Recommendations for participation in leisure-time physical activity and competitive sports of patients with arrhythmias and potentially arrhythmogenic conditions. Part II: ventricular arrhythmias, channelopathies and implantable defibrillators.

This consensus paper on behalf of the Study Group on Sports Cardiology of the European Society of Cardiology follows a previous one on guidelines for sports participation in competitive and recreational athletes with supraventricular arrhythmias and pacemakers. The question of imminent life-threatening arrhythmias is especially relevant when some form of ventricular rhythm disorder is documented, or when the patient is diagnosed to have inherited a pro-arrhythmogenic disorder. Frequent ventricular premature beats or nonsustained ventricular tachycardia may be a hallmark of underlying pathology and increased risk. Their finding should prompt a thorough cardiac evaluation, including both imaging modalities and electrophysiological techniques. This should allow distinguishing idiopathic rhythm disorders from underlying disease that carries a more ominous prognosis. Recommendations on sports participation in inherited arrhythmogenic conditions and asymptomatic gene carriers are also discussed: congenital and acquired long QT syndrome, short QT syndrome, Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia, arrhythmogenic right ventricular cardiomyopathy and other familial electrical disease of unknown origin. If an implantable cardioverter defibrillator is indicated, it is no substitute for the guidelines relating to the underlying pathology. Moreover, some particular recommendations for patients/athletes with an implantable cardioverter defibrillator are to be observed.     

Filament Transport Control for Enhancing Mechanical Properties of Parts Realised by Fused Filament Fabrication

The fused filament fabrication (FFF) process is widely used for producing prototypes and functional parts for diverse applications. While FFF is particularly attractive due to its cost-effectiveness, on the other hand, the fabricated parts have limitations in terms of large manufacturing time and reduced mechanical properties. The latter is strongly influenced by the fabrication process parameters, which affect the interlayer bonding and the adhesion between consecutive layers. Several works presented in the literature analysed the correlation between mechanical properties and process parameters. It was demonstrated that an increase in the fabrication feed rate causes slippage between filament and the feeding system, which leads to a decrease in the extruded material flow, and thus in part density. This work aims to investigate how the limitation of the slippage phenomenon affects the mechanical properties of parts fabricated using the FFF process. A prototype machine, equipped with a closed-loop control system on filament transport, was used to fabricate samples for tensile tests and dynamical mechanical analysis. Samples fabricated enabling the filament transport control showed an increase both in ultimate tensile strength and elongation at break for those fabricated with disabled control, whilst a decrease in stiffness was observed. In addition, the results showed that the use of a filament transport control system on a FFF machine increases the possibility of fabricating high value-added parts.     

Experimental First-Pass Method for Testing and Comparing Sorbent Polymers Used in the Clearance of Iodine Contrast Materials

Background: Sorbents have been shown to adsorb iodinated radiocontrast media. Objective: In this study we describe a simple method to compare various sorbents in terms of capacity to adsorb radiocontrast media. Methods: Iodixanol solution was injected into columns filled with three types of sorbent at filtration velocities of increasing magnitude. Two variables of interest - contrast removal rate and matched iodine retention (MIR) - were calculated to measure the adsorption efficiency and the mass of contrast iodine adsorbed versus sorbent used, respectively. Results: The highest contrast removal and MIR for Porapak Q, CST 401 and Amberlite XAD4 were 41, 38 and 16% (p = 0.22 and 0.0005 for comparisons between Porapak Q-CST 401 and CST 401-Amberlite XAD4) and 0.060, 0.055 and 0.024, respectively (p = 0.18 and 0.0008). Extrapolation to a clinical scenario may suggest that removal of 8 ml iodixanol could be achieved by masses of sorbents of 43, 47 and 107 g, respectively. Conclusion: In this study we set a benchmark for comparing the radiocontrast-adsorbing efficiency of polymer sorbents during first-pass experiments, using a readily available methodology.     

Corticotropin-releasing activity of the renin-angiotensin system peptides in rat and in man

In this study we investigated in the rat the binding and corticotropin-releasing factor (CRF) activity of various constituents of the renin-angiotensin system and the possible angiotensin II receptor changes following procedures known to alter plasma renin activity. We investigated also the CRF activity of angiotensin II in vitro and in vivo in humans. The CRF activity of peptides was studied by their ability to stimulate ACTH release from pituitary cells. Deleting amino acids from the N-terminus of angiotensin II resulted in decreased CRF activity; while the ED50 for angiotensin II was 2 nM, it increased to about 10 nM for the (2-8)-heptapeptide. Angiotensin I had a weak CRF activity, whereas the substrate angiotensinogen had no stimulatory effect even at a concentration of 100 nM. There was a strong correlation between the activation and binding properties of all peptides tested. Dietary salt load or depletion as well as dexamethasone treatment did not affect the number nor the affinity of pituitary angiotensin II receptors. Angiotensin II had a CRF activity on human pituitary cells in vitro. However, peripherally injected agiotensin II at a pressive dose of 7 ng/kg/min did not produce any ACTH release in normal male volunteers. These data suggest that angiotensin II may play a modulatory role in the physiological regulation of ACTH secretion, but this role might be attributed to the endogenous brain angiotensin II as it is not closely dependent on the angiotensin II plasma levels.     

Treatment by angioplasty of obstructions of arteriovenous fistulas for hemodialysis access

The angioaccess for chronic hemodialysis is often complicated by obstructing lesions. Recently, angioplasty has been introduced as a treatment of choice for these lesions. Seven patients with obstructed arteriovenous fistulas have been treated with angioplasty on an outpatient basis. In all cases a definite raise in flux values occurred. In two patients a restenosis appeared respectively 6 and 9 months after the dilatation. These new stenosis were successfully treated by means of angioplasty. No complications occurred because of the procedure. The average follow-up was 8 months (max 12 months).     

Principles of surgical technique of the anterior access to the thoraco-lumbar spine

General surgeons are more and more frequently requested to prepare an operative exposure of the spine, in order to perform anterior maneuvers of removal and stabilization of the vertebral bodies. Since 1989 to date, in collaboration with the neurosurgical équipe of Prof. G. Cantore, Neurological Sciences Department, La Sapienza University of Rome, the Authors have collected 116 cases of vertebral diseases: among them, 48 involved the thoraco-lumbar junction of the spine (D12-L2). In this paper, Authors' aim is to state precisely the surgical technique of the anterior access to the thoraco-lumbar junction: attention has been focused on this tract of the column stating its anatomical complexity and the high invasivity of the procedures requested for its exposure. Therefore, such notes of technique have been elaborated to make safer the neurosurgical demolitive and reconstructive procedures and, most of all, to reduce the surgical trauma whenever it is possible.     

Abdominal approach to the treatment of the vestigial retrorectal tumors: our experience

Although the vestigial retrorectal cysts are still rare, the number of the observed ones is destined to increase, as methods by imaging become routinely used in the clinical practice. Once diagnosed, the removal of retrorectal lesions should be mandatory. Therefore, by reporting three clinical cases, the Authors propose notes of technique above the abdominal approach used for the surgical treatment of these retrorectal congenital neoformations. In their experience, the anterior route had no postoperative complications, short stay, no neurological consequences and good long-term results.