Left ventricular ejection time in atrial fibrillation

Left ventricular ejection time (LVET; indirect carotid pulse) was studied in 48 patients with atrial fibrillation. In comparison with normal individuals in normal sinus rhythm, ejection times for similar cycle lengths were usually short in patients with atrial fibrillation. Patients without mitral valve disease usually show increasing ejection times following increasing cycle lengths until a certain cycle length is reached (usually around 0.85 sec). Further prolongation of cycle length will not further lengthen the LVET. By contrast, patients with significant mitral stenosis show a continuously sloping curve, i.e. continue to show prolongation of ejection times with progressive lengthening of cycles, eventually reaching ejection times (if cycles are sufficiently long) which exceed those of patients without mitral stenosis. Conversion to normal sinus rhythm (six patients) produced variable results, usually lengthening of ejection time for similar cycle length. Postconversion lengthening of LVET was most pronounced in those cases which lacked progressive increase in LVET with longer cycles during atrial fibrillation. This effect was evident in those patients manifesting relatively slow sinus rates after conversion. Our results indicate that in order to derive information from ejection times in atrial fibrillation one must plot these values against cycle lengths. Moreover, he cannot use data obtained from patients in normal sinus rhythm to interpret ejection times in those manifesting atrial fibrillation.