RESUMEN
Drug-resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) are a target for new antimicrobial technologies. Far-UVC technology is an emerging disinfection method that directly kills microorganisms using light. In contrast with conventional UV sterilization, far-UVC light has antimicrobial capabilities without apparent harm to mammalian cells. This study examines the application of 224 nm far-UVC light delivered from a laser using an optical diffuser towards the goal of protecting against bacterial invasion around skin penetrating devices. Delivery of far-UVC using a laser and optical fibers enables exposure to unique geometries that would otherwise be shielded when using a lamp. Testing of the bactericidal potential of diffusing the far-UVC laser output over a large area was tested and yielded qualitative area killing results. The killing of MRSA using this method was also examined using an in vitro survival assay. Results followed a classic log-linear disinfection model with a rate constant of k = 0.51 cm2/mJ, which corresponds to an inactivation cross section of D90 = 4.5 mJ/cm2. This study establishes far-UVC delivered from a laser through an optical diffuser as a viable solution for disinfection of susceptible regions such as around catheters, drivelines, or other skin penetrating medical devices.
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Desinfección/instrumentación , Desinfección/métodos , Rayos Láser , Staphylococcus aureus Resistente a Meticilina/efectos de la radiación , Fibras Ópticas , Rayos Ultravioleta , Tecnología de Fibra Óptica , Técnicas In VitroRESUMEN
Analysis of the emission pattern from optical diffuser tips is vital to their usage in biomedical applications, especially as they find growing functionality beyond established phototherapy techniques. The use of ultraviolet radiation with diffuser tips increases the need to accurately characterize these devices, both for effective application and to avoid potentially dangerous exposure conditions. This study presents a new method to capture the diffusion pattern at a high resolution through the use of radiochromic film. The film is positioned in a cylinder around the diffuser, light is emitted from the diffuser onto the film and the film expresses a color change relative to the exposure amount. The resulting emission map shows the distribution of power from the diffuser in all direction. This method, which is both quick and inexpensive, generates high-resolution data much simpler than previously published works which required precise goniometric positioning.
RESUMEN
Measurement of ultraviolet (UV) radiation is important for human health, especially with the expanded usage of short wavelength UV for sterilization purposes. This work examines unlaminated Gafchromic EBT3 film for UV radiation monitoring. The authors exposed the film to select wavelengths in the UV spectrum, ranging from 207 to 328 nm, and measured the change in optical density. The response of the film is wavelength dependent, and of the wavelengths tested, the film was most sensitive to 254 nm light, with measurable values as low as 10 µJ/cm2. The film shows a dose-dependent response that extends over more than four orders of magnitude. The response of the film to short wavelength UV is comparable to the daily safe exposure limits for humans, thus making it valuable as a tool for passive UV radiation monitoring.
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Dosimetría por Película/métodos , Rayos Ultravioleta , Calibración , Humanos , Análisis Espectral/métodosRESUMEN
The Columbia University Cardiothoracic Surgery Program dates back to the earliest days of the specialty itself, when the first pioneers ventured into the chest, and eventually the heart, to treat diseases previously believed to be beyond the reach of medicine. This spirit of innovation, creativity, and vision has grown over the ensuing century and has driven the development of advances that have defined the specialty and saved countless lives. From novel techniques for the repair of complex congenital cardiac defects and acquired cardiovascular diseases, to comprehensive management of lung and esophageal maladies, and to the marvel of minimally invasive and percutaneous interventions, the march of progress has never been stronger, more dramatic, or more consequential that it is at Columbia today. Fueled by people who -- as descendants of those early pioneers -- have been raised in the "Columbia culture," the commitment to innovation and education has never been greater.
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Centros Médicos Académicos/historia , Procedimientos Quirúrgicos Cardíacos/historia , Cardiología/historia , Educación Médica/historia , Cardiopatías/historia , Cirugía Torácica/historia , Cateterismo Cardíaco/historia , Procedimientos Quirúrgicos Cardíacos/educación , Cardiología/educación , Difusión de Innovaciones , Cardiopatías/cirugía , Historia del Siglo XX , Historia del Siglo XXI , Humanos , Ciudad de Nueva York , Cirugía Torácica/educaciónRESUMEN
OBJECTIVE: Right parasternal mediastinotomy with right atriotomy has been used clinically for pacemaker insertion. A similar approach might facilitate access to the coronary sinus for biventricular pacing and other manipulations when more conventional approaches are not feasible. The primary barrier to this is lack of appropriate introducers and techniques. METHODS: Anatomically derived introducers were developed in 2 anesthetized domestic pigs using data from computerized axial thoracic tomography. Each digitized tomogram defined a unique introducer shape and was constructed using 3-dimensional (3D) modeling software and printing. Each parent pig then underwent surgery demonstrating coronary sinus lead insertion, using its custom-configured introducer. Next, with institutional review board approval, 65 patients were identified who had undergone conventional endocardial coronary sinus lead insertion followed by thoracic scanning. These tomograms were used to design appropriately curved introducers for human anatomy. RESULTS: Fifty-one introducer paths were defined following anatomic pathways and avoiding bends inconsistent with materials used for commercial peel-away introducers. Each path was defined by a bend and distance toward the coronary sinus ostium and a hook and twist out of plane to align with the local orientation of the coronary sinus. The average dimensions were the following: distance, 67 mm; bend angle, 47 degrees; hook angle, 39 degrees; and twist angle, 20 degrees. A prototype cannula was tested for fit in a fresh frozen postmortem human specimen. CONCLUSIONS: Parasternal mediastinotomy access to the coronary sinus for cardiac resynchronization, mitral annuloplasty, and instrumentation is feasible. Human computerized tomographic scans can be used to define curvatures and dimensions for marketed introducers.
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Seno Coronario/anatomía & histología , Seno Coronario/cirugía , Mediastino/cirugía , Esternón/cirugía , Animales , Terapia de Resincronización Cardíaca/métodos , Atrios Cardíacos/cirugía , Humanos , Imagenología Tridimensional , Mediastino/anatomía & histología , Procedimientos Quirúrgicos Mínimamente Invasivos/instrumentación , Procedimientos Quirúrgicos Mínimamente Invasivos/métodos , Anuloplastia de la Válvula Mitral/instrumentación , Anuloplastia de la Válvula Mitral/métodos , Modelos Animales , Esternón/anatomía & histología , Porcinos , Tomografía Computarizada por Rayos XRESUMEN
OBJECTIVE: Post-cardiopulmonary bypass biventricular pacing improves hemodynamics but without clearly defined predictors of response. Based on preclinical studies and prior observations, it was suspected that diastolic dysfunction or pulmonary hypertension is predictive of hemodynamic benefit. DESIGN: Randomized controlled study of temporary biventricular pacing after cardiopulmonary bypass. SETTING: Single-center study at university-affiliated tertiary care hospital. INTERVENTIONS: Patients who underwent bypass with preoperative ejection fraction ≤40% and QRS duration ≥100 ms or double-valve surgery were enrolled. At 3 time points between separation from bypass and postoperative day 1, pacing delays were varied to optimize hemodynamics. PARTICIPANTS: Data from 43 patients were analyzed. MEASUREMENTS AND MAIN RESULTS: Cardiac output and arterial pressure were measured under no pacing, atrial pacing, and biventricular pacing. Preoperative echocardiograms and pulmonary artery catheterizations were reviewed, and measures of both systolic and diastolic function were compared to hemodynamic response. Early after separation, improvement in cardiac output was positively correlated with pulmonary vascular resistance (R(2) = 0.97, p<0.001), ventricle wall thickness (R(2) = 0.72, p = 0.002)), and E/e', a measure of abnormal diastolic ventricular filling velocity (R(2) = 0.56, p = 0.04). Similar trends were seen with mean arterial pressure. QRS duration and ejection fraction did not correlate significantly with improvements in hemodynamics. CONCLUSIONS: There may be an effect of biventricular pacing related to amelioration of abnormal diastolic filling patterns rather than electrical resynchronization in the postoperative state.
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Terapia de Resincronización Cardíaca , Ventrículos Cardíacos/fisiopatología , Hipertensión Pulmonar/complicaciones , Hipertensión Pulmonar/fisiopatología , Complicaciones Posoperatorias/diagnóstico , Disfunción Ventricular/complicaciones , Anciano , Estudios Cruzados , Diástole , Femenino , Humanos , Masculino , Complicaciones Posoperatorias/fisiopatología , Disfunción Ventricular/fisiopatologíaRESUMEN
Ventricular dyssynchrony is associated with morbidity and mortality after palliation of a single ventricle. The authors hypothesized that resynchronization with optimized temporary multisite pacing postoperatively would be safe, feasible, and effective. Pacing was assessed in the intensive care unit within the first 24 h after surgery. Two unipolar atrial pacing leads and four bipolar ventricular pacing leads were placed at standardized sites intraoperatively. Pacing was optimized to maximize mean arterial pressure. The protocol tested 11 combinations of the 4 different ventricular lead sites, 6 atrioventricular delays (50-150 ms), and 14 intraventricular delays. Optimal pacing settings were thus determined and ultimately compared in four configurations: bipolar, unipolar, single-site atrioventricular pacing, and intrinsic rhythm. Each patient was his or her own control, and all pacing comparisons were implemented in random sequence. Single-ventricle palliation was performed for 17 children ages 0-21 years. Pacing increased mean arterial pressure (MAP) versus intrinsic rhythm, with the following configurations: bipolar multisite pacing increased MAP by 2.2 % (67.7 ± 2.4 to 69.2 ± 2.4 mmHg; p = 0.013) and unipolar multisite pacing increased MAP by 2.8 % (67.7 ± 2.4 to 69.6 ± 2.7 mmHg; p = 0.002). Atrioventricular single-site pacing increased MAP by 2.1 % (67.7 ± 2.4 to 69.1 ± 2.5 mmHg: p = 0.02, insignificant difference under Bonferroni correction). The echocardiographic fractional area change in nine patients increased significantly only with unipolar pacing (32 ± 3.1 to 36 ± 4.2 %; p = 0.02). No study-related adverse events occurred. Multisite pacing optimization is safe and feasible in the early postoperative period after single-ventricle palliation, with improvements in mean arterial pressure and fractional area shortening. Further study to evaluate clinical benefits is required.
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Terapia de Resincronización Cardíaca/métodos , Procedimientos Quirúrgicos Cardíacos/métodos , Sistema de Conducción Cardíaco/fisiopatología , Cardiopatías Congénitas/cirugía , Ventrículos Cardíacos/anomalías , Cuidados Posoperatorios/métodos , Taquicardia Ventricular/terapia , Adolescente , Niño , Preescolar , Ecocardiografía , Electrocardiografía , Femenino , Cardiopatías Congénitas/complicaciones , Cardiopatías Congénitas/fisiopatología , Ventrículos Cardíacos/diagnóstico por imagen , Ventrículos Cardíacos/fisiopatología , Humanos , Lactante , Recién Nacido , Masculino , Cuidados Paliativos , Taquicardia Ventricular/etiología , Taquicardia Ventricular/fisiopatología , Adulto JovenRESUMEN
OBJECTIVES: Effects of temporary biventricular pacing after cardiopulmonary bypass are unpredictable, and the utility of speckle-tracking echocardiography in this setting is unclear. Accordingly, speckle-tracking analysis of transgastric echocardiograms taken during cardiac surgery was assessed as a potential tool to measure strain, synchrony, and twist as indices to predict response. DESIGN: Prospective observational study, in part, with a randomized controlled study of temporary permanent biventricular pacing after cardiopulmonary bypass. SETTING: Single-center study at university-affiliated tertiary care hospital. PARTICIPANTS: Twenty-one cardiac surgery candidates with ejection fraction ≤40% and QRS duration ≥100 ms or who were undergoing double-valve surgery. INTERVENTIONS: Transgastric views of the basal, midpapillary, and apical levels of the left ventricle were acquired before and after bypass. MEASUREMENTS AND MAIN RESULTS: Midpapillary sections were analyzable in 38% of patients. The remainder had epicardial borders extending beyond the field of view (24%) or inadequate image quality (38%). Only 9% of basal or apical sections were analyzable. Midpapillary radial strain and synchrony changed insignificantly after bypass. Variation in fractional area change correlated with changes in radial strain (p = 0.041) but not with synchrony. CONCLUSIONS: Intraoperative transgastric echocardiography is inadequate for speckle-tracking analysis with current techniques. Intraoperative predictors of temporary biventricular pacing response are lacking.
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Puente Cardiopulmonar/efectos adversos , Ecocardiografía/métodos , Disfunción Ventricular Izquierda/diagnóstico por imagen , Anciano , Estudios de Factibilidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Disfunción Ventricular Izquierda/etiologíaRESUMEN
In this article an international group of CRT specialists presents a comprehensive classification system for present and future schemes for optimising CRT. This system is neutral to the measurement technology used, but focuses on little-discussed quantitative physiological requirements. We then present a rational roadmap for reliable cost-effective development and evaluation of schemes. A widely recommended approach for AV optimisation is to visually select the ideal pattern of transmitral Doppler flow. Alternatively, one could measure a variable (such as Doppler velocity time integral) and "pick the highest". More complex would be to make measurements across a range of settings and "fit a curve". In this report we provide clinicians with a critical approach to address any recommendations presented to them, as they may be many, indistinct and conflicting. We present a neutral scientific analysis of each scheme, and equip the reader with simple tools for critical evaluation. Optimisation protocols should deliver: (a) singularity, with only one region of optimality rather than several; (b) blinded test-retest reproducibility; (c) plausibility; (d) concordance between independent methods; and (e) transparency, with all steps open to scrutiny. This simple information is still not available for many optimisation schemes. Clinicians developing the habit of asking about each property in turn will find it easier to win now down the broad range of protocols currently promoted. Expectation of a sophisticated enquiry from the clinical community will encourage optimisation protocol-designers to focus on testing early (and cheaply) the basic properties that are vital for any chance of long term efficacy.
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Terapia de Resincronización Cardíaca/métodos , Terapia de Resincronización Cardíaca/normas , Sistema de Conducción Cardíaco/fisiología , Insuficiencia Cardíaca/fisiopatología , Insuficiencia Cardíaca/terapia , Terapia de Resincronización Cardíaca/clasificación , Sistema de Conducción Cardíaco/diagnóstico por imagen , Insuficiencia Cardíaca/diagnóstico por imagen , Humanos , Modelos Cardiovasculares , Reproducibilidad de los Resultados , UltrasonografíaRESUMEN
BACKGROUND: 0.5% to 10% of clean surgeries result in surgical-site infections, and attempts to reduce this rate have had limited success. Germicidal UV lamps, with a broad wavelength spectrum from 200 to 400 nm are an effective bactericidal option against drug-resistant and drug-sensitive bacteria, but represent a health hazard to patient and staff. By contrast, because of its limited penetration, ~200 nm far-UVC light is predicted to be effective in killing bacteria, but without the human health hazards to skin and eyes associated with conventional germicidal UV exposure. AIMS: The aim of this work was to test the biophysically-based hypothesis that ~200 nm UV light is significantly cytotoxic to bacteria, but minimally cytotoxic or mutagenic to human cells either isolated or within tissues. METHODS: A Kr-Br excimer lamp was used, which produces 207-nm UV light, with a filter to remove higher-wavelength components. Comparisons were made with results from a conventional broad spectrum 254-nm UV germicidal lamp. First, cell inactivation vs. UV fluence data were generated for methicillin-resistant S. aureus (MRSA) bacteria and also for normal human fibroblasts. Second, yields of the main UV-associated pre-mutagenic DNA lesions (cyclobutane pyrimidine dimers and 6-4 photoproducts) were measured, for both UV radiations incident on 3-D human skin tissue. RESULTS: We found that 207-nm UV light kills MRSA efficiently but, unlike conventional germicidal UV lamps, produces little cell killing in human cells. In a 3-D human skin model, 207-nm UV light produced almost no pre-mutagenic UV-associated DNA lesions, in contrast to significant yields induced by a conventional germicidal UV lamp. CONCLUSIONS: As predicted based on biophysical considerations, 207-nm light kills bacteria efficiently but does not appear to be significantly cytotoxic or mutagenic to human cells. Used appropriately, 207-nm light may have the potential for safely and inexpensively reducing surgical-site infection rates, including those of drug-resistant origin.
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Rayos Ultravioleta , Supervivencia Celular/efectos de la radiación , Daño del ADN/efectos de la radiación , Humanos , Staphylococcus aureus Resistente a Meticilina/efectos de la radiación , Piel/metabolismo , Piel/microbiología , Piel/efectos de la radiación , Infección de la Herida Quirúrgica/prevención & control , Infección de la Herida Quirúrgica/terapia , Terapia Ultravioleta/economíaRESUMEN
In selected patients undergoing cardiac surgery, our research group previously showed that optimized temporary biventricular pacing can increase cardiac output one hour after weaning from cardiopulmonary bypass. Whether pacing is effective after beating-heart surgery is unknown. Accordingly, in this study we examined the feasibility of temporary biventricular pacing after off-pump coronary artery bypass grafting. The effects of optimized pacing on cardiac output were measured with an electromagnetic aortic flow probe at the conclusion of surgery in 5 patients with a preoperative mean left ventricular ejection fraction of 0.26 (range, 0.15-0.35). Atrioventricular (7) and interventricular (9) delay settings were optimized in randomized order. Cardiac output with optimized biventricular pacing was 4.2 ± 0.7 L/min; in sinus rhythm, it was 3.8 ± 0.5 L/min. Atrial pacing at a matched heart rate resulted in cardiac output intermediate to that of sinus rhythm and biventricular pacing (4 ± 0.6 L/min). Optimization of atrioventricular and interventricular delay, in comparison with nominal settings, trended toward increased flow. This study shows that temporary biventricular pacing is feasible in patients with preoperative left ventricular dysfunction who are undergoing off-pump coronary artery bypass grafting. Further study of the possible clinical benefits of this intervention is warranted.
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Terapia de Resincronización Cardíaca , Puente de Arteria Coronaria Off-Pump/efectos adversos , Enfermedad de la Arteria Coronaria/cirugía , Disfunción Ventricular Izquierda/terapia , Función Ventricular Izquierda , Anciano , Terapia de Resincronización Cardíaca/métodos , Enfermedad de la Arteria Coronaria/diagnóstico , Enfermedad de la Arteria Coronaria/fisiopatología , Electrocardiografía , Estudios de Factibilidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Volumen Sistólico , Factores de Tiempo , Resultado del Tratamiento , Disfunción Ventricular Izquierda/diagnóstico , Disfunción Ventricular Izquierda/fisiopatologíaRESUMEN
BACKGROUND: The Biventricular Pacing After Cardiac Surgery trial investigates hemodynamics of temporary pacing in selected patients at risk of left ventricular dysfunction. This trial demonstrates improved hemodynamics during optimized biventricular pacing compared with atrial pacing at the same heart rate 1 and 2 hours after bypass and reduced vasoactive-inotropic score over the first 4 hours after bypass. However, this advantage of biventricular versus atrial pacing disappears 12 to 24 hours later. We hypothesized that changes in intrinsic heart rate can explain variable effects of atrial pacing in this setting. METHODS: Heart rate, mean arterial pressure, cardiac output, and medications depressing heart rate were analyzed in patients randomized to continuous biventricular pacing (n = 16) or standard of care (n = 18). RESULTS: During 30-second testing periods without pacing, intrinsic heart rate was lower in the paced group 12 to 24 hours after bypass (76.5 ± 17.5 vs 91.7 ± 13.0 beats per minute; P = .040) but not 1 or 2 hours after bypass. Cardiac output (4.4 ± 1.2 vs 3.6 ± 1.9 L/min; P = .054) and stroke volume (53 ± 2 vs 42 ± 2 mL; P = .051) increased overnight in the paced group. Vasoactive medication doses were not different between groups, whereas dexmedetomidine administration was prolonged over postoperative hours 12 to 24 in the paced group (793 ± 528 vs 478 ± 295 minutes; P = .013). CONCLUSIONS: These observations suggest that hemodynamic benefits of biventricular pacing 12 to 24 hours after cardiopulmonary bypass lead to withdrawal of sympathetic drive and decreased intrinsic heart rate. Depression of intrinsic rate increases the apparent benefit of atrial pacing in the chronically paced group but not in the control group. Additional study is needed to define clinical benefits of these effects.
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Terapia de Resincronización Cardíaca/métodos , Procedimientos Quirúrgicos Cardíacos/efectos adversos , Frecuencia Cardíaca , Disfunción Ventricular Izquierda/terapia , Anciano , Presión Arterial , Gasto Cardíaco , Puente Cardiopulmonar , Fármacos Cardiovasculares/uso terapéutico , Cuidados Críticos , Femenino , Atrios Cardíacos/fisiopatología , Frecuencia Cardíaca/efectos de los fármacos , Humanos , Masculino , Persona de Mediana Edad , Ciudad de Nueva York , Factores de Tiempo , Resultado del Tratamiento , Disfunción Ventricular Izquierda/diagnóstico , Disfunción Ventricular Izquierda/etiología , Disfunción Ventricular Izquierda/fisiopatología , Función Ventricular IzquierdaRESUMEN
BACKGROUND: Biventricular pacing (BiVP) improves cardiac output (CO) in selected cardiac surgery patients, but response remains variable, necessitating a better understanding of the mechanism. Accordingly, we used speckle tracking echocardiography (STE) to analyze BiVP during acute right ventricular pressure overload (RVPO). MATERIALS AND METHODS: In nine pigs, the inferior vena cava (IVC) was snared to decrease CO and establish a control model. Heart block was induced, the pulmonary artery snared, and BiVP initiated. Echocardiograms of the left ventricular midpapillary level were taken at varying atrioventricular delay (AVD) and interventricular delay (VVD) for STE analysis of regional circumferential strain (CS) and radial strain (RS). Echocardiograms were taken of the left ventricular base, midpapillary, and apex during baseline, IVC occlusion, and each BiVP setting for STE analysis of twist, apical and basal rotations, CS, RS, and synchrony. Indices were correlated against CO with mixed linear models. RESULTS: During IVC occlusion, CO correlated with twist, apical rotation, RS, RS synchrony, and CS (P < 0.05). During RVPO with BiVP, CO only correlated with RS synchrony and CS (P < 0.05). During AVD and VVD variations, CO was associated with free wall RS (P < 0.008). CO correlated with septal wall CS during AVD variation and free wall CS during VVD variation (P < 0.008). CONCLUSIONS: In an open chest model, twist, RS, RS synchrony, and CS analyzed by STE may be noninvasive surrogates for changes in CO. During RVPO, changes in RS synchrony and CS with varying regional strain contributions may be the primary mechanism in which BiVP improves CO. Lack of correlation of remaining indices may reflect postsystolic function.
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Terapia de Resincronización Cardíaca/métodos , Bloqueo Cardíaco/fisiopatología , Bloqueo Cardíaco/terapia , Insuficiencia Cardíaca/fisiopatología , Insuficiencia Cardíaca/terapia , Animales , Gasto Cardíaco/fisiología , Modelos Animales de Enfermedad , Ecocardiografía/métodos , Bloqueo Cardíaco/diagnóstico por imagen , Insuficiencia Cardíaca/diagnóstico por imagen , Hipertensión Pulmonar/diagnóstico por imagen , Hipertensión Pulmonar/fisiopatología , Hipertensión Pulmonar/terapia , Masculino , Contracción Miocárdica/fisiología , Porcinos , Torsión Mecánica , Vena Cava Inferior/fisiopatología , Presión Ventricular/fisiologíaRESUMEN
BACKGROUND: This study sought to determine whether optimized biventricular pacing increases cardiac index in patients at risk of left ventricular dysfunction after cardiopulmonary bypass. Procedures included coronary artery bypass, aortic or mitral surgery and combinations. This trial was approved by the Columbia University Institutional Review Board and was conducted under an Investigational Device Exemption. METHODS: Screening of 6,346 patients yielded 47 endpoints. With informed consent, 61 patients were randomized to pacing or control groups. Atrioventricular and interventricular delays were optimized 1 (phase I), 2 (phase II), and 12 to 24 hours (phase III) after bypass in all patients. Cardiac index was measured by thermal dilution in triplicate. A 2-sample t test assessed differences between groups and subgroups. RESULTS: Cardiac index was 12% higher (2.83±0.16 [standard error of the mean] vs 2.52±0.13 liters/minute/square meter) in the paced group, less than predicted and not statistically significant (p=0.14). However, when aortic and aortic-mitral surgery groups were combined, cardiac index increased 29% in the paced group (2.90±0.19, n=14) versus controls (2.24±0.15, n=11) (p=0.0138). Using a linear mixed effects model, t-test revealed that mean arterial pressure increased with pacing versus no pacing at all optimization points (phase I 79.2±1.7 vs 74.5±1.6 mm Hg, p=0.008; phase II 75.9±1.5 vs 73.6±1.8, p=0.006; phase III 81.9±2.8 vs 79.5±2.7, p=0.002). CONCLUSIONS: Cardiac index did not increase significantly overall but increased 29% after aortic valve surgery. Mean arterial pressure increased with pacing at 3 time points. Additional studies are needed to distinguish rate from resynchronization effects, emphasize atrioventricular delay optimization, and examine clinical benefits of temporary postoperative pacing.
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Terapia de Resincronización Cardíaca/métodos , Procedimientos Quirúrgicos Cardíacos/métodos , Cuidados Posoperatorios/métodos , Disfunción Ventricular Izquierda/terapia , Anciano , Presión Arterial/fisiología , Terapia de Resincronización Cardíaca/estadística & datos numéricos , Procedimientos Quirúrgicos Cardíacos/efectos adversos , Puente Cardiopulmonar/efectos adversos , Puente Cardiopulmonar/métodos , Puente de Arteria Coronaria/efectos adversos , Puente de Arteria Coronaria/métodos , Ecocardiografía/métodos , Femenino , Estudios de Seguimiento , Pruebas de Función Cardíaca , Implantación de Prótesis de Válvulas Cardíacas/métodos , Humanos , Modelos Lineales , Masculino , Persona de Mediana Edad , Valores de Referencia , Medición de Riesgo , Volumen Sistólico/fisiología , Tasa de Supervivencia , Resultado del Tratamiento , Disfunción Ventricular Izquierda/diagnóstico por imagen , Disfunción Ventricular Izquierda/mortalidad , Disfunción Ventricular Izquierda/fisiopatologíaRESUMEN
BACKGROUND: Transtelephonic monitoring (TTM) of pediatric patients with cardiac pacemakers (PMs) has been shown to have high sensitivity and specificity in identifying PM malfunction. The objective of this study is to determine if there is a difference in the rate of abnormal TTM findings in transvenous versus epicardial PM systems. METHODS: Our TTM database was reviewed. Patients younger than 21 years of age enrolled for TTM between 1990 and 2010 were included. The abnormal TTM recordings (not including elective replacement indicator) were identified. Logistic regression was used for statistical analysis. Note that P < 0.05 was considered significant. RESULTS: We identified 186 patients. There were 75 (40%) epicardial systems. The mean age at TTM enrollment was 6.8 ± 5.9 years (2 months-20.2 years). There were 41 (22%) patients with abnormal TTM findings. The abnormalities were found in 23/75 (31%) epicardial and 18/111 (16%) transvenous systems (odds ratio [OR]: 2.3, 95% confidence interval [CI]: 1.13-4.62, P = 0.02). When controlling for age and presence of heart disease the OR for abnormal transmission in epicardial systems compared with transvenous was 2.1 (95% CI: 1.03-4.43, P = 0.04). Patients with epicardial systems were more likely to have capture abnormalities on TTM than transvenous systems (OR: 6.1, 95% CI: 1.9-19.5, P = 0.002). CONCLUSION: Pediatric patients with epicardial PM systems are more likely to have abnormal TTM test (particularly capture problems) than patients with transvenous systems regardless of age or presence of heart disease. Consequently, patients with epicardial PM systems should be followed closely with TTM.
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Análisis de Falla de Equipo/estadística & datos numéricos , Falla de Equipo/estadística & datos numéricos , Marcapaso Artificial/estadística & datos numéricos , Telemedicina/estadística & datos numéricos , Adolescente , Niño , Preescolar , Análisis de Falla de Equipo/métodos , Femenino , Humanos , Lactante , Masculino , New York/epidemiología , Prevalencia , Reproducibilidad de los Resultados , Estudios Retrospectivos , Sensibilidad y Especificidad , Adulto JovenRESUMEN
OBJECTIVES: Biventricular pacing may ameliorate symptoms of acute heart failure. Speckle-tracking echocardiography can assess cardiac function to elucidate mechanisms of benefit. Accordingly, radial and circumferential strain and radial and circumferential strain synchrony were measured with speckle-tracking echocardiography during biventricular pacing in a model of left ventricular (LV) volume overload. METHODS: Heart block was established in 4 open-chest anesthetized pigs. Left ventricular volume overload was induced with an ascending aorta-LV apex conduit. Measurements included cardiac output by an aortic flow probe, the maximum derivative of LV pressure versus time (dP/dtmax), and transseptal pressure synchrony. Biventricular pacing was performed for combinations of 3 interventricular delays and 3 LV pacing sites. Speckle-tracking echocardiographic analysis was applied to short-axis images at the midpapillary LV for 9 pacing combinations. Strain and synchrony parameters were correlated with hemodynamics. RESULTS: Increased cardiac output correlated with improved global circumferential strain (P = .002) but not changes in global radial strain or radial strain synchrony. Increased LV dP/dtmax was associated with improved circumferential strain in the septum (P < .001) and radial strain in the lateral wall (P = .046). Improved transseptal pressure synchrony was associated with improved global circumferential strain, but primarily in the septum (P < .001). Aortic valve closure occurred before peak radial strain in 62% of beats and before peak circumferential strain in 6%. CONCLUSIONS: During acute LV volume overload, hemodynamic improvement with biventricular pacing was associated with improved circumferential strain primarily in the septum. Radial strain and radial strain synchrony did not correlate with improvement, possibly due to delayed systolic contraction. An increase in circumferential strain in the septum associated with optimum transseptal pressure synchrony suggested improvement by interventricular assist from the right ventricle.