Pacemaker induced mitral regurgitation: an alternative form of pacemaker syndrome.

A patient in atrial fibrillation was referred for mitral valve replacement due to severe mitral regurgitation. A cardiac pacemaker had previously been implanted. Cardiac catheterization demonstrated large V waves in the wedge pressure tracing during ventricular pacing, which were not present during native conduction. A left ventriculogram demonstrated severe mitral regurgitation during ventricular pacing, but not during native conduction. This patient, in atrial fibrillation, had severe mitral regurgitation induced by ventricular pacing and not by native conduction. Pacemaker syndrome may be caused by mitral regurgitation that is probably not secondary to AV dissociation, but rather the result of dyssynchronous ventricular contraction.