[Augmentation of left ventricular outflow tract gradient by digitalis glycosides in a case of cardiac (AL-) amyloidosis].

History And Clinical Findings: A 61-year-old man suffering from histologically confirmed amyloidosis associated with coagulation disturbances presented with exercise induced shortness of breath and symptoms of cardiac asthma after four cycles of chemotherapy with melphalan and prednisolone. As a result, treatment with digitoxin was initiated. In addition furosemide and an oral nitrate were administered.

Investigations: Disparity between electrocardiogram and echocardiographic findings was observed in that, while the electrocardiogram showed loss of 'R wave in precordial leads V(2 - 4), excessive thickening of both left and right ventricular wall was shown in the echocardiogram. Doppler-echocardiography revealed a left ventricular outflow tract obstruction at rest with a peak pressure gradient of 64 mm Hg which rose to 145 mm Hg during Valsalva manoeuvre. Colour Doppler presented a moderate mitral insufficiency and the transmitral Doppler flow studies detected a restrictive left ventricular filling pattern.

Diagnosis, Treatment And Course: Digitalis therapy was stopped because of the outflow tract obstruction complicating cardiac amyloidosis. Cardiac symptoms abated over the following weeks. This improvement was reflected in a significant reduction of the outflow tract gradient, the gradients now being 16 mm Hg under resting conditions and a maximum of 36 mm Hg during the Valsalva manoeuvre. The transmitral Doppler flow pattern showed a pseudonormalisation and the mitral regurgitation regressed nearly completely. The patient was free from cardiac complaints until his sudden death 21 months after the diagnosis of cardiac amyloidosis.

Conclusion: Cardiac amyloidosis can present with left ventricular outflow tract obstruction mimicking hypertrophic obstructive cardiomyopathy. This fact must be borne in mind to avoid therapy with preload-reducing or positive inotropic drugs and especially glycosides.