Electrocardiographic criteria for differentiating aberrancy and ventricular extrasystole in chronic atrial fibrillation: validation by intracardiac recordings

Many electrocardiographic criteria have been proposed for the differentiation of ventricular extrasystole and supraventricular conduction with aberrancy in atrial fibrillation but the validity of these have not been confirmed by intracardiac studies. We recorded His bundle electrograms in nineteen patients (eleven men, eight women) referred for diagnosis of abnormal QRS complexes in the context of chronic atrial fibrillation. Of 1,068 wide QRS complexes analyzed, 91% proved to be of ventricular origin. Electrocardiographic criteria which were specific for ventricular extrasystole included: left bundle branch block morphology, right bundle branch block morphology with a monophasic R in lead V1 or an RS or QS pattern in lead V6, presence of a "compensatory pause", i.e., compensatory cycle (V2-V3) longer than the average cycle length of ten normally conducted beats preceding the abnormal complex (927 +/- 317 vs 780 +/- 199, mean +/- SD in msec. p less than 0.005), frontal QRS axis of the abnormal complex directed superiorly or to the right and the presence of a "short-long" cycle sequence. Right bundle branch morphology with a triphasic R in lead V1 or QRS pattern in V6 and concordant initial vector in lead V1 or in more than one ECG leads were very specific for supraventricular conduction with aberrancy. Analysis of coupling interval and Ashman's phenomenon, i.e., the long-short cycle sequence, were not specific for supraventricular conduction with aberrancy. We conclude that in digitalis-treated patients with chronic atrial fibrillation the majority of abnormal QRS complexes are of ventricular origin. The diagnosis of ventricular extrasystole or aberrancy can be made using a single ECG lead (V1) and applying a combination of easily applied criteria.     

Mechanical strain of glomerular mesangial cells in the pathogenesis of glomerulosclerosis: clinical implications.

Due to their elasticity, glomeruli will undergo excessive expansion and repetitive cycles of distension contraction under conditions of impaired glomerular pressure autoregulation and systemic arterial hypertension. These alterations in glomerular volume are associated with mesangial cell stretch which in turn stimulates the synthesis and deposition of ECM with eventual mesangial expansion and glomerulosclerosis. Hyperactivity of growth factors with prosclerotic activity is an important component in the translation of cellular mechanical strain into the abnormal metabolism of ECM components. Although mesangial cell mechanical strain is expected to occur in both remnant glomeruli and in glomeruli of diabetic kidneys, quantitatively different factors will determine the resultant metabolic consequences. In remnant glomeruli, the mechanical stretch is intense, being accounted for largely by the marked glomerular hypertrophy and increased glomerular compliance. In diabetic glomeruli, however, the mechanical stretch is less prominent but its effect on ECM synthesis is markedly aggravated by the presence of hyperglycaemia. There are presently no methods clinically available to diminish the prosclerotic action of growth factors at the glomerular level. In addition, there are no effective means to specifically improve glomerular pressure autoregulation. Therefore, current therapies must be aimed at decreasing systemic arterial pressure, blocking angiotensin II action and reducing glomerular hypertrophy. While there are effective drugs for the treatment of hypertension and for angiotensin II inhibition, protein restriction is the only measure available to diminish glomerular hypertrophy. Finally, in diabetes correction of systemic and glomerular hypertension should be coupled with strict glycaemic control to correct both glomerular autoregulation and increased ECM deposition.     

Two-incision technique for minimally invasive total hip arthroplasty

Recently, there has been considerable interest and debate over the application of minimally invasive surgical approaches to primary total hip arthroplasty. The 2-incision technique employs intermuscular and internervous planes to gain access to the hip joint while minimizing the disruption of muscles and tendons. Through the anterior incision, the femoral neck is osteotomized and the head removed, followed by preparation and cementless reconstruction of the acetabulum. The posterior incision permits femoral preparation and reconstruction with a cementless stem. The potential benefits of this technique include decreased perioperative blood loss and pain, more rapid recovery of hip function and return to normal activity, a reduced length of hospital stay, and cosmetically appealing small scars. Other essential considerations include appropriate patient selection, adherence to surgical principles, and familiarity with specialized instruments and implants.     

Targeting Insulin and Insulin-Like Growth Factor Signaling in Breast Cancer

The insulin and insulin like growth factor (IGF) signaling systems are implicated in breast cancer biology. Thus, disrupting IGF/insulin signaling has been shown to have promise in a number of preclinical models. However, human clinical trials have been less promising. Despite evidence of some activity in early phase trials, randomized phase III studies have thus far been unable to show a benefit of blocking IGF signaling in combination with conventional strategies. In breast cancer, combination anti IGF/insulin signaling agents with hormone therapy has not yet proven to have benefit. This inability to translate the preclinical findings into useful clinical strategies calls attention to the need for a deeper understanding of this complex pathway. Development of predictive biomarkers and optimal inhibitory strategies of the IGF/insulin system should yield better clinical strategies. Furthermore, unraveling the interaction between the IGF/insulin pathway and other critical signaling pathways in breast cancer biology, namely estrogen receptor-α (ERα) and epidermal growth factor receptor (EGFR) pathways, provides additional new concepts in designing combination therapies. In this review, we will briefly summarize the current strategies targeting the IGF/insulin system, discuss the possible reasons of success or failure of the existing therapies, and provide potential future directions for research and clinical trials.     

Laparoscopic live donor nephrectomy: Current practice and results of renal transplantation

Objective: In 2009, 1659 patients with end‐stage renal failure in Hong Kong were waiting for a renal transplant. The overall number of renal transplants carried out locally remains low, with an even lower number being live donor donations. Yet, live donor kidney transplantation yields results that are consistently superior to those of deceased donor kidney transplantation, and laparoscopic donor nephrectomy (LDN) is increasingly accepted worldwide as a safe and preferred surgical option. We aim to evaluate the outcome of LDN in our setting, and to compare with that of deceased donors in this retrospective review. Patients and Methods: A total of 12 patients received LDN over the study period of 2006–2009. Standard left transperitoneal LDN was carried out. Grafts including three with double vessels were prepared using the bench technique. The postoperative outcomes up to 1 year for both the donors and the recipients were studied. Contemporary results for the 47 deceased donor kidneys were studied and compared. Results: All donors had an eventful recovery. The operating time was 225.0 ± 67.4 min. The hospital stay was 5.6 ± 2.3 days. The recipient outcomes including hospital stay and creatinine levels at discharge and 1 year were 11 days, 121 umol/L and 116 umol/L, respectively. Specifically, no ureteric stricture or graft loss was noted at the 1‐year follow up. Recipient complications included haematoma (1 patient), renal artery stenosis (1 patient) and redo of vascular anastomosis (1 patient). In contrast, the deceased donor graft recipients had a hospital stay of 11 days, and creatinine levels of 205 umol/L on discharge and 205 umol/L at 1 year, respectively. The delayed graft function rates for the live donor and deceased donors group were 0% and 14.9%, whereas the 1‐year graft survival rates were 100% and 87.2% respectively. Conclusion: The results showed that the donor morbidity rate was low, as reflected by the short hospital stay. Also, the overall parameters of recipients were good. In particular, no ureteric stricture was noted, and graft survival was 100% at 1 year. Living donor kidney transplant program using the laparoscopic technique is a viable option to improve the pool of kidneys for transplantation.     

Recommendations for the management of septic arthritis after ACL reconstruction

Purpose

To evaluate the current evidence for the management of septic arthritis after anterior cruciate ligament (ACL) reconstruction, the factors that affect the outcome after treatment and the retention of graft and implants.

Methods

A systematic literature search of the PubMed database was performed on septic arthritis after ACL reconstruction. A total of 301 publications were initially identified, and 17 papers were found to fulfil the criteria to be included in the review.

Results

There were 196 cases of septic arthritis after ACL reconstruction in over 30,000 ACL reconstructions, making the proportion of infection 0.6 %. Most patients (114/123, 92.6 %) had an acute or subacute infection at an average of 16.8 ± 10.5 days after ACL reconstruction. Coagulase-negative Staphylococci (CNS) was the most common organism (67/147, 45.6 %) followed by Staphylococcus aureus (SA) (35/147, 23.8 %); 86.9 % underwent surgical treatment of which 92.8 % had an average of 1.54 (up to 4) arthroscopic debridements. The group with SA infection had a higher graft removal rate (33.3 %, p = 0.019), a longer antibiotic duration (35.4 days, p = 0.047) and a worse range of flexion (111.5°, p = 0.036) than the CNS group.

Conclusions

CNS was the most common organism in septic arthritis after ACL reconstruction followed by SA. For most authors, arthroscopic debridement combined with intravenous antibiotic therapy was the initial treatment of choice. Antibiotic therapy with or without multiple irrigations of the joint is not recommended based on the high failure rates. Delayed diagnosis of more than 7 days or SA infection required a longer duration of antibiotic therapy and increased the likelihood for graft removal and restricted range of motion. Fungal infection and tubercular infection had a high prevalence of late diagnosis and open debridement.

Level of evidence

Systematic review, Level IV.