METHODS A Vietnamese woman, now 68 years old, had for ten years been known to have a monoclonal lambda light-chain gammopathy. Two years before the present admission her resting ECG had shown absent R waves in V2 to V4, first-degree A-V block and preterminal negative T waves. Results of left heart catheterization and echocardiography were essentially normal. Gradually increasing dyspnoea over the preceding 9 months, recently even at rest, and a poor general state with clinical signs of heart failure led to her hospital admission. METHODS Laboratory tests confirmed the known gammopathy without evidence of plasmacytoma. An echocardiogram now demonstrated a moderately enlarged left atrium and hypertrophied left ventricular wall, as well as restrictive function with an increased ratio of early to late diastolic filling velocity and shortened deceleration time. Myocardial echogenicity was increased. Rectal biopsy showed numerous interstitial and paravascular amyloid fibrillae. All these findings indicated restrictive cardiomyopathy as part of primary systemic amyloidosis. METHODS After treatment with frusemide (80 mg twice daily) and pacemaker implantation she was discharged, her cardiac status now in NYHA class III. Neither chemotherapy nor cardiac transplantation is contemplated.