Non-invasive assessment of endothelial function. Intra and inter-observer variability

BACKGROUND AND OBJECTIVES: Non-invasive evaluation of endothelial function with high resolution ultrasound has become a widely accepted tool in determination of high risk subjects for early atherosclerosis. Despite its simple appearance, ultrasonographic assessment of brachial artery changes, is technically challenging and has a significant learning curve. In the present study, we evaluate the intra and inter-observer variability in assessing peripheral endothelial function with high resolution ultrasound at a tertiary referral center. METHODS: Assessment of endothelial function was performed by 2 physicians in 20 volunteers without evidence of coronary artery disease. Endothelial function is evaluated with a high frequency bidimensional ultrasound with a 10.0-MHz linear-array transducer used for the study. Each volunteer was examined by both observers using an identical protocol, measuring brachial artery diameter on three occasions. RESULTS: Excellent correlation was observed for all brachial artery measures with a Spearman's correlation coefficient > 0.9 (p < 0.0001). Flow-mediated dilation (FMD) in the study population was of 10.45+/-6.9%. Flow independent dilation (FID) was of 24.35+/-7.63%. Intra-observer variability was of 2.1% for observer A and 1.1 % for observer B. CONCLUSIONS: Non-invasive assessment of endothelial function using brachial artery ultrasound is reproducible and can be performed with low intra and inter-observer variability.

Utilidad de la adenosina para evidenciar bloqueo auriculoventricular avanzado paroxÝstico como causa de sÝncope / Usefulness of adenosine to detect advanced paroxysmal atrioventricular block as a cause of syncope

We present the case of a 66 years old man with recurrent episodes of syncope, up to three times during the last two months without previous symptoms. An ECG after the syncope showed a bilateral block (left anterior fascicle block and right bundle branch block) and first grade atrioventricular block. The exercise test did not demonstrate either AV conduction disorders or tachyarrhythmia episodes. Holter monitoring showed premature ventricular complexes; tilt testing and carotid sinus massage were normal. The electrophysiologic study revealed no alteration in the conduction system. Throughout atrial and ventricular stimulation documented no tachyarrhythmias. However, intravenous administration of 12 mg of adenosine induced complete AV infra-His block with ventricular asystolia of 7.2 sec duration. Adenosine testing can identify patients with syncope due to paroxysmal AV block even when the electrophysiological findings and other conventional tests are not conclusive.

Seguimiento de un grupo de pacientes con desfibrilador automßtico implantable / Follow-up of a group of patients with automatic implantable defibrillator

The automatic implantable defibrillator (AID) is the treatment of choice for primary and secondary prevention of sudden death. At the Instituto Nacional de CardiologÝa, since October 1996 until January 2002, 25 patients were implanted with 26 AID. There were 23 men (92) and the mean age of the whole group, was 51.4 years. Twenty-three patients (92) presented structural heart disease, the most common was ischemic heart disease in 13 patients (52), with a mean ejection fraction of 37.8. One patient without structural heart disease had Brugada Syndrome. The most frequent clinical arrhythmia was ventricular tachycardia in 14 patients (56). The mean follow-up was of 29.3 months during which a total of 30 events of ventricular arrhythmia were treated through AID; six of them were inappropriate due to paroxismal atrial fibrillation; 10 AID patients (34) have not applied for therapy. Three patients (12) of the group died due to congestive heart failure refractory to pharmacologic treatment. CONCLUSION: The implant of the AID is a safe and effective measure for primary and secondary prevention of sudden death. World-wide experience evidences, that this kind of device has not modified the mortality rate due to heart failure in these patients, but it has diminished sudden arrhythmic death.

Desenmascaramiento del "síndrome de Brugada" con propafenona endovenosa / Disclosure of

We present the case of a woman with familial antecedents of a brother who died suddenly at the age of 39 years, and an other with Brugada syndrome. The ECG had not shown the typical pattern of the Brugada syndrome. Based on these antecedents, we decided to perform a pharmacological test with endovenous propafenone, which revealed the electrocardiographic alterations at 10 min after the administration. This is the first case in our knowledge in which endovenous propafenone manifested a concealed Brugada syndrome.