Cardiac Amyloidosis: A Known Disease with an Unknown Presentation

Abstract

Cardiac amyloidosis is an increasingly recognized entity that causes significant morbidity and mortality. Transthyretin amyloidosis (ATTR) is present in about 16% of patients with severe aortic stenosis and up to 17% of patients with heart failure with preserved ejection fraction 9,10 . Though the screening test of choice, echocardiography is not highly sensitive or specific, and it should not be relied upon to rule out cardiac amyloidosis, especially if clinical suspicion is high. We present a case of a 58-year-old woman with a history of bilateral carpal tunnel syndrome who presented with paresthesia and syncope. Extensive workup for neurologic, infectious, and malignant etiologies was negative. EKG was remarkable for low voltage. Transthoracic echocardiogram (TTE) was not suggestive of infiltrative disease. Subsequent cardiac MRI demonstrated diffuse biventricular late gadolinium enhancement and technetium 99M pyrophosphate scan revealed diffuse (3+) uptake, which was in stark contrast to the TTE. The diagnosis of ATTR amyloidosis allowed for prompt initiation of treatment in this patient. Syncope is an uncommon presentation of cardiac amyloidosis. Such significant cardiac burden of disease without appreciable changes on TTE or clinical heart failure, demonstrates the importance of clinical vigilance and thorough workup when suspicion for amyloidosis is high, particularly if characteristic signs and symptoms consistent with systemic disease are present, as timely treatment can significantly reduce the morbidity and mortality of this disease.