Recording of high V1-V3 precordial leads may be essential to the diagnosis of Brugada syndrome during the ajmaline test.

Sodium channel-blocking agents are routinely used to unveil the Brugada syndrome in patients in whom the typical electrocardiographic pattern is absent or doubtful. In this article, the authors report a patient with syncopal episodes of unknown origin in whom the conventional electrocardiographic result was normal and a negligibly small "saddle back" type repolarization was present in lead V2 recorded 2 intercostal spaces above the conventional site. Intravenous ajmaline (50 mg) did not elicit the type 1 pattern of the Brugada syndrome in the precordial leads obtained at their usual level, but a clear-cut coved-type repolarization was apparent in high right precordial leads. These findings indicate that high precordial leads should be routinely recorded while assessing the ajmaline test in patients suspected of having the Brugada syndrome.

Bloqueo AV de alto grado transitorio por compromiso nodal y acción vagal en un deportista. ¿Es necesaria la electroestimulación cardíaca permamente? / Transient high degree AV blockade due to node engagement and vagal tone in an athlete. Is permanent cardiac electric stimulation necessary?

Un deportista de 26 años, asintomático, fue evaluado por bloqueo AV de larga data con pausas nocturnas de hasta 4,7 segundos. El estudio electrofisiológico mostró bloqueo AV suprahisiano de segundo grado tipo Mobitz I con prueba de ajmalina negativa. En el ECG Holter, el mayor grado de bloqueo AV coincidió con la frecuencia sinusal más baja. El hallazgo se interpretó como lesión crónica nodal AV, de etiología indeterminada, con paroxismos de bloqueo AV por acción vagal. No se indicó electroestimulación cardíaca permanente y se le permitió continuar con actividad física.

[Atypical behavior of QTc and ST-T intervals in a patient with the Brugada syndrome]. / Comportamiento atípico del QTc y del ST-T en un caso con síndrome de Brugada.

We present a 56-year-old man who was admitted to an emergency service after receiving an electric shock. The ECG showed a J point and ST segment elevation of up to 5 mm in leads V1 to V3, which normalized in 24 hours. The ajmaline test caused elevation of the J point and of the ST segment up to 12 mm in leads V1 to V3, QTc lengthening, and QTc and T wave alternans. These results denoted alterations in the duration of myocardial action potentials, a common finding in patients with Brugada syndrome and long QT syndrome.

Unusual response to the ajmaline test in a patient with Brugada syndrome.

We present a Brugada syndrome patient who suffered an aborted sudden death. The ajmaline test (1 mg/kg body weight) induced accentuated alternans ST-segment elevation in V1-V2 without ventricular arrhythmias. It could represent silent ischaemia not detected before, failure of myocardial regions to repolarize in alternate beats due to transmural dispersion of conduction and refractoriness in the right ventricular outflow tract or a rate dependent sodium channel block by ajmaline. We need more studies to know whether this electrocardiographic sign is a risk factor for life-threatening ventricular arrhythmias in Brugada syndrome patients.

General approach for the synthesis of sarpagine/ajmaline indole alkaloids. Stereospecific total synthesis of the sarpagine alkaloid (+)-vellosimine.

[reaction: see text] (+)-Vellosimine has been synthesized enantiospecifically in 27% overall yield from commercially available D-(+)-tryptophan methyl ester via the asymmetric Pictet-Spengler reaction and a stereocontrolled intramolecular palladium-coupling reaction as key steps.

Muerte súbita: Síndrome de Brugada / Death sudden: Brugada syndrome

Se comunica el diagnóstico y tratamiento efectivo de un caso de muerte súbita con Síndrome de Brugada, efectuándose una revisión de la literatura existente al respecto. Para ello se describe el caso de una mujer de 39 años que fue recuperada de una muerte súbita, documentándose un registro ECG de fibrilación ventricular, y en quien la evaluación cardiológica muestra en ECG en ritmo sinusal con bloqueo de rama derecha y elevación del segmento S-T de V1-V3. Se descartaron todas las causas reversibles de muerte súbita arrítmica. Durante el estudio electrofisiológico se indujo con facilidad una taquicardia ventricular polimórfica-fibrilación ventricular. La administración de ajmalina incrementa las alteraciones del segmento S-T en las precordiales derechas. La paciente fue tratada con un cardiodefibrilador implantable, sin el uso de drogas antiarrítmicas y se encuentra bien al mes de seguimiento (AU)

Muerte súbita: Síndrome de Brugada / Death sudden: Brugada syndrome

Se comunica el diagnóstico y tratamiento efectivo de un caso de muerte súbita con Síndrome de Brugada, efectuándose una revisión de la literatura existente al respecto. Para ello se describe el caso de una mujer de 39 años que fue recuperada de una muerte súbita, documentándose un registro ECG de fibrilación ventricular, y en quien la evaluación cardiológica muestra en ECG en ritmo sinusal con bloqueo de rama derecha y elevación del segmento S-T de V1-V3. Se descartaron todas las causas reversibles de muerte súbita arrítmica. Durante el estudio electrofisiológico se indujo con facilidad una taquicardia ventricular polimórfica-fibrilación ventricular. La administración de ajmalina incrementa las alteraciones del segmento S-T en las precordiales derechas. La paciente fue tratada con un cardiodefibrilador implantable, sin el uso de drogas antiarrítmicas y se encuentra bien al mes de seguimiento

Detección no invasiva de lesiones miocárdicas subclínicas en pacientes con infección chagásica crónica / Non-invasive detection of subclinical myocardial involvement in patients with chronic Chagas infection

La detección de compromiso miocárdico precoz en la enfermedad de Chagas es muy importante para la elaboración de estrategias terapéuticas y/o preventivas. Para ello se utilizaron diferentes procedimientos de diagnóstico no invasivo. Con el propósito de evaluar en forma comparativa la capacidad de detectar anormalidades miocárdicas subclínicas se analizaron hallazgos en el ecocardiograma bidimensional, la prueba ergométrica graduada, la prueba de ajmalina y el electrocardiograma ambulatorio de 24 horas con sistema Holter. Se estudiaron 140 pacientes (78 varones y 62 mujeres) con serología positiva para la enfermedad de Chagas. Los resultados de este estudio muestran que la prueba de ajmalina es un marcador más sensible de daño miocárdico que el ecocardiograma bidimensional, el Holter o la prueba ergométrica y permite detectar el compromiso miocárdico chagásico en etapas más tempranas, aunque en algunos pacientes es posible demostrar anormalidades ecocardiográficas en presencia de una prueba de ajmalina negativa (AU)

Detección no invasiva de lesiones miocárdicas subclínicas en pacientes con infección chagásica crónica / Non-invasive detection of subclinical myocardial involvement in patients with chronic Chagas' infection

La detección de compromiso miocárdico precoz en la enfermedad de Chagas es muy importante para la elaboración de estrategias terapéuticas y/o preventivas. Para ello se utilizaron diferentes procedimientos de diagnóstico no invasivo. Con el propósito de evaluar en forma comparativa la capacidad de detectar anormalidades miocárdicas subclínicas se analizaron hallazgos en el ecocardiograma bidimensional, la prueba ergométrica graduada, la prueba de ajmalina y el electrocardiograma ambulatorio de 24 horas con sistema Holter. Se estudiaron 140 pacientes (78 varones y 62 mujeres) con serología positiva para la enfermedad de Chagas. Los resultados de este estudio muestran que la prueba de ajmalina es un marcador más sensible de daño miocárdico que el ecocardiograma bidimensional, el Holter o la prueba ergométrica y permite detectar el compromiso miocárdico chagásico en etapas más tempranas, aunque en algunos pacientes es posible demostrar anormalidades ecocardiográficas en presencia de una prueba de ajmalina negativa

Overdrive prolongation of refractoriness and fatigue in the early stages of human bundle branch disease.

OBJECTIVES: The aim of this study was to assess the response of refractoriness in normal and diseased human bundle branches to changes in cycle length, as well as during a long period of continuous overdrive pacing. BACKGROUND: The anterograde refractory period of the bundle branches in patients with functional bundle branch block shortens as the rate is increased. The rate-dependent response of refractoriness in diseased bundle branches is quite different. However, this difference has not been precisely delineated, and its physiologic meaning is uncertain. METHODS: Refractoriness of the bundle branches was measured by the extrastimulus technique in 16 patients with tachycardia-dependent bundle branch block and 10 patients with functional bundle branch block, both after basic trains of 8 atrial-paced impulses at different cycle lengths and during a 10-min period of continuous overdrive pacing. RESULTS: The baseline refractory period in the bundle branches of patients with functional bundle branch block measured 430 +/- 32 ms (mean +/- SD) and shortened to 368 +/- 30 ms at the shortest cycle length. The maximal effect was reached within the 1st min of overdrive pacing. The baseline refractory period of the bundle branches was significantly longer in patients with tachycardia-dependent bundle branch block (611 +/- 184 ms) and demonstrated a cumulative overdrive prolongation in 15 (83%) of 18 studies with typical manifestations of fatigue. In two other studies, this occurred only after ajmaline administration. CONCLUSIONS: A rate- and time-dependent prolongation of refractoriness frequently occurs in diseased human bundle branches. When absent, this response may be induced under the effects of sodium channel blockers. This would suggest that an abnormality in the recovery from inactivation of the sodium channel might underlie the early stages of bundle branch disease.

Changes in electrocardiographic patterns at different stages of Chagas' heart disease in rats.

1. The resting electrocardiogram was obtained from 25 Trypanosoma cruzi-infected rats 30 days after infection (phase I). The resting electrocardiogram was abnormal in 12 (group I) and normal in 13 (group II) animals. Nineteen similar but non-infected animals served as controls. Both the resting electrocardiogram and the ajmaline test were performed 120 and 350 days after infection (phases II and III, respectively). 2. With regard to the resting electrocardiogram of group I animals, left axis deviation was found in 10 of 12 (83%) in phase I, one of 12 (8%) in phase II (P less than 0.05) and in none of phase III (P less than 0.05). An intraventricular conduction delay was found in four of 12 (33%) rats in phase I, two of 12 rats (16%) in phase II (P greater than 0.05) and six of 12 rats (50%) in phase III (P greater than 0.05). The ajmaline test was abnormal in nine of 10 (90%) rats of group I with normal resting electrocardiogram in phase II, and in three of six (50%) animals in phase III (P greater than 0.05). 3. An intraventricular conduction delay was found in the resting electrocardiogram of one of 13 (7%) rats of group II in phase III. The ajmaline test was abnormal in one of 13 (7%) rats in phase II and in one of 12 (8%) rats in phase III. 4. No control rat showed pathological changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Efecto de la reinfeccion sobre la evalucion de ratas infectadas con Trypanosoma cruzi / Effect of reinfection on the evolution of rats infected with Trypanosoma cruzi

El objetivo de este trabajo fue comprobar si una de las variables medio-ambientales, la reinfeccion, puede modificar el comportamiento observado en un modelo de rata a nivel de parasitemia, anticuerpos sericos, manifestaciones electrocardiograficas y/o lesion miocardica. Los grupos experimentales fueron: GI: ratas infectadas al destete com 1 x "10 POT 6" T. cruzi; GR: igual a GI mas reinfecciones cada 30 dias hasta los 150 dias post-infeccion inicial (p.i.i.); "GI IND 1". Los xenodiagnosticos fueron negativos en los tres grupos. Los anticuerpos sericos no se modificaron significativamente en GR respecto de GI, salvo en los anticuerpos 7S, pues los del GR presentaron titulos superiores en algunos de los dias estudiados. Los ECG basales no mostraron cambios distintivos en las ratas infectadas. La pruieba de ajmalina mostro una disminucion de la FC independiente del tratamiento; el PR, QaT y QRS se prolongaron significativamente en todos los grupos respecto del basal (p < 0.05), salvo el QaT en el GT; ademas el cambio de PR y QaT fue mayor en los infectados (p < 0.05). En los grupos infectados hubo tambien una amplia variacion en la orientacion del eje electrico respecto del valor basal, acompanado de cambios morfologicos mas manifiestos emGR. La proporcion de lesion cardiaca detectada histologicamente en los grupos

[Effect of reinfection on the development of rats infected with Trypanosoma cruzi]. / Efecto de la reinfección sobre la evolución de ratas infectadas con Trypanosoma cruzi.

The present study was undertaken in order to demonstrate that reinfection could modify parasitemia, serum antibodies, electrocardiographic patterns and/or myocardial lesions already observed in a rat model. Experimental groups IG: rats infected at weaning with 1 x 10(6) T. cruzi; RG: same as IG plus reinoculations each 30 days until completion on day 150; IG1: 51 day old infected rats; C: controls. A high parasitemia was detected in IG and RG until day 20 showing a tendency to become negative on day 30. No parasites were observed in RG after the first reinoculation which could not be attributed to the old age of the host since there was no parasitemia in IG1. Xenodiagnosis were negative in all three groups. Serum antibodies were not significantly modified in RG in comparison with IG, except for 7S antibodies, since RG showed higher titres in some days under study. No distinct patterns of basal ECG were observed in infected rats. The ajmaline test reduced the heart rate (HR) showing no treatment dependence. The PR, QaT and QRS were significantly lengthened in all groups regarding the basal one (p less than 0.05), except for the QaT in C. Besides, the PR and QaT alterations were greater in the infected rats (p less than 0.05). There was also present a wide variety of electric axis orientations, regarding the basal value, accompanied by morphological changes more evident in the RG. The incidence of cardiac lesions histologically detected in the infected group was significantly higher than in C (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Caracterízación de los efectos del bitartrato de N-n-propil ajmalina: sobre las corrientes de sodio y calcio en células cardíacas aisladas / Characterization of the effects of N-n propyl ajmaline bitartrate on sodium and calcium currents in isolated cardiac cells

Los efectos de diferentes concentraciones de bitertrato de N-n propil ajmalina (BNPA), sintetizado en Cuba) sobre las corrientes de Na y Ca, fueron estudiados en células ventriculares aisladas de corazón de rana, con la técnica de patch-clamp. El BNPA redujo i en forma dependiente de la concentración. Esta reducción en i ocurrió con desplazamientos hacia las hiperpolarizaciones, en la curva de disponibilidad. Los resultados muestran que a concentraciones a las cuales el BNPA tiene efectos importantes sobre i Na, su acción antiarritmica esencial provoca un incremento en i Ca. Esto sugiere que a niveles terapéuticos, su acción carecería de inotropismo negativo. Se discute la importancia de estos resultados

The surface electrocardiogram: a simple and reliable method for detecting overt and latent heart disease in rats.

1. The following changes may be observed in the resting ECG of Wistar rats having different forms of heart disease: pathological Q wave, QRS deviations, lengthening of both P wave and QRS complex, increased PR interval and J point alterations. 2. The ajmaline test, when applied to rats with myocardial disease but with normal resting ECG, presented the following ECG alterations which were not observed in normal rats: indeterminate axis (QRS axis in the 3rd space), increased PR interval and lengthening of both P wave and QRS complex. 3. When compared with histopathological studies, the ECG changes have a high positive predictive value for detecting underlying myocardial disease. 4. The surface ECG can be a useful tool for detecting myocardial disease in different experimental models of rat heart disease. It can also be used to characterize rat models of heart disease and to evaluate treatment of experimental rat heart disease.

The surface electrocardiogram: a simple and reliable method for detecting overt and latent heart disease in rats

1. The following changes may be observed in the resting ECG of Wistar rats having different forms of heart disease: pathological Q wave, QRS deviations, lengthening of both P wave and QRS complex, increased PR interval and J point alterations. 2. The ajmaline test, when applied to rats with myocardial disease but with normal resting ECG, presented the following ECG alterations which were not observed in normal rats: indeterminate axis (QRS axis in the 3 rd space), increased PR interval and lengthening of both P wave and QRS complex. 3. When compared with histopathological studies, the ECG changes have a high positive predictive value for detecting underlying myocardial disease. 4. The surface ECG can be a useful tool for detecting myocardial disease in different experimental models of rat heart disease. It can also be used to characterize rat models of heart disease and to evaluate treatment of experimental rat heart disease