Effectiveness of direct-current cardioversion for treatment of supraventricular tachyarrhythmias,in particular atrial fibrillation,in surgical intensive care patients

OBJECTIVE: To evaluate primary success rate and effectiveness of direct-current cardioversion in postoperative critically ill patients with new-onset supraventricular tachyarrhythmias. DESIGN: Prospective intervention study. SETTING: Twelve-bed surgical intensive care unit in a university teaching hospital. PATIENTS: Thirty-seven consecutive, adult surgical intensive care unit patients with new-onset supraventricular tachyarrhythmias without previous history of tachyarrhythmias. INTERVENTIONS: Direct-current cardioversion using a monophasic, damped sinus-wave defibrillator. Energy levels used were 50, 100, 200, and 300 J for regular supraventricular tachyarrhythmias (n = 6) and 100, 200, and 360 J for irregular supraventricular tachyarrhythmias (n = 31). MEASUREMENTS AND MAIN RESULTS: None of the patients was hypoxic, hypokalemic, or hypomagnesemic at onset of supraventricular tachyarrhythmia. Direct-current cardioversion restored sinus rhythm in 13 of 37 patients (35% primary responders). Most patients responded to the first or second direct-current cardioversion shock. Only one of 25 patients requiring more than two direct-current cardioversion shocks converted into sinus rhythm. Primary responders were significantly younger and demonstrated significant differences in arterial Po2 values at onset of supraventricular tachyarrhythmias compared with nonresponders. At 24 and 48 hrs, only six (16%) and five (13.5%) patients remained in sinus rhythm, respectively. CONCLUSIONS: In contrast to recent literature, direct-current cardioversion proved to be an ineffective method for treatment of new-onset supraventricular tachyarrhythmias and, in particular, atrial fibrillation with a rapid ventricular response in surgical intensive care unit patients.     

Effects of muscarinic receptor stimulation on Ca2+ transient, cAMP production and pacemaker frequency of rabbit sinoatrial node cells

We investigated the contribution of the intracellular calcium (Ca _i ²⁺ ) transient to acetylcholine (ACh)-mediated reduction of pacemaker frequency and cAMP content in rabbit sinoatrial nodal (SAN) cells. Action potentials (whole cell perforated patch clamp) and Ca _i ²⁺ transients (Indo-1 fluorescence) were recorded from single isolated rabbit SAN cells, whereas intracellular cAMP content was measured in SAN cell suspensions using a cAMP assay (LANCE^®). Our data show that the Ca _i ²⁺ transient, like the hyperpolarization-activated “funny current” (I _f) and the ACh-sensitive potassium current (I _K,ACh), is an important determinant of ACh-mediated pacemaker slowing. When I _f and I _K,ACh were both inhibited, by cesium (2 mM) and tertiapin (100 nM), respectively, 1 μM ACh was still able to reduce pacemaker frequency by 72%. In these I _f and I _K,ACh-inhibited SAN cells, good correlations were found between the ACh-mediated change in interbeat interval and the ACh-mediated change in Ca _i ²⁺ transient decay (r ² = 0.98) and slow diastolic Ca _i ²⁺ rise (r ² = 0.73). Inhibition of the Ca _i ²⁺ transient by ryanodine (3 μM) or BAPTA-AM (5 μM) facilitated ACh-mediated pacemaker slowing. Furthermore, ACh depressed the Ca _i ²⁺ transient and reduced the sarcoplasmic reticulum (SR) Ca²⁺ content, all in a concentration-dependent fashion. At 1 μM ACh, the spontaneous activity and Ca _i ²⁺ transient were abolished, but completely recovered when cAMP production was stimulated by forskolin (10 μM) and I _K,ACh was inhibited by tertiapin (100 nM). Also, inhibition of the Ca _i ²⁺ transient by ryanodine (3 μM) or BAPTA-AM (25 μM) exaggerated the ACh-mediated inhibition of cAMP content, indicating that Ca _i ²⁺ affects cAMP production in SAN cells. In conclusion, muscarinic receptor stimulation inhibits the Ca _i ²⁺ transient via a cAMP-dependent signaling pathway. Inhibition of the Ca _i ²⁺ transient contributes to pacemaker slowing and inhibits Ca _i ²⁺ -stimulated cAMP production. Thus, we provide functional evidence for the contribution of the Ca _i ²⁺ transient to ACh-induced inhibition of pacemaker activity and cAMP content in rabbit SAN cells.     

Immediate and long-term effects of addition of exercise to a 16-week very low calorie diet on low-grade inflammation in obese, insulin-dependent type 2 diabetic patients

Objective

To assess the short- and long-term effects of addition of exercise to a very low calorie diet (VLCD) on low-grade inflammation in obese patients with type 2 diabetes mellitus (T2DM).

Methods

Twenty seven obese, insulin-dependent T2DM patients followed a 4-month VLCD with (n = 13) or without (n = 14) exercise and were followed up to 18 months. Anthropometric measurements, metabolic and inflammatory parameters were assessed before, directly after the intervention and at 6 and 18 months follow-up. The same measurements were performed only once in 56 healthy lean and 56 healthy obese controls.

Results

At baseline hsCRP, IL10 and IL8 were significantly elevated in obese T2DM compared to lean healthy controls. After 4 months, despite substantial weight loss (−25.4 ± 1.3 kg), neither the VLCD nor VLCD + exercise had an effect on plasma cytokines. At 6 months, in the weight-stabilizing period, measures of low-grade inflammation had decreased substantially and equally in both intervention groups. Despite subsequent weight regain, beneficial effect was sustained up to 18 months in both groups, except for IL1 and hsCRP which had returned to baseline in the VLCD-only group.

Conclusion

Our findings suggest that severe caloric restriction increases cytokine production by adipose tissue macrophages and that the beneficial effects of weight loss become apparent only in the eucaloric state.     

Bladder pain syndrome/interstitial cystitis: a sense of urgency

A classic triad of symptoms (bladder pain, urinary frequency, and urgency) has served to define bladder pain syndrome/painful bladder syndrome/interstitial cystitis (BPS/PBS/IC) syndrome. BPS/PBS/IC is a distinct condition and it is likely that the urgency experienced by these patients differs from that experienced by those with overactive bladder syndrome. It is unclear how best to define urgency in the BPS/PBS/IC setting. Differences in the other primary symptoms associated with these conditions probably influence how urgency is perceived. Advances in research into the pathophysiology of urgency and underlying disease processes will help to optimize both the diagnosis and treatment of BPS/PBS/IC.     

Status of international consensus on interstitial cystitis/bladder pain syndrome/painful bladder syndrome: 2008 snapshot

Over the last 6 years there have been ongoing efforts around the world to standardize nomenclature, definition, and evaluation of interstitial cystitis/bladder pain syndrome/painful bladder syndrome. The convergence this year of several new projects stimulated an effort to bring together thought leaders from around the world to give a snapshot of current thinking with regard to this disorder. The Society for Urodynamics and Female Urology brought together thought leaders from Europe, Asia, and the United States to Miami, and a broad, structured discussion ensued which is the subject of this report. The most appropriate name of the disease remains an area of contention. A final “definition” of BPS/IC did garner substantial agreement among participants: An unpleasant sensation (pain, pressure, discomfort) perceived to be related to the urinary bladder, associated with lower urinary tract symptoms of more than 6 weeks duration, in the absence of infection or other identifiable causes. It seems that the world is moving to a presumptive diagnosis based on history and physical examination, and relying on invasive procedures for more complex cases, although this is by no means a universal opinion, being more prevalent in the United States and Asia than in Europe. It is hoped that the conference proceedings can serve as a basis for future efforts to develop formal definitions, guidelines, and best practice policies to further advancement of the field. Neurourol. Urodynam. 28:274–286, 2009. © 2009 Wiley‐Liss, Inc.     

Effect of chronic Giardia lamblia infection on epithelial transport and barrier function in human duodenum

BACKGROUND: Giardia lamblia causes infection of the small intestine, which leads to malabsorption and chronic diarrhoea. AIM: To characterise the inherent pathomechanisms of G lamblia infection. METHODS: Duodenal biopsy specimens from 13 patients with chronic giardiasis and from controls were obtained endoscopically. Short-circuit current (I(SC)) and mannitol fluxes were measured in miniaturised Ussing chambers. Epithelial and subepithelial resistances were determined by impedance spectroscopy. Mucosal morphometry was performed and tight junction proteins were characterised by immunoblotting. Apoptotic ratio was determined by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labelling staining. RESULTS: In giardiasis, mucosal surface area per unit serosa area was decreased to 75% (3%) of control, as a result of which epithelial resistance should increase. Instead, epithelial resistance of giardiasis biopsy specimens was decreased (19 (2) vs 25 (2) Omega cm(2); p<0.05) whereas mannitol flux was not significantly altered (140 (27) vs 105 (16) nmol/h/cm(2)). As structural correlate, reduced claudin 1 expression and increased epithelial apoptosis were detected. Furthermore, basal I(SC) increased from 191 (20) in control to 261 (12) microA/h/cm(2) in giardiasis. The bumetanide-sensitive portion of I(SC) in giardiasis was also increased (51 (5) vs 20 (9) microA/h/cm(2) in control; p<0.05). Finally, phlorizin-sensitive Na(+)-glucose symport was reduced in patients with giardiasis (121 (9) vs 83 (14) microA/h/cm(2)). CONCLUSIONS: G lamblia infection causes epithelial barrier dysfunction owing to down regulation of the tight junction protein claudin 1 and increased epithelial apoptoses. Na(+)-dependent d-glucose absorption is impaired and active electrogenic anion secretion is activated. Thus, the mechanisms of diarrhoea in human chronic giardiasis comprise leak flux, malabsorptive and secretory components.     

Percutaneous Vein Occlusion with Small Intestinal Submucosa: An Experimental Pilot Study in Swine and Sheep

Purpose The objective of this study was to investigate the feasibility, outcomes, and amount of small intestinal submucosa (SIS) material needed for embolization of jugular vein (JV) in a swine and sheep model. Our hypothesis was that SIS would cause vein occlusion. Materials and Methods The external JVs (EJV) in swine (n = 6) and JVs in sheep (n = 6) were occluded with SIS fan-folded compressed strips. After percutaneous puncture of the peripheral portion of the EJV or JV, a TIPS set was used to exit their lumen centrally through the skin. The SIS strips were delivered into the isolated venous segment with a pull-through technique via a 10-Fr sheath. Follow-up venograms were done immediately after placement and at the time of sacrifice at 1 or 3 months. Gross examinations focused on the EJV or JV and their surrounding structures. Specimens were evaluated by histology. Results SIS strip(s) placement was successful in all cases, with immediate vein occlusion seen in 23 of 24 veins (95.8%). All EJVs treated with two strips and all JVs treated with three or four strips remained closed on 1- and 3-month follow-up venograms. Two EJVs treated with one strip and one JV treated with two strips were partially patent on venograms at 1 and 3 months. There has been one skin inflammatory reaction. Necropsies revealed excluded EJV or JV segments with SIS incorporation into the vein wall. Histology demonstrated various stages of SIS remodeling with fibrocytes, fibroblasts, endothelial cells, capillaries, and inflammatory cells. Conclusion We conclude that EJV and JV ablation with SIS strips using percutaneous exit catheterization is feasible and effective in animal models. Further exploration of SIS as vein ablation material is recommended.