Catheter Ablation for Ventricular Tachycardia in Structural Heart Disease

The management of ventricular tachyarrhythmias has changed significantly over the past several decades. The advent of readily available implantable cardioverter defibrillators (ICDs) has had the greatest effect, with important mortality effects in patients with ventricular tachycardia and structural heart disease. ICDs have been shown to reduce sudden death in patients with ischemic and nonischemic cardiomyopathies; evidence of adverse consequences of ICD shocks, however, is mounting. In addition to the negative effects on patient-reported quality of life, anxiety, and depression, frequent ventricular arrhythmias and ICD shocks have also been associated with increased mortality. It is therefore important to identify and implement effective ventricular tachycardia-suppressive strategies. Antiarrhythmic drugs represent one such method, but are challenged by unfavourable side effect profiles and proarrhythmic risk. Catheter ablation of ventricular tachycardia is now a well-accepted intervention, which has been demonstrated to reduce recurrent arrhythmias. Questions persist regarding the optimal role for ablation compared with drug therapy.     

Allosensitization in Heart Transplantation: An Overview

Transplant candidates might manifest circulating antibodies against human leukocyte antigens and nonhuman leukocyte antigens, a condition termed allosensitization. The presence of these antibodies decreases a given candidate's possible donor pool, thereby prolonging the time to transplantation. They are also associated with poorer posttransplant outcomes including increased morbidity and mortality. With the increasing use of ventricular assist devices as a bridge to transplantation, the prevalence of allosensitized transplant candidates has increased. This has implications for transplant programs in terms of donor-recipient matching and managing transplant-related complications, which are more common in this high risk cohort. Controversy exists as to the best approach in managing sensitized patients, before and after transplantation. Transplant centres have used various strategies to reduce antibody loads with mixed results being reported; moreover, it remains unclear as to whether attempts at desensitization translate into better posttransplant outcomes. As an alternative management approach, some centres participate in large organ sharing strategies and allocate organs based on the probability of finding a successful donor-recipient match. In this article, the immunological basis of allosensitization, its causes, implications, and therapeutic strategies to manage sensitized patients are reviewed. The literature in relation to desensitization therapies in heart transplant candidates is also reviewed.     

Bedside Ultrasound Is a Practical and Reliable Measurement Tool for Assessing Quadriceps Muscle Layer Thickness

Background: Critically ill patients commonly experience skeletal muscle wasting that may predict clinical outcome. Ultrasound is a noninvasive method that can measure muscle quadriceps muscle layer thickness (QMLT) and subsequently lean body mass (LBM) at the bedside. However, currently the reliability of these measurements are unknown. The objectives of this study were to evaluate the intra‐ and interreliability of measuring QMLT using bedside ultrasound. Methods: Ultrasound measurements of QMLT were conducted at 7 centers on healthy volunteers. Trainers were instructed to perform measurements twice on each patient, and then a second trainee repeated the measurement. Intrarater reliability measured how consistently the same person measured the subject according to intraclass correlation (ICC). Interrater reliability measured how consistently trainer and trainee agreed when measuring the same subject according to the ICC. Results: We collected 42 pairs of within operator measurements with an ICC of .98 and 78 pairs of trainer‐to‐trainee measurements with an ICC of .95. There were no statistically significant differences between the trainer and trainee results (trainer and trainee mean = ?0.028 cm, 95% CI = ?0.067 to ?0.011, P = .1607). Conclusions: Excellent intra‐ and interrater reliability for ultrasound measurements of QMLT in healthy volunteers was observed when performed by a range of providers with no prior ultrasound experience, including dietitians, nurses, physicians, and research assistants. This technique shows promise as a method to evaluate LBM status in ICU or hospital settings and as a method to assess the effects of nutrition and exercise‐based interventions on muscle wasting.     

Parenteral Fish Oil Lipid Emulsions in the Critically Ill

Introduction: ω‐3 Polyunsaturated fatty acids contained in fish oils (FO) possess major anti‐inflammatory, antioxidant, and immunologic properties that could be beneficial during critical illness. We hypothesized that parenteral FO‐containing emulsions may improve clinical outcomes in the critically ill. Methods: We searched computerized databases from 1980–2012. We included randomized controlled trials (RCTs) conducted in critically ill adult patients that evaluated FO‐containing emulsions, either in the context of parenteral nutrition (PN) or enteral nutrition (EN). Results: A total of 6 RCTs (n = 390 patients) were included; the mean methodological score of all trials was 10 (range, 6–13). When the results of these studies were aggregated, FO‐containing emulsions were associated with a trend toward a reduction in mortality (risk ratio [RR], 0.71; 95% confidence interval [CI], 0.49–1.04; P = .08; heterogeneity I² = 0%) and a reduction in the duration of mechanical ventilation (weighted mean difference in days [WMD], ?1.41; 95% CI, ?3.43 to 0.61; P = .17). However, this strategy had no effect on infections (RR, 0.76; 95% CI, 0.42–1.36; P = .35) and intensive care unit length of stay (WMD, ?0.46; 95% CI, ?4.87 to 3.95; P = .84, heterogeneity I² = 75%). Conclusion: FO‐containing lipid emulsions may be able to decrease mortality and ventilation days in the critically ill. However, because of the paucity of clinical data, there is inadequate evidence to recommend the routine use of parenteral FO. Large, rigorously designed RCTs are required to elucidate the efficacy of parenteral FO in the critically ill.     

Incat disability score: A critical analysis of its measurement properties

Background: The INCAT (Inflammatory Neuropathy Cause and Treatment) disability score is a measure of activity limitation. It is used frequently as a primary endpoint in inflammatory polyneuropathy clinical trials. A comprehensive critical analysis of its measurement properties has not been performed. Methods: Critical analysis of measurement properties. Results: The INCAT disability score was derived based on items from Guy's Neurological Disability Scale (GNDS), a disability measure intended for application in multiple sclerosis. Strengths of the INCAT score include evaluation of upper and lower limb dysfunction, ease of administration (feasibility), high face validity, and high reliability. Weaknesses of the scale include concerns about methodological quality of validation studies; failure to properly capture activity limitations due to proximal arm weakness, or fatigue; heavy individual item weighting; and poor sensitivity for detection of clinically important change. Conclusions: Although the INCAT scale has been an effective tool in inflammatory polyneuropathy studies, its limitations may warrant development of new scales. Muscle Nerve 50:164–169, 2014