Her ECG, shown again here, reveals sinus rhythm with normal PR, QRS and QT intervals. The frontal plane QRS spatial vector is directed inferiorly and slightly to the right with an axis of +100 degrees. The amplitude of the S waves in leads V2 and V3 are at the upper limits of normal for a woman of this age. These ECG findings, in combination with the systolic click and murmur suggest mitral valve prolapse with mild mitral insufficiency. This diagnosis was confirmed by the echocardiogram.