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Biomedical subjects

Sergio Dubner

Publications and source records attributed to Sergio Dubner.

5 recordsLinked to original sources
PubMed2005

Is there an overlap between Brugada syndrome and arrhythmogenic right ventricular cardiomyopathy/dysplasia?

The Brugada syndrome is a congenital syndrome displaying an autosomal dominant mode of transmission in patients with a structurally normal heart. The disease has been linked to mutations in SCN5A , a gene located on the short arm of chromosome 3 (p21-24) that encodes for the alpha subunit of the sodium channel. The syndrome is characterized by a dynamic ST-segment elevation (accentuated J wave) in leads V 1 to V 3 of the ECG followed by negative T wave. Right bundle-branch block of varying degrees is observed in some patients. The syndrome is associated with syncope and a relatively high incidence of sudden cardiac death secondary to the development of polymorphic ventricular tachycardia that may degenerate into ventricular fibrillation. An acquired form of the Brugada syndrome is also recognized, caused by a wide variety of drugs and conditions that alter the balance of currents active during the early phases of the action potential. Among patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia, there is a subpopulation with a clinical and electrocardiographic pattern similar to that of the Brugada syndrome. These cases of arrhythmogenic right ventricular cardiomyopathy/dysplasia are thought to represent an early or concealed form of the disease. This review examines the overlap between these 2 syndromes.

Arrhythmogenic Right Ventricular Dysplasia↗
PubMed2005

Electromagnetic interference with implantable cardiac pacemakers by video capsule.

BACKGROUND: Electromagnetic fields, such as those generated by cellular phones and metal detectors, may interfere with normal pacemaker function. However, it remains unclear whether the wireless capsule endoscope interacts with implanted pacemakers. This prospective study evaluated potential interactions between the M2A video capsule (Given Imaging, Yoknam, Israel) and implanted pacemakers. METHODS: A total of 100 consecutive patients (70 men, 30 women) with an implanted pacemaker (95 on bipolar mode) were studied. The testing was performed with a functional testing device (Test Cap) for the Given Diagnostic System that reproduces the effect of the video capsule by transmitting at exactly the same frequency. During continuous electrocardiographic monitoring and recording, 100 tests were carried out without changing the pacemaker settings. Those with a positive result were retested 1 week later. RESULTS: The 100 pacemakers evaluated in the study population included the following: 70 dual chamber (11 DDD, 56 DDDR, 3 VDD) and 30 ventricular inhibited (12 VVI, 18 VVIR). In 4 of the 100 patients, pacemaker interference (noise-mode function forcing a synchronous mode) was registered during the Test Cap operation. Three patients had a dual-chamber pacemaker, and one had a single-chamber pacemaker. The interference was reproducible in all cases 1 week later. None of the implanted pacemakers tested was affected by oversensing. CONCLUSIONS: Electromagnetic interferences with pacemakers from the M2A video capsule can occur, but this is without clinical significance. No potentially dangerous pacemaker inhibition was observed.

Adult↗
PubMed2005

A Latin American registry of implantable cardioverter defibrillators: the ICD-LABOR study.

OBJECTIVE: Despite the progress that has been reached in emergency medical systems and resuscitation, sudden cardiac death (SCD) continues to be the major cause of the death, and remains a significant public health problem. In this publication we are reporting our Latin American experience in the secondary prevention of SCD, by means of an ongoing registry involving seven Latin American countries and 770 patients. METHODS: Every individual within the present registry to date has presented with antecedents of aborted sudden death or cardiac arrest due to ventricular tachycardia or ventricular fibrillation. Patients included have fulfilled the Class I indication for implantable cardioverter defibrillator (ICD) and they were implanted with a Biotronik ICD (all models). The study was not sponsored by Biotronik, nor did they have access to the data. A specific protocol was designed for implantation and follow-up of patients. The database was completely registered through the Internet and a personal password was assigned to each group of investigators. The primary end point was death from all causes. Secondary end points were SCD and death due to congestive heart failure (CHF). RESULTS: The etiology of cardiac disease was found to be predominantly coronary artery disease (CAD) 39.7% (306 patients), followed by Chagas disease (ChD), 26.1% (201 patients), and idiopathic dilated cardiomyopathy (DCM), 17% (131 patients). Any remaining pathologies were included as miscellaneous 13.2% (101 patients). In 31 patients (4%) the etiology was unknown. The age did not differ within the principal pathologies, but was significantly older than the miscellaneous group (62.0 +/- 11.3 years vs 48.2 +/- 18.9 years, P < 0.0001). The follow-up period was 27 +/- 25 months (1-113 months) for the whole group. The mortality in functional classes I-II was significantly lower than mortality for functional classes III-IV (relative risk 1.46, CI 95%, P < 0.0001). Mean left ventricular ejection fraction (LVEF) for the whole group was 37.7 +/- 14.3%. Male LVEF was 36.1 +/- 14.1% and female LVEF was 42.2 +/- 13.8% P < 0.0001. During the follow-up period, 130 deaths were reported (global mortality 16.9 +/- 9.7%), out of which 84 (64.6%) were attributed to cardiac causes (10.9 +/- 5.1% of the total population). The annual adjusted cardiac mortality was 5.2 +/- 1.72% (range 3.5-7.0%). Among cardiac deaths the most common cause was progressive heart failure, 48 patients (57%) including 3 patients with pulmonary embolism. The second main cause of cardiac death was SCD, 36 patients (43%), including 4 patients with electrical storm and 3 patients with electromechanical dissociation after multiple shock therapy treatments. CONCLUSIONS: Despite the differences in terms of pathologies between the ICD-LABOR (Latin American bioelectronic ongoing registry) and randomized ICD trials, a parallel evolution in all cause mortality and cardiac mortality was observed. Independent risk factors for mortality included age >70 years, male gender, NYHA III/IV, and ejection fraction <0.30. The etiology of heart disease (Chagas vs Coronary Disease) was not found to be a risk factor.

Arrhythmias, Cardiac↗