A case report of an infiltrative cardiomyopathy in everyday practice: a specific cause that cannot be missed in the elderly

BACKGROUND : Transthyretin amyloid cardiomyopathy (ATTR-CM) is a commonly misdiagnosed cardiac condition due to low disease awareness and perceived rarity, which frequently results in incorrect management and poor outcomes. Early and prompt diagnosis has become critical with emerging therapies that improve patient survival. CASE SUMMARY : A 68-year-old woman presented to a tertiary care centre with acute decompensated heart failure following recurrent hospitalizations for the same issue over the past several months. Transthoracic echocardiography revealed severe concentric left ventricular hypertrophy with grade III diastolic dysfunction. However, QRS voltage by 12-lead electrocardiogram (ECG) was discordant with the degree of left ventricular hypertrophy seen by echocardiography, and the patient had recurrent non-sustained ventricular tachycardia that necessitated implantable cardioverter-defibrillator implantation a few months prior. After aggressive diuresis, the patient completed cardiac magnetic resonance imaging that raised concern for cardiac amyloidosis. Subsequent serum and urine protein electrophoresis with associated immunofixation were within normal limits. Finally, ATTR-CM was confirmed by technetium-99m pyrophosphate scintigraphy with plans to initiate tafamidis after genetic testing. DISCUSSION : Patients >60 years of age with diastolic heart failure phenotypically similar to hypertrophic cardiomyopathy and/or hypertensive heart disease should always be evaluated for ATTR-CM. Features that increase suspicion include discordance between left ventricular wall thickness and ECG voltage, and signs/symptoms of a primary peripheral and autonomic neuropathy. Useful non-invasive diagnostic testing has also made the diagnosis of ATTR-CM inexpensive and possible without the need for an endomyocardial biopsy. Unfortunately, this patient’s diagnosis of ATTR-CM came late in her disease course, which delayed the onset of definitive therapy.