RESUMEN
We study the wrinkle patterns obtained when applying a thin polymeric film on a uniaxially prestretched soft foundation. The film is coated onto a substrate where it drains under the action of gravity, thereby introducing a continuous variation in its thickness. We first study the fluid mechanics component of the problem and derive the coating profile as a function of the curing properties of the polymeric solution. Upon polymerization, the prestretch is released and yields the formation of wrinkles, which are arranged in organized patterns, including fractals. We study a variety of scenarios depending on the relative orientation of the gradient of film thickness and the stretching direction. In particular, we characterize and rationalize the distribution of singular events in our problem where wrinkles merge to allow a variation of the average value of the wrinkle wavelength across the sample.
RESUMEN
Bacteria entering the bloodstream via translocation from the gastrointestinal tract spread hematogenously and can trigger bacterial chondronecrosis with osteomyelitis (BCO) by infecting osteochondrotic microfractures in the epiphyseal-physeal cartilage of the proximal femora and tibiae. In experiment 1, broilers were fed control feed or the same feed containing BacPack 2X, which includes the prebiotic IMW50 (a mannan oligosaccharide beta-glucan yeast cell wall product) plus the probiotic Calsporin (Bacillus subtilis C-3102). Broilers reared on wire flooring consistently developed higher incidences of BCO than hatchmates reared on wood shavings litter (≥24 vs. ≤4%, respectively; P=0.001). Adding BacPack 2X to the feed on d 1 through 56 delayed the age of onset and reduced the cumulative incidence of BCO on wire flooring when compared with broilers fed the control feed (24.0 vs. 40.7%, respectively; P=0.003). In experiment 2, broilers reared on wire flooring received tap water on d 1 through 62 (control group) or therapeutic levels of the potent fluoroquinolone antimicrobial enrofloxacin in the water on d 35 through 54 (enrofloxacin group). During enrofloxacin administration, half as many birds developed BCO in the enrofloxacin group when compared with the control group (8.1 vs. 19.5%, respectively, on d 35 through 54; P=0.001), whereas both groups had similar BCO incidences subsequent to withdrawing enrofloxacin on d 55 through 62 (14.8 vs. 18.2% for the enrofloxacin vs. control groups; P=0.386). Cumulative lameness incidences for d 1 through 62 were higher for the control group than for the enrofloxacin group (39.0 vs. 25.8%, respectively; P=0.003). These results demonstrate that wire flooring imposes a rigorous challenge that leads to high incidences of BCO that can be difficult to suppress, even with therapeutic doses of enrofloxacin. Prophylactically adding BacPack 2X to the feed reduced the incidence of BCO lameness by a proportion similar to that achieved with enrofloxacin, indicating that probiotics potentially can provide effective alternatives to antibiotics for reducing BCO lameness attributable to bacterial translocation and hematogenous distribution.
Asunto(s)
Antibacterianos/uso terapéutico , Profilaxis Antibiótica/veterinaria , Pollos , Cojera Animal/tratamiento farmacológico , Osteomielitis/veterinaria , Enfermedades de las Aves de Corral/tratamiento farmacológico , Animales , Enrofloxacina , Pisos y Cubiertas de Piso , Fluoroquinolonas/uso terapéutico , Vivienda para Animales , Incidencia , Cojera Animal/epidemiología , Cojera Animal/microbiología , Masculino , Necrosis/tratamiento farmacológico , Necrosis/epidemiología , Necrosis/microbiología , Necrosis/veterinaria , Osteomielitis/tratamiento farmacológico , Osteomielitis/epidemiología , Osteomielitis/microbiología , Enfermedades de las Aves de Corral/epidemiología , Enfermedades de las Aves de Corral/microbiología , Prebióticos/análisis , Probióticos/uso terapéuticoAsunto(s)
Complejos Atriales Prematuros/fisiopatología , Sistema de Conducción Cardíaco/fisiopatología , Taquicardia por Reentrada en el Nodo Atrioventricular/fisiopatología , Potenciales de Acción , Adulto , Complejos Atriales Prematuros/diagnóstico , Complejos Atriales Prematuros/cirugía , Ablación por Catéter , Electrocardiografía , Técnicas Electrofisiológicas Cardíacas , Femenino , Sistema de Conducción Cardíaco/cirugía , Frecuencia Cardíaca , Humanos , Taquicardia por Reentrada en el Nodo Atrioventricular/diagnóstico , Taquicardia por Reentrada en el Nodo Atrioventricular/cirugíaAsunto(s)
Aneurisma de la Aorta Torácica/diagnóstico , Disección Aórtica/diagnóstico , Dolor en el Pecho/etiología , Infarto del Miocardio/diagnóstico , Troponina/sangre , Disección Aórtica/complicaciones , Aneurisma de la Aorta Torácica/complicaciones , Biomarcadores/sangre , Toma de Decisiones , Diagnóstico Diferencial , Electrocardiografía , Humanos , Masculino , Persona de Mediana Edad , Tomografía Computarizada por Rayos XRESUMEN
BACKGROUND: Pacing lead-related tricuspid regurgitation (TR), a recognized complication of ventricular pacing lead implantation, may be affected by lead position or diameter. OBJECTIVE: This study sought to determine the effect of ventricular pacing lead position and diameter on pacing lead-related TR. METHODS: A randomized prospective trial compared pacing leads in the right ventricular apex (RVA), right ventricular septum (RVS), or left ventricle via the coronary sinus (LV-CS) in a 1:1:1 fashion. Patients undergoing implantable cardioverter-defibrillator lead implantation in the RVA (RVA-ICD) were enrolled in a comparison group. Patients with preexisting moderate or greater TR were excluded. Prospective clinical evaluation, transthoracic echocardiograms, and device interrogation occurred 24 hours and 12 months after device implantation. RESULTS: Sixty-three patients undergoing pacemaker implantation were randomized to RVA, RVS, or LV-CS pacing, and 48 RVA-ICD patients were enrolled as a comparison group. At 12 months, 6 patients (6.4%) developed moderate or greater TR. Moderate or greater TR was not significantly different between groups if analyzed by intention to treat (RVA 5.9%, RVS 10.0%, LV-CS 6.7%, and RVA-ICD 4.8%) or if analyzed by final lead location (RVA 4.8%, RVS 10.5%, LV-CS 8.3%, and RVA-ICD 5.1%). Ventricular lead-related complications occurred in 3 patients with right ventricular leads (3.2%) and 2 patients with LV-CS leads (11.1%) (P = .184). CONCLUSION: Neither pacing lead position nor diameter appears to affect TR development significantly. LV-CS leads failed to achieve a statistically significant reduction in TR as compared with right ventricular leads.
Asunto(s)
Desfibriladores Implantables/efectos adversos , Ventrículos Cardíacos/diagnóstico por imagen , Marcapaso Artificial/efectos adversos , Taquicardia Ventricular/terapia , Insuficiencia de la Válvula Tricúspide/etiología , Anciano , Ecocardiografía , Falla de Equipo , Femenino , Estudios de Seguimiento , Humanos , Masculino , Estudios Prospectivos , Insuficiencia de la Válvula Tricúspide/diagnóstico , Insuficiencia de la Válvula Tricúspide/fisiopatologíaRESUMEN
In patients with unexplained cardiomyopathy, electroanatomical mapping can identify abnormal tissue to target during electrophysiology-guided endomyocardial biopsy (EP-guided EMB). The objective of this study is to determine whether catheter ablation performed in the same setting as EP-guided EMB increases procedural risk. Sixty-seven patients (mean age 54.4 ± 13.8, 57% male) undergoing EP-guided EMB were included. Radiofrequency catheter ablation was performed in 17 patients (25%) for ventricular arrhythmias and in 2 (3%) for typical atrial flutter. Femoral arterial access was obtained in 90% ablation patients and 40% biopsy-only patients; vascular access complications were more common in the ablation group than in the EMB-only group (p = 0.02). There were no significant differences in rate of tricuspid regurgitation, thromboembolism, or pericardial effusion, whether procedural anticoagulation was used. In conclusion, catheter ablation and procedural anticoagulation can be combined with EP-guided EMB with an increased risk of vascular access complications, but no significant increase in intracardiac complications.
Asunto(s)
Arritmias Cardíacas/patología , Biopsia/métodos , Cardiomiopatías/patología , Ablación por Catéter/métodos , Endocardio/patología , Miocarditis/patología , Miocardio/patología , Sarcoidosis/patología , Adulto , Anciano , Arritmias Cardíacas/etiología , Arritmias Cardíacas/cirugía , Aleteo Atrial/etiología , Aleteo Atrial/patología , Aleteo Atrial/cirugía , Bloqueo Atrioventricular/patología , Bloqueo Atrioventricular/cirugía , Cardiomiopatías/complicaciones , Técnicas Electrofisiológicas Cardíacas , Endocardio/cirugía , Estudios de Factibilidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Miocarditis/complicaciones , Complicaciones Posoperatorias/epidemiología , Sarcoidosis/complicaciones , Taquicardia Ventricular/etiología , Taquicardia Ventricular/patología , Taquicardia Ventricular/cirugía , Complejos Prematuros Ventriculares/etiología , Complejos Prematuros Ventriculares/patología , Complejos Prematuros Ventriculares/cirugíaRESUMEN
BACKGROUND: Patients with heart failure (HF) have increased risk for thromboembolic events. Real-world incidences of efficacy and safety outcomes of direct oral anticoagulants (DOACs) in patients with left ventricular systolic dysfunction (LVSD) are of growing clinical interest. HYPOTHESIS: Real-world efficacy and safety outcomes of DOACs in patients with LVSD will be similar to those of LVSD or HF subgroups in the RE-LY, ROCKET-AF, and ARISTOTLE trials. METHODS: We performed a retrospective review of adult patients with LVSD (left ventricular ejection fraction ≤40%) on DOAC therapy between 2010 and 2016. Incidences of safety and efficacy outcomes of anticoagulation with DOACs were extracted from primary and secondary hospital discharge diagnoses. RESULTS: DOACs were prescribed to 287 patients with LVSD over a mean follow-up of 313.3 ± 52.3 days. Many patients had moderate and severe chronic kidney disease (28.9% and 10.1%, respectively) and indications for anticoagulation therapy other than atrial fibrillation (19.9%). For efficacy outcomes, the calculated incidence rates of ischemic stroke and systemic embolism were 1.2 (95% confidence interval [CI]: 0.25-3.56) and 0.81 (95% CI: 0.10-2.94) events per 100 person-years, respectively. For the safety outcomes, incidence rates of GI bleeding and intracranial hemorrhage were 2.4 (95% CI: 0.8-5.3) and 0.41 (95% CI: 0.1-2.2) events per 100 patient-years, respectively. CONCLUSIONS: Our findings are largely compatible with the results of LVSD or HF subgroups in RE-LY, ROCKET-AF, and ARISTOTLE trials and add to increasing confidence that DOACs can be safely used for stroke and systemic embolism prevention in patients with LVSD.
Asunto(s)
Anticoagulantes/administración & dosificación , Fibrilación Atrial/complicaciones , Ventrículos Cardíacos/fisiopatología , Centros de Atención Terciaria/estadística & datos numéricos , Tromboembolia/prevención & control , Disfunción Ventricular Izquierda/epidemiología , Función Ventricular Izquierda/efectos de los fármacos , Administración Oral , Anciano , Fibrilación Atrial/tratamiento farmacológico , Relación Dosis-Respuesta a Droga , Femenino , Estudios de Seguimiento , Ventrículos Cardíacos/diagnóstico por imagen , Mortalidad Hospitalaria/tendencias , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Minnesota/epidemiología , Pronóstico , Estudios Retrospectivos , Sístole , Tromboembolia/epidemiología , Tromboembolia/etiología , Disfunción Ventricular Izquierda/etiología , Disfunción Ventricular Izquierda/fisiopatologíaRESUMEN
Given the high incidence of atrial fibrillation (AF) in the surgical population and the associated morbidity, physicians managing these complicated patients in the perioperative period need to be aware of the new and emerging trends in its therapy. The cornerstones of AF management have always been rate/rhythm control as well as anticoagulation. Restoration of sinus rhythm remains the fundamental philosophy as it maintains the atrial contribution to cardiac output and improves ventricular function. The recent years have seen a dramatic increase in the number of randomized AF trials that have made significant advances to our understanding of both pharmacologic and procedural management, from the introduction of the new generation of oral anticoagulants (NOAC's) to catheter approaches for AF ablation. This paper will summarize the newest data that will affect the perioperative management of these patients.
Asunto(s)
Fibrilación Atrial/terapia , Atención Perioperativa/métodos , Antiarrítmicos/uso terapéutico , Anticoagulantes/uso terapéutico , Fibrilación Atrial/tratamiento farmacológico , Ablación por Catéter/métodos , Cardioversión Eléctrica/métodos , Fibrinolíticos/uso terapéutico , HumanosRESUMEN
INTRODUCTION: Despite many advances in nonpharmacologic management of ventricular arrhythmias, antiarrhythmic drugs remain important in both the acute conversion and chronic prevention of ventricular arrhythmias. AREAS COVERED: Key trials related to antiarrhythmic drug use are reviewed, emphasizing the impact of recent discoveries. Sodium channel blockers are discussed with an emphasis on recently identified specialized uses. Beta blockers, amiodarone, sotalol, and dofetilide are discussed together in the context of structural heart disease, because they do not increase mortality in this group of patients. Other medications found to reduce ventricular arrhythmia burden are discussed last. EXPERT OPINION: Since most patients with ventricular arrhythmias have structural heart disease, pharmacologic treatment is limited to amiodarone, d-,l-sotalol, and dofetilide (off-label indication), in conjunction with defibrillator implantation. While amiodarone has superior reduction in arrhythmias, its long-term extracardiac toxicities can cause significant morbidity. A trial of sotalol is reasonable if there are no contraindications, recognizing that over 20% of patients have to discontinue it because of adverse effects. Beta blockers are first line therapy for most patients. Genetic testing is particularly informative regarding treatment approach in long QT syndrome, Brugada syndrome, and catecholaminergic polymorphic VT. Research should continue to focus on developing more effective antiarrhythmic medications with less long-term toxicity.
Asunto(s)
Antiarrítmicos/uso terapéutico , Taquicardia Ventricular/tratamiento farmacológico , Fibrilación Ventricular/tratamiento farmacológico , Antagonistas Adrenérgicos beta/uso terapéutico , Quimioterapia Combinada , Humanos , Bloqueadores de los Canales de Potasio/uso terapéutico , Ensayos Clínicos Controlados Aleatorios como Asunto , Bloqueadores de los Canales de Sodio/uso terapéuticoRESUMEN
A sudden outbreak of mortality in one house of 600 48-week-old male breeder turkeys on a five-house turkey breeder farm was suspected to be feed-related. The turkeys gasped and became recumbent; 21.7% of affected turkeys died. No significant gross lesions were found at necropsy. Histological lesions, limited to skeletal muscle, consisted of degeneration and necrosis and were judged compatible with ionophore toxicosis. Feed samples from the affected house were analyzed by three techniques and shown to contain 13.4 to 18.4 g of salinomycin per ton of feed. An error at the feed mill was blamed for allowing contamination of the turkey feed with broiler starter feed containing salinomycin.
Asunto(s)
Coccidiostáticos/toxicidad , Ionóforos/toxicidad , Intoxicación/veterinaria , Enfermedades de las Aves de Corral/inducido químicamente , Piranos/toxicidad , Animales , Masculino , Intoxicación/patología , Enfermedades de las Aves de Corral/patología , PavosRESUMEN
Feed artificially contaminated with various levels of nalidixic-acid-resistant Salmonella montevideo was fed to newly hatched chicks for 7 days. Cloacal and cecal swabs were obtained from the chicks at 7, 14, and 21 days of age to monitor Salmonella colonization relative to the feed contamination level. In one of three trials, less than one Salmonella montevideo per gram of feed was sufficient to establish colonization in 1-to-7-day-old chicks.
Asunto(s)
Alimentación Animal , Pollos/microbiología , Microbiología de Alimentos , Enfermedades de las Aves de Corral/microbiología , Salmonelosis Animal/microbiología , Animales , Animales Recién Nacidos/microbiología , Susceptibilidad a Enfermedades , Salmonella/crecimiento & desarrollo , Salmonella/aislamiento & purificación , Intoxicación Alimentaria por Salmonella/microbiología , Intoxicación Alimentaria por Salmonella/veterinariaRESUMEN
Two floor pen studies were conducted to determine whether compensatory growth occurs following withdrawal of the anticoccidial drug salinomycin from the feed of broilers reared to 46 days of age. There were no significant differences in weight gain or feed conversion between medicated and unmedicated birds whether overall performance or performance during the 1-wk withdrawal period was measured. Feed intake of birds given salinomycin, however, was significantly lower than that of unmedicated birds, and feed intake following withdrawal was greater than that of birds still receiving the drug.
Asunto(s)
Pollos/crecimiento & desarrollo , Coccidiostáticos/administración & dosificación , Dieta , Piranos/administración & dosificación , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Ingestión de Alimentos , Masculino , Aumento de PesoRESUMEN
Patients with episodic sinus tachycardia and associated orthostatic intolerance present a diagnostic and management dilemma to the clinician. We define this group of disorders to include sinus node reentrant tachycardia (SNRT), inappropriate sinus tachycardia (IAST), and postural orthostatic tachycardia syndrome (POTS). After a brief review of the current understanding of the pathophysiology and epidemiology of this group of disorders, we focus on the diagnosis and management of IAST and POTS. Our approach attempts to recognize the considerable overlap in pathophysiology and clinical presentation between these two heterogeneous conditions. Thus, we focus on a mechanism-based workup and therapeutic approach. Sinus tachycardia related to identifiable causes should first be ruled out in these patients. Next, a basic cardiovascular and autonomic workup is suggested to exclude structural heart disease, identify a putative diagnosis, and guide therapy. We review both nonpharmacologic and pharmacologic therapy, with a focus on recent advances. Larger randomized control trials and further mechanistic studies will help refine management in the future.
Asunto(s)
Manejo de la Enfermedad , Intolerancia Ortostática , Postura , Taquicardia Sinusal , Humanos , Intolerancia Ortostática/complicaciones , Intolerancia Ortostática/fisiopatología , Intolerancia Ortostática/terapia , Nodo Sinoatrial/fisiopatología , Taquicardia Sinusal/complicaciones , Taquicardia Sinusal/fisiopatología , Taquicardia Sinusal/terapiaRESUMEN
The management of ventricular tachycardia and ventricular fibrillation in the cardiac intensive care unit can be complex. These arrhythmias have many triggers, including ischemia, sympathetic stimulation, and medication toxicities, as well as many different substrates, ranging from ischemic and nonischemic cardiomyopathies to rare genetic conditions such as Brugada syndrome and long QT syndrome. Different settings, such as congenital heart disease, postoperative ventricular arrhythmias, and ventricular assist devices, increase the complexity of management. This article reviews the variety of situations and cardiac conditions that give rise to ventricular arrhythmias, focusing on inpatient management strategies.