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.