Incidence of ventricular fibrillation during coronary arteriography in the rabbit. A comparative study of isotonic ioxaglate and iohexol

The incidence of major ECG changes, particularly ventricular fibrillation, was evaluated in rabbits during prolonged, selective right coronary injection of sodium/meglumine ioxaglate (Hexabrix 160) and iohexol (Omnipaque 140), two isotonic contrast media. The anesthetized animals (n = 12) per test solution) each received 1.5 ml of contrast material, delivered at a rate of 3 ml/minute. Both contrast media caused major ECG changes, which were reversible within seconds after administration. No fibrillation occurred with ioxaglate, but ventricular fibrillation was seen in seven animals given iohexol. There was a significant difference in the incidence of ventricular fibrillation between the contrast media (P less than .01). Both test solutions induced transient, more or less marked bradycardia, but without significant differences. The intracoronary injections produced similar decreases in blood pressure for both contrast agents. Reactive hypertension was observed only in those animals in which an episode of fibrillation occurred with iohexol. The causes underlying these effects are analyzed for both contrast agents.     

Epicardial distribution of ST segment and T wave changes produced by stimulation of intrathoracic ganglia or cardiopulmonary nerves in dogs

Sixty-three ventricular epicardial electrograms were recorded simultaneously in 8 atropinized dogs during stimulation of acutely decentralized intrathoracic autonomic ganglia or cardiopulmonary nerves. Three variables were measured: (1) isochronal maps representing the epicardial activation sequence, (2) maps depicting changes in areas under the QRS complex and T wave (regional inhomogeneity of repolarization), and (3) local and total QT intervals. Neural stimulations did not alter the activation sequence but induced changes in the magnitude and polarity of the ST segments and T waves as well as in QRST areas. Stimulation of the same neural structure in different dogs induced electrical changes with different amplitudes and in different regions of the ventricles, except for the ventral lateral cardiopulmonary nerve which usually affected the dorsal wall of the left ventricle. Greatest changes occurred when the right recurrent, left intermediate medial, left caudal pole, left ventral lateral cardiopulmonary nerves and stellate ganglia were stimulated. Local QT durations either decreased or did not change, whereas total QT duration as measured using a root-mean-square signal did not change, indicating the regional nature of repolarization changes. Taken together, these data indicate that intrathoracic efferent sympathetic neurons can induce regional inhomogeneity of repolarization without prolonging the total QT interval.     

A report of a national mutation testing service for the MEN1 gene: clinical presentations and implications for mutation testing

Introduction: Mutation testing for the MEN1 gene is a useful method to diagnose and predict individuals who either have or will develop multiple endocrine neoplasia type 1 (MEN 1). Clinical selection criteria to identify patients who should be tested are needed, as mutation analysis is costly and time consuming. This study is a report of an Australian national mutation testing service for the MEN1 gene from referred patients with classical MEN 1 and various MEN 1-like conditions. Results: All 55 MEN1 mutation positive patients had a family history of hyperparathyroidism, had hyperparathyroidism with one other MEN1 related tumour, or had hyperparathyroidism with multiglandular hyperplasia at a young age. We found 42 separate mutations and six recurring mutations from unrelated families, and evidence for a founder effect in five families with the same mutation. Discussion: Our results indicate that mutations in genes other than MEN1 may cause familial isolated hyperparathyroidism and familial isolated pituitary tumours. Conclusions: We therefore suggest that routine germline MEN1 mutation testing of all cases of "classical" MEN1, familial hyperparathyroidism, and sporadic hyperparathyroidism with one other MEN1 related condition is justified by national testing services. We do not recommend routine sequencing of the promoter region between nucleotides 1234 and 1758 (Genbank accession no. {"type":"entrez-nucleotide","attrs":{"text":"U93237","term_id":"1945388","term_text":"U93237"}}U93237) as we could not detect any sequence variations within this region in any familial or sporadic cases of MEN1 related conditions lacking a MEN1 mutation. We also suggest that testing be considered for patients <30 years old with sporadic hyperparathyroidism and multigland hyperplasia.     

The heart reinnervates after transplantation

Background. Whether cardiac reinnervation occurs after transplantation remains controversial. If reinnervation does occur, how sympathetic and parasympathetic efferent neurons do this remains unknown.

Methods. Power spectral analysis of heart rate variability was assessed for 1 year after cardiac autotransplantation in 9 dogs. After induction of anesthesia 13 months after transplantation, cardiac and intrinsic cardiac neuronal responses elicited by both electrical stimulation of parasympathetic or sympathetic efferent neurons and systemic or local coronary artery administration of nicotine (5 μg/kg), angiotensin II (0.75 μg/kg), and tyramine (1.2 μg/kg) were studied. The transmembrane electrical properties of intrinsic cardiac neurons were studied in vitro. Ventricular tissue catecholamine content, -tubulin expression, and β-adrenergic receptor density and affinity were studied. The presence of axons crossing suture lines was sought histologically.

Results. Nerves were identified crossing suture lines. Electrical or chemical (ie, nicotine or angiotensin II) activation of sympathetic efferent neurons enhanced cardiodynamics, as did tyramine. Stimulating vagal efferent preganglionic axons induced bradycardia in half of the dogs. Functional reinnervation did not correlate with specific power spectra derived from rate variability in the conscious state. Responding to nicotine and angiotensin II in situ, transplanted intrinsic cardiac neurons generated spontaneous activity. These neurons displayed nicotine-dependent synaptic inputs in vitro. Ventricular tissue had normal β-adrenergic receptor affinity and density but reduced catecholamine and -tubulin contents.

Conclusions. The intrinsic cardiac nervous system receives reduced input from extracardiac sympathetic efferent neurons after transplantation and inconsistent input from parasympathetic efferent preganglionic neurons. These heterogeneous neuronal inputs are not reflected in heart rate variability or ventricular β-adrenergic receptor function. Transplanted angiotensin II–sensitive intrinsic cardiac neurons exert greater cardiac control than do nicotine-sensitive ones. The intrinsic cardiac nervous system remodels itself after cardiac transplantation, and this indicates that direct assessment of extracardiac and intrinsic cardiac neuronal behavior is required to fully understand cardiac control after transplantation.     

Novel Z Scores to Correct Biases Due to Ventricular Volume Indexing to Body Surface Area in Adolescents and Young Adults

BackgroundReference values for cardiac magnetic resonance imaging (cMRI) in children and young adults are scarce. This leads to risk stratification of patients with congenital heart diseases being based on volumes indexed to body surface area (BSA). We aimed to produce cMRI Z score equations for ventricular volumes in children and young adults and to test whether indexing to BSA resulted in an incorrect assessment of ventricular dilation according to sex, body composition, and growth.MethodsWe retrospectively included 372 subjects aged < 26 years with either normal hearts or conditions with no impact on ventricular volumes (reference group), and 205 subjects with repaired tetralogy of Fallot (TOF) aged < 26 years. We generated Z score equations by means of multivariable regression modelling. Right ventricular dilation was assessed with the use of Z scores and compared with indexing to BSA in TOF subjects.ResultsVentricular volume Z scores were independent from age, sex, and anthropometric measurements, although volumes indexed to BSA showed significant residual association with sex and body size. In TOF subjects, indexing overestimated dilation in growing children and underestimated dilation in female compared with male subjects, and in overweight compared with lean subjects.ConclusionsIndexed ventricular volumes measured with cMRI did not completely adjust for body size and resulted in a differential error in the assessment of ventricular dilation according to sex and body size. Our proposed Z score equations solved this problem. Future studies should evaluate if ventricular volumes expressed as Z scores have a better prognostic value than volumes indexed to BSA.     

Depression self-management support: A systematic review

Objective

To systematically review empirical evidence regarding the efficacy of depression self-management support (SMS) interventions for improving depression symptomatology and preventing relapse.

Methods

Pubmed and PsycINFO databases were searched for relevant articles on depression SMS interventions. Scanning of references in the articles and relevant reviews and communications with field experts yielded additional articles. Two independent reviewers analyzed the articles for inclusion and data was extracted from the selected articles.

Results

13 papers met the inclusion criteria and reported the results of six separate studies, including three pilot studies. The results were mostly positive. A majority of the trials assessing depression severity changes found SMS to be superior to care as usual. SMS interventions were found to improve self-management behaviors and self-efficacy. Mixed results were found concerning relapse rates. Promising results were found on assessments of functional status. Based on the findings, cost-effectiveness remains unclear.

Conclusion

SMS has been mostly examined through pilot studies with insufficient power. The results are promising, but larger randomized controlled trials are needed.

Practice implications

SMS interventions can be administered by non-physician professionals and are well accepted by patients, but more research is needed before we can recommend implementing specific depression SMS approaches in primary care.     

Trypanosoma cruzi infection in Triatoma sordida before and after community-wide residual insecticide spraying in the Argentinean Chaco

Triatoma sordida is a secondary vector of Trypanosoma cruzi in the Gran Chaco and Cerrado eco-regions where it frequently infests peridomestic and domestic habitats. In a well-defined area of the humid Argentine Chaco, very few T. sordida were found infected when examined by optical microscopic examination (OM). In order to further assess the role of T. sordida and the relative magnitude of subpatent bug infections, we examined the insects for T. cruzi infection, parasite Discrete Typing Units (DTUs) and bloodmeal sources using various molecular techniques. Among 205 bugs with a negative or no OM-based diagnosis, the prevalence of infection determined by kDNA-PCR was nearly the same in bugs captured before (6.3%) and 4 months after insecticide spraying (6.4%). On average, these estimates were sixfold higher than the prevalence of infection based on OM (1.1%). Only TcI was identified, a DTU typically associated with opossums and rodents. Chickens and turkeys were the only bloodmeal sources identified in the infected specimens and the main local hosts at the bugs’ capture sites. As birds are refractory to T. cruzi infection, further studies are needed to identify the infectious bloodmeal hosts. The persistent finding of infected T. sordida after community-wide insecticide spraying highlights the need of sustained vector surveillance to effectively prevent T. cruzi transmission in the domestic and peridomestic habitats.