[Mechanical ventilation in a respiratory ward. Evolution from 1994 to 2000]. / Ventilación mecánica en hospitalización neumológica. Evolución en el período 1994-2000.

OBJECTIVE: To investigate the absolute and relative frequency of mechanical ventilation in the management of patients on a respiratory medicine ward between 1994 and 2000. To describe reasons for admission, mean hospital stay and outcomes. SETTING: A tertiary-care university hospital. METHODS: Observational, descriptive study of a case series. RESULTS: During the study period, 257 admissions involved mechanical ventilation of 132 patients. During that time, there was a progressive increase in the total number of ventilated patients as well as in the relative frequency, such that ventilated patients eventually accounted for 6.1% of all admissions for respiratory care in 2000. Nearly 80% of admissions were related to the service's home mechanical ventilation program, either to initiate and adapt ventilation for new patients or to treat exacerbations or diagnose and treat other medical or surgical problems in already-ventilated patients. Patients transferred from the intensive care unit (ICU) because of weaning difficulties (median ventilation, 31 days) had the highest mean stay. Nine of the 132 patients had to be transferred to the ICU and 18 died while hospitalized (7% of admissions and 13.6% of patients). The patients who died were those who were more acutely and severely ill (acute exacerbation in home-ventilated patients, patients with acute respiratory failure treated initially with non-invasive ventilation and patients transferred from the ICU due to weaning difficulties). CONCLUSIONS: Admissions requiring mechanical ventilation have increased and most are related to the home mechanical ventilation program. The mean stay and the mortality rate were related to the reason for admission.

Ventilación mecánica en hospitalización neumológica. Evolución en el período 1994-2000 / Mechanical ventilation in a respiratory ward. Evolution from 1994 to 2000

OBJETIVO: Conocer la frecuencia absoluta y relativa de pacientes que han utilizado la ventilación mecánica como parte de su tratamiento en una sala de hospitalización neumológica en el período 1994-2000, describir las causas que han motivado la indicación y analizar su estancia media y sus resultados. ÁMBITO: Hospital terciario universitario. PACIENTES Y MÉTODOS: Estudio observacional descriptivo de serie de casos. RESULTADOS: En el período de estudio hubo 257 ingresos hospitalarios con ventilación mecánica en 132 pacientes. Durante ese tiempo se produjo un incremento progresivo en el número anual absoluto y relativo de pacientes que, en el año 2000, representó el 6,1 por ciento del total de las hospitalizaciones en la planta de neumología. Casi el 80 por ciento de los ingresos estaban relacionadas con el programa de ventilación mecánica domiciliaria, bien para inicio programado de adaptación a la misma, o estando en tratamiento previo con ella por agudización respiratoria o para el diagnóstico y tratamiento de otros problemas médicos o quirúrgicos. El grupo de mayor estancia media fue el de los pacientes trasladados desde la unidad de cuidados intensivos por ventilación mecánica prolongada (mediana de 31 días). Del total de pacientes (n = 132), nueve fueron trasladados a la unidad de cuidados intensivos y 18 fallecieron (el 7 por ciento del total de las hospitalizaciones y 13,6 por ciento de los pacientes).La mortalidad se concentró en los grupos con pacientes más agudos y graves: pacientes con ventilación mecánica domiciliaria previa y agudización respiratoria, pacientes con ventilación mecánica no invasiva para tratamiento de la insuficiencia respiratoria aguda y pacientes trasladados desde la UCI por ventilación mecánica prolongada y dificultades en la desconexión. CONCLUSIONES: Se ha producido un incremento progresivo del número de pacientes hospitalizados con ventilación mecánica, en la mayor parte de los casos relacionados con el programa de ventilación mecánica domiciliaria. La estancia media y la mortalidad dependieron del motivo de la ventilación mecánica (AU)

[Hemodynamic benefits of left ventricular pacing in two pacemakers syndromes with refractory heart failure]. / Beneficio hemodinámico de la estimulación ventricular izquierda en dos síndromes de marcapasos con insuficiencia cardíaca refractaria.

We describe two cases in which right ventricular pacing produced severe hemodynamic deterioration and in which changing the pacing from the right to the left ventricle sharply corrected these alterations, while simultaneous biventricular pacing did not. Chronic left ventricular pacing can solve hemodynamic alterations in severe pacemaker syndromes, thereby avoiding the need for mitral prosthesis implantation in some cases. The use of this procedure today should be individualized, including acute hemodynamic and echocardiographic studies, because the width of the QRS complex during pacing is not a significant predictor of hemodynamic efficiency.

[Atrioventricular nodal reentrant tachycardia as a trigger for atrial fibrillation]. / Taquicardia reentrante intranodal como inductora de fibrilación auricular.

We report the case of a 43 year-old male with a long history of paroxysmal palpitations aborted by vagal manoeuvres, where atrial fibrillation was the only documented arrhythmia. During the electrophysiological study an AV nodal reentrant tachycardia was demonstrated with rapid degeneration into atrial fibrillation. After slow pathway ablation, nodal tachycardia became non-inducible. No palpitations were reported and no arrhythmic event was recorded after a follow-up of 20 months. In selected cases, the electrophysiological study could reveal potentially curable causes of atrial fibrillation.

[Radiofrequency ablation as the first line of treatment in patients with common atrial flutter. The arguments con]. / La ablación con radiofrecuencia como primer tratamiento de elección en pacientes con aleteo auricular común. Argumentos en contra.

After years of development, radiofrequency ablation of common flutter circuits is a well established procedure. Once the structure of the circuit, and its critical isthmus, were defined, effective approaches to ablation have been developed, improving initial results. The problem of recurrence has been largely controlled, and the present recurrence rate is 10-15%. The large majority of recurrences can be treated successfully by a new ablation, with a very low incidence of second recurrence. Nevertheless, isthmus ablation is not a curative procedure, because it does not address the cause of flutter, only a necessary link in the circuit. The electrophysiologic and/or anatomic abnormalities of the atrium or atria persist after ablation. Perhaps for this reason there is an incidence of atrial fibrillation in 25-30% of cases after successful flutter ablation. On the other hand, some clinical data suggest that a first episode of flutter has a low incidence of recurrence after cardioversion. For all these reasons flutter ablation should not be considered as first line treatment in all episodes of atrial flutter, but of those with recurrences and/or poor tolerance.

[The ablation of atrial flutter. The long-term results after 8 years of experience]. / Ablación de flúter auricular. Resultados a largo plazo tras 8 años de experiencia.

OBJECTIVE: Since the 1990's radiofrequency ablation radiofrequency ablation of atrial flutter has evolved in its methods and results. We have reviewed the long term outcome in 62 patients with typical (common) or reversed (clockwise) flutter undergoing radiofrequency ablation between 1990 and 1997. PATIENTS AND METHODS: Fifty men and 12 women, aged 22-78 years (57 +/- 12) with flutter recurring after cardioversion and antiarrhythmic drugs make this series. Flutter was typical in 59 cases and reversed in 3. There was no heart disease in 14, bronchopulmonary disease in 10, coronary disease in 9, cardiomyopathies in 6 and other processes in the remainder. In 5 cases with previous surgery for atrial or ventricular septal defect, Ebstein's anomaly or myxoma, we treated also a macro-reentry tachycardia around the atriotomy in the right atrium. Radiofrequency ablation was directed to the inferior vena cava-tricuspid isthmus in typical and reversed flutter, and to the isthmus between the inferior end of the atriotomy and the inferior vena cava, in the lateral right atrium, in the atriotomy tachycardias. We subdivided our patients in Group 1 (24 patients), treated until the end of 1994, and Group 2 (38 patients) treated since 1995 using specially designed catheters and trying to produce isthmus block as the endpoint of the procedure. RESULTS: Radiofrequency ablation interrupted flutter in 61 of 62 cases (98.4%), and the atriotomy tachycardia in all 5. The number of application in Group 1 was 18.6 +/- 10.1 vs 12 +/- 10 in Group 2 (p < 0.05). Follow-up was 40 +/- 24 months in Group 1 vs 16 +/- 9.5 in Group 2. Flutter recurred in 58% of Group 1 and 13% of Group 2 patients (p < 0.001), usually 1-3 months after radiofrequency ablation and they were successfully treated by new radiofrequency ablation with a small number of applications. There was no recurrence of atriotomy tachycardia. Atrial fibrillation occurred in 14 patients (23%) (11 paroxysmal, 3 persistent), with equal incidence in both groups. At the end of follow-up 85% of the patients were in sinus rhythm, although 6 needed pacemakers for sinus node dysfunction (3) or AV ablation (3). Antiarrhythmic drugs were used by 46% of patients in Group 1 and 26% in Group 2 (p = NS) for atrial arrhythmias or recurrent flutter. CONCLUSIONS: Radiofrequency ablation is an effective treatment for flutter and macro-reentry atriotomy tachycardia. Progress in methods have improved results significantly. Atrial fibrillation can still be a problem in 20-25% of the patients after flutter control.

[Immediate hemodynamic response to atrioventricular+ stimulation in severe hypertrophic obstructive myocardiopathy]. / Respuesta hemodinámica inmediata a la estimulación bicameral en la miocardiopatía hipertrófica obstructiva severa.

INTRODUCTION AND OBJECTIVES: Atrial synchronized ventricular pacing has shown to be an alternative to surgery in the therapeutic management of obstructive hypertrophic cardiomyopathy. Our purpose is the analysis of the hemodynamic mechanisms associated with the reduction of left ventricular outflow tract gradient and the changes in left ventricular diastolic function induced by dual-chamber pacing. PATIENTS AND METHODS: We studied twenty patients (age range 40-78 years; mean 63 +/- 10), who were evaluated while receiving their current medication with cardiac catheterization and angiography, at baseline and under dual-chamber pacing. RESULTS: The atrioventricular delay was 127 +/- 26 ms. The subaortic gradient was reduced from 96 +/- 38 to 36 +/- 28 mmHg (p < 0.001), the ejection period index was shortened from 523 +/- 26 to 491 +/- 30 ms (p < 0.001) and the left ventricular end-diastolic pressure fell from 22 +/- 6 to 13 +/- 5 mmHg (p < 0.001). There was no remarkable change in cardiac output. The median wedge pressure decreased from 17 +/- 5 to 12 +/- 2.5 mmHg (p < 0.01), the pulmonary systolic pressure from 39 +/- 15 to 30 +/- 10 mmHg (p < 0.01), the pulmonary diastolic pressure from 19 +/- 5 to 13 +/- 4 mmHg (p < 0.01) and the right ventricular end-diastolic pressure from 7 +/- 3 to 5 +/- 3 mmHg (p < 0.05). The left ventricular ejection fraction was reduced from 79 +/- 6 to 72 +/- 6 per cent (p < 0.001). The initial ejection fraction diminished from 49 +/- 13 to 34 +/- 13 per cent (p < 0.01), the early diastolic filling increased from 39 +/- 11 to 52 +/- 10 per cent (p < 0.001) and the atrial contribution was reduced from 36 +/- 10 to 24 +/- 10 per cent (p < 0,001). The degree of mitral regurgitation changed from 1.4 +/- 1.2 to 0.7 +/- 0.9 (p < 0.01). CONCLUSIONS: There is an obstruction in the left ventricular outflow tract in patients with obstructive hypertrophic cardiomyopathy that is relieved with dual-chamber pacing. The reduction in the intraventricular pressure seems to improve the ventricular relaxation and the diastolic function. The decrease in the degree of mitral regurgitation and the improvement in diastolic function diminish pulmonary capillary and right circuit pressures.

[Pharmacologic maintenance of sinusal rhythm and/or control of the ventricular response in patients with atrial fibrillation or flutter]. / Mantenimiento farmacológico del ritmo sinusal y/o control de la respuesta ventricular en pacientes con fibrilación o flutter auricular.

Atrial fibrillation is the most common cardiac arrhythmia and is usually responsible for symptoms requiring some treatment. Antiarrhythmic drugs are the first choice therapy, but their potential risks are significant. This together with their limited efficacy restricts their use. Antiarrhythmic drug use should be tailored; mainly according to the underlying heart disease. When reversion to sinus rhythm is not eligible, the adequate control of ventricular rate and the reduction of embolic risk are the therapeutic goals. Atrial flutter shows different behaviour regarding the very limited efficacy of antiarrhythmic drugs for reversion to and maintenance in sinus rhythm.

[Hemodynamic and electrophysiologic changes in hypertrophic cardiomyopathy]. / Alteraciones hemodinámicas y electrofisiológicas en la miocardiopatía hipertrófica.

Hypertrophic cardiomyopathy is characterized by abnormalities of the myocardium, and the activation and conduction tissues, that may have separate manifestations, but often occur together in complex clinical pictures. The subaortic gradient, although not always present, is the most classical manifestation of the disease, with its typical dynamic behavior, changing with preload, afterload and contractility. In most cases it is due to systolic motion of the mitral valve against the septum in systole, but in a few it is caused by midventricular "constriction". Alteration of diastolic ventricular function is important, and probably the main cause of heart failure, that is usually accompanied by normal systolic function. Mitral insufficiency is common in the obstructive forms, due to the abnormal mitral valve motion, but in some cases it may be due to structural abnormalities of the valve. There may be systolic constriction, or nonatherosclerotic occlusion of the intramyocardial coronary arteries, causing myocardial infarction and ventricular aneurysms, that may lead to systolic dysfunction. The electrocardiogram is rarely normal. Hypertrophy patterns, deeply inverted T waves, deep Q waves, QRS slurring suggestive of WPW syndrome without true preexcitation are the most common manifestations. Rhythm disturbances are common and include sinus node dysfunction, superconductor atrioventricular node or heart block. Atrial fibrillation is frequent and may have catastrophic consequences, including systemic embolism. Non-sustained ventricular arrhythmias are often present, but its predictive value for sudden death is unclear. Monomorphic ventricular tachycardia is infrequent, and programmed stimulation is more likely to precipitate polymorphic ventricular tachycardia of difficult clinical interpretation. Sudden death may be due to multiple mechanisms, and it is difficult to predict and prevent.

[Chronotropic competence in patients with the sick sinus syndrome wearing AAI or DDD pacemakers]. / Capacidad de taquicardización en pacientes con enfermedad del nódulo sinusal portadores de marcapasos AAI o DDD.

The prevalence of chronotropic incompetence in patients with sinus node disease (SND) is not well defined. To assess this, we evaluated 18 patients (7 men, 11 women; mean age: 64 +/- 11) with SND and permanent pacemakers (AAI/DDD) with Holter monitoring and treadmill stress test. Only 2 patients received active cardiac drugs (1, L-dopa an 1 propafenone). The treadmill tests results were compared with a control group of 15 men and 18 women (mean age: 66 +/- 5, p = NS) without organic heart disease. During ambulatory activity all pacemaker patients increased their own cardiac rate to a value higher than the programmed basic pacemaker rate. In 8 patients the maximal rate attained was over 100/min (mean 95 +/- 19/min). The maximal rate during treadmill test in pacemaker patients was 131 +/- 25 (control group 138 +/- 14, p = NS). Exercise tolerance in METs was similar in pacemaker patients (5.2 +/- 2.6) and in controls (5.8 +/- 1.2) (p = NS). Two pacemaker patients (12%) didn't reach 100/min during stress test. Most patients with SND and permanent pacemakers (AAI/DDD) are able to increase cardiac rate during exercise. Rate responsive pacing (AAIR/DDDR) should be limited to a minority of patients with true chronotropic incompetence.

[Exercise-induced atrioventricular block]. / Bloqueo auriculoventricular inducido por el ejercicio.

Exercise-induced atrioventricular block in patients with normal atrioventricular conduction at rest is uncommon. Electrophysiologic studies have documented block distal to the atrioventricular node in these patients. Implantation of a permanent pacemaker is recommended because of a high incidence of subsequent symptomatic block. We report three symptomatic patients with exercise-induced atrioventricular block. Two patients showed a bundle branch block in the baseline electrocardiogram, suggesting a distal location of the block. In the remainder, with a normal QRS, the electrophysiologic study revealed AV block within the His bundle in response to atrial pacing.

[The efficacy of propafenone in preventing recurrent auricular fibrillation and flutter]. / Eficacia de la propafenona en la prevención de fibrilación y flúter auricular recurrente.

In order to investigate the efficacy of propafenone in the prevention of paroxysmal flutter or fibrillation, we treated 21 patients without left ventricular disfunction. Age was 60 +/- 14 (mean +/- sd) years, left atrial diameter by echocardiography 37 +/- 7 mm, cardiothoracic index 0.48 +/- 0.05 (0.41-0.57) and P wave duration 100 +/- 17 ms. The frequency of recurrences before treatment was: daily in five (23%), weekly or more in eight (38%), monthly-weekly in seven (33%) and quarterly-monthly in one (5%). Propafenone (671 +/- 187 mg/24 h) was given after recurrences were demonstrated under treatment with 1-3 antiarrhythmic drugs per patient. During 8.9 +/- 3.5 months of follow-up (range 6-19) 5 patients (23%) were completely free of recurrences; in seven (33%) the incidence decreased by greater than 50% with a marked decrease in duration. Side effects appeared in 12 cases (57%), leading to its discontinuation in four (19%). Arrhythmogenic effects were observed in 2 cases (9%). Propafenone is effective in greater than 50% of patients with paroxysmal atrial flutter or fibrillation, resistant to other antiarrhythmic agents. The incidence of side effects is high, but they are usually not severe and reversible.

[Severe hypoxemia due to a right-left shunt at the level of the foramen ovale. A complication of right ventricular infarct]. / Hipoxemia grave por cortocircuito derecha-izquierda a nivel del foramen oval. Una complicación del infarto de ventrículo derecho.

A 76-year-old woman with an inferior wall myocardial infarction, with right ventricular involvement, developed severe arterial hypoxemia with neurological involvement. Pulmonary edema or embolism and chronic obstructive pulmonary disease were ruled-out, and a right-to-left shunt was demonstrated by contrast echocardiography at the level of the foramen ovale. After inotropic support and oxygen supplementation, the patient recovered, although with significant neurological sequelae. No focal lesions were detected in the central nervous system by computerized tomography. Hypoxemia improved, coinciding with the disappearance of right-to-left shunt by contrast echocardiography.

[Relationship between echocardiographic measurement of left atrial size and the incidence of systemic embolism in mitral stenosis]. / Relación entre el tamaño ecocardiográfico auricular izquierdo con la incidencia de embolia sistémica en la estenosis mitral.

In order to correlate left atrial diameter (LAD) with the prevalence of systemic embolism (SE) in mitral stenosis (MS), we assessed LAD by M mode tracings in 51 patients with SE and in 50 patients with MS without ES as control group (C). Mean age was similar in both groups (SE 47.3 +/- 12 vs C 46.8 +/- 14 years; p NS) (mean +/- SD). Functional class, cardiothoracic ratio and association of other valvular lesions were similar in both groups. Atrial fibrillation (AF) was more frequent in SE group (n = 39) than in C group (n = 20) (p less than 0.01). LAD in SE patients ranged from 2.9 to 9 cm (5.2 +/- 1) whereas in C patients range was from 2.8 to 7.5 (4.6 +/- 1) (p less than 0.01). Nevertheless, LAD in patients with AF was rather similar in both groups (SE 5.3 +/- 1.1 vs C 5.3 +/- 1; p NS). Our results suggest that LAD is not a good predictive parameter for SE in MS. The main risk factor for SE was the existence of AF. Echocardiographic LAD is not a useful parameter to prescribe chronic oral anticoagulation as prophylaxis for SE in patients with MS.

[Acute myopericarditis with pulmonary infiltration and hypereosinophilia]. / Miopericarditis aguda con infiltrados pulmonares e hipereosinofilia.

A 31 year-old male had the sudden onset of left ventricular failure, left ventricular apical thrombus, large pericardial effusion, pulmonary infiltrates and up to 59% eosinophils in the differential leucocyte count. A pericardial biopsy showed eosinophilic infiltration. The whole clinical picture improved dramatically with corticosteroid therapy. After 1 year of treatment with prednisone left ventricular function improved markedly, pericardial effusion disappeared, eosinophils were absent on the peripheral blood smear and the patient was asymptomatic. No endocardial thickening was detected by echocardiography.