AAIR Versus DDDR Pacing in Patients with Impaired Sinus Node Chronotropy: An Echocardiographic and Cardiopulmonary Study

The aim of this study was to compare AAIR and DDDR pacing at rest and during exercise. We studied 15 patients (10 men, age 65 ± 6 years) who had been paced for at least 3 months with activity sensor rate modulated dual chamber pacemakers. All had sick sinus syndrome (SSS) with impaired sinus node chronotropy. The patients underwent a resting echocardiographic evaluation of systolic and diastolic LV function at 60 beats/min during AAIR and DDDR pacing with an AV delay, which ensured complete ventricular activation capture. Cardiac output (CO) was also measured during pacing at 100 beats/min in both pacing modes. Subsequently, the oxygen consumption (VO₂at) and VO₂at pulse at the anaerobic threshold were measured during exercise in AAIR mode and in DDDR mode with an AV delay of 120 ms. The indices of diastolic function showed no significant differences between the two pacing modes, except for patients with a stimulus-R interval > 220 ms, for whom the time velocity integral of LV filling and LV inflow time were significantly lower under AAI than under DDD pacing. At 60 beats/min, CO was higher under AAI than under DDD mode only when the stimulus-R interval was below 220 ms. For stimulus-R intervals longer than 220 ms, and also during pacing at 100 beats/min, the CO was higher in DDD mode. The stimulus-R interval decreased in all patients during exercise. The time to anaerobic threshold, VO₂at ond VO₂at pulse showed no significant differences between the two pacing modes. Our results indicate that, at rest, although AAIR pacing does not improve diastolic function in patients with SSS, it maintains a higher CO than does DDDR pacing in cases where the stimulus-R interval is not excessively prolonged. On exertion, the two pacing modes appear to be equally effective, at least in cases where the stimulus-R interval decreases in AAIR mode.     

Long-Term Results of Nervous Tissue Alterations Caused by Epineurial Electrode Application: An Experimental Study in Rat Sciatic Nerve

In order to evaluate the long-term effects of epineurial electrode application for functional electrical stimulation (FES) the left sciatic nerve of seven rats was exposed. Four ring-shaped stainless steel wire electrodes were sutured to the epineurium of each nerve in the same manner as performed clinically for carrousel stimulation in man. The nerves were reexposed 1 year after implantation and the stimulation threshold to obtain a tetanic contraction in the lower limb was determined for each electrode. Afterwards the animals were sacrificed. The electrodes were excised and cross sections of the sciatic nerve directly at site of the electrodes, 2-mm proximal and 2-mm distal to them were harvested for histologic and planimetric assessment of nerve lesions. The area of damaged neural tissue was expressed as a percentage of the total cross-sectional area within the perineural sheath. The sciatic nerves of the right side served as controls. The values for the stimulation thresholds ranged between 0.1 and 1.0 mA (mean 0.43 mA). By morphometric examination five of seven nerves were seen altered, the altered areas captured between 1% and 4.8% of the total cross-sectional area of the nerves within the perineural sheath. Besides two specimens, all altered nerve segments exhibited distinct signs of nerve fiber regeneration. The clinical implications of the results for long-term electrical stimulation, such as phrenic pacing, are discussed.     

Metabolic syndrome is associated with hearing loss among a middle-aged and older Chinese population: a cross-sectional study

Abstract

Background: Although the association of metabolic syndrome (MetS) and hearing loss has been evaluated, findings are controversial. This study investigated this association in a Chinese population.

Methods: A cross-sectional study including a total of 18,824 middle-aged and older participants from the Dongfeng-Tongji Cohort study was conducted. Hearing loss was defined as the pure-tone average (PTA) of frequencies 0.5, 1.0, 2.0, and 4.0?kHz?>25 decibels hearing level (dB HL) in the better ear and graded as mild (PTA 26–40?dB HL), moderate (PTA?>40 to?≤60?dB HL), and severe (PTA?>60?dB HL). MetS was defined according to the International Diabetes Foundation (IDF) criteria of 2005. Association analysis was performed by logistic regression.

Results: After adjustment for potential confounders, participants with MetS showed higher OR of hearing loss (OR, 1.11; 95% CI: 1.03–1.19). The MetS components including central obesity (OR, 1.07; 95% CI: 1.01–1.15) and hyperglycemia (OR, 1.12; 95% CI: 1.04–1.20) were also positively associated with hearing loss. Low HDL-C levels were also associated with higher OR of moderate/severe hearing loss (OR, 1.21; 95% CI: 1.07–1.36).

Conclusions: The MetS, including its components central obesity, hyperglycemia, and low HDL-C levels were positively associated with hearing loss.

• Key messages

• Studies indicated that cardiovascular disease and diabetes might be risk factors of hearing loss. However, few efforts have been made to establish a direct relationship between metabolic syndrome and hearing loss, especially in Chinese population.

• In the present study, a cross-sectional design using data from the Dongfeng-Tongji Cohort study was conducted to assess the association between metabolic syndrome and hearing loss.

• The metabolic syndrome, as well as its components central obesity, hyperglycemia, and low HDL-C levels were positively associated with hearing loss.

     

Occipital Nerve Stimulator Lead Pathway Length Changes with Volunteer Movement: An In Vitro Study

Background:   Occipital nerve stimulation is a modality reserved for refractory headache disorders. Leads (wires) are inserted subcutaneously in the occipital region to stimulate the distal C1-3 nerves; lead migration may result from repeated mechanical forces on the lead associated with patient movement. The primary aim of this study was to determine implantation pathways associated with the least pathway length change secondary to body movement in an in vitro model of an occipital stimulator system.
Methods:   After institutional review board approval, 10 volunteers were recruited. The expected pathway of an occipital stimulator system was identified and measured externally, and then changes in pathway length were measured during various volunteer movements, including neck and low back flexion, extension, rotation, and lateral flexion. The pathways studied included those that connect internal pulse generators in the gluteal, low abdominal, and infraclavicular regions to occipital leads inserted via a cervical or retromastoid approach.
Results:   The flexion/extension pathway length changes associated with midline occipital and retromastoid sites to the infraclavicular site were significantly less than those pathways to the periscapular site. Also, the abdominal site was associated with less pathway length change during flexion/extension than the gluteal site.
Conclusions:   Internal pulse generators in sites other than the buttock, including infraclavicular or low abdomen, may be associated with lower lead migration risk.
There are many considerations when selecting insertion sites and lead pathways for occipital nerve stimulation. Implanters and patients may consider these results when contemplating surgical approaches to this challenging form of peripheral nerve stimulation.     

Parenting children with hypoplastic left heart syndrome: Finding a balance

Purpose. This study described the role normalization played for parents related to their young children with hypoplastic left heart syndrome. Design and Methods. The data source for this secondary analysis was 30 interviews with 16 parents. Results. Three themes were identified: normalization, parental perception of child vulnerability, and optimistic appraisal. Parents engaged in a balancing act between worrying about their children's vulnerability and marveling at their children's survival, using normalization as a coping strategy. Practice Implications. Nurses can collaborate with parents to determine strategies to restore a sense of normalcy to simultaneously promote child independence and parent well‐being.     

Clinical review: a paradigm shift: the bidirectional effect of inflammation on bacterial growth. Clinical implications for patients with acute respiratory distress syndrome

Clinical studies have shown positive associations among sustained and intense inflammatory responses and the incidence of bacterial infections. We hypothesized that cytokines secreted by the host during acute respiratory distress syndrome may indeed favor the growth of bacteria and explain the association between exaggerated and protracted systemic inflammation and the frequent development of nosocomial infections. To test this hypothesis, we conducted in vitro studies evaluating the extracellular and intracellular growth response of three clinically relevant bacteria in response to graded concentrations of pro-inflammatory cytokines tumor necrosis factor-alpha, IL-1beta, and IL-6. In these studies, we identified a U-shaped response of bacterial growth to pro-inflammatory cytokines. When the bacteria were exposed in vitro to a lower concentration of cytokines, extracellular and intracellular bacterial growth was not promoted and human monocytic cells were efficient in killing the ingested bacteria. Conversely, when bacteria were exposed to higher concentrations of pro-inflammatory cytokines, intracellular and extracellular bacterial growth was enhanced in a dose-dependent manner. The bidirectional effects of proinflammatory cytokines on bacterial growth may help to explain the frequent occurrence of nosocomial infections in patients with unresolving acute respiratory distress syndrome.     

Effect of a warm footbath before bedtime on body temperature and sleep in older adults with good and poor sleep: An experimental crossover trial

Background

The decrease in core body temperature before sleep onset and during sleep is associated with dilation of peripheral blood vessels, which permits heat dissipation from the body core to the periphery. A lower core temperature coupled with a higher distal (hands and feet) temperature before sleep are associated with shorter sleep latency and better sleep quality. A warm foot bath is thought to facilitate heat dissipation to improve sleep outcomes.

Objectives

This study examined the effect of a warm footbath (40 °C water temperature, 20-min duration) on body temperature and sleep in older adults (≥55 years) with good and poor sleep.

Design

Two groups and an experimental crossover design was used.

Setting and participants

Forty-three adults responded to our flyer and 25 participants aged 59.8 ± 3.7 years (poor sleeper with a Pittsburgh Sleep Quality Index score ≥ 5 = 17; good sleepers with a Pittsburgh Sleep Quality Index score < 5 = 8) completed this study.

Methods

All participants had body temperatures (core, abdomen, and foot) and polysomnography recorded for 3 consecutive nights. The first night was for adaptation and sleep apnea screening. Participants were then randomly assigned to either the structured foot bathing first (second night) and non-bathing second (third night) condition or the non-bathing first (second night) and foot bathing second (third night) condition.

Results

A footbath before sleep significantly increased and retained foot temperatures in both good and poor sleepers. The pattern of core temperatures during foot bathing was gradually elevated (poor sleepers vs. good sleepers = +0.40 ± 0.58 °C vs. +0.66 ± 0.17 °C). There were no significant changes in polysomnographic sleep and perceived sleep quality between non-bathing and bathing nights for both groups.

Conclusion

A footbath of 40 °C water temperature and 20-min duration before sleep onset increases foot temperatures and distal–proximal skin temperature gradients to facilitate vessel dilatation and elevates core temperature to provide heat load to the body. This footbath does not alter sleep in older adults with good and poor sleep.     

Attack‐Related Brainstem Activation in a Patient With SUNCT Syndrome: An Ictal fMRI Study

The authors report functional magnetic resonance imaging (fMRI) study data of a 60‐year‐old patient having short‐lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) syndrome. Three consecutive pain attacks were detected during the imaging session and strong brainstem activation was found. It was concluded that the brainstem can be involved in the pain signal transmission in SUNCT syndrome.     

Age‐Specific Differences in Women with Implantable Cardioverter Defibrillators: An International Multi Center Study

Background: Common psychological adjustment difficulties have been identified for groups of implantable cardioverter defibrillator patients, such as those who are young (<50 years old), have been shocked, and are female. Specific aspects and concerns, such as fears of death or shock and body image concerns, that increase the chance of distress, have not been examined in different aged female implantable cardioverter defibrillator (ICD) recipients. The aim of the study was to investigate these areas of adjustment across three age groups of women from multiple centers. Methods: Eighty‐eight female ICD patients were recruited at three medical centers: Shands Hospital at the University of Florida, Brigham and Women's Hospital in Boston, and Royal North Shore Hospital in Sydney, Australia. Women completed individual psychological assessment batteries, measuring the constructs of shock anxiety, death anxiety, and body image concerns. Medical record review was conducted for all patients regarding cardiac illnesses and ICD‐specific data. Results: Multivariate and univariate analyses of variance revealed that younger women reported significantly higher rates of shock and death anxiety (Pillai's F = 3.053, P = 0.018, η²_p= 0.067) and significantly greater body image concerns (Pillai's F = 4.198, P = 0.018, η²_p= 0.090) than middle‐ and older‐aged women. Conclusions: Women under the age of 50 appear to be at greater risk for the development of psychosocial distress associated with shock anxiety, death anxiety, and body image. Clinical‐based strategies and interventions targeting these types of adjustment difficulties in younger women may allow for improved psychosocial and quality of life outcomes.     

A case report: First presentation of diabetes mellitus type 1 with severe hyperosmolar hyperglycemic state in a 35‐month‐old girl

Hyperglycemic hyperosmolar syndrome (HHS) is a rare complication of diabetes mellitus among pediatric patients. Since its treatment differs from diabetic ketoacidosis (DKA), hence, pediatricians should be aware of its diagnosis and management.     

Bart's syndrome associated with a disorder of sexual differentiation: An atypical presentation in a Cameroonian newborn

Bart''s syndrome consists of congenital aplasia of the skin affecting only the lower limbs, associated with bullae over the skin and/or mucous membranes, as well as a nail anomaly. It is an extremely rare genetic disorder, which can be associated with other birth defects. We report the case of a newborn baby admitted at day 0 of life in the neonatal department, for multifocal skin detachment predominantly at the lower limbs. In addition, examination of the external genitalia revealed a clitoridomegaly genital bud measuring 14 mm, scrotalized and unfused genital bulges with the presence of 2 orifices. No gonad was palpated. The clinical diagnosis of Bart''s syndrome associated with a disorder of sexual differentiation was retained. We hereby report the first case of Bart''s syndrome described in Cameroon in association with a disorder of sexual differentiation.     

The Validity of Ultrasonographic Assessment in Cubital Tunnel Syndrome: The Value of a Cubital-to-Humeral Nerve Area Ratio (CHR) Combined with Morphologic Features

Diagnosis of a typical idiopathic cubital tunnel syndrome (CuTS) is straight forward but the work-up of mild forms is clinically challenging. The diagnostic value of high-resolution ultrasound (HRUS) relying solely on nerve measurements is doubtful. Additional textural analysis of the nerve may possibly overcome this drawback. Thirty-eight prospectively enrolled patients with idiopathic CuTS and 23 healthy volunteers underwent standardized HRUS. A cubital-to-humeral nerve area ratio (CHR) was calculated and the texture of the most swollen nerve segment assessed. CHR was significantly different among patients and volunteers (p < 0.001) but with a marked overlap. Combination of at least partial inner fascicular masking plus a CHR > 1.4 showed a positive linear coherence with idiopathic CuTS at a specificity > 95% and a PPV > 90%. Thus, the combined textural analysis and CHR calculation seems a powerful tool for the sonographic diagnosis of idiopathic CuTS. (E-mail: hannes.gruber@i-med.ac.at)