Sinus rhythm pattern

Abstract

Patient 26 years old, G5P1O3 with gestation of 30 weeks. Hospitalized at 25 weeks due to Rh isoimmunization, with Anti-D titers of 1:1024. She underwent two intrauterine transfusions, with improvement of the results of the systolic peak of the middle cerebral artery in the Doppler ultrasonography. Management was complemented with intravenous immune globulin and plasmapheresis to reduce circulating antibody titers. Despite management, 48 hours after the last transfusion and with elevation of antibody titers to 1:512, she presented the following tracing (Figure 1), which met all the criteria of a sinusoidal pattern.

The sinusoidal pattern is a regular, smooth, oscillating sine wave-shaped tracing that occurs with a frequency of two to five cycles per minute and an amplitude in the range of five to fifteen beats per minute. It is also characterized by a stable basal fetal heart rate between 120-160 beats per minute and absence of variability. It is associated with severe fetal anemia or severe hypoxia.