Cardiac rhythm and pacemaking abnormalities in patients affected by endemic pemphigus in Colombia may be the result of deposition of autoantibodies, complement, fibrinogen, and other molecules

BACKGROUND We previously showed that one-third of patients affected by endemic pemphigus foliaceus in E Bagre, Colombia (El Bagre-EPF), display autoreactivity to the heart. OBJECTIVE The purpose of this study was to investigate rhythm disturbances with the presence of autoantibodies and correlate them with ECG changes in these patients. METHODS We performed a study comparing 30 patients and 30 controls from the endemic area, matched by demographics, including age, sex, weight, work activities, and comorbidities. ECG as well as direct and indirect immunofluorescence, immunohistochemistry, and confocal microscopic studies focusing on cardiac node abnormalities were performed. Autopsies of 7 patients also were reviewed. RESULTS The main ECG abnormalities seen in the El Bagre-EPF patients were sinus bradycardia (in one-half), followed by left bundle branch block, left posterior fascicular block, and left anterior fascicular block compared with the controls. One-third of the patients displayed polyclonal autoantibodies against the sinoatrial and/or AV nodes and the His bundle correlating with rhythm anomalies and delays in the cardiac conduction system (P < .01). The patient antibodies colocalized with commercial antibodies to desmoplakins I and II, p0071, armadillo repeat gene deleted in veto-cardio-facial syndrome (ARVCF), and myocardium-enriched zonula occludens-1-associated protein (MYZAP; Progen Biotechnik) (P < .01). CONCLUSION One-third of the patients affected by El Bagre-EPF have rhythm abnormalities that slow the conduction of impulses in cardiac nodes and the cardiac conduction system. These abnormalities likely occur as a result of deposition of autoantibodies, complement, and other inflammatory molecules. We show for the first time that MYZAP is present in cardiac nodes.