Cardioembolic Stroke in Patients with Patent Foramen Ovale and Implanted Cardiac Leads

Implanted cardiac devices, including pacemakers, defibrillators, and resynchronization devices, are known to develop thrombus on their intravascular leads. Patent foramen ovale (PFO) occurs in approximately one‐quarter of the adult population. It is unclear whether paradoxical cardioembolism and clinically relevant stroke occur in patients with implanted cardiac leads and PFO. We present a case series of four patients with cardioembolic stroke, presumed to arise from intravascular cardiac leads and associated PFO that required device closure of the PFO. (PACE 2013; 36:50–54)     

Bird migration--An energy-based analysis of costs and benefits

We look at a model of migration as part of a whole ecologicalsystem. The purpose is to investigate the mutual relationshipof population dynamics and migration strategies. In particular,we deal with the question of justifying the cost and dangerof migration. We evaluate the flight costs in terms of energyand try to model annual events that influence migration ratherthan emphasizing single aspects. We apply estimates of the totalannual energy budget to assess the motivation for migration.We give simulation runs of our model for the migration behaviourof one bird-of-prey species (Houbara bustard, Chlamydotis undulatamacqueenii) and of one passerine species (stonechat, Saxicolatorquata). In our model the most important factors determiningmigration success are overwinter survival and reproductive success.This is in agreement with experimental studies. The model allowsstrategies to be checked with respect to evolutionary stabilityin simulating species with very small initial values for thepopulation size. During a period of warm winters a nonmigratorybehaviour can be an evolutionary-stable strategy (ESS), butspecies which do not migrate are endangered and they can easilybe extinguished during seasons with food supply below the averageminimum (strong winters), even if such seasons are rare.     

Doppler Echocardiography in Pulmonary Stenosis

Doppler ultrasound has dramatically improved the accuracy of noninvasive detection of pulmonary stenosis. Combined with careful two-dimensional imaging, the site and severity of obstruction to pulmonary flow can be detected and quantified. Although there are some limitations to the technique, interpretive errors are avoidable with an understanding of the method and careful attention to detail during the performance of the examination. Doppler echocardiography has become a valuable adjunct to the nonsurgical treatment of valvular pulmonary stenosis and promises to provide more information for developing new management schemes in congenital heart disease.     

Heterogeneity in electrical activity of the canine ileal circular muscle: interaction of two pacemakers

Abstract In cross-sectioned slabs from the muscularis externa or in the isolated circular muscle devoid of longitudinal muscle and myenteric plexus (MyP) of ileum, a slow wave, sigmoidal or triangular in shape, was recorded from microelectrode impalements near the deep muscular plexus (DMP) region in the whole-thickness preparation. From the MyP region of whole-thickness preparations, a slow wave which oscillated at a similar frequency (9–10 cycles min^?1) was characterized by a fast upstroke and a square shape. Slow waves of μmixed pattern were recorded in the outer circular muscle (OCM) while triangular slow waves were present near the submucous plexus (SMP). In this preparation but not in isolated circular muscle, the inhibitory junction potentials (IJPs) produced by supramaximal electrical field stimulation triggered slow waves. The amplitudes (15–25 mV) of spontaneous and triggered slow waves (TSWs) were greatest in the MyP region, significantly so compared to those of DMP and SMP regions and to those in all regions of isolated circular muscle. Frequencies of slow waves recorded from the MyP and DMP were slightly but significantly higher than those recorded from either the OCM or the SMP or from all regions of isolated circular muscle. A 10–15 mV gradient in resting membrane potential (more hyperpolarized near MyP) existed across the intact (but not the isolated) circular muscle layer. Both types of slow waves, TSWs and IJPs were unaffected by muscarinic, adrenergic or tachykinergic blockade. We suggest that a MyP pacemaker network generated a plateau-type slow wave while a DMP one induced a triangular slow wave. Each source can function independently but the MyP network may dominate and entrain DMP slow waves.     

Cytokine mRNA levels in the hearts of inbred mice that develop different degrees of cardiomyopathy during infection with Trypanosoma cruzi

Profiles of cytokine mRNA expression were examined by semiquantitative RT-PCR in the hearts of DBA/2 (pathopermissive) and B10.D2 (pathoresistant) mice during infection with the Brazil strain of Trypanosoma cruzi . The levels and time-course profiles of IFNγ, IL-1β and IL-10 mRNA expression were similar in each strain. TNFα, iNOs, and IL-13 mRNA expression peaked at comparable levels and times after infection in each strain, but declined more rapidly in B10.D2 than in DBA/2 mice. Peak IL-2 mRNA levels were also similar between the two strains, but occurred earlier in DBA/2 than in B10.D2 mice. Levels of IL-4, IL-6 and IL-12 mRNA were significantly higher in DBA/2 than in B10.D2 mice from day 10 through day 50 of infection. With the exception of IL-1β, which was expressed constitutively in both strains, the levels of mRNA of all other cytokines examined reached their peak no later than day 20 and declined significantly by day 50 after infection. The inflammatory infiltrate paralleled the latter cytokines; starting at day 10 in DBA/2 mice and at day 15 in the B10.D2 s, peaking between days 20 and 30 in both strains, decreasing to minimal levels by day 50 in the pathoresistant mice, but maintaining a mild amount through day 70 in the pathopermissive strain. The inflammation was composed mostly of lymphocytes and histiocytes throughout the entire process. These data demonstrate differences in the profiles of cytokine mRNA that may be related to the differential degree of cardiac pathology that develops in these two strains of mice upon infection with T. cruzi.