Atrial fibrillation after isolated coronary surgery. Incidence, long term effects and relation with operative technique.

INTRODUCTION: Postoperative atrial fibrillation after isolated coronary revascularization has been associated with increased morbidity and mortality. Aim of present investigation was to evaluate incidence of postoperative atrial fibrillation and its prognostic role in patients undergoing isolated coronary artery by-pass and disclose possible differences between off-pump and cardiopulmonary assisted revascularization. METHODS: Prospective cohort study of 229 patients undergoing isolated coronary artery by-pass at a tertiary heart surgery Centre. Off-pump treated patients were significantly older (70.5 vs 64.9 years, p<0.001). No other baseline differences were found. Patients who developed postoperative atrial fibrillation were followed up for an average period of 2 years. RESULTS: Post-operative occurred in 56/229 (24.1% after cardiopulmonary and 24.6% after off-pump coronary artery by-pass). Left atrium diameter was the only independent predictive factor (odds ratio =1.15, 95% confidence interval 1.02-1.30, p<0.001). All patients with postoperative atrial fibrillation were treated and discharged in sinus rhythm, in 6/56 recurred, only in one persisted. One patient died during follow up. No stroke was recorded. CONCLUSIONS: After isolated surgical revascularization, atrial fibrillation occurred in 24% without differences related to operative technique. Recurrence of atrial fibrillation occurred in 6/56 patients (10.7%) however only in 1 persisted. Early and late mortality did not show relation with post-operative atrial fibrillation probably due to immediate treatment with recovery of sinus rhythm before discharge.

Effect of atorvastatin on circulating hsCRP concentrations: a sub-study of the achieve cholesterol targets fast with atorvastatin stratified titration (ACTFAST) study.

BACKGROUND: Elevated C-reactive protein (CRP) concentration is a risk factor for cardiovascular events that may add prognostic information. Statin treatment is associated with significant reductions in CRP concentrations, which appear to be unrelated to the magnitude of LDL-cholesterol reduction. We investigated the effect of atorvastatin, across its dose range, on high sensitivity (hs)CRP in subjects at high cardiovascular risk. METHODS: ACTFAST was a 12 week, prospective, multicenter, open-label trial in which high-risk subjects were assigned a starting dose of atorvastatin (10, 20, 40 or 80 mg/d) based on LDL-C and status of statin use at screening (1345 statin-free [SF] and 772 previously statin-treated [ST]). RESULTS: At baseline, ST subjects had significantly lower hsCRP levels than SF subjects (ST group 2.31, 95% CI 2.15, 2.48 mg/L vs. SF group 3.16, 95% CI 2.98, 3.34 mg/L, p<0.05). In the SF group, atorvastatin 10 to 80 mg significantly (p<0.01) reduced hsCRP levels in a dose dependent-manner. In ST group, additional hsCRP reductions were observed over the statin used at baseline, which were not dose-dependent. Atorvastatin significantly decreased hsCRP concentrations in subjects with or without diabetes or the metabolic syndrome. CONCLUSIONS: Atorvastatin treatment at different doses, particularly 80 mg, significantly reduced hsCRP serum concentrations. This reduction was observed in both SF and ST groups and was independent of the presence of metabolic syndrome and/or diabetes. The beneficial effect of atorvastatin was evident at 6 weeks, supporting the practice of early introduction of higher doses of atorvastatin in high-risk patients.

[Invasive pneumococcal pneumonia in children 0-24 months old: does bacterial resistance affect outcome]. / Neumonía neumocócica invasiva en niños de 0 a 24 meses: influye la resistencia bacteriana en la evolución?

INTRODUCTION: In Uruguay community acquired bacterial pneumonia is a significant cause of morbidity and mortality. S. pneumoniae is the most frequent agent. The disease is more severe in children less than two years old. The relationship between pneumococcal penicillin resistance and outcome is still an unresolved problem. OBJECTIVES: To compare the outcome of children 0 to 24 months old hospitalized in the Hospital Pediátrico-Centro Hospitalario Pereira Rossell, with invasive pneumococcal pneumonia caused by S. pneumoniae susceptible and resistant to penicillin. PATIENTS AND METHODS: Children 0 to 24 months old with invasive pneumococcal pneumonia, admitted between January 1st 1998 and December 31st 2005 were included. Susceptibility to penicillin was defined as a MIC < 0.06 microg/ml, reduced susceptibility was defined as a MIC of 0.1 to 1 microg/ml (intermediate) and as a MIC >or= 2 microg/ml (resistant). Outcome was evaluated with the following criteria: empyema, sepsis, septic shock, mechanical ventilation, and death. Length of hospital stay and outcome were compared in both groups. RESULTS: Inclusion criteria were met by 168 children. S. pneumoniae was susceptible to penicillin in 90 children and with reduced susceptibility in 78. Both groups were similar in age, comorbidity, nutritional status and initial antibiotic treatment. There were no significant differences in outcome and length of hospital stay. CONCLUSIONS: S. pneumoniae resistance to penicillin did not affect the outcome of pneumonia in this group of children.

Neumonía neumocócica invasiva en niños de 0 a 24 meses: ¿influye la resistencia bacteriana en la evolución? / Invasive pneumococcal pneumonia in children 0-24 months old: does bacterial resistance affect outcome?

Introducción. En Uruguay, la neumonía bacteriana adquirida en la comunidad causa una importante morbimortalidad. Streptococcus pneumoniae es el agente etiológico más frecuente. La enfermedad es más grave en niños menores de 2 años. Un interrogante aún no totalmente aclarado es la relación que existe entre la susceptibilidad disminuida del neumococo a la penicilina y su evolución. Objetivos. Comparar la evolución de niños de 0 a 24 meses de edad hospitalizados en el Hospital Pediátrico del Centro Hospitalario Pereira Rossell con neumonía invasiva por cepas de S. pneumoniae sensibles y con susceptibilidad disminuida a la penicilina. Pacientes y métodos. Se incluyó a los niños de 0 a 24 meses, hospitalizados entre el 1 de enero de 1998 y el 31 de diciembre de 2005, con neumonía neumocócica invasiva, en los que se determinó la concentración inhibitoria mínima (CIM) para la penicilina. Se consideraron sensibles las cepas con CIM <0,06 g/ml y con una susceptibilidad disminuida las cepas con CIM entre 0,1 y 1 g/ml (susceptibilidad intermedia) y las cepas con CIM 3 2 g/ml (resistentes). Se comparó la duración de la estancia hospitalaria y la evolución de ambos grupos a través de la presencia de los siguientes criterios de gravedad: empiema, sepsis, shock séptico, necesidad de asistencia ventilatoria mecánica y muerte. Resultados. Cumplieron los criterios de inclusión 168 niños. Las cepas de S. pneumoniae fueron sensibles a penicilina en 90 niños y con susceptibilidad disminuida en 78. Ambos grupos fueron comparables en relación con la edad, la comorbilidad, el estado nutricional y el tratamiento antibiótico al ingreso. La evolución medida por los criterios de gravedad mencionados no mostró diferencias significativas. El promedio de estancia hospitalaria fue similar en ambos grupos. Conclusiones. La resistencia de S. pneumoniae a la penicilina no influyó en la evolución de la neumonía en este grupo de niños

Introduction. In Uruguay community acquired bacterial pneumonia is a significant cause of morbidity and mortality. S. pneumoniae is the most frequent agent. The disease is more severe in children less than two years old. The relationship between pneumococcal penicillin resistance and outcome is still an unresolved problem. Objectives. To compare the outcome of children 0 to 24 months old hospitalized in the Hospital Pediátrico-Centro Hospitalario Pereira Rossell, with invasive pneumococcal pneumonia caused by S. pneumoniae susceptible and resistant to penicillin. Patients and methods. Children 0 to 24 months old with invasive pneumococcal pneumonia, admitted between January 1st 1998 and December 31st 2005 were included. Susceptibility to penicillin was defined as a MIC < 0.06 g/ml, reduced susceptibility was defined as a MIC of 0.1 to 1 g/ml (intermediate) and as a MIC 3 2 g/ml (resistant). Outcome was evaluated with the following criteria: empyema, sepsis, septic shock, mechanical ventilation, and death. Length of hospital stay and outcome were compared in both groups. Results. Inclusion criteria were met by 168 children. S. pneumoniae was susceptible to penicillin in 90 children and with reduced susceptibility in 78. Both groups were similar in age, comorbidity, nutritional status and initial antibiotic treatment. There were no significant differences in outcome and length of hospital stay. Conclusions. S. pneumoniae resistance to penicillin did not affect the outcome of pneumonia in this group of children

Biosolids application in the Chihuahuan desert: effects on runoff water quality.

Surface-applied biosolids, the option most often used on range-lands, can increase the concentration of macronutrients and trace elements in the runoff water and can potentially produce eutrophication or contamination of surface waters. In this study, the effects of postapplication age of biosolids (18, 12, 6, and 0.5 mo) and rate of application (0, 7, 18, 34, and 90 Mg ha(-1)) on the quality of runoff water from shrubland and grassland soils were assessed. Between July and October 1996 simulated rainfall was applied to 0.50-m2 plots for 30 min at a rate of 160 mm h(-1). All of the runoff water was collected. The concentration of NH4+ -N, NO3- -N, PO4(3-)-P, total dissolved phosphorus (TDP), Cu, and Mn in the runoff water increased with rate of biosolids application and decreased with time of postapplication on the two soils. The highest PO4(3-)-P and NH4+ -N concentrations, 4.96 and 97 mg L(-1), respectively, were recorded in the grassland soil treated with 90 Mg ha(-1) of biosolids 0.5 mo postapplication. For the same soil, rate, and postapplication age of biosolids, Cu exceeded the upper limit (0.50 mg L(-1) in drinking water for livestock. Ammonium N and PO4(3-)-P should be the main compounds considered when surface-applying biosolids. Ammonium N at concentrations found in all biosolids-treated plots may affect the quality of livestock drinking water by causing taste and smell problems. Orthophosphate can contribute to eutrophication if the runoff from biosolids-treated areas enter surface waters.

[Arrhythmia risk stratification based on clinical and functional data]. / Stratificazione del rischio aritmico alla luce dei dati clinici e funzionali.

The term "sudden death" indicates a natural and rapid death, an unexpected event in patients with high mortality rates such as those with heart failure. Sudden death in patients with heart failure is responsible for some of 40% of all deaths. A detailed clinical evaluation in patients with heart failure is extremely helpful for risk stratification. Although sex has been shown to have no prognostic relevance, heart failure due to coronary artery disease is associated with a higher mortality rate when compared to other etiologies. Left ventricular ejection fraction is the independent risk factor with the highest predictive value of survival. However, in patients with heart failure, except for the advanced stages, sudden death shows an incidence comparable with that of progressive pump failure. Like left ventricular ejection fraction, even the functional classifications of heart failure (such as NYHA) are to be considered as a non-specific marker of overall mortality. In fact, despite the close relation between advanced disease stages and a higher mortality rate, a large overlap has been demonstrated for the intermediate classes. The noninvasive assessment of oxygen consumption during cardiopulmonary exercise testing has been recognized as an independent risk factor and patients with a peak oxygen consumption < 10 ml/kg/min should be recommended for cardiac transplantation. In these patients no clear relation with an increased risk of sudden death has been demonstrated. In conclusion, the commonly employed clinical-functional indexes (left ventricular ejection fraction, functional classifications, peak oxygen consumption during cardiopulmonary testing) are significant predictors of overall mortality, however they are useless in the risk stratification for death due to fatal arrhythmias.

Comparison of different methods of functional evaluation in patients with chronic heart failure.

BACKGROUND: Stratification of the severity of heart failure has major prognostic and therapeutic implications. AIMS: To prospectively compare different methods of assessment of functional capacity in patients with chronic heart failure (CHF). METHODS AND RESULTS: We studied 143 patients (78 male and 65 female) with CHF aged less than 70 years (mean 57.3 years). Functional assessment was made clinically according to NYHA classification and according to the Goldman Activity Scale Classification (GASC). Cardiovascular performance was measured by peak O(2) consumption (pVO(2)) and anaerobic threshold (AT) at cardiopulmonary exercise test and by the distance walked during a 6-min walk test (6-MWT). Clinical scales resulted significantly related. Peak VO(2) and AT showed a mild relation with distance covered at 6-MWT (r=0.56 and r=0.46, respectively). Concordance between NYHA classification and levels of performance at cardiopulmonary exercise test or at 6-MWT was less than 50%. CONCLUSION: Our results suggest that none of the usually employed methods give a definitive assessment of functional capacity of cardiovascular system and a high degree of discordance exists among the results of different tests in the same patient. Although NYHA classification maintains its value in clinical evaluation of patients with CHF, the 6-min walk test is recommended in patients with mild-to-moderate CHF (II-III NYHA classes) as a simple and useful screening test to select patients for further diagnostic evaluation.

Prognostic value of baroreflex sensitivity assessed by phase IV of Valsalva manoeuvre in patients with mild-to-moderate heart failure.

BACKGROUND: In patients with heart failure, impairment of baroreflex function occurs early and contributes to sympathetic activation, however, at present its prognostic role has not been definitively established. AIMS: To evaluate the prognostic significance of baroceptor impairment in patients with different degrees of heart failure. METHODS: We enrolled 52 consecutive patients with heart failure, referred to our institution for functional evaluation. Twenty-eight suffered from ischemic cardiomyopathy and 26 from dilated cardiomyopathy. Thirteen patients were in NYHA class I, 20 in NYHA class II and 19 in class III. All patients underwent baroreflex assessment by phase IV Valsalva manoeuvre using Finapres finger monitoring of arterial blood pressure, echocardiography [with evaluation of left ventricular ejection fraction (LVEF), fractional shortening (LVFS), left ventricular end diastolic diameter (LVEDD) and mean pulmonary artery pressure] and functional evaluation by cardiopulmonary exercise test and 6-min walk corridor test within 2 days of hospital admission. RESULTS: Mean duration of follow-up was 26 months (range 6-35 months). At baseline, evaluation in 13 patients BRS was normal (>5 ms/mmHg), in 17 moderately impaired (1.5-5 ms/mmHg) and in 22 severely depressed (<1.5 ms/mmHg). Baroreflex function was relatively preserved in patients in NYHA class I (5.1+/-2.5) in comparison to patients in NYHA class II and III (2.1+/-2.3 and 2.08+/-1.9 ms/mmHg, respectively). Of the 52 patients who entered the study at the end of follow-up 15 died of cardiac cause and 5 underwent heart transplantation. Survival free from heart transplantation was 62% in patients with normal baroreflex function, 62% in patients with moderate impairment of baroreflex and 66% in patients with major derangement. NYHA class, LVEF, LVFS and LVEDD were significantly associated with event free survival while baroreflex function was not. CONCLUSIONS: Our results suggest that evaluation of BRS impairment by phase IV Valsalva manoeuvre has limited prognostic value in patients with heart failure.

[The effects of training on skeletal and cardiac muscle mass in professional soccer players]. / Effetti dell'allenamento sulla massa muscolare scheletrica e cardiaca in calciatori professionisti.

Ongoing physical exercise is able to increase skeletal and cardiac muscle mass. Echocardiography and body impedance analysis permit non-invasive evaluation of these two parameters. The aim of this study was to evaluate the effects of training and detraining on the heart and skeletal muscles of professional soccer players. Twenty-one professional athletes (average age 24 +/- 3.5 years) were evaluated during five different phases of their athletic training and compared with 21 age- and height-matched healthy, non-obese sedentary subjects. All subjects underwent measurement of body mass distribution by means of bioelectrical impedance analysis and of left ventricular mass by means of echocardiography. The control group had lower values of lean and cellular body mass, as well as lower left ventricular mass than the professional athletes. Over the 13-month study period, the athletes showed no substantial modifications in fat and muscle mass parameters. Instead, left ventricular mass values increased during the playing season, evidencing physiological hypertrophy after 6 months of competitive activity. No subsequent increases were observed over the next 2 months, and after detraining, left ventricular mass returned to baseline values. We thus conclude that exercise training brings about changes in cardiac mass without producing parallel changes in skeletal muscular mass.

Decreased baroreflex sensitivity assessed from phase IV of Valsalva maneuver in mild congestive heart failure.

Decreased sensitivity of cardiopulmonary and arterial baroreceptors has been hypothesized to sustain sympathetic activation in patients with heart failure. In the present investigation the relationship between the impairment of baroreflex sensitivity and clinical severity of congestive heart failure was investigated. The authors studied 58 patients with heart failure (14 in NYHA class I, 22 in NYHA class II, and 22 in NYHA class III), 38 women and 20 men, age range 28-65 years. Thirty-two patients suffered from idiopathic dilated cardiomyopathy and 26 from coronary heart disease. As control group they examined 21 age-matched subjects. Baroreceptor sensitivity was studied by using the Valsalva maneuver as stimulus. Arterial pressure and heart rate were measured noninvasively by Finapres instrument (Ohmeda) and signals were recorded and elaborated with a personal computer. A decrease of baroreflex sensitivity was already demonstrable in NYHA class I patients (4.72 +/- 3.31 vs 9.25 +/- 5.05 msec/mm Hg in control group) (p < 0.005). A further impairment of baroreceptor response was found in patients in NYHA class II (1.94 +/- 2.88 msec/mm Hg, p < 0.001) and class III (1.78 +/- 1.52 msec/mm Hg, p < 0.001). Baroreceptor response showed a significant correlation with functional NYHA class (r = 0.61, p < 0.001) and anaerobic threshold (r = 0.57, p < 0.001) while the correlation was less tight with left ventricular end-diastolic diameter, fractional shortening, left ventricular ejection fraction, pulmonary mean arterial blood pressure, cardiac index, distance at 6 minutes walk corridor test, and maximal oxygen consumption (VO2max). These results suggest that baroreceptor function may be impaired early in the clinical course of heart failure and may contribute to sympathetic activation.

Partial anomalous venous return associated with intact atrial septum and persistent left superior vena cava: a case report and literature review.

Left-sided partial anomalous pulmonary venous return (PAPVR) with an intact atrial septum is a rare cardiovascular anomaly. This report deals with the case of a 22-year-old woman who was referred to our Institution because of resting palpitation and exertional dyspnea. Two-dimensional echocardiography revealed right heart volume overload and a dilated coronary sinus. A left-sided PAPVR draining into a persistent left superior vena cava which, in turn, entered a dilated coronary sinus, was correctly detected by magnetic resonance imaging. Diagnosis was confirmed by cardiac catheterization. The literature on this subject is reviewed.

Doppler echocardiography in suspected lone atrial fibrillation.

Echocardiography is frequently required in patients with atrial fibrillation (AF) to exclude underlying heart disease. In the present investigation the authors evaluated 56 patients with paroxysmal AF (PAF) (27 men, 29 women, mean age 54+/-11.3 years) in whom lone AF was suspected on clinical grounds. M-mode, B-mode, and Doppler examination were performed and measurements taken according to American Society of Echocardiography criteria. Left atrial diameter, left and right atrial volumes, left ventricular (LV) diameters, LV fractional shortening, and Doppler indexes of LV diastolic function were not different in patients with PAF in comparison with those of a control group of 56 age-matched subjects free from cardiovascular diseases. Echocardiographic examination results were entirely normal in 32/56 patients (57%) vs 39/56 of the control group (69%). Mitral valve prolapse was found in five patients (9%), but only one showed mild mitral regurgitation. Doppler examination disclosed a mild (+/++) mitral regurgitation in eight patients and a small aortic or pulmonary diastolic flow in four and two patients, respectively, in the absence of significant morphologic valvular abnormalities. In these patients the sizes of heart chambers were entirely normal. Aneurysm of the interatrial septum was found in one patient and an increased thickness of the epipericardial junction in another two patients. Finally two patients had a small increase of right atrial volume without demonstrable causes. The results suggest that lone AF can be correctly suspected on the basis of clinical findings (history, physical examination, and ECG) and that in these patients echocardiography rarely discloses organic heart disease.

Treatment options for acute venous thromboembolism in the older patient.

The incidence of deep venous thrombosis and pulmonary embolism increases exponentially with age. This pattern reflects the age-related increase in the frequency of serious medical diseases that require prolonged bed rest and predispose to the activation of hemostatic processes. Treatment with heparin and thrombolytic agents is clearly effective in patients age 65 and older, even though an elevated susceptibility to hemorrhagic complications has been demonstrated. Careful evaluation of individual hemorrhagic risk, a slight decrease of doses, and careful laboratory monitoring may decrease the number of clinically significant bleedings without impairing therapeutic results. Low-molecular weight heparin may represent a major advance in the treatment of thromboembolic disease, but studies that specifically address its use in older patients are needed.

Relationship between depressed baroreflex function and exaggerated sympathetic response to exercise in patients with heart failure.

The relationship between impaired baroreflex sensitivity (BS) and the degree of sympathetic activation during exercise in patients with heart failure (HF) has not been studied in detail. For this purpose, we studied BS and measured plasma norepinephrine (NE) at rest, and during and after treadmill exercise in 15 patients and 10 controls. HF patients showed lower BS in comparison to controls (3. 51 +/- 3.62 vs. 9.74 +/- 4.56 ms/mm Hg; p < 0.001), and higher levels of plasma NE at rest (449.3 +/- 147.1 vs. 261.1 +/- 82.48 pg/ml; p < 0.001) and during exercise (1,542 +/- 361.2 vs. 524.6 +/- 92.61 pg/ml; p < 0.001). BS was directly related to pVO2 (r = 0.62; p = 0.0008) and inversely related to NE at peak exercise and to the increase in NE during exercise (r = 0.59, p = 0.005, and r = 0.53; p = 0.0058). Thus, during exercise, a marked sympathetic activation exists in patients with moderate HF. The relationship between increased plasma NE during exercise and decreased BS suggests that impaired baroreceptor function may be present in sympathetic activation in HF patients.

[Anticoagulant therapy in patients with dilated cardiomyopathy]. / La terapia anticoagulante nel paziente con miocardiopatia dilatativa.

Heart failure due to dilated cardiomyopathy is associated with a significant increase in risk of thromboembolism. The incidence can be estimated, on the average, at 2.0-2.5 events per 100 patients per year. At this time, in the absence of randomized trials, limited evidence exists to support the use of anticoagulant treatment for patients with heart failure due to dilated cardiomyopathy in sinus rhythm, even if these subjects appear to be at higher risk than those with ischemic cardiomyopathy and comparable degree of left ventricular dysfunction. Women with left ventricular ejection fraction < 25% constitute a remarkable exception to this rule, and anticoagulation is strongly indicated for them. Unless there are contraindications, anticoagulant treatment is mandatory for patients with heart failure and atrial fibrillation. As studies on preventive treatment in atrial fibrillation have indicated, a target International Normalized Ratio between 2.0 and 3.0 seems appropriate. Patients with intraventricular thrombi present a difficult therapeutic challenge inasmuch as no strong evidence exists that anticoagulant treatment significantly decreases the risk of embolization particularly in patients with flat thrombus. Therapy should thus probably be limited to patients with pedunculated or floating thrombus.

Acute T-cell activation is detectable in unstable angina.

BACKGROUND: Recent studies suggest a role for inflammation in the pathophysiology of unstable angina. This study was designed to investigate whether circulating lymphocytes are involved in the inflammatory reaction associated with the episodes of unstable angina. METHODS AND RESULTS: Twenty-nine patients with proven unstable angina, 36 with stable angina, and 30 healthy subjects were studied. Both early and short-lived (interleukin-2 receptor [IL-2R], alpha-chain CD25, and transferrin receptor CD71) and late antigen (HLA-DR) expression were investigated by flow cytometric analysis. Soluble IL-2R (sIL-2R) was also measured in plasma by ELISA. Lymphocyte activation was studied at day 1 of hospital admission and after 7, 15, 30, 60, and 90 days. In patients with unstable angina, the number of HLA-DR+ CD3 lymphocytes and levels of sIL-2R were higher (P < .001) than in patients with stable angina and control subjects. Both CD4+ and CD8+ lymphocytes expressed HLA-DR antigens. No differences were found among the different groups of subjects in regard to the expression of CD25 and CD71. Lymphocyte activation was more marked in patients with urgent revascularization. No relationships were found between the number of HLA-DR+ lymphocytes and either the severity of coronary angiographic lesions or the number of ischemic episodes. Observations over time showed a gradual decrease in the number of HLA-DR+ lymphocytes and sIL-2R levels from weeks 3 through 8 to 12. CONCLUSIONS: The present results indicate that (1) CD4+ and CD8+ circulating lymphocytes are activated in patients with unstable angina, and their activation state lasts 6 to 8 weeks; and (2) activation of lymphocytes is not a consequence of myocardial ischemia. These results support the immune system-mediated inflammatory nature of unstable angina.

Left atrial size changes in patients with paroxysmal lone atrial fibrillation. An echocardiographic follow-up.

Left atrial enlargement has been demonstrated to occur as a consequence of the arrhythmia in patients with chronic atrial fibrillation (AF) in the absence of organic heart disease, whereas contrasting results have been reported in patients with paroxysmal lone AF. In the present investigation the behavior of left atrial size was followed up for an average period of 30.3 months in 20 patients with paroxysmal lone AF since their first arrhythmic episode. No significant changes in left atrial size were found at the end of the follow-up period. In 65% of patients the arrhythmia recurred at least once yearly. Left atrial size at enrollment was not significantly different in these patients from those without recurrences and did not change in either group during follow-up. The results suggest that in patients with lone AF left atrial dilatation occurs only after the arrhythmia becomes chronic. Early restoration of sinus rhythm may interrupt the vicious circle leading to atrial enlargement.

[Oxygen therapy and pulmonary hypertension in chronic obstructive bronchopneumopathies]. / Ossigenoterapia ed ipertensione polmonare nelle broncopneumopatie croniche ostruttive.

Pulmonary hypertension has a negative prognostic value in the progression of chronic obstructive lung disease. The hypoxic vasoconstriction and subsequent morphological alterations that occur in the small arteries and in the pre-capillary arterioles may contribute to the reduction of the pulmonary vascular bed. The evolution of pulmonary hypertension in patients with chronic obstructive lung disease is not rapid except during relapses of the disease. Oxygen therapy reduces pulmonary arterial pressure values not only via a reduction in the functional abnormalities of the vessels but also via a regression in the anatomic changes induced by hypoxemia. Thus, long-term oxygen therapy may slow the progression of pulmonary hypertension in the course of chronic obstructive lung disease and the longer is oxygen administration the better haemodynamic results are obtained. The Medical Research Council (MRC) Study and the Nocturnal Oxygen Therapy Trial (NOTT) have clearly demonstrated that mortality among hypoxiemic patients treated with low-flow oxygen therapy is reduced; the NOTT also reported a reduction of about 10% in the levels of pulmonary vascular resistances in patients treated with long-term oxygen therapy, while an increase of about 7% has been observed in patients treated with oxygen therapy only during the night. Nevertheless, the reduction of mortality observed during long-term oxygen therapy not always is accompanied by an haemodynamic improvement; in particular a reduction in the pulmonary arterial pressure seems not to reduce mortality. In conclusion long term oxygen therapy may slow the progression of pulmonary hypertension during chronic obstructive lung disease while the improvement in pulmonary haemodynamic due to oxygen therapy is not strictly correlated with a reduction of mortality.