Publications by authors named "Marco Mercader"

In January 2020, the first Medtronic VDD leadless pacemaker Micra AV was approved by FDA to treat patients with advanced AV block, based on the encouraging results from the Micra Atrial tRacking using a Ventricular accELerometer 2 (MARVEL 2). There is reassuring data about safety and short-term outcomes of traditional leadless pacemaker implant after recent surgical tricuspid valve replacement, but only few cases are reported in literature. No data was found regarding AV Micra implant safety and outcomes in patients following bioprosthetic tricuspid valve replacement as of today.

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To study the outcomes of a series of consecutive tilt table tests combined with video-EEG (TTVE) at a single center, and assess their cost-effectiveness compared with other neurophysiological tests. We retrospectively reviewed medical records of patients who underwent TTVE studies between March 1, 2013 to April 1, 2018. Detailed clinical history, including patient demographics, reasons for referral, anti-seizure medications, and neurophysiological studies obtained prior to the TTVE studies were extracted from chart reviews.

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Background: Atrial fibrillation is the most commonly encountered sustained arrhythmia and is associated with significant morbidity and mortality. Several trials have demonstrated that no mortality benefit exists when choosing a rhythm-control strategy over a rate-control strategy, with some trials suggesting an increase in mortality. Using the AFFIRM trial database we sought to determine the effect of rhythm control strategy in patients with normal or mild atrial enlargement.

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Transcatheter aortic valve implantation (TAVI) is an acceptable treatment for severe aortic stenosis in high or intermediate risk patients. Conduction abnormalities are a known complication of TAVI. Most abnormalities occur perioperatively but can develop later.

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Junctional ectopic tachycardia (JET) and atrial fibrillation (AF) occur in patients recovering from open-heart surgery (OHS). Pharmacologic treatment is used for the control of post-operative atrial arrhythmias (POAA), but is associated with side effects. There is a need for a reversible, modulated solution to rate control.

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Background: Currently, there are limited means for high-resolution monitoring of tissue injury during radiofrequency ablation procedures.

Objective: To develop the next generation of visualization catheters that can reveal irreversible atrial muscle damage caused by ablation and identify viability gaps between the lesions.

Methods: Radiofrequency lesions were placed on the endocardial surfaces of excised human and bovine atria and left ventricles of blood perfused rat hearts.

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Radiofrequency ablation (RFA) is a widely used treatment for atrial fibrillation, the most common cardiac arrhythmia. Here, we explore autofluorescence hyperspectral imaging (aHSI) as a method to visualize RFA lesions and interlesional gaps in the highly collagenous left atrium. RFA lesions made on the endocardial surface of freshly excised porcine left atrial tissue were illuminated by UV light (365 nm), and hyperspectral datacubes were acquired over the visible range (420-720 nm).

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Background: Percutaneous cryoballoon ablation is a commonly used procedure to treat atrial fibrillation. One of the major limitations of the procedure is the inability to directly visualize tissue damage and functional gaps between the lesions. We seek to develop an approach that will enable real-time visualization of tissue necrosis during cryo- or radiofrequency ablation procedures.

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Background: Supraventricular arrhythmias (junctional ectopic tachycardia [JET] and atrial tachyarrhythmias) frequently complicate recovery from open heart surgery in children and can be difficult to manage. Medical treatment of JET can result in significant morbidity. Our goal was to develop a nonpharmacological approach using autonomic stimulation of selective fat pad (FP) regions of the heart in a young canine model of open heart surgery to control 2 common postoperative supraventricular arrhythmias.

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Objective: Junctional ectopic tachycardia complicates the postoperative recovery from open heart surgery in children. The reported risk factors include younger age, prolonged cardiopulmonary bypass times, and administration of inotropic agents. Junctional ectopic tachycardia occurs early after open heart surgery, in the setting of relative postoperative sinus node dysfunction, and exhibits QRS morphology consistent with an origin from the atrioventricular node or proximal conduction system.

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Radiofrequency ablation (RFA) aims to produce lesions that interrupt reentrant circuits or block the spread of electrical activation from sites of abnormal activity. Today, there are limited means for real-time visualization of cardiac muscle tissue injury during RFA procedures. We hypothesized that the fluorescence of endogenous NADH could be used as a marker of cardiac muscle injury during epicardial RFA procedures.

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A 65-year-old male with an ischaemic cardiomyopathy and an implantable cardioverter defibrillator got a shock at home. A web-based monitoring system was used to check his device, and the interrogation showed that he had had several episodes of ventricular fibrillation and new onset of complete heart block that required back-up pacing by his defibrillator. The combination of enhanced automaticity (frequent premature ventricular complexes and ventricular arrhythmias) and impaired conduction (heart block) are the hallmarks of digitalis toxicity.

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Tricuspid stenosis secondary to ventricular pacemaker leads is uncommon. We present a unique case of iatrogenic tricuspid stenosis secondary to fusion of the valve leaflets to transvenous implanted pacing leads. This occurred in an adult with childhood repaired Tetralogy of Fallot and high grade surgical heart block following multiple pacemaker procedures.

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Objective: To determine the health-care resource use and costs attributable to treating atrial fibrillation (AF) in the United States.

Methods: Retrospective analyses of three federally funded US databases (2001 data): 1) hospital inpatient stays (the Healthcare Cost and Utilization Project [HCUP]); 2) physician office visits (the National Ambulatory Medical Care Survey [NAMCS]); and 3) emergency department (ED) and hospital outpatient department visits (OPD) (the National Hospital Ambulatory Medical Care Survey [NHAMCS]). Identification of AF medical encounters was based on occurrence of AF-specific International Classification of Diseases (9th Edition)--Clinical Modification (ICD-9-CM) diagnosis code 427.

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