From Stroke to the Final Diagnosis: Cardiac Amyloidosis.

Cardiac amyloidosis is an infiltrative cardiomyopathy that often presents with nonspecific clinical manifestations, leading to delayed diagnosis. Early recognition is essential, particularly in patients with extracardiac manifestations suggestive of systemic amyloidosis. A 43-year-old woman was admitted with an ischemic stroke of unknown origin. During the evaluation for a potential cardioembolic source, transthoracic and transesophageal echocardiography revealed diffuse myocardial and left atrial abnormalities suggestive of an infiltrative process. Electrocardiography demonstrated low QRS voltage despite increased ventricular wall thickness. Cardiac magnetic resonance imaging showed diffuse late gadolinium enhancement, markedly elevated native T1 values, and increased extracellular volume, strongly supporting the diagnosis of cardiac amyloidosis. Although serum and urine immunofixation and bone marrow biopsy were inconclusive, renal biopsy confirmed monoclonal lambda light-chain deposition, establishing the diagnosis of amyloid light-chain (AL) amyloidosis. The patient received standard heart failure therapy and was referred for daratumumab-based chemotherapy. Despite treatment, she rapidly developed anuric renal failure and multiorgan failure, resulting in death shortly after the second chemotherapy cycle. This case highlights the diagnostic value of multimodality imaging in suspected cardiac amyloidosis and emphasizes the importance of considering systemic amyloidosis in younger patients presenting with stroke, nephrotic syndrome, increased ventricular wall thickness, and low QRS voltage. Early diagnosis remains crucial, although prognosis may be poor in advanced AL cardiac amyloidosis.