A case of transthyretin amyloid cardiomyopathy (ATTR-CM) presented with symptoms generally associated with a different heart condition, according to a case report recently published in Cureus.
The case, involving an 81-year-old woman, included symptoms of midventricular obstruction (MVO) and paradoxical jet flow (PJF), the report said.
What is ATTR-CM?
Transthyretin amyloidosis cardiomyopathy (ATTR-CM) is a rare progressive disease of the heart muscle that leads to congestive heart failure. It occurs when the transthyretin protein produced by the liver is unstable. Symptoms include fatigue; shortness of breath; irregular heart rate or palpitations; swelling of the legs, ankles and stomach; brain fog; wheezing; and dizziness. It often goes underdiagnosed because of a lack of awareness and knowledge of the disease. There is currently no cure for ATTR-CM.
“Midventricular obstruction (MVO) accompanied by paradoxical jet flow (PJF), which is an early diastolic flow from the apex to the base of the left ventricle, has been observed almost exclusively in hypertrophic cardiomyopathy (HCM),” report authors said.
Read more about ATTR-CM testing and diagnosis
Several cardiac diseases share some clinical characteristics with ATTR-CM, and physicians should consider them before making a diagnosis, the authors said. Patients with HCM, for example, also present increased wall thickness, which compromises diastolic filling. Other conditions, such as aortic stenosis and hypertensive cardiomyopathy, can also cause ventricular hypertrophy and mimic some of the clinical characteristics of ATTR-CM.
The woman presented with increasing difficulty breathing during exertion in the previous four months. Her past medical history was remarkable for hypertension, diabetes mellitus Type 2 and hyperuricemia.
Her physicians detected a systolic heart murmur, suggestive of turbulent ventricular blood flow, and a fourth cardiac sound suggestive of hypertrophic heart failure. Laboratory workup reported a normal troponin and slightly elevated brain natriuretic peptide, both important cardiac damage biomarkers.
Echocardiography revealed a midventricular obstruction with paradoxical jet flow. This means that due to increased concentric cardiac growth (hypertrophy), there was a blood flow obstruction in the left ventricle. The obstruction caused an inversion of the normal blood flow during the diastole, making it from the apex to the base, thus the term paradoxical.
The echocardiographic pattern is almost exclusively associated with HCM. But further interrogation revealed that the patient also suffered from carpal tunnel syndrome, a common ATTR clinical feature.
The finding prompted cardiac bone scintigraphy, which revealed increased uptake consistent with ATTR-CM. A subsequent biopsy confirmed the diagnosis, and the patient started disease-modifying therapy with tafamidis.
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