Diagnostic sensitivity and cost per diagnosis of ambulatory cardiac monitoring strategies in unexplained syncope patients.

Diagnosing cardiac pauses that could produce syncopal episodes is important to guide appropriate therapy. However, the infrequent nature of these episodes can make detection challenging with conventional monitoring (CM) strategies with short-term ECG monitors. Insertable cardiac monitors (ICMs) continuously monitor for arrhythmias but present a higher up-front cost. It is not well understood whether these higher costs are offset by the costs of repeat evaluation in CM strategies. We simulated the likelihood of diagnostic success and cost-per-diagnosis of pause arrhythmias with CM strategies compared to ICM monitoring. ICM device data from syncope patients diagnosed with pause arrhythmias was utilized to simulate patient pathways and diagnostic success with CM. We assumed that detected true pause episodes (≥5 seconds) were symptomatic and prompted a hospital encounter and further evaluation with CM. Subsequent true pause episodes in yet-undiagnosed patients triggered additional rounds of CM. Costs of monitoring were accrued at each encounter and represent the U.S. payer perspective. Cost per diagnosed patient was calculated as the total costs accrued for all patients divided by the number of patients diagnosed, across 1,000 simulations. During a mean 505±333 days of monitoring ICM detected 2.4±2.7 pause events per patient, with an average of 109±94 days until the first event. CM was projected to diagnose between 13.8% (24-hour Holter) and 30.2% (two 30-day monitors) of the ICM-diagnosed patients. Total diagnostic costs per ICM-diagnosed patient averaged $7,847, whereas in the CM strategies average cost-per-diagnosis ranged from $12,950±2,589 with 24-hour Holter to $32,977±14,749 for two 30-day monitors. Relative to patients diagnosed with pause arrhythmias via ICM, CM strategies diagnose fewer patients and incur higher costs per diagnosed patient.

Rapamycin nanoparticles target defective autophagy in muscular dystrophy to enhance both strength and cardiac function.

Duchenne muscular dystrophy in boys progresses rapidly to severe impairment of muscle function and death in the second or third decade of life. Current supportive therapy with corticosteroids results in a modest increase in strength as a consequence of a general reduction in inflammation, albeit with potential untoward long-term side effects and ultimate failure of the agent to maintain strength. Here, we demonstrate that alternative approaches that rescue defective autophagy in mdx mice, a model of Duchenne muscular dystrophy, with the use of rapamycin-loaded nanoparticles induce a reproducible increase in both skeletal muscle strength and cardiac contractile performance that is not achievable with conventional oral rapamycin, even in pharmacological doses. This increase in physical performance occurs in both young and adult mice, and, surprisingly, even in aged wild-type mice, which sets the stage for consideration of systemic therapies to facilitate improved cell function by autophagic disposal of toxic byproducts of cell death and regeneration.

Focal but reversible diastolic sheet dysfunction reflects regional calcium mishandling in dystrophic mdx mouse hearts.

Cardiac dysfunction is a primary cause of patient mortality in Duchenne muscular dystrophy, potentially related to elevated cytosolic calcium. However, the regional versus global functional consequences of cellular calcium mishandling have not been defined in the whole heart. Here we sought for the first time to elucidate potential regional dependencies between calcium mishandling and myocardial fiber/sheet function as a manifestation of dystrophin-deficient (mdx) cardiomyopathy. Isolated-perfused hearts from 16-mo-old mdx (N = 10) and wild-type (WT; N = 10) were arrested sequentially in diastole and systole for diffusion tensor MRI quantification of myocardial sheet architecture and function. When compared with WT hearts, mdx hearts exhibited normal systolic sheet architecture but a lower diastolic sheet angle magnitude (|ß|) in the basal region. The regional diastolic sheet dysfunction was normalized by reducing perfusate calcium concentrations. Optical mapping of calcium transients in isolated hearts (3 mdx and 4 WT) revealed a stretch-inducible regional defect of intracellular calcium reuptake, reflected by a 25% increase of decay times (T(50)) and decay constants, at the base of mdx hearts. The basal region of mdx hearts also exhibited greater fibrosis than did the apex, which matched the regional sheet dysfunction. We conclude that myocardial diastolic sheet dysfunction is observed initially in basal segments along with calcium mishandling, ultimately culminating in increased fibrosis. The preservation of relatively normal calcium reuptake and diastolic/systolic sheet mechanics throughout the rest of the heart, together with the rapid reversibility of functional defects by reducing cytosolic calcium, points to the significance of regional mechanical factors in the progression of the disease.

Label-free photoacoustic microscopy of myocardial sheet architecture.

Cardiac myofibers are organized into sheet architectures, which contribute to up to 40% of the heart wall thickening for ejection of blood for circulation. It is important to delineate the sheet architecture for a better understanding of cardiac mechanisms. However, current sheet imaging technologies are limited by fixation-induced dehydration/deformation and low spatial resolution. Here we implemented high-resolution label-free photoacoustic microscopy (PAM) of the myocardial sheet architecture. With high endogenous optical-absorption contrast originating mainly from cytochrome, myoglobin, and melanin, PAM can image the unfixed, unstained and unsliced heart without introducing deformation artifacts. A fresh blood-free mouse heart was imaged by PAM ex vivo. The three-dimensional branching sheets were clearly identified within 150 [micro sign]m depth. Various morphological parameters were derived from the PAM image. The sheet thickness (80 ± 10 µm) and the cleavage height (11 ± 1 µm) were derived from an undehydrated heart for the first time. Therefore, PAM has the potential for the functional imaging of sheet architecture in ex vivo perfused and viable hearts.

Effect of endoscopic sinus surgery on irradiation-induced rhinosinusitis in patients with nasopharyngeal carcinoma.

OBJECTIVES: We evaluated the effect of endoscopic sinus surgery on irradiation-induced rhinosinusitis of the maxillary-sinus mucosa among patients with nasopharyngeal carcinoma (NPC). DESIGN: Surgical outcomes were evaluated by changes to the ultrastructure of the antral mucosa and nasomucociliary clearance. METHODS: Twenty-one NPC patients with irradiation-induced chronic sinusitis were enrolled in the study, along with five controls. Specimens were taken from 42 maxillary sinuses during surgery and 1 year after surgery. Saccharin transit time was measured before the initial surgery and 1 year after surgery. RESULTS: In the postoperative cases, we found a decrease in the number of the submucosal gland openings (P < 0.05), the cilia in the antral mucosa regenerated (P < 0.05), and the saccharin transit time reduced (P < 0.05); the number of goblet cells did not change. CONCLUSION: Endoscopic sinus surgery is an effective treatment for irradiation-induced rhinosinusitis in NPC patients, improving ventilation and drainage of the paranasal sinuses, and facilitating regeneration of the sinus mucosa.

Vascular endothelial growth factor and children featuring nasal polyps.

BACKGROUND: The aim of this study is to explore the expression of vascular endothelial growth factor within nasal polyps, and the implication of such expression as regards the development of nasal polyps amongst children. MATERIAL AND METHODS: Sixty children suffering from chronic rhinosinusitis were enrolled in this study. Amongst them, 30 patients featured rhinosinusitis with associated nasal polyps. A biopsy specimen was taken from the stalk or the base of the nasal polyp for nasal-polyp sufferers, and the ethmoid sinus for study participants who featured no nasal polyps. The primary lesions biopsied were immunohistochemically stained with a specific endothelial-cell marker and also stained for the presence of vascular endothelial growth factor. The specific level of vascular endothelial growth factor and the mean number of blood vessels present in a visual microscopic (biopsied-specimen) field were calculated under light microscopy (x400). RESULTS: The number of vascular endothelial growth factor-expressing cells for the nasal-polyp group and for the sinusitis group was, respectively, 20.8+/-4.0 and 11.5+/-3.4 per visual field. Correspondingly, the mean intra-polyp blood-vessel density for the nasal-polyp group and that for the control group was, respectively, 10.5+/-2.6 and 5.0+/-1.9 per visual field. The mean intra-polyp blood-vessel density and the number of vascular endothelial growth factor-expressing cells proved to be significantly greater amongst individuals from the nasal-polyp group than was the case for their analogs from the sinusitis group (P<0.01, for both). The presence of vascular endothelial growth factor was found to be distributed predominantly within the vascular endothelium and the mast cells of polyp tissue. In addition, the level of vascular endothelial growth-factor expression and the mean blood-vessel count per field correlated significantly for nasal-polyp tissue (P<0.001). Furthermore, the relative size of nasal polyps correlated significantly with the number of (intra-polyp) vascular endothelial-cell growth factor-expressing cells and the mean blood-vessel density (P<0.05, for both). CONCLUSION: The level of expression of vascular endothelial-cell growth factor (VEGF) and the mean blood-vessel density were shown to be significantly greater within nasal polyps than within corresponding sinusitis mucosa. Clinically, the expression of both of these parameters correlated well with the relative size of nasal polyps. Vascular endothelial growth factor participates in the formation of nasal polyps amongst children suffering from chronic rhinosinusitis (CRS).