Non-invasive Detection of Latent Cardiac Sarcoidosis Using Signal Averaged Electrocardiogram

Abstract

Backgrounds: Electrographic conduction abnormalities including development of atrioventricular block, bundle branch block, ventricular arrhythmias are characteristic manifestations of cardiac sarcoidosis. However, it is unclear whether minute conduction abnormalities are latent in sarcoidosis patients without such obvious cardiac manifestations. Patients and Methods: Consecutive 114 subjects consisted of 10 patients with cardiac sarcoidosis, 52 patients with pulmonary sarcoidosis who had no abnormal findings in standard cardiovascular examinations on electrocardiogram and echocardiogram, and 52 normal controls were studied. All subjects underwent SAECG from which f-QRS, RMS40, and LAS40 were measured to detect late potential (LP). Differences in SAECG parameters, numbers of PVCs on 24h Holter monitoring, ACE and BNP levels were examined. Results: In patients with cardiac sarcoidosis (CS group), LP was detected in 8(80.0%) patients. Among 52 patients with pulmonary sarcoidosis, LP was detected in 25 patients (46.2%) (PS-LP(+) group), comparing only 3(5.8%) of normal controls (p<0.001). The remaining 27 patients with pulmonary sarcoidosis negative for LP were classified in PS-LP(-) group. In CS group, number of PVCs, and BNP levels were significantly higher than those in PS-LP(+) and PS-LP(-) groups. However, there found no significant differences in these parameters between PS-LP(+) and PS-LP(-) groups. Conclusion: Among sarcoidosis patients without obvious cardiac manifestations, the prevalence of LP was high, suggesting latent conduction abnormality. Close follow up should be needed in these patients.