Images in Clinical Medicine
Electrical Alternans
N Engl J Med 1999; 341:2060December 30, 1999
- Article
Figure 1 A 42-year-old woman who had a six-year history of breast cancer and bony metastasis, which had been treated with surgery, adjunctive chemotherapy, and radiation to the thoracic spine, presented with a two-week history of progressive dyspnea on exertion and fatigue. Physical examination demonstrated a pulse of 110 beats per minute, with disappearance of the radial pulse with inspiration; blood pressure of 104/62 mm Hg; jugular venous pressure of more than 15 cm of water; clear lungs; and distant heart sounds. The 12-lead electrocardiogram revealed sinus tachycardia with low voltage and electrical alternans (Panel A). Two-dimensional transthoracic echocardiography confirmed the diagnosis of cardiac tamponade with massive pericardial effusion. Echocardiographic images obtained during consecutive cardiac cycles show a dramatic change (nearly 90 degrees) in the position of the heart from one beat (Panel B) to the next (Panel C). This motion is responsible for the electrical alternans seen on the electrocardiogram. Pericardiocentesis, with the removal of 1200 ml of bloody fluid, resulted in prompt clinical improvement and disappearance of the electrical alternans. PE denotes pericardial effusion, RVOT right ventricular outflow tract, LV left ventricle, and PL pleural effusion.
Michael J. Longo, M.D.
Virginia Mason Medical Center, Seattle, WA 98111C. Carl Jaffe, M.D.
Yale University School of Medicine, New Haven, CT 06520
