ERYTHEMA INDURATUM OE BAZIN

Background. There has been a long controversy about the tuberculous cause of erythema induratum, a chronic form of nodular vasculitis. Method. We investigated clinical, histopathologic, and immunohistochemical features of patients with erythema induratum who showed positive tuberculin hypersensitivity reactions or had associated active tuberculosis. Results. The ages of the 32 patients (M 7: W 25) ranged from 13 to 66 years (mean 36.6 years). All patients displayed recurrent crops of tender, painful, violaceous nodules or plaques. Most lesions presented on the legs, but they also occurred on thighs, feet, buttocks, and forearms. The skin lesions evolved for several weeks and healed with scarring and residual pigmentation. Twenty-two patients were treated with isoniazid alone and the remaining 10 patients received combinations of antituberculous drugs. Relapses were encountered in four patients who received isoniazid alone or stopped the medication against medical advice. In most biopsies, histologic examination revealed lobular or septolobular panniculitis with varying combinations of granulomatous inflammation, primary vasculitis, and necrosis. Immunohistochemical labeling revealed a preponderance of T lymphocytes, monocyte-macrophages, and Langerhans' cells, indicative of a type IV hypersensitivity reaction. Conclusion. Erythema induratum of Bazin has distinct clinical, histopathologic, and immunohistochemical features. Erythema induratum of Bazin should be considered as a separate entity of nodular vasculitis caused by latent foci of tuberculous infection.     

Programmed Electrical Stimulation of the Ventricle: An Efficient, Sensitive, and Specific Protocol

A relatively simple and evident ventricular programmed electrical stimulation (PES) protocol was developed, capable of achieving high degrees of sensitivity and specificity. In a series of 481 subjects, 1, 2, and 3 extrasfimuli (ES) were used successively during sinus rhythm and ventricular pacing at two drive cycle lengths, at one or more ventricular sites, together with rapid ventricular pacing, and other maneuvers such as isoproterenol infusion. Three ES were used immediately after two ES at each drive rate, rather than returning after completion of the protocol with two ES. Using the protocol, appropriate arrhythmias could be induced in 88% of all patients with ventricularfibrillation, 84% of all patients with sustained ventricular tachycardia (91% with underlying coronary disease), and 58% of patients with severe nonsus-tained ventricular tachycardia. There were significant differences in inducibility between patients whose ventricular arrhythmias were due to coronary artery disease and other causes. In contrast, sustained ventricular arrhythmias fall ventricular fibrillation) could be induced in only 5% of a control group of control patients, for a specificity of 95%. The protocol described is simpler and more efficient than those that use exhaustive testing of two ES before going to three ES. Three ES during sinus rhythm proved to be the most productive step, with a higher yield ratio (true:false-positives) than two ES or three ES during pacing, especially at fasterrates. Greater efficiency is also achieved by leaving the timing of an extrastimulus just beyond its effective refractory period when an additional extrastimulus is to be added, compared to protocols in which the extrastimulus is moved later in the cycle and then decremented in tandem with the additional extrastimulus. Coupling intervals < 200 msec produced some false-positives, but fewer overall than intervals < 200 msec, and with yield ratios comparable to other protocol steps. The protocol described meets NASPE standardsfor ventricular programmed stimulation protocols, and with its demonstrated specificity and relative simplicity and efficiency may be useful as a model for groups not yet committed to an alternative protocol.