Masquerading bundle branch block obscuring the diagnosis of Brugada syndrome: an electrocardiographic and vectorcardiographic study.

We describe the induction of a masquerading bundle branch block in two patients with Brugada syndrome following the administration of Ajmaline. The development of this conduction disturbance prevented the correct electrocardiographic diagnosis. However, the simultaneously obtained vectocardiogram identified both the Brugada pattern and the masquerading bundle branch block.

Right bundle branch block and middle septal fiber block with or without left anterior fascicular block manifested as aberrant conduction in apparent healthy individuals: Electro-vectorcardiographic characterization.

BACKGROUND: Right bundle branch block (RBBB) evident in the precordial ECG leads may be associated with evidence of left bundle branch involvement in the limb leads. Any of the components of the left bundle can be involved, and this complex interventricular conduction abnormality has previously been described in patients with underlying heart disease. OBJECTIVES: To analyze the electro-vectorcardiographic manifestations of RBBB with left middle septal fiber block (LMSFB), with or without left anterior fascicular block (LAFB) in premature atrial beats of patients without apparent structural heart disease. METHODS: Twelve patients (8 men/4 women; mean age: 32±8years) with premature atrial contractions with this conduction abnormality were included. Surface 12 simultaneous lead ECG recordings and the corresponding vectorcardiographic loops were analyzed. RESULTS: The QRS complexes with RBBB and also LMSFB persisted for between 150 and 190ms. There were no q waves in lead I. The maximum spatial vector (72-86ms) was directed posteriorly, superiorly, and leftward, and the terminal forces were oriented anteriorly, inferiorly and rightward. In 10 patients, small q waves were apparent in leads V1-V2 and the frontal QRS axis was -60° and -70°, with the 46ms vector located at -50°±5. All of these patients most probably had LAFB in addition to LMSFB. In two patients, the initial electrical forces were directed anteriorly, inferiorly, and leftward, and the 46ms vector axis in the frontal plane was 6° and 11°, respectively, indicating absence of LAFB. CONCLUSIONS: The combination of RBBB and LMSFB occurring in patients without apparent structural heart disease may be related to the simultaneous occurrence of block of conduction through these components of the Purkinje network. The anterior fascicle of the left bundle may also be involved.

[Usefulness of pulsed Doppler tissue imaging in the early detection of diastolic myocardial abnormalities in first-degree relatives of patients with familial hypertrophic cardiomyopathy]. / Utilidad del Doppler pulsado tisular en la detección precoz de anormalidades diastólicas en familiares de primer grado de pacientes con miocardiopatía hipertrófica familiar.

INTRODUCTION AND OBJECTIVES: Doppler tissue imaging (DTI) enables regional myocardial function to be assessed irrespective of preload. Our aim was to determine the usefulness of DTI in healthy relatives of patients with familial hypertrophic cardiomyopathy. PATIENTS AND METHOD: We studied 47 first-degree relatives of patients with familial hypertrophic cardiomyopathy (group GI) and 47 normal subjects (group GII). Echocardiographic studies, including DTI, were performed in both groups. DTI was used to measure myocardial velocities during systole (S'), early diastole (E') and atrial contraction (A') at the mitral annulus, septum, and tricuspid annulus. Isovolumic relaxation and contraction times were corrected for heart rate. With DTI assessment of regional diastolic myocardial function and use of the E'/A' ratio, normal (i.e., E'/A'>1) and abnormal (i.e., E'/A'<1) diastolic function could be distinguished. RESULTS: There were no abnormalities in regional diastolic function in group GII (right E'/A' 1.78 (0.58), septum E'/A' 2.03 (0.53), and left E'/A' 2.55 (0.80). However, in group GI, two subgroup could be distinguished using E'/A' ratio values: group GIa comprised 37 first-degree relatives with normal diastolic function (right E'/A' 1.8 (0.44), septum E'/A' 2.07 (0.41), and left E/A 2.35 (0.6) who did not differ significantly from control subjects, and group GIb comprised 10 first-degree relatives with abnormal right diastolic function (right E'/A' 0.70 (0.28), P<.001) but with less significant differences at the septum (1.57 (0.49), P<.01) and mitral annulus (1.85 (0.53), P<.01). CONCLUSIONS: In 10 of 47 (21.3%) first-degree relatives of patients with familial hypertrophic cardiomyopathy, DTI enabled the detection of ventricular diastolic abnormalities, which were more evident in the right ventricle. They could be a preclinical manifestation of disease.

Utilidad del Doppler pulsado tisular en la detección precoz de anormalidades diastólicas en familiares de primer grado de pacientes con miocardiopatía hipertrófica familiar / Usefulness of pulsed doppler tissue imaging in the early detection of diastolic myocardial abnormalities in first-degree relatives of patients with familial hypertrophic cardiomyopathy

Introducción y objetivos. El Doppler pulsado tisular (DPT) permite analizar la función miocárdica regional independientemente de la precarga. Se realizó DPT a los familiares de primer grado de pacientes con miocardiopatía hipertrófica familiar (MHF) para detectar anormalidades precoces. Pacientes y método. Se estudió a 47 familiares de primer grado de pacientes con MHF (grupo GI) y se los comparó con un grupo control de 47 sujetos normales (grupo GII). Se realizó ecocardiografía 2D y Doppler pulsado de los flujos mitral y tricuspídeo. Mediante DPT en la pared lateral del ventrículo izquierdo, el ventrículo derecho y el septo interventricular se midieron las velocidades pico S', E' y A' y los períodos de relajación y contracción isovolumétricos. Se consideró función diastólica regional normal a una relación E'/A' > 1 y disfunción diastólica a una relación E'A'< 1. Resultados. No hubo alteraciones de la relajación ventricular en el GII (E'A' derecho, 1,78 ± 0,58; septo, 2,03 ± 0,53; izquierdo, 2,55 ± 0,80), mientras que en el GI la relación E'/A' permitió diferenciar 2 subgrupos: GIa de 37 familiares de primer grado que presentaron patrón de relajación normal (E'/A' derecho, 1,8 ± 0,44; septo, 2,07 ± 0,41; izquierdo, 2,35 ± 0,6, sin diferencias significativas con el grupo control) y GIb de 10 familiares de primer grado con relajación prolongada en el ventrículo derecho (E'/A', 0,70 ± 0,28; p < 0,001), con menor tendencia significativa en el septo (1,57 ± 0,49; p < 0,01) y el lateral izquierdo (1,85 ± 0,53; p < 0,01). Conclusiones. En familiares de primer grado de pacientes con MHF, el DPT permitió diferenciar anormalidades de la relajación ventricular en 10 de los 47 casos (21,3%), más manifiestas en el ventrículo derecho, que podrían ser un marcador preclínico de la enfermedad

Introduction and objectives. Doppler tissue imaging (DTI) enables regional myocardial function to be assessed irrespective of preload. Our aim was to determine the usefulness of DTI in healthy relatives of patients with familial hypertrophic cardiomyopathy. Patients and method. We studied 47 first-degree relatives of patients with familial hypertrophic cardiomyopathy (group GI) and 47 normal subjects (group GII). Echocardiographic studies, including DTI, were performed in both groups. DTI was used to measure myocardial velocities during systole (S'), early diastole (E') and atrial contraction (A') at the mitral annulus, septum, and tricuspid annulus. Isovolumic relaxation and contraction times were corrected for heart rate. With DTI assessment of regional diastolic myocardial function and use of the E'/A' ratio, normal (i.e., E'/A'>1) and abnormal (i.e., E'/A'<1) diastolic function could be distinguished. Results. There were no abnormalities in regional diastolic function in group GII (right E'/A' 1.78 (0.58), septum E'/A' 2.03 (0.53), and left E'/A' 2.55 (0.80). However, in group GI, two subgroup could be distinguished using E'/A' ratio values: group GIa comprised 37 first-degree relatives with normal diastolic function (right E'/A' 1.8 (0.44), septum E'/A' 2.07 (0.41), and left E/A 2.35 (0.6) who did not differ significantly from control subjects, and group GIb comprised 10 first-degree relatives with abnormal right diastolic function (right E'/A' 0.70 (0.28), P<.001) but with less significant differences at the septum (1.57 (0.49), P<.01) and mitral annulus (1.85 (0.53), P<.01). Conclusions. In 10 of 47 (21.3%) first-degree relatives of patients with familial hypertrophic cardiomyopathy, DTI enabled the detection of ventricular diastolic abnormalities, which were more evident in the right ventricle. They could be a preclinical manifestation of disease

[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.

Muerte súbita ambulatoria / Ambulatory sudden death

Se seleccionaron en forma retrospectiva 12 registros de muerte súbita ambulatoria. Se analizaron las arritmias causantes de la muerte súbita, las alteraciones del ritmo y del electrocardioograma que la precedieron y las circunstancias en las que ocurrió. En diez pacientes (83,33 por ciento) la muerte súbita se debió a fibrilación ventricular, precedida en 6 por taquicardia ventricular sostenida, en 2 por torsades de pointes y en los otros 2 pacientes la fibrilación ventricular fue la única arritmia. Dos pacientes fallecieron en bradiarritmia (16,66 por ciento), uno en asistolia y el otro en disociación electromecánica. Las taquiarritmias ventriculares son la causa más común de muerte súbita ambulatoria

Muerte súbita ambulatoria / Ambulatory sudden death

Se seleccionaron en forma retrospectiva 12 registros de muerte súbita ambulatoria. Se analizaron las arritmias causantes de la muerte súbita, las alteraciones del ritmo y del electrocardioograma que la precedieron y las circunstancias en las que ocurrió. En diez pacientes (83,33 por ciento) la muerte súbita se debió a fibrilación ventricular, precedida en 6 por taquicardia ventricular sostenida, en 2 por torsades de pointes y en los otros 2 pacientes la fibrilación ventricular fue la única arritmia. Dos pacientes fallecieron en bradiarritmia (16,66 por ciento), uno en asistolia y el otro en disociación electromecánica. Las taquiarritmias ventriculares son la causa más común de muerte súbita ambulatoria (AU)