Scintigraphic assessment of double-chambered right ventricle.

A double-chambered right ventricle is often clinically misdiagnosed and may be missed even during cardiac catheterization. We encountered a 56-year-old male who had abnormal right ventricular thallium-201 uptake and a photon deficient area in the right ventricle by radionuclide cardioangiography. These findings strongly suggested the existence of anomalous muscle band in the right ventricle. It was demonstrated by contrast angiography that the right ventricle was divided into two chambers by a hypertrophic muscular band; the pressure gradient in the right ventricle was 98 mmHg.