Publications by authors named "Ronald Pachon"

Background The WATCHMAN™ device is a Food and Drug Administration (FDA)-approved device that reduces the risk of stroke from atrial fibrillation (AF) in those who have a contraindication to taking oral anticoagulation. A key aspect of this device implantation is the choice of medical therapy in the months after device implantation with Vitamin K antagonist oral anticoagulants (OAC) being the mainstay of therapy but dual antiplatelet therapy (DAPT) poses as a potential alternative to patients who have a contraindication to OAC use. Methods Our single-center study retroactively followed 150 patients post-WATCHMAN™ implantation and evaluated outcomes at 12 months post-implantation in two cohorts, those treated with OAC or DAPT.

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Sarcolipin (SLN) is an inhibitor of sarco/endoplasmic reticulum (SR) Ca-ATPase (SERCA) and expressed at high levels in the ventricles of animal models for and patients with Duchenne muscular dystrophy (DMD). The goal of this study was to determine whether the germline ablation of SLN expression improves cardiac SERCA function and intracellular Ca (Ca) handling and prevents cardiomyopathy in the mouse model of DMD. Wild-type, , SLN-haploinsufficient (), and SLN-deficient () mice were used for this study.

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Background: Electrophysiologists have developed a computational mapping approach to localize sources that may perpetuate persistent atrial fibrillation (AF). Focal impulse and rotor modulation (FIRM)-guided ablation of these sources have produced variable results. The current study further assesses single-procedure success rates of FIRM-guided ablation for preventing AF or atrial tachyarrhythmia recurrence and analyzes different baseline characteristics as prognostic indicators for individuals experiencing these undesired outcomes.

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Sarcolipin (SLN) is an inhibitor of the sarco/endoplasmic reticulum (SR) Ca ATPase (SERCA) and is abnormally elevated in the muscle of Duchenne muscular dystrophy (DMD) patients and animal models. Here we show that reducing SLN levels ameliorates dystrophic pathology in the severe dystrophin/utrophin double mutant (mdx:utr ) mouse model of DMD. Germline inactivation of one allele of the SLN gene normalizes SLN expression, restores SERCA function, mitigates skeletal muscle and cardiac pathology, improves muscle regeneration, and extends the lifespan.

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A Food and Drug Administration-approved antiviral agent, known as vidarabine or adenine 9-β-D-arabinofuranoside (AraA), has features of inhibiting adenylyl cyclase type 5 (AC5) and protects against chronic coronary artery occlusion (CAO). The goal of this investigation was to determine whether AraA protects against myocardial ischemia, even when delivered after coronary artery reperfusion (CAR). AraA, delivered after CAR in wild-type mice, reduced infarct size by 55% compared with vehicle-treated controls, whereas an equal dose of adenosine reduced infarct size only when administered before CAR.

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The most important physiological mechanism mediating enhanced exercise performance is increased sympathetic, beta adrenergic receptor (β-AR), and adenylyl cyclase (AC) activity. This is the first report of decreased AC activity mediating increased exercise performance. We demonstrated that AC5 disruption, that is, knock out (KO) mice, a longevity model, increases exercise performance.

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Objective: Stimulation of cardiac α1A-adrenergic receptors (α1A-AR) has been proposed for treatment of heart failure, since it increases myocardial contractility. We investigated a different mechanism, induction of angiogenesis.

Approach And Results: Four to 6 weeks after permanent coronary artery occlusion, transgenic rats with cardiomyocyte-specific α1A-adrenergic receptor overexpression had less remodeling than their nontransgenic littermates, with less fibrosis, hypertrophy and lung weight, and preserved left ventricular ejection fraction and wall stress (all P<0.

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Mice with disruption of adenylyl cyclase type 5 (AC5 knockout, KO) live a third longer than littermates. The mechanism, in part, involves the MEK/ERK pathway, which in turn is related to protection against oxidative stress. The AC5 KO model also protects against diabetes, obesity, and the cardiomyopathy induced by aging, diabetes, and cardiac stress and also demonstrates improved exercise capacity.

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Our review of the literature of the major cardiovascular journals for the past three years showed that for all studies using anesthesia for mouse echocardiography, the predominant anesthetic was isoflurane, which was used in 76% of the studies. The goal of this investigation was to determine if isoflurane is indeed the best anesthetic. Accordingly, we compared isoflurane with 2,2,2-tribromoethanol (Avertin), ketamine-xylazine, and ketamine on different days in the same 14 mice, also studied in the conscious state without anesthesia.

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The functional importance of threonine 5 (T5) in modulating the activity of sarcolipin (SLN), a key regulator of sarco/endoplasmic reticulum (SR) Ca2+ ATPase (SERCA) pump was studied using a transgenic mouse model with cardiac specific expression of threonine 5 to alanine mutant SLN (SLNT5A). In these transgenic mice, the SLNT5A protein replaces the endogenous SLN in atria, while maintaining the total SLN content. The cardiac specific expression of SLNT5A results in severe cardiac structural remodeling accompanied by bi-atrial enlargement.

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Sudden cardiac death in 5-10% of cases is explained by patients with congenital abnormalities that include coronary artery malformations such as anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA). We report a case of sudden cardiac death as the first presentation of ALCAPA in a young female with no history of hypertrophic cardiomyopathy.

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