Overdose de Drogas/tratamento farmacológico , Humanos , Recém-Nascido , MasculinoRESUMO
A literature review was conducted to assess the evidence for recruitment manoeuvres used in conventional mechanical positive pressure ventilation. A total of 61 studies on recruitment manoeuvres were identified: 13 experimental, 31 ICU, 6 PICU and 12 anaesthesia studies. Recruitment appears to be a continuous process during inspiration and expiration and is determined by peak inspiratory pressure (PIP) and positive end expiratory pressure (PEEP). Single or repeated recruitment manoeuvres may result in a statistically significant increase in oxygenation; however, this is short lasting and clinically irrelevant, especially in late ARDS and pneumonia. Temporary PIP elevation may be effective but only after PEEP loss (for example disconnection and tracheal suctioning). Continuous PEEP elevation and prone positioning can increase P(a)O2 significantly. Adverse haemodynamic or barotrauma effects are reported in various studies. No data exist on the effect of recruitment manoeuvres on mortality, morbidity, length of stay or duration of mechanical ventilation. Although recruitment manoeuvres can improve oxygenation, they can potentially increase lung injury, which eventually determines outcome. Based on the presently available literature, prone position and sufficient PEEP as part of a lung protective ventilation strategy seem to be the safest and most effective recruitment manoeuvres. As paediatric physiology is essentially different from adult, paediatric studies are needed to determine the role of recruitment manoeuvres in the PICU.
Assuntos
Unidades de Terapia Intensiva Pediátrica , Respiração com Pressão Positiva/métodos , Anestesia , Animais , Criança , Cuidados Críticos/métodos , Humanos , Oxigênio/sangue , Pressão Parcial , Alvéolos Pulmonares/fisiopatologiaRESUMO
UNLABELLED: Two unrelated patients are reported: one with isolated familial asplenia diagnosed postmortem, the other with isolated hyposplenism diagnosed after recurring invasive bacterial infections. Because both children died of fulminant septic shock, the importance of early diagnosis of splenic dysfunction is evident. Clues for an early diagnosis of congenital asplenia are recurrent invasive bacterial infections, Howell-Jolly bodies in the blood smear or a relative with congenital isolated asplenia. Although the guidelines for infection prevention in asplenism--patient education, antibiotic prophylaxis and vaccination--are well defined, controversy remains as to how to differentiate hyposplenism from functional asplenism. CONCLUSION: Based on the present observations, we define a patient as functionally asplenic--and therefore at risk for life-threatening infections-when Howell-Jolly bodies are present in the blood smear, a very small spleen is found by ultrasound, or splenic blood flow is compromised.
Assuntos
Baço/anormalidades , Pré-Escolar , Inclusões Eritrocíticas , Evolução Fatal , Feminino , Humanos , Fluxo Sanguíneo Regional , Baço/irrigação sanguínea , Baço/diagnóstico por imagem , UltrassonografiaRESUMO
Cerebral cavernous hemangiomas (CCH) are relatively rare vascular hamartomas. Since the introduction of MRI there has been an increase in the number of case reports of CCH in the medical literature. CCH are often asymptomatic; they may, however, cause epilepsy or neurological deficits due to their space-occupying effects or hemorrhagic sequelae. The tendency of CCH to bleed has been well recognized, though gross hemorrhage is infrequent owing to the relatively low blood pressure and small blood flow in CCH. MRI findings of a CCH are characteristic and can differentiate the lesions from other vascular abnormalities. To date, there has been no consensus on indications for surgical intervention. Three cases are presented, which together demonstrate by their different presentation, clinical course and MRI findings that each patient with a CCH requires an individually tailored management. Presentation, clinical course and accessibility for operation are the factors that determine whether a surgical or a conservative approach should be adopted.
Assuntos
Neoplasias Encefálicas/cirurgia , Hemangioma Cavernoso/cirurgia , Adolescente , Biópsia , Encéfalo/patologia , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/patologia , Criança , Pré-Escolar , Feminino , Hemangioma Cavernoso/diagnóstico , Hemangioma Cavernoso/patologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Prognóstico , Resultado do TratamentoRESUMO
Isolated noncompaction of ventricular myocardium is a rare cardiomyopathy, presumed to originate from a developmental abnormality in the evolution of the heart, and resulting in sponge-like myocardium. Isolated ventricular noncompaction can present with a variety of symptoms, but usually includes heart failure. The diagnosis is often made by echocardiography, which reveals a very distinct image of the myocardium, with many deep, confluent recesses and dense trabeculations. We encountered such findings in a moribund neonate presenting with cardiogenic shock with extremely low shortening fractions. After treatment with intravenous and oral cardiotonics, coupled with afterload reduction, we were able to optimize the balance between ventricular filling and myocardial contractility, resulting in markedly improved cardiac function as judged clinically, and as measured by echocardiography. As far as we know, this is one of the youngest patients yet reported to have a good recovery.
Assuntos
Cardiopatias Congênitas/diagnóstico , Cardiomiopatias/diagnóstico , Cardiomiopatias/etiologia , Ecocardiografia , Feminino , Cardiopatias Congênitas/complicações , Humanos , Recém-Nascido , Miocárdio/patologia , Miocárdio/ultraestrutura , PrognósticoRESUMO
In conscious dogs with chronic atrioventricular (AV) block, we recently demonstrated that flunarizine is effective against ouabain-induced arrhythmias (triggered activity resulting from delayed afterdepolarizations, DADs) but fails to suppress spontaneous ventricular tachycardias (VT) occurring 24 h after left anterior descending coronary artery occlusion (abnormal automaticity). Neither does flunarizine affect normal automaticity, which suggests that flunarizine could be used as a clinical tool to recognize cardiac arrhythmias based on triggered activity. To elucidate further the arrhythmia mechanism-specific action of flunarizine, we investigated (a) its hemodynamic and electrophysiologic effects in 6 anesthetized dogs, (b) its ability to prevent pacing-induced VT 7 days after myocardial infarction (reentry) in 9 anesthetized animals, and (c) its effect on premature escape beats (PEBs) in 9 conscious dogs with chronic AV block. PEBs are probably caused by DADs. Flunarizine decreased systemic blood pressure (p less than 0.01), and left ventricular dP/dt (p less than 0.01), but did not affect AH or HV internal, QRS duration, QT time, or the effective refractory period of either AV node or right ventricle over a wide range of (paced) cycle lengths. Flunarizine decreased the inducibility of PEBs by 42% (p less than 0.01), but not that of the reentrant VT in any of the 6 inducible dogs. Therefore, we conclude that although flunarizine has no electrophysiologic effects in normal heart, it prevents induction of PEBs. The inability of flunarizine to prevent induction of reentrant VT confirms the mechanism-specific action of flunarizine against triggered activity.