Alternation of Left Ventricular Performance with Electrical Alternans

Systolic time intervals (STIs) were measured in a patient with massive pericardial effusion and electrical alternans. The total electromechanical systole and the left ventricular ejection time (LVET) were significantly shorter in beats following the smaller QRS complexes, while the pre-ejection time (PEP) was longer and the ratio of PEP/LVET larger. This beat-to-beat difference in the STIs suggests than an alternation in left ventricular performance accompanied the electrical alternans. After evacuation of the pericardial fluid, electrical alternans and STI alternation disappeared.