Ventricular pre-excitation and prolonged Q-T interval syndromes in a patient with mitral valve prolapse.

A 34-year-old woman with mitral valve prolapse, frequent ventricular dysrhythmias, and chest pain was studied. Surface electrocardiograms demonstrated short PR and prolonged Q-T intervals. A-V nodal conduction times during atrial pacing were characteristic of A-V nodal bypass tract function. The case is thus interpreted to be one of overlap between three syndromes known to predispose to cardiac dysrhythmias, i.e., mitral valve prolapse, Lown-Ganong-Levine syndrome, and prolonged Q-T interval syndrome.