F. Crea

An uncommon presentation for a severe invasive infection due to methicillin-resistant Staphylococcus aureus clone USA300 in Italy: a case report

BackgroundMethicillin resistant Staphylococcus aureus (MRSA) has been considered for many years a typical nosocomial pathogen. Recently MRSA has emerged as a frequent cause of infections in the community. More commonly, community-acquired (CA)-MRSA is a cause of infections of the skin and soft-tissues, but life-threatening infections such as necrotizing pneumonia and sepsis can occasionally occur.Case presentationThis report describes an uncommon presentation of invasive CA-MRSA infection in an adolescent without known risk factors. The presentation was typical for bacterial meningitis, but the clinical findings also revealed necrotizing pneumonia. Following the development of deep venous thrombosis, the presence of an inherited trombophilic defect (factor V Leiden) was detected. The patient was successfully treated with an antibiotic combination including linezolid and with anticoagulant therapy. CA-MRSA was isolated from both cerebrospinal fluid and blood. The isolates were resistant to oxacillin and other beta-lactam antibiotics and susceptible to the other antibiotics tested including erythromycin. Molecular typing revealed that the strains contained the Panton-Valentine leukocidin genes and type IV SCCmec, and were ST8, spa type t008, and agr type 1. This genetic background is identical to that of the USA300 clone.ConclusionThis report highlights that meningitis can be a new serious presentation of CA-MRSA infection. CA-MRSA strains with the genetic background of the USA300 clone are circulating in Italy and are able to cause severe infections.

Prognostic value of ventricular arrhythmias and heart rate variability in patients with unstable angina

Objectives: To assess the prognostic value of ventricular arrhythmias (VA) and heart rate variability (HRV) in patients with unstable angina. Design: Multicentre prospective study. Setting: 17 cardiological centres in Italy. Patients: 543 consecutive patients with unstable angina and preserved left ventricular function (ejection fraction ⩾40%) enrolled in the SPAI (Stratificazione Prognostica dell’Angina Instabile) study. Methods: Patients underwent 24 h ECG Holter monitoring within 24 h of hospital admission. Tested variables were frequent ventricular extrasystoles (⩾10/h), complex (that is, frequent or repetitive) VA, and bottom quartile values of time-domain and frequency-domain HRV variables. Primary end points were in-hospital and six-month total and cardiac deaths. Results: Eight patients died in hospital (1.5%) and 32 (5.9%, 29 cardiac) during follow up. Both complex VA and frequent extrasystoles were strongly predictive of death in hospital and at follow up, even after adjustment for clinical (age, sex, cardiac risk factors and history of myocardial infarction) and laboratory (troponin I, C reactive protein and transient myocardial ischaemia on Holter monitoring) variables. At univariate analysis bottom quartile values of three HRV variables (standard deviation of RR intervals index, low-frequency amplitude and low to high frequency ratio) were associated with in-hospital death, and bottom quartile values of most HRV variables predicted six-month fatal events. At multivariate Cox survival analysis reduced low-frequency amplitude was consistently found to be independently associated with fatal end points. Conclusion: In patients with unstable angina with preserved myocardial function, both VA and HRV are independent predictors of in-hospital and medium-term mortality, suggesting that these factors should be taken into account in the risk stratification of these patients.

Diagnostic and prognostic value of ST segment depression limited to the recovery phase of exercise stress test

Objectives: To investigate the diagnostic and prognostic value of ST segment depression limited to the recovery phase of an exercise stress test, as compared with that of ST segment depression appearing during exercise. Setting: Exercise stress test laboratory of a university hospital. Patients and design: Clinical and angiographic data were compared for 574 consecutive patients who developed ST segment depression during the active phase of an exercise test (group 1) and for 79 patients who developed ST segment depression only during the recovery phase of the exercise test (group 2). Results: There were no differences between the two groups in major clinical features. Significant coronary artery stenoses were found in 488 group 1 patients (85%) and in 62 group 2 patients (78%, p  =  0.14). Three vessel or left main disease was found in 166 (29%) group 1 and in 14 (18%) group 2 patients (p  =  0.045). At a median follow up of 55.3 months of 321 group 1 and 54 group 2 patients, there were no significant differences in major cardiac events between the groups (univariate relative risk 0.81, 95% confidence interval 0.25 to 2.68, p  =  0.72). Conclusion: The diagnostic and prognostic power of ST segment depression limited to the recovery phase of an exercise test is largely similar to that of ST segment depression induced during effort; thus, assessing ST segment depression during recovery can significantly improve the clinical information derived from exercise stress tests.

C reactive protein is associated with malignant ventricular arrhythmias in patients with ischaemia with implantable cardioverter-defibrillator

Patients with ischaemic heart disease and low ejection fraction (EF) are at increased risk of sudden death. MADIT (Multicenter Automated Defibrillator Implantation Trial) II has shown that implantable cardioverter-defibrillators (ICDs) reduce the risk of death by 31% at two years in patients with previous myocardial infarction and EF < 30%.1 The absolute risk reduction over an average follow up of 20 months, however, was only 5.6%. In addition, the high prevalence of patients who have had a myocardial infarction with EF ⩽ 30% makes the cost of this strategy high. This has led to an ongoing search for reliable markers of future episodes of life-threatening ventricular tachycardia (VT) or ventricular fibrillation (VF) to identify a higher-risk subgroup in which ICD therapy can be more beneficial and cost effective. The difficulty in predicting major ventricular arrhythmias probably reflects a limited understanding of their complex mechanisms. This is particularly true for patients who have had a myocardial infarction and with LV dysfunction, in whom myocardial ischaemia may trigger major ventricular arrhythmias. C reactive protein (CRP) concentration has been shown to be raised both in subjects studied …

Increased platelet sodium–hydrogen exchanger activity in patients with variant angina

The causes of coronary artery spasm in patients with variant angina remain unknown. The segmental location of spasm indicates local hyperreactivity, but a diffuse increased coronary vasoconstriction, suggesting a substrate which could facilitate spasmogenic modifications, has been reported in many patients.1 The membrane sodium–hydrogen (Na+–H+) exchanger (NHE) is a major regulator of intracellular pH (pHi).2 An increased activity of the NHE isoform 1 (NHE-1) in smooth muscle cells has been suggested to favour vasoconstriction by causing intracellular alkalinisation and calcium overload.3 Furthermore, potential triggers of spasm (catecholamines, endothelin-1) have been shown to increase NHE-1 activity.4 In this study we investigated NHE-1 activity in platelets of patients with variant angina. The study group included 17 patients (13 men, 58 (9) years) with variant angina (angina attacks at rest, associated with transient ST segment elevation). Patients with hypertension and diabetes were excluded. The control group included 17 healthy subjects (13 men, 55 (6) years) without any history of chest pain, and with normal physical examination, ECG, and laboratory tests. ### Study protocol Because of ethical reasons, calcium antagonist drugs could not be withdrawn in patients, who, however, were invited not to take these drugs on the day of the study. Other drugs were withdrawn for more than one week before the study. A blood sample of 50 ml was drawn from an antecubital vein. To …

Cardiac magnetic resonance of healthy children and young adults with frequent premature ventricular complexes

Objective To assess whether magnetic resonance imaging could detect any cardiac morphological or functional myocardial alterations in healthy children and young adults with ventricular arrhythmias. Methods Twenty-three subjects (14 male, mean age 15.6 ± 6.5 years) with frequent (≥30/h) premature ventricular complexes (PVCs) on Holter monitoring and normal echocardiographic and electrocardiographic findings underwent cardiac magnetic resonance (CMR) on a 1.5T scanner and an exercise stress test. Subjects were also followed up for a period of 71 ± 24 months. Results CMR showed no evidence of structural cardiac abnormalities, but functional assessment revealed significant impairment in 17 subjects (74%): mild to moderate right ventricular enlargement was found in all of these subjects associated with a mild reduction of ventricular function in five cases (22%) and mild free wall and/or apex contraction abnormalities in eight subjects (35%). PVCs persisted during stress test in three subjects (13%) and disappeared in 19 (83%). No serious cardiac event was observed during the follow-up. Conclusions Our study shows that subjects with PVCs without detectable electrocardiographic and echocardiographic abnormalities frequently exhibit functional impairment of the right ventricle at CMR, potentially responsible for ventricular arrhythmias. Although the causes of these abnormalities remain to be elucidated, the long-term outcome of these subjects is excellent.

Changes in platelet receptor expression and leukocyte-platelet aggregate formation following exercise in Cardiac Syndrome X

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Irbesartan significantly reduces C reactive protein concentrations after 1 month of treatment in unstable angina

The renin–angiotensin system (RAS) has been demonstrated to play not only an important role in cardiovascular homeostasis by influencing vascular tone and fluid–electrolyte balance, but is also involved in the atherothrombotic process, cardiac remodelling, and apoptosis. Agents that inhibit the RAS, such as angiotensin converting enzyme (ACE) inhibitors and angiotensin II type 1 receptor blockers (ARBs), exert considerable benefits in hypertension and heart failure. However, ACE inhibitors may not provide total inhibition of angiotensin II (Ag II) generation, because of non-ACE dependent Ag II producing mechanisms. ARBs are able to exert more specific and complete blockade of the RAS, overcoming some of the ACE inhibitor limitations. In fact they block Ag II effects on catecholamine production, vasoconstriction, aldosterone secretion, low density lipoprotein transport, hypertrophy, and cell growth, without affecting the Ag II mediated positive effects on the type II receptor, such as vasodilatation and inhibition of cell growth.1 A growing body of data has consistently described an anti-inflammatory action of ARBs. In patients with early atherosclerosis, irbesartan decreases markers of inflammation.2 It has also been described that Ag II blockade improves the anti-inflammatory response of aspirin and statins in stable coronary heart disease patients.3,4 However, a potential anti-inflammatory role of ARBs has not been evaluated in acute coronary syndromes (ACS), a condition in which inflammation is an acknowledged pathophysiological mechanism. In ACS both cellular …