Pacemaker-masked hypertension in a patient with mitral stenosis.

Severe hypertension was seen in a patient with mitral stenosis when in sinus rhythm. A large fall in systolic blood pressure and in left ventricular end-diastolic pressure was caused by ventricular pacing. Contrary to the usual situation in mitral stenosis this patient paradoxically is a subject who improved haemodynamically with the loss of sinus rhythm and of atrial systole.