The effect of atrial pacing on the mitral echocardiogram of mitral stenosis recorded simultaneously with haemodynamic data.

Simultaneous mitral echocardiograms and haemodynamic data were recorded in six cases of mitral stenosis during atrial pacing. Due to the prolongation of the P-R interval during atrial pacing, the diastolic closure rate E-F was measurable up to a heart rate of 80 per min. only. At a heart rate of 80 or less, both in sinus rhythm and during atrial pacing the diastolic closure rate remained essentially the same in each case. However, above 80/min E-F became too short and post-atrial systolic closure A-B only was available for measurement which was higher in each case than its corresponding E-F value. This contrasts with cases with sinus rhythm where the diastolic closure rate E-F measurable up to a heart rate of 110 per minute.