Myocardial fibrosis is associated with biventricular dysfunction in patients with hypertrophic cardiomyopathy

Aims: To assess left (LV) and right ventricular (RV) function by two‐dimensional (2D) speckle tracking echocardiography and its relation to myocardial fibrosis in hypertrophic cardiomyopathy (HCM). Methods: We enrolled 50 HCM patients (30 male; 47.3 ± 9.9 years) in our study. Each patient received echocardiography with modern high‐end scanners. For speckle tracking analysis of LV and RV function the dedicated software was used. The presence of myocardial fibrosis was detected by cardiac magnetic resonance imaging (MRI). Results: For intraobserver variability of RV global longitudinal strain, we found a correlation of r = 0.89 (p < 0.001) with a minor bias of 4.9 ± 2.9%. On cardiac MRI 30 patients (60%) demonstrated late gadolinium‐enhancement (LGE) of the LV. Of these patients only 7% showed LGE of the RV. HCM patients with myocardial fibrosis had less global longitudinal LV strain in comparison to patients without myocardial fibrosis (?12.8 ± 2.2 vs ?21.1 ± 2.6, P < 0.001), thicker interventricular septums (23.7 ± 4.0 vs 19.2 ± 5.1, P < 0.001), larger left atria (34.9 ± 7.1 vs 23.9 ± 5.1, P < 0.001), and impaired diastolic function (E/A‐ratio: 1.02 ± 0.22 vs 1.15 ± 0.18, P < 0.01). Comparable results were found for RV function. LV and RV strain correlated with r = 0.85 (p < 0.001). Conclusions: HCM is not only a disease of the LV. LGE in HCM is associated with both LV and RV dysfunction. Although RV LGE occurs only in a minority of patients with HCM and LV fibrosis, speckle tracking echocardiography is feasible for evaluating LV and RV dysfunction in these patients. (Echocardiography 2012;29:438‐444)     

Neuropathy‐associated NaV1.7 variant I228M impairs integrity of dorsal root ganglion neuron axons

Small‐fiber neuropathy (SFN) is characterized by injury to small‐diameter peripheral nerve axons and intraepidermal nerve fibers (IENF). Although mechanisms underlying loss of IENF in SFN are poorly understood, available data suggest that it results from axonal degeneration and reduced regenerative capacity. Gain‐of‐function variants in sodium channel Na_V1.7 that increase firing frequency and spontaneous firing of dorsal root ganglion (DRG) neurons have recently been identified in ～30% of patients with idiopathic SFN. In the present study, to determine whether these channel variants can impair axonal integrity, we developed an in vitro assay of DRG neurite length, and examined the effect of 3 SFN‐associated variant Na_V1.7 channels, I228M, M932L/V991L (ML/VL), and I720K, on DRG neurites in vitro. At 3 days after culturing, DRG neurons transfected with I228M channels exhibited ～20% reduced neurite length compared to wild‐type channels; DRG neurons transfected with ML/VL and I720K variants displayed a trend toward reduced neurite length. I228M‐induced reduction in neurite length was ameliorated by the use‐dependent sodium channel blocker carbamazepine and by a blocker of reverse Na‐Ca exchange. These in vitro observations provide evidence supporting a contribution of the I228M variant Na_V1.7 channel to impaired regeneration and/or degeneration of sensory axons in idiopathic SFN, and suggest that enhanced sodium channel activity and reverse Na‐Ca exchange can contribute to a decrease in length of peripheral sensory axons. Ann Neurol 2012     

The impact of primary care organization on avoidable hospital admissions for diabetes in 23 countries

Objective: Diabetes is a so-called ambulatory care sensitive condition. It is assumed that by appropriate and timely primary care, hospital admissions for complications of such conditions can be avoided. This study examines whether differences between countries in diabetes-related hospitalization rates can be attributed to differences in the organization of primary care in these countries. Design: Data on characteristics of primary care systems were obtained from the QUALICOPC study that includes surveys held among general practitioners and their patients in 34 countries. Data on avoidable hospitalizations were obtained from the OECD Health Care Quality Indicator project. Negative binomial regressions were carried out to investigate the association between characteristics of primary care and diabetes-related hospitalizations. Setting: A total of 23 countries. Subjects: General practitioners and patients. Main outcome measures: Diabetes-related avoidable hospitalizations. Results: Continuity of care was associated with lower rates of diabetes-related hospitalization. Broader task profiles for general practitioners and more medical equipment in general practice were associated with higher rates of admissions for uncontrolled diabetes. Countries where patients perceive better access to care had higher rates of hospital admissions for long-term diabetes complications. There was no association between disease management programmes and rates of diabetes-related hospitalization. Hospital bed supply was strongly associated with admission rates for uncontrolled diabetes and long-term complications. Conclusions: Countries with elements of strong primary care do not necessarily have lower rates of diabetes-related hospitalizations. Hospital bed supply appeared to be a very important factor in this relationship. Apparently, it takes more than strong primary care to avoid hospitalizations.

• Key points

• Countries with elements of strong primary care do not necessarily have lower rates of diabetes-related avoidable hospitalization.

• Hospital bed supply is strongly associated with admission rates for uncontrolled diabetes and long-term complications.

• Continuity of care was associated with lower rates of diabetes-related hospitalization.

• Better access to care, broader task profiles for general practitioners, and more medical equipment in general practice was associated with higher rates of admissions for diabetes.