R-R interval (RRI) changes were recorded from 15 healthy volunteers in response to volitional unloaded cycling and passively induced cycling (PC). PC was also combined with electrical stimulation (n = 5) to increase muscle mechanoreceptor activation. The electrocardiogram and leg electromyographic activity were continuously sampled by computer at 1,000 Hz, and an electronic trigger was used to designate the instant of pedal movement within an RRI. Changes in RRI were expressed as the difference of the interval in which the trigger was activated (onset RRI) and the average of resting intervals (4-8 intervals). Volitional unloaded cycling produced the greatest decrease in the onset RRI [907 +/- 11 (SE) to 855 +/- 10 ms; -5.4 +/- 0.4%; P < 0.01] when movement was initiated within the first one-third of the interval. A shortening of the onset RRI was also detected when trigger activation occurred in the last one-third of the interval (906 +/- 12 to 875 +/- 11 ms; -3.1 +/- 0.4%; P < 0.01). There were no significant effects of PC alone on the onset RRI. However, PC+electrical stimulation shortened the onset RRI (906 +/- 12 to 883 +/- 11 ms; -2.5 +/- 0.2%; P < 0.05) but only when the movement was initiated within the first one-third of the interval.(ABSTRACT TRUNCATED AT 250 WORDS)

Background: Velocardiofacial syndrome (VCFS) is one of the most common multiple anomaly syndromes in humans. Pharyngeal hypotonia, one of the most common findings in VCFS, contributes to hypernasal speech, which occurs in approximately 75% of individuals with VCFS. Objective: To evaluate the thickness and histologic and histochemical properties of the superior pharyngeal constrictor (SPC) muscle in patients with VCFS to determine whether a muscle abnormality exists that might contribute to the hypotonia seen in these patients. Subjects: The SPC muscle thickness in 26 VCFS patients (18 male and 8 female; age range, 3-29 years) was compared with SPC muscle thickness in age-and sex-matched controls using magnetic resonance images. The histologic and histochemical properties of the SPC muscle in 9 VCFS patients (6 male and 3 female; age range, 4-12 years) were compared with SPC muscle in 3 adult cadavers without VCFS (all male; age range, 80-86 years) using specimens obtained during pharyngeal flap surgery. Results: The thickness of the SPC muscle was significantly less in patients with VCFS (2.03 mm) than in patients without VCFS (2.85 mm). The SPC muscle contained a significantly greater proportion of type 1 fibers in patients with VCFS (27.7%) than in adults without VCFS (17.9%), and the diameter of the type 1 fibers was significantly smaller in patients with VCFS (21.6 µm) than in adults without VCFS (26.6 µm). Conclusions: Differences in the thickness and histologic and histochemical properties of the SPC muscle found in patients with VCFS compared with individuals without VCFS may offer insight into the cause of pharyngeal hypotonia and hypernasal speech seen in these patients.

Based on the data collected in these 8 individuals, patients with reflux disease (known or unknown) can develop severe laryngospasm and possible syncope. The key factor seems to be the association of a recent or concurrent upper respiratory infection that results in a protracted cough that is more severe when supine and at times violent. The cough increases the amount of the refluxate, which is the noxious insult to the larynx.

Reconstruction of the microtic ear remains one of the most challenging procedures encountered by the reconstructive surgeon. The use of autogenous rib cartilage continues to be the gold standard for microtia repair. Numerous refinements and modifications in the original technique described by Tanzer have paved the way for exceptional results in experienced hands. However, ideal results are not always achieved, and there continue to be drawbacks with the standard approach to reconstruction with autogenous rib cartilage. In an attempt to circumvent these shortcomings, surgeons have developed alternative or adjuvant techniques to repair the microtic ear, including the use of tissue expansion, alloplastic implants, and osseointegrated prostheses. Finally, greater emphasis is being placed on early atresia repair in appropriate candidates.