Clinical significance of low voltage in asymptomatic patients with pericardial effusion free of heart disease.

STUDY OBJECTIVE The purpose of this study was to evaluate the diagnostic value of low voltage with PR-segment and ST-T wave changes in determining the amount of clinically silent pericardial effusion detected in a routine echocardiography. DESIGN Consecutive case series analysis. SETTING Noninvasive cardiology department of a university hospital. PATIENTS Among 8,041 consecutive patients referred to our echocardiography laboratory, 121 asymptomatic patients with pericardial effusion free of heart disease were studied. INTERVENTIONS Echocardiography and ECG. MEASUREMENTS AND RESULTS The amount (small or moderate/large) of pericardial effusion was correlated with ECG. Among 121 patients with pericardial effusion, low voltage was detected in 32 patients (26%), while widespread PR-segment depression was observed in 32 patients (26%) and widespread ST-segment elevation in 8 patients (7%). Although there was a significantly higher incidence of low voltage in patients with moderate/large pericardial effusion compared to that of small pericardial effusion, 13 of 32 patients (41%) with low voltage had a small pericardial effusion. In patients with a small pericardial effusion, 7 of 13 patients (54%) with low voltage had PR-segment depression, while 15 of 85 patients (18%) without low voltage had PR-segment depression; the difference was significant (p = 0.011). In patients with moderate/large pericardial effusions, there was no significant difference in the incidence of PR-segment depression between patients with and without low voltage (47% vs 25%, respectively; p = 0.791). CONCLUSIONS In the presence of PR-segment depression, even a small pericardial effusion may cause low voltage in the surface ECG.