DIRECT EFFECTS OF DC CARDIOVERSION ON BLOOD ECHOGENICITY - AN IN-VITRO STUDY

Exacerbation of left atrial spontaneous echo contrast (SEC) after card ioversion of atrial fibrillation has been attributed to left atrial me chanical dysfunction induced by the procedure (''atrial stunning''). A n in vitro model was devised to determine whether electrically induced changes in blood properties might contribute to SEC formation after c ardioversion. Human blood echogenicity was examined quantitatively by videodensitometry before and after shocks of 1, 2, 5, and 20 J. Change s in blood cell numbers, cell morphology, and erythrocyte sedimentatio n rate were determined by haematological analysis. Immediately followi ng electrical discharges, transient and dose-related, highly echogenic microbubbles were noted, but shocks of increasing intensity did not i nduce SEC at high blood velocity or alter the severity of SEC at low b lood velocity. No quantitative or qualitative changes in haematologica l parameters were observed. These results suggest that direct effects of electrical shock on blood do not contribute to SEC after cardiovers ion. Systemic haematological responses to electric shock that might in directly promote red cell aggregation in vivo cannot be excluded by th is in vitro study. Copyright (C) 1997 World Federation for Ultrasound in Medicine & Biology.