Relation between maximum phonation time and exercise capacity in chronic heart failure patients

BACKGROUND

Patients with chronic heart failure (CHF) commonly fatigue easily due to low peak oxygen uptake (peak VO(2)), an important index of exercise capacity. Maximum phonation time (MPT) is widely used to evaluate maximum vocal capabilities because it is non-invasive, quick, and inexpensive.

AIM

The aim of this study was to determine the relation between MPT and exercise capacity, and MPT required to attain an exercise capacity of ≥5 metabolic equivalents (METs) in CHF outpatients.

DESIGN

Cross-sectional study.

SETTING

Outpatient cardiac rehabilitation unit.

POPULATION

We enrolled 111 CHF outpatients (mean age 54.2±10.1 years).

METHODS

Peak VO(2) was assessed during cardiopulmonary exercise testing (CPX) as the index of exercise capacity. After CPX, we divided the patients into two groups according to exercise capacity: ≥5 METs group (N.=68) and <5 METs group (N.=43). Measurements of MPT were taken in the seated position. All patients were asked to produce a sustained vowel /a:/ for as long as possible and were verbally encouraged during respiratory effort.

RESULTS

After adjustment for patient clinical characteristics, MPT in the CHF patients was found to be significantly higher in the ≥5 METs group than in the <5 METs group (22.1±8.4 vs. 17.0±11.6 s, F=13.5, P<0.001). Receiver-operating characteristic curve analysis of exercise capacity of ≥5 METs extracted a cutoff value for MPT of 18.27 s, with a sensitivity of 0.76, 1-specificity of 0.33, and AUC value of 0.81 (95% CI: 0.70-0.87, P<0.001).

CONCLUSION

There were differences in MPT in relation to an exercise capacity threshold of ≥5 METs in CHF outpatients. A MPT of 18.27 sec may be the best cutoff value to identify people with or without exercise capacity of ≥5 METs.

CLINICAL REHABILITATION IMPACT

Measurement of MPT may be a useful method for estimating exercise capacity in CHF outpatients.

Blockade of I(Ca) suppresses early afterdepolarizations and reduces transmural dispersion of repolarization in a whole heart model of chronic heart failure

BACKGROUND AND PURPOSE Chronic heart failure (CHF) is associated with action potential prolongation and Ca(2+) overload, increasing risk of ventricular tachyarrhythmias (VT). We therefore investigated whether I(Ca) blockade was anti-arrhythmic in an intact perfused heart model of CHF. EXPERIMENTAL APPROACH CHF was induced in rabbits after 4 weeks of rapid ventricular pacing. Hearts from CHF and sham-operated rabbits were isolated and perfused (Langendorff preparation), with ablation of the AV node. VT was induced by erythromycin and low [K(+) ] (1.5mM). Electrophysiology of cardiac myocytes, with block of cation currents, was simulated by a mathematical model. KEY RESULTS Repolarization was prolonged in CHF hearts compared with sham-operated hearts. Action potential duration (APD) and overall dispersion of repolarization were further increased by erythromycin (300 µM) to block I(Kr) in CHF hearts. After lowering [K(+) ] to 1.5mM, CHF and sham hearts showed spontaneous episodes of polymorphic non-sustained VT. Additional infusion of verapamil (0.75 µM) suppressed early afterdepolarizations (EAD) and VT in 75% of sham and CHF hearts. Verapamil shortened APD and dispersion of repolarization, mainly by reducing transmural dispersion of repolarization via shortening of endocardial action potentials. Mathematical simulations showed that EADs were more effectively reduced by verapamil assuming a state-dependent block than a simple block of I(Ca) . CONCLUSIONS AND IMPLICATIONS Blockade of I(Ca) was highly effective in suppressing VT via reduction of transmural dispersion of repolarization and suppression of EAD. Such blockade might represent a novel therapeutic option to reduce risk of VT in structurally normal hearts and also in heart failure. LINKED ARTICLE This article is commented on by Stams et al., pp. 554-556 of this issue. To view this commentary visit http://dx.doi.org/10.1111/j.1476-5381.2011.01818.x.

[Effectiveness of nephroprotection by the selection of contrast media used during vascular interventions in patients with chronic renal failure?]

BACKGROUND

The increasing number of endovascular procedures made aware of a kidney disease induced by contrast media (CM). Contrast-induced nephropathy (= CIN) can develop in 0.6-44 % of the treated patients by angiography and / or endovascular intervention. The incidence in high-risk patients ranges from 50 to 70 %. In most cases CIN is inconspicuous and reversible. But pre-existing chronic kidney disease, diabetes mellitus, age and variable different risk factors (e. g., PAOD) can induce irreversible renal impairment. The purpose of the presented trial is to investigate incidence, predictors, and out-come of CIN in chronic renal failure patients using two different CM; one non-ionic isoosmolar -iodixanol and the other non-ionic low-osmolar iopromide.

METHODS

To evaluate the incidence of CIN after endovascular diagnostics and intervention two collectives of 100  patients with chronic renal insufficiency were treated with different contrast media (CM). Inclusion followed prospectively in two collectives. One collective received iopromide (Ultravist™, Bayer Health Care, Lever-kusen, Germany), and the second hundred patients received iodixanol (Visipaque™, Nycomed Amersham, Princeton, New Jersey). Demographics, comorbidities, procedure-related data were completed by serum creatinine levels and GFR (= glomerular filtration rate). Inclusion criteria were a serum creatinine level ≥ 1.5 mg% and a GFR ≤ 60 mL / min. Those parameters were measured twice pre-interventionally, and one time 48-72  hours after the endovascular procedure.

RESULTS

Collectives were homogenous and comparable concerning pre-existing risk factors, age and gender. Renal function stayed at a constant level and was independent of contrast medium selection, repectively. Average creatinine levels ranged around 1.77 mg% ± 0.75  standard deviation (SD) pre-interventionally; postinterventional measurement exposed a creatinine level of 1.74 mg% ± 0.74 SD as mean of both collectives. GFR (preinterventional 39.64 mL / min ± 12.48 SD) increased non-significantly to 45.48 mL / min ± 16.82 SD. Pre-existing chronic kidney disease had no effect on renal function parameters; no other risk factors could be evaluated.

CONCLUSION

According to cost-effectiveness a low-osmolar monomeric contrast medium (LOCM) is a sufficient selection, under careful renal function control.

["Münsteraner foot- and shoe score"--objectivation of patient satisfaction after provision with orthopedic shoes]

BACKGROUND

Means to improve patient satisfaction and their compliance are essential for the successful outcome of medical interventions, e.g. supply of orthopedic shoes or orthoses in orthopedic patients. A useful validated questionnaire to monitor the subjective opinion of the patients is still lacking.

METHODS

In a randomised single blinded study we created a new questionnaire with two parts. Part one deals with ten questions on patient data and illness. Part two consists of 13 questions about pain, disabilities in activities of daily life (ADL), use of painkillers, satisfaction, history of ulceration, correction of shoes and orthoses, handling and compliance using a scale of 1-6. Questions were chosen by asking a group of experts (four experienced physicians of two universities and four shoemaker master-craftsmen). Then an items reduction was performed. The reliability was tested in a pre- and retest in 20 patients of our orthopedic clinic. Then the questionnaire was validated by comparing 40 patients of our orthopedic clinic (intervention group) with 180 subjects without orthopedic treatment (control group) chosen at random. The questionnaire was always done anonymously and without the help of the interviewer. Exclusion criteria for the control group were any kind of orthopedic treatment of the lower limb in the last 2 years, orthopedic shoes or lumbar sciatic pain. Exclusion criteria for both groups were minor or major amputations, inability to walk outdoors without help.

RESULTS

We demonstrated highly significant differences for each single question and the total score between orthopedic patients and healthy probands. Additionally, we saw significantly poorer scores for patients suffering from diabetes in the control group, patients with polyneuropathy and those without polyneuropathy, as well as for women vs. men. There was a high rate of diabetics (11 %) in the control group in analogy to the current literature.

DISCUSSION

The new questionnaire discriminates highly significantly between healthy and ill probands. Interindividually a screening of people at risk is possible or a comparison of different interventions. Intraindividually it could be used to monitor patient satisfaction after interventions. Objectivation of patient satisfaction is important to improve their compliance and outcome.

Erythrocyte magnesium and prostaglandin dynamics in chronic sleep deprivation

BACKGROUND AND HYPOTHESIS

The mechanism of sudden cardiac death occurring in patients with chronic fatigue is controversial. This study was designed to define a hypothesis that coronary arterial spasm and thrombus formation can occur during chronic fatigue.

METHODS

For evaluating the feasibility of coronary arterial spasm, erythrocyte magnesium (Mg) was measured. Blood coagulability was evaluated by the change of prostaglandin concentration. Subjects included 16 healthy male volunteers (mean age 21.6 +/- 2.5 years). Test conditions were as follows: (A) control state: a day following a night of good sleep; (B) temporary sleep deprivation: a day preceded by < 3 h of sleep; (C) chronic sleep deprivation: a day preceded by a month during which sleep lasted < 60% of that in condition (A) above. The erythrocyte Mg concentration was measured by the atomic absorption method. The plasma concentration of thromboxane B2 and 6-keto-prostaglandin F1 alpha were measured in eight subjects by radioimmunoassay method.

RESULTS

(1) Mean erythrocyte Mg concentration was significantly less in chronic sleep deprivation (1.1 +/- 0.4 mg/dl) than in the control state (1.8 +/- 0.4 mg/dl, p < 0.01) or in temporary sleep deprivation (1.6 +/- 0.4, p < 0.01). (2) The level of thromboxane B2 was significantly higher during chronic sleep deprivation than under control conditions (104.4 +/- 78.0 vs. 20.4 +/- 9.0 pg/ml, p < 0.05). (3) There were no significant intergroup differences in 6-keto-prostaglandin F1 alpha level.

CONCLUSION

These findings could support the hypothesis that coronary arterial spasm and thrombus formation occur in chronic sleep deprivation.

Positive and negative regulation of adenovirus infection by CAR-like soluble protein, CLSP

Coxsackievirus and adenovirus receptor (CAR) is a member of the immunoglobulin (Ig) superfamily and a component of epithelial tight junction. CAR also functions as a primary receptor for coxsackievirus B and adenovirus (Ad) infection. In this study, we report the identification of a novel protein, CAR-like soluble protein (CLSP), which is closely related to CAR. Mouse CLSP (mCLSP) was composed of 390 amino acids, including three Ig domains, and showed strong homology to the IgV domain of CAR. Interestingly, mCLSP lacks a transmembrane domain, indicating that this is a soluble protein. mCLSP mRNA was detected primarily in the brain and ovary. When mCLSP cDNA was introduced into SK HEP-1 cells, which were known to be CAR positive and easily infected with Ad vector, the infection with Ad vector was severely inhibited. On the other hand, mCLSP promoted the infection with Ad vector in CAR-negative NIH3T3 cells. Furthermore, recombinant CLSP directly bound to Ad and inhibited the Ad vector-mediated transduction in SK HEP-1 cells. Computational analysis for a genome database showed that the CLSP gene is rodent-specific, and that human and bovine lack this gene. These results suggest that CLSP may play a role in the antiviral defense of the host in rodent animals.

[Changes in shape and size of the foot during pregnancy]

Many women report an increase in foot size during their pregnancy. Our objective was to verify this anecdotal evidence. In an initial survey of 21 mothers in 2 Münster nursery schools we found a tendency towards an increase in foot size during pregnancy. We therefore developed a measuring system to measure changes in foot length, width, height and volume. A total of 40 women recruited from the antenatal clinic of the University Hospital of Münster and a participating practice were seen three times during their pregnancy. The results were analysed using the Wilcoxon test. We found a statistically significant increase in foot length, width and volume, whereas foot height decreased slightly. This difference was, however, not significant. Especially in diabetic women with polyneuropathy it is important to pay attention to shoe size to prevent pressure sores.

[The influence of proprioceptive insoles (Bourdiol) on the sagittal curvature and inclination of the trunk]

Proprioceptive insoles rely on the concept of Réné-Jaques Bourdiol, a French neurologist. The aim is to modulate plantar surface sensibility and to influence posture and statics of patients: it is hypothesized that the effect of modified afferent sensory input through proprioceptive stimulation of terminal muscle chains will have either a relaxing or stimulating effect on the whole body, which may be realized by affecting the posture. Small pads with a thickness of typically 1-3 mm are embedded into the insole to provide a specific stimulation. In fitting the insoles selectively to the individual patient the effect of the insoles on the trunk posture is taken as a feedback. This study investigates the influence of proprioceptive insoles on the sagittal curve in 20 selected patients. The protocol used a repeated measures research design. The measures of the sagittal curve were obtained using raster stereography. The four different conditions were: (1) barefoot, (2) convenient shoes without the insoles, (3) the same shoes with a placebo insole, and (4) the same shoes with neurological insoles. Evaluation of raster stereographs provided the kyphotic angle between T4 and T12 and lordotic angle between T12 and S1. Statistical evaluation was performed with the t-test for paired measurements. No significant differences were found in the sagittal profile. Only trunk inclination in normal posture was found to yield a significant difference (0.38 degrees) between placebo and neurological insoles. However, no clear statement on the efficiency of neurological insoles can be made.

Perivascular axillary brachial plexus block and patient positioning: the influence of a lateral, head-down position

The aim of this study was to examine the effect of a 20 degrees Trendelenburg position on the blockade of nerves that exit the brachial plexus proximally in patients undergoing single-injection axillary brachial plexus block. After a pilot study of eight cadavers suggested that a head-down and lateral position would encourage the proximal spread of local anaesthetic, 72 patients undergoing elective surgery were divided into two equal groups: a Supine group and a Modified Position group (lateral position, 20 degrees head-down tilt). Patients were left in the allocated position for 30 min after an axillary block had been performed with alkalinised mepivacaine 1% 49.5 ml. Sensory and motor blockade evaluation showed that there was a significantly higher proportion of axillary nerve (76% vs. 0%, p < 0.001), thoracodorsal nerve (86% vs. 0%, p < 0.001) and subscapular nerve (89% vs. 0%, p < 0.001) blockade in the Modified Position group. Sensory block of the radial nerve was also improved by the modified position (100% vs. 86%, p < 0.05).

Langfristiger Einfluss der anatomisch angepassten spongiösen Endoprothese auf den periprothetischen Knochen

INTRODUCTION

The anatomically shaped, cementless total hip replacement (THR) (S and G, ESKA Lübeck) has a fully porous coating for secondary osseointegration. The aim of the present study was to analyse the long-term effect of the prosthesis on periprosthetic bone remodelling.

METHODS

137 THR in 117 patients were analysed clinically and radiographically 12.8 years (10-14.9 years) postoperatively. The average age at the last follow-up was 71.8 years (range: 34-87 years). Osteodensitometric DEXA measurements of the periprosthetic bone in comparison to the contralateral non-operated femora were performed.

RESULTS

Cumulative survival rates of all implanted THR (n = 231) at 14.9 years were 86.2 % (+/-5.3 %) for the fully porous coated stem and 90.1 % (+/- 8 %) for the cup. Five stem fractures (3.6 %) at the middle part were recorded. The Harris hip score of the non-revised THR at the last follow-up averaged 88.3 (34-100) points. Bony atrophy in the proximal periprosthetic femora in Gruen zones I (16.8 %) and VII (34.6 %) confirmed a proximal stress-shielding. Osteodensitometric analyses demonstrated in comparison to the contralateral femora (BMD 1.3 g/cm (2)) a significantly reduced bone density at the calcar femoris (BMD 0.9 g/cm (2)) (p < 0.001).

CONCLUSION

The original goal of a physiological load transfer has not been realised with this fully porous, cementless THR. The anatomic S & G stem will mainly be osseointegrated by distal load transfer.

Crown development in a pioneer tree, Rhus trichocarpa, in relation to the structure and growth of individual branches

Based on an allometric reconstruction, the structure and biomass-allocation patterns of branches and current-year shoots were investigated in branches of various heights in the pioneer tree Rhus trichocarpa, to evaluate how crown development is achieved and limited in association with height. Path analysis was conducted to explore the effects of light availability, basal height and size of individual branches on branch structure and growth. Branch angle was affected by basal height, whereas branch mass was influenced primarily by light availability. This result suggests that branch structure is strongly constrained by basal height, and that trees mediate such constraints under different light environments. Previous-year leaf area and light availability showed positive effects on current-year stem mass. In contrast, branch basal height and mass negatively affected current-year stem mass. Moreover, the length of stems of a given diameter decreased with increasing branch height. Therefore the cost of biomass investment for a unit growth in length is greater for branches of larger size and at upper positions. Vertical growth rate in length decreased with increasing height. Height-dependent changes in stem allometry and angle influenced the reduction in vertical growth rate to a similar degree.

Branching, biomass distribution, and light capture efficiency in a pioneer tree, Rhus trichocarpa, in a secondary forest

Crown architecture and biomass distribution patterns were investigated in relation to branching and tree size in a pioneer species, Rhus trichocarpa Miq. (Anacardiaceae), in a Japanese secondary forest. Crown architecture changed with tree size and with branching. Crown depth and area were greater in taller trees. In addition, branched trees had crowns of greater depth, and crown area increased more rapidly with increasing height in branched trees as compared with unbranched trees. In contrast, biomass distribution to nonphotosynthetic and photosynthetic organs changed only with tree size and was similar in unbranched and branched trees of similar size. Light capture efficiency was related to neither height nor branching status for trees with heights of 1–2.5 m. Coexistence of unbranched and branched trees at the height around the onset of branching is possible because these trees realize similar biomass distribution patterns and light capture efficiencies. Individual leaf area and leaf area index increased with tree size in unbranched trees but decreased with tree size in branched trees. These results suggest that several leaf clusters of limited size are sparsely arranged in a large three-dimensional space in tall trees.