ELECTROPHYSIOLOGIC ABNORMALITIES OF CARDIAC-FUNCTION IN PROGRESSIVE SYSTEMIC-SCLEROSIS

The heart has been generally recognized as a target organ in progressi ve systemic sclerosis. Noninvasive studies have assessed the incidence and prognostic importance of cardiac arrhythmias in these patients. H owever, detailed exploration of the function of impulse formation and the conduction system of the heart in these patients has never been re ported. Therefore, invasive electrophysiologic studies were performed in 30 patients with systemic sclerosis, all of whom had neither obviou s cardiac involvement nor cardiac arrhythmias, and in 32 subjects with no evidence of heart disease, who served as a control group. Correcte d sinus node recovery time in patients with systemic sclerosis was sig nificantly longer (P < .001) than in the control group, as was the HV interval (P < .05). Of the 30 patients with systemic sclerosis, 10 had an HV interval of 60 ms or longer. In four patients with systemic scl erosis, the recorded AH interval exceeded 125 ms. The intra-atrial con duction time tended to increase to a significant degree (P < .05) in p atients with systemic sclerosis. The interatrial conduction time was m uch longer (P < .001), and the maximal conduction delay to the atriove ntricular junction and to the distal coronary sinus was much greater i n the patients with systemic sclerosis than in the control group (P < .001 for both). Supraventricular tachyarrhythmias were induced in 15 p atients with systemic sclerosis versus 3 control group subjects (P < . 001). With respect to corrected sinus node recovery time, AH and HV in tervals, atrial vulnerability, and ventricular tachycardia, 3 of the 3 0 patients with systemic sclerosis had abnormal Endings in one of thes e parameters and 14 had abnormalities in more than one. These results suggest that a broad spectrum of electrophysiologic abnormalities is p resent in patients with systemic sclerosis, which can be revealed only by invasive studies. Furthermore, this study provides additional supp ort for the hypothesis that diffuse myocardial involvement is characte ristic of scleroderma patients, since a number of these patients showe d more than one electrophysiologic defect.