[Analyses of ventricular arrhythmias in patients with progressive systemic scleroderma (PSS) by ambulatory electrocardiography]. 
Disorder of cardiac conduction and automaticity have been widely reported in patients with progressive systemic scleroderma (PSS).  In the present study, ventricular arrhythmias were monitored by 24-hour ambulatory electrocardiographic recording (Holter monitor) in 30 female patients with PSS and 20 apparently healthy female controls.  The following results were obtained: 1) In the waking state, 8 cases of 30 patients showed grade III, IVA or IVB of ventricular arrhythmias, according to Lown's classification.  On the other hand, ventricular arrhythmias, such as grade III, IVA or IVB, were not observed in the control group.  2) In the patient group, grade IVA arrhythmias were observed during defecation, driving or light working, and grade IVB were during defecation, urination, light working or sleeping.  These results suggest that it is important to examine arrhythmias by Holter monitors in patients with PSS.