Initially correctible heart disease frequently ends in intractable congestive heart failure. This outcome can be prevented in many patients by employing various available modalities of treatment followed by corrective heart surgery. Such a "double-barrelled attack" is made possible by the application of artificial renal dialysis before the heart surgery. In the case presented cardiac catheterization was also necessary. The report illustrates the application of these various coordinated diagnostic and therapeutic measures in a patient admitted with the diagnosis of mitral stenosis. Special studies revealed a patent ductus arteriosus, divided and sutured successfully.