Brugada syndrome: Eligibility for subcutaneous implantable cardioverter-defibrillator after exercise stress test.

INTRODUCTION: Brugada syndrome (BrS) is a channelopathy associated with ventricular arrhythmias and sudden cardiac death. In patients at high risk of sudden death, an implantable cardioverter-defibrillator is indicated. Subcutaneous implantable cardioverter-defibrillators (S-ICDs) are an alternative to transvenous systems, with reduced risk of infection and complications associated with system extraction or explantation. OBJECTIVE: To test electrocardiographic eligibility for S-ICD placement after exercise stress testing (EST) in patients with BrS. METHODS: The sample included 35 consecutive patients with BrS. Electrocardiographic eligibility was assessed using the Boston Scientific model 2889 EMBLEM™ S-ICD automated screening tool, in four phases: decubitus and orthostatism, and before and after EST. Those who had at least one acceptable vector in the four measurements were considered eligible. RESULTS: In this study, 71.4% of patients were male and mean age was 53.86±12 years. In screening prior to EST, 14.3% of patients (n=5) were not eligible for an S-ICD. There was a statistically significant association between ineligibility and presence of complete right bundle branch block and history of syncope. After EST, 16.7% of initially eligible patients no longer had eligible vectors (n=5). CONCLUSION: In this study, 16.7% of patients previously eligible for an S-ICD were no longer eligible after EST. This result demonstrates the importance of screening after EST in all patients with BrS and with indication for an S-ICD, and may influence decisions concerning which ICD to implant or whether to institute pharmacological measures that avoid inappropriate therapies.

Importance of cardiac implantable eletronic devices in the diagnosis of Sleep Apnea Syndrome. / Importância dos dispositivos eletrónicos cardíacos implantáveis no diagnóstico da Síndrome da Apneia do Sono.

INTRODUCTION: Sleep Apnea Syndrome (SAS) is a prevalent respiratory disease with marked expression in the population with cardiovascular disease. The diagnosis is based on polysomnography. In patients with cardiac implantable electronic devices (CIED), the prevalence of SAS may reach 60%. The objective of this study was to evaluate the value of DEC in the SAS screening. METHODS: Prospective study that included patients with CIED with sleep apnea algorithm. The frequency response function was activated and simplified polygraphy was performed. The data of the device were collected on the day of the polygraph. RESULTS: The sample included 29 patients, with a mean age of 76.1 years, 71.4% of the male gender. The prevalence of SAS was 77%. For SAS, the agreement between polysomnography and the Pacemaker was Kappa = 0.54 (p = 0.001), 95% CI (0.28, 0.81) (moderate agreement); for moderate to severe SAS, the agreement was Kappa = 0.73 (p <0.001), 95% CI (0.49, 0.976) (substantial agreement). Severe SAS was obtained: sensitivity 60%, specificity 100%, positive predictive value 100%, negative predictive value 60% and diagnostic accuracy 75%; for moderate to severe SAS: sensitivity of 90%, specificity of 83%, positive predictive values of 90% and negative of 87.5%, with a diagnostic accuracy of 87.5%. CONCLUSION: SAS is highly prevalent in patients with CIED. The values obtained through these devices have a strong positive correlation with the Apnea-Hypopnea Índex, which makes them a good tool for the screening of severe SAS.

RIVER: Portuguese registry to monitor unnecessary right ventricular pacing.

The aim of this prospective registry is to evaluate a new algorithm designed to reduce the percentage of unnecessary ventricular pacing (%VP) in patients implanted with a dual-chamber pacemaker, through a dedicated pacing mode (called AAISafeR2) operating in AAI mode with back-up ventricular pacing in DDD mode, and to describe the incidence and distribution of atrioventricular (AV) block in this population. Investigators were free to assign patients to AAISafeR2 mode or to standard DDD (if AAISafeR was contraindicated, mainly due to permanent high-degree AV block). Patients underwent routine follow-up visits at 3, 6, 12, 18 and 24 months after implantation. At each follow-up visit, data were retrieved from pacemaker memories and analyzed to extract %VP and incidence of AV block. Up to December 2006, 158 patients (94 men, mean age 69 +/- 14 years) from nine Portuguese centers had been consecutively included. We also determined the distribution of AV block (according to the criteria used by the pacemaker to classify AV block and switch to DDD mode). AAISafeR was shown to be effective in reducing unnecessary VP in our patient population. The analysis also reveals a high incidence of paroxysmal AV block, often unknown at the time of implantation. There were no complications associated with AAISafeR programming.

Use of an implantable loop recorder: initial experience.

OBJECTIVE: Retrospective analysis of the initial experience at our department with an implantable loop recorder (ILR) for the evaluation of patients with recurrent syncope, palpitations or dizziness. METHODS: We studied ten patients aged 31-65 (52.3) years referred to our center after an inconclusive evaluation that included ECG, Holter monitoring, events recorder, stress test, echocardiogram and electrophysiological study. Seven patients had structural heart disease. We used a Reveal Plus (Medtronic, USA) ILR, which allows up to 41 minutes of electrocardiographic recording, over a period of 24 months, patient or device activated, according to the programmed parameters. Follow-up was scheduled every three months or after every event activated by the patient. Symptoms and recorded events were analyzed. RESULTS: Eight patients activated events, out of a total of 45 episodes, and five patients reported two or more symptoms. Dizziness was reported by five patients (24 episodes), palpitations by three (seven episodes), syncope by three (seven episodes) and nonspecific symptoms by five patients (seven episodes). The first symptom occurred between the twelfth day and the sixth month after implantation. Four episodes (three syncope and one dizziness) occurred with significant AV conduction disturbance (complete or high grade AV block) and in 41 episodes no rhythm or AV disturbance was recorded. Thirty events were automatically activated. There were no device-related complications. None of the patients died during follow-up.