RESUMEN
BACKGROUND: Hypertension decreases myocardial perfusion capacity in adults for several reasons, including insufficient coronary angiogenesis with left ventricular (LV) hypertrophy, arteriolar hypertrophy, and altered vasomotion. Heparin influences growth factors that promote angiogenesis and vasodilation and inhibit arteriolar wall thickening. METHODS AND RESULTS: Adult sheep were given heparin 200 U/kg body wt SC twice daily throughout 6 weeks of LV and coronary hypertension from a progressively constricted ascending aortic band (n=14). They were compared with untreated sheep with (n=13) and without (n=13) aortic stenosis. After 6 weeks, maximum myocardial perfusion was measured during adenosine infusion in the conscious state by the microsphere method. Sheep with aortic stenosis had less maximum coronary flow per gram, less conductance reserve, and thicker arteriolar walls in the LV and nonhypertrophied right ventricle. Capillary density decreased in the LV endomyocardium and remained unchanged in the right ventricle. Heparin-treated sheep had significant partial normalization of coronary conductance reserve and maximum perfusion in both ventricles and capillary density in the LV endomyocardium. Arteriolar wall thickness was unchanged. Compared with untreated sheep with aortic stenosis, in heparin-treated sheep LV FGF-2 protein increased 2-fold, whereas FGF-2 mRNA remained unchanged. VEGF mRNA and protein increased 3-fold and 1.4-fold, respectively, whereas TGF-beta(1) mRNA declined 3-fold. CONCLUSIONS: Heparin administration during LV hypertension increases heparin-binding angiogenic factors FGF-2 and VEGF in the LV and ameliorates decreases in LV perfusion capacity and capillary density.
Asunto(s)
Anticoagulantes/farmacología , Circulación Coronaria/efectos de los fármacos , Vasos Coronarios/efectos de los fármacos , Factores de Crecimiento Endotelial/metabolismo , Factor 2 de Crecimiento de Fibroblastos/metabolismo , Heparina/farmacología , Hipertensión/fisiopatología , Hipertrofia Ventricular Izquierda/fisiopatología , Linfocinas/metabolismo , Adaptación Fisiológica/efectos de los fármacos , Animales , Anticoagulantes/administración & dosificación , Arteriolas/efectos de los fármacos , Arteriolas/patología , Circulación Colateral/efectos de los fármacos , Vasos Coronarios/patología , Esquema de Medicación , Factores de Crecimiento Endotelial/genética , Femenino , Factor 2 de Crecimiento de Fibroblastos/genética , Heparina/administración & dosificación , Hipertensión/metabolismo , Hipertensión/patología , Hipertrofia Ventricular Izquierda/metabolismo , Hipertrofia Ventricular Izquierda/patología , Linfocinas/genética , ARN Mensajero/metabolismo , Ovinos , Factor A de Crecimiento Endotelial Vascular , Factores de Crecimiento Endotelial Vascular , Vasodilatación/efectos de los fármacosRESUMEN
BACKGROUND: Intraatrial reentrant tachycardia (IART) is a common problem in patients with congenital heart disease (CHD). The progression of clinical symptoms of IART and their response to radiofrequency (RF) ablation are not yet well described. OBJECTIVES: The objective of the study was to determine the early and midterm success rates of RF ablation in effecting a reduction of clinical arrhythmic events in patients with IART and CHD. METHODS: Clinical records of patients undergoing early, successful RF ablation were analyzed retrospectively to document the occurrence and frequency of documented IART, cardioversion and arrhythmia-related hospital visits before and after ablation. RESULTS: Fifty-five catheterizations for intended RF ablation of IART were performed in 45 patients (mean [+/-SD] age 24.5 +/- 10.5 years, 40 after surgical palliation of CHD). Early success was achieved for one or more IART circuits in 33 patients (73%). Mean clinical follow-up of those patients with successful ablation is 17.4 +/- 11.3 months (total 574 patient-months). Documented IART recurrence was noted after 21 (53%) of 40 early, successful catheterizations in 17 (52%) of 33 patients, with a mean time to recurrence of 4.1 months, often with electrocardiographically novel configurations. A more prolonged and frequent history of IART was a univariate risk factor for recurrence. Seven patients underwent repeat RF ablations, and eight patients were restarted on antiarrhythmic medications after ablation. Two patients who had severe ventricular dysfunction before RF ablation died 1.5 and 11 months after RF ablation without known arrhythmia recurrence. Clinical events related to IART increased steadily in frequency for 24 months before RF ablation. Radiofrequency ablation resulted in a reduction of event frequency to levels significantly lower than those in the 12-month period before RF ablation and not significantly different from those levels observed at baseline 3 to 4 years before RF ablation. CONCLUSIONS: In patients with successful RF ablation, the frequency of subsequent events was reduced compared with the 2 preceding years. However, recurrence of IART in patients who showed clinical improvement was frequent, and often revealed the presence of new IART configurations.
Asunto(s)
Ablación por Catéter , Cardiopatías Congénitas/complicaciones , Taquicardia por Reentrada en el Nodo Atrioventricular/etiología , Taquicardia por Reentrada en el Nodo Atrioventricular/cirugía , Adolescente , Adulto , Análisis de Varianza , Niño , Cardioversión Eléctrica , Electrocardiografía , Hospitalización , Humanos , Incidencia , Recurrencia , Estudios Retrospectivos , Factores de Riesgo , Factores de Tiempo , Resultado del TratamientoRESUMEN
OBJECTIVE: A review of the results of the first 5 years of radiofrequency catheter ablation procedures performed at Children's Hospital, Boston, a large tertiary referral center for patients with congenital heart disease and arrhythmias common to the infant, child, and young adult. STUDY DESIGN: A retrospective review of 410 consecutive procedures in 346 patients who underwent at least one application of radiofrequency energy for the treatment of recurrent supraventricular or ventricular tachycardia. RESULTS: The overall final success rate for all diagnoses was 90%, with a higher success rate in patients with an accessory pathway (96%). During the 5-year study period, the success rate improved while the rates of failures and late recurrences declined. The incidence of serious complications was 1.2% (1 late death, 1 ventricular dysfunction, 1 complete heart block, 1 cardiac perforation, and 1 cerebrovascular accident). CONCLUSIONS: This report of a large series of radiofrequency catheter ablation procedures performed at an institution committed to treating congenital heart disease and pediatric arrhythmias confirms the safety and efficacy of this procedure. The pediatric cardiologist/electrophysiologist treating such patients must be aware of specific technical, anatomic, and electrophysiologic variations in the pediatric patient that are critical to the success of this therapy.
Asunto(s)
Arritmias Cardíacas/cirugía , Ablación por Catéter/métodos , Cardiopatías Congénitas/cirugía , Terapia por Radiofrecuencia , Adolescente , Adulto , Arritmias Cardíacas/etiología , Ablación por Catéter/efectos adversos , Distribución de Chi-Cuadrado , Niño , Preescolar , Femenino , Estudios de Seguimiento , Cardiopatías Congénitas/complicaciones , Cardiopatías/complicaciones , Cardiopatías/diagnóstico , Cardiopatías/cirugía , Humanos , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Recurrencia , Estudios Retrospectivos , Taquicardia/clasificación , Taquicardia/etiología , Taquicardia/cirugía , Síndrome de Wolff-Parkinson-White/etiología , Síndrome de Wolff-Parkinson-White/cirugíaRESUMEN
This study found that pigs in the early stages of perinephritic hypertension had enhanced plasma norepinephrine (NE) and heart rate (HR) responses to behaviorally arousing stimuli (lifting in a canvas sling) and exercise. In the hypertensive animals, the increase in plasma NE in response to behavioral arousal caused by lifting was double that of the intact group, and the HR response was 50% greater. The increase in plasma NE in response to exercise was six times greater in hypertensive pigs. By contrast, mean arterial pressure changes were not enhanced in the hypertensive group. Exaggerated catecholamine responses in plasma to lifting and exercise stimulation were present when hemodynamic responses were not exaggerated.
Asunto(s)
Nivel de Alerta , Hipertensión Renal/sangre , Norepinefrina/sangre , Animales , Estado de Conciencia , Femenino , Frecuencia Cardíaca , Hipertensión Renal/fisiopatología , Masculino , Norepinefrina/líquido cefalorraquídeo , Condicionamiento Físico Animal , PorcinosRESUMEN
To study the effects of airway obstruction (AWO) and arousal on coronary blood flow, mean arterial pressure (MAP), and heart rate, pigs were chronically instrumented with arterial catheters, Doppler flow probes on the left circumflex coronary artery, and electrodes for determination of sleep stages. A modified tracheostomy tube was placed in the trachea to obstruct the upper airway during sleep sessions. In control studies, during non-rapid-eye-movement (NREM) sleep, MAP was 84 +/- 2 mmHg before AWO and increased by 5 +/- 2 mmHg on arousal. MAP was lower during rapid-eye-movement (REM) sleep (62 +/- 2 mmHg), and the increase on arousal was fourfold greater (22 +/- 2 mmHg). Heart rate was similar in both sleep stages (NREM: 120 +/- 4 beats/min; REM: 124 +/- 5 beats/min) and increased significantly on arousal (NREM: 12 +/- 2 beats/min; REM: 18 +/- 1 beats/min). Coronary blood flow was similar during both stages (NREM: 43 +/- 4 ml/min; REM: 46 +/- 8 ml/min) and increased by 12-15% on arousal. Coronary vascular resistance index increased significantly by 24% on arousal from AWO during REM sleep. All increases and decreases were significant at P < 0.05. Receptor blockade studies were performed to assess alpha-adrenergic receptor involvement.
Asunto(s)
Nivel de Alerta/fisiología , Hemodinámica/fisiología , Síndromes de la Apnea del Sueño/fisiopatología , Obstrucción de las Vías Aéreas/fisiopatología , Animales , Presión Sanguínea/fisiología , Circulación Coronaria/fisiología , Modelos Animales de Enfermedad , Electrodos , Masculino , Fentolamina/farmacología , Polisomnografía , Sueño REM/fisiología , Porcinos , Tráquea/fisiología , Resistencia Vascular/fisiologíaRESUMEN
OBJECTIVES: Using a new mapping system that allows the simultaneous acquisition of data from 25 right atrial bipolar electrodes during cardiac catheterization, we mapped normal sinus rhythm and atrial reentrant tachycardia in 24 sheep (20 to 49 kg) and 7 pigs (25 to 35 kg). BACKGROUND: Rapid, high resolution mapping during cardiac catheterization may shorten ablation procedures and permit ablation of otherwise refractory arrhythmias. METHODS: A flexible, elliptic, basket-shaped recording catheter has five spokes, each with 10 electrodes arranged as 5 bipolar pairs. Catheter shape, electrode spacing and introduction technique were modified in response to the results of experiments in the first 23 animals. In the most recent eight animals, retraction of a string attached to the distal tip distended the basket, providing safe tissue contact. Filtered (30 to 250 Hz) bipolar recordings from all 25 electrode pairs, as well as a surface electrocardiogram, were recorded and digitized at 1,000 Hz using custom software. An activation map was digitally constructed and superimposed on anteroposterior and lateral fluoroscopic catheter images. Bipolar recordings were made in normal sinus rhythm (31 animals), with adequate signals recorded from > 95% of electrode pairs. Rapid burst pacing and intentional right atrial air embolus (30 to 50 ml) induced sustained atrial reentrant tachycardia in five animals, which was also adequately recorded. RESULTS: Catheter positioning and complete atrial mapping required < 10 min after venous access in the most recent eight experiments. The catheter was left in position for up to 4 h. Postmortem evaluation revealed minor superficial abrasion of the venae cavae or right atrial endocardium in six animals and moderate abrasion in two. No other damage was observed. CONCLUSIONS: This new system may ultimately assist in mapping simple or complex atrial arrhythmias during cardiac catheterization.
Asunto(s)
Cateterismo Cardíaco/métodos , Ablación por Catéter/métodos , Electrocardiografía/métodos , Procesamiento de Señales Asistido por Computador , Taquicardia por Reentrada en el Nodo Atrioventricular/diagnóstico , Animales , Cateterismo Cardíaco/instrumentación , Ablación por Catéter/efectos adversos , Ablación por Catéter/instrumentación , Modelos Animales de Enfermedad , Electrocardiografía/instrumentación , Electrodos , Diseño de Equipo , Estudios de Evaluación como Asunto , Atrios Cardíacos , Radiografía , Ovinos , Porcinos , Taquicardia por Reentrada en el Nodo Atrioventricular/diagnóstico por imagen , Taquicardia por Reentrada en el Nodo Atrioventricular/cirugíaRESUMEN
Giant colonic diverticula are an uncommon manifestation of colonic diverticular disease. This report documents another case of this rare entity. The clinical presentation is variable, but abdominal pain and the presence of an abdominal mass are common. Their etiology is uncertain, but they are thought to originate from pulsion diverticula. Abdominal plain films and barium enema are helpful in making the diagnosis. Computerized tomography is useful when the diagnosis is unclear. Surgical resection is recommended to alleviate symptoms and avoid complications.