'That's when I struggle' Exploring challenges faced by care givers of children with tuberculosis in Botswana.

SETTING: Government-funded public health clinics in and around Gaborone, Botswana. OBJECTIVE: To explore the challenges faced by care givers of children on treatment for tuberculosis (TB) to inform a more child-friendly approach to Botswana's National TB Programme (NTP) strategy. DESIGN: Qualitative study using 28 in-depth interviews with care givers of children receiving anti-tuberculosis treatment. RESULTS: Care givers identified five main challenges: long delays in their child's diagnosis, difficulty attending clinic for daily treatment, difficulty administering TB medications, stock-outs of TB medications leading to treatment interruptions, and inadequate TB education. Care givers prioritized these same five areas to improve the overall management of their child's TB. CONCLUSION: Our findings suggest that despite accessing care through an NTP that adheres to World Health Organization guidelines, care givers for children on treatment in Botswana continue to encounter significant challenges. While each of these represents a potential threat to successful treatment, they can be addressed with relatively small systematic and programmatic adjustments. These results will inform the next version of the Botswana NTP guidelines towards a more child- and care giver-centered approach.

The relationship of myocardial contraction and electrical excitation--the correlation between scintigraphic phase image analysis and electrophysiologic mapping.

BACKGROUND: Phase imaging derived from equilibrium radionuclide angiography presents the ventricular contraction sequence. It has been widely but only indirectly correlated with the sequence of electrical myocardial activation. OBJECTIVES: We sought to determine the specific relationship between the sequence of phase progression and the sequence of myocardial activation, contraction and conduction, in order to document a noninvasive method that could monitor both. METHODS: In 7 normal and 9 infarcted dogs, the sequence of phase angle was correlated with the epicardial activation map in 126 episodes of sinus rhythm and pacing from three ventricular sites. RESULTS: In each episode, the site of earliest phase angle was identical to the focus of initial epicardial activation. Similarly, the serial contraction pattern by phase image analysis matched the electrical epicardial activation sequence completely or demonstrated good agreement in approximately 85% of pacing episodes, without differences between normal or infarct groups. CONCLUSIONS: A noninvasive method to accurately determine the sequence of contraction may serve as a surrogate for the associated electrical activation sequence or be applied to identify their differences.

Heterogeneous sympathetic innervation influences local myocardial repolarization in normally perfused rabbit hearts.

BACKGROUND: Heterogeneity of sympathetic innervation is thought to contribute to the potential for fatal arrhythmia. However, little is known about the effects of heterogeneous innervation on repolarization. METHODS AND RESULTS: To assess this relationship, we measured activation recovery intervals (ARIs) from 64 epicardial sites in 11 rabbits studied 2 weeks after regional denervation produced by phenol and 4 sham-operated rabbits. ARI results were compared with the distribution of sympathetic innervation measured from 3D reconstructions of serial autoradiographs of [(125)I]metaiodobenzylguanidine and (99m)Tc-sestamibi. ARIs were recorded during baseline sinus rhythm, norepinephrine (NE) infusion (0.1 microg. kg(-1). min(-1)), and left stellate ganglion stimulation (SS). NE shortened ARI in 98% of electrodes in the denervated region. The degree of ARI shortening and dispersion increased (P<0.001 and P<0.01, respectively) as denervation became more severe. SS shortened ARI in 30% of electrodes in the denervated area, with increased shortening and dispersion related to increased severity of denervation (P<0.01). SS prolonged ARI in 70% of electrodes in the denervated area, with no correlation with severity of denervation. CONCLUSIONS: The magnitude and dispersion of local repolarization responses are related to the severity of denervation, as well as the type of stimulation: neural (SS) versus humoral (NE). The differences may relate to the concentration of NE released.

Electrophysiological effects of long, linear atrial lesions placed under intracardiac ultrasound guidance.

BACKGROUND: A curative atrial fibrillation procedure will most likely rely on creating transmural linear ablative lesions. However, it is currently unknown whether endocardial radiofrequency lesions can create lines of conduction block. METHODS AND RESULTS: In six pigs, intracardiac echocardiography was used to guide the positioning of multiple coil array catheters to bridge endocardial structures in three right atrial locations: (1) from the crista terminalis to the tricuspid annulus; (2) from the fossa ovalis to the crista terminalis; and (3) from the inferior vena cava to the tricuspid annulus. Once the catheter was positioned, linear lesions were made by radiofrequency energy applied sequentially to each of the four coils. After 15 days, the chest was opened and a 112-electrode epicardial plaque was positioned over the atrial free wall lesion to determine activation patterns. Three lesions were placed in each animal, with a mean procedure time of 47+/-11 minutes. Once adequate contact was determined by intracardiac echocardiography, a single series of radiofrequency application was required to achieve tissue heating (65+/-4 degrees C) with a power of 21+/-10 W. Epicardial mapping demonstrated complete conduction block across the lesions in all animals, with split potentials and disparate activation times (64+/-16 ms) across the lesion. At autopsy, all lesions were discrete, continuous, and without evidence of charring. The lesions were within 0.3+/-0.5 mm of their targeted anatomic locations and measured 21+/-4 mm long and 2.8+/-0.6 mm wide. Histology revealed transmural fibrosis throughout the length of each lesion. CONCLUSIONS: Linear lesions that are electrophysiologically transmural and continuous can be placed in the right atrium of normal pigs. With intracardiac echocardiography, adequate tissue contact over several coil electrodes can be ensured, resulting in short procedure times, efficient energy application, and accurate anatomically linked lesion placement.

Myocardial perfusion imaging with a combined x-ray CT and SPECT system.

UNLABELLED: We evaluated a novel combined x-ray CT and SPECT medical imaging system for quantitative in vivo measurements of 99mTc-sestamibi uptake in an animal model of myocardial perfusion. METHODS: Correlated emission-transmission myocardial images were obtained from 7- to 10-kg pigs. The x-ray CT image was used to generate an object-specific attenuation map that was incorporated into an iterative ML-EM algorithm for reconstruction and attenuation correction of the coregistered SPECT images. The pixel intensities in the SPECT images were calibrated in units of radionuclide concentrations (MBq/g), then compared against in vitro 99mTc activity concentration measured from the excised myocardium. In addition, the coregistered x-ray CT image was used to determine anatomical boundaries for quantitation of myocardial regions with low perfusion. RESULTS: The accuracy of the quantitative measurement of in vivo activity concentration in the porcine myocardium was improved by object-specific attenuation correction. However, an additional correction for partial volume errors was required to retrieve the true activity concentration from the reconstructed SPECT images. CONCLUSION: Accurate absolute SPECT quantitation required object-specific correction for attenuation and partial volume effects. Additional anatomical information from the x-ray CT image was helpful in defining regions of interest for quantitation of the SPECT images.

Heterogeneous sympathetic innervation in German shepherd dogs with inherited ventricular arrhythmia and sudden cardiac death.

BACKGROUND: Recently, a colony of German shepherd dogs with inherited spontaneous cardiac arrhythmias and associated sudden death has been developed and characterized. Due to the median age of onset of the arrhythmia (4.5 months), the tendency for the arrhythmia to occur during REM sleep or after exercise, and the absence of structural heart disease, we hypothesized a developmental abnormality of the sympathetic innervation to the heart. METHODS AND RESULTS: We studied 11 dogs from this colony, ranging in age from 6 months to 6 years, and four 7-month-old German shepherd dogs unrelated to the colony as controls. We imaged the distribution of functional myocardial sympathetic innervation and perfusion with [123I]metaiodobenzylguanidine (MIBG) and 201Tl, respectively. Sympathetic nerve distribution was evaluated morphologically by immunocytochemical localization of tyrosine hydroxylase. All of the hearts showed evidence of a regional decrease in MIBG uptake, ranging from 5.3% to 53.4% of the myocardium, whereas control dogs showed homogeneous MIBG uptake. Immunocytochemical studies on sections from regions with decreased MIBG uptake showed a striking paucity of nerves compared with regions with normal MIBG uptake, confirming denervation. When the dogs were grouped into those with (n=6) and without (n=5) evidence of ventricular tachycardia on ambulatory ECG, the group with ventricular tachycardia showed 35+/-16.5% denervation, whereas the group without ventricular tachycardia showed 12+/-5.6% denervation (P<.02). CONCLUSIONS: Abnormal heterogeneous sympathetic innervation exists in these dogs with inherited ventricular arrhythmia and sudden cardiac death. Mechanisms relating the presence and extent of regional denervation to the incidence of ventricular arrhythmia remain to be defined.

Radiofrequency catheter modification of sinus pacemaker function guided by intracardiac echocardiography.

BACKGROUND: The sinus P wave arises from a pacemaker complex distributed along the crista terminalis. We investigated the feasibility of modification of sinus pacemaker function using graded applications of radiofrequency energy along the crista terminalis in dogs to achieve sinus rate control. METHODS AND RESULTS: Modification of sinus pacemaker function (30 +/- 5% reduction in intrinsic heart rate with retention of a normal P-wave axis) was performed in 11 dogs (group 1). Total sinus pacemaker ablation (> 50% reduction in intrinsic heart rate with development of a low ectopic atrial or a junctional rhythm) was performed in 4 dogs (group 2). Intracardiac echocardiography was used to identify the crista terminalis as an anatomic marker of sinus node location. Sinus pacemaker modification caused a significant decrease in intrinsic heart rate (31% reduction, P < .001), heart rate responsiveness to isoproterenol (30% reduction, P < .0001), and average (20% reduction, P = .0002) and maximal (22% reduction, P = .0007) heart rates during 24-hour Holter monitoring. In 6 of the 11 animals, the targeted rate reduction of 30 +/- 5% was accurately achieved (mean, 31.6 +/- 4.3%; P < .001), and in the other 5, significant reduction of intrinsic heart rate was achieved but with greater variation (28.0 +/- 17.3%, P < .005). Corrected sinus node recovery time was not prolonged. After modification, earliest activation was mapped to the crista terminalis inferior to the lesion in all animals. In long-term follow-up (3.7 +/- 1.0 months), effects were maintained. After total sinus pacemaker ablation, junctional and low atrial escape pacemakers were unstable. CONCLUSIONS: This study demonstrates the feasibility of modification of sinus pacemaker function for sinus rate control using catheter-based radiofrequency ablation guided by intracardiac echocardiography. This can be done while pacemaker stability and attenuated responsiveness to autonomic influences are preserved. Intracardiac echocardiography accurately defined the crista terminalis and provided a reliable means to anatomically localize catheter position in relation to the sinus node.