Mayo - Cardiac Amyloid AI

Vocabulary flashcards summarizing core terms related to echocardiographic features, diagnostic work-up, genetic variants, prognostic markers, and emerging treatments in cardiac amyloidosis.

Cardiac Amyloidosis

Infiltrative cardiomyopathy caused by misfolded protein deposition (AL or TTR) leading to thickened, stiff ventricular walls and heart failure.

AL (Light-Chain) Amyloidosis

Amyloid formed from immunoglobulin light chains; originates in bone marrow and is rapidly progressive, often requiring hematology-directed therapies (e.g., stem cell transplant).

TTR (Transthyretin) Amyloidosis

Amyloid derived from misfolded transthyretin made in the liver; exists as wild-type (senile) or hereditary mutant forms.

Wild-Type TTR

Non-mutated transthyretin that aggregates with age; now the most common amyloid seen in clinics, often presenting with HFpEF, carpal tunnel, and AFib.

Hereditary TTR (ATTRm)

Mutant transthyretin causing earlier amyloid deposition; the V122I (Val122Ile) variant affects ≈4 % of African Americans.

Monoclonal Gammopathy of Undetermined Significance (MGUS)

Asymptomatic clonal plasma-cell disorder that can evolve into AL amyloidosis; presence mandates tissue biopsy before labeling TTR by scan.

Technetium-99m PYP Scan

Bone scintigraphy that binds myocardial TTR deposits; grade 2–3 uptake with absent monoclonal protein is diagnostic for TTR amyloid.

Relative Apical Sparing ("Cherry-on-Top")

Speckle-tracking strain pattern with preserved apical strain and reduced basal/mid strain; suggestive, but not pathognomonic, for cardiac amyloid.

Stroke Volume Index (SVI)

SV normalized to body surface area; in AL amyloid, SVI ≤ 33 mL/m² predicts survival < 5 months, whereas > 33 mL/m² predicts ≈65 months.

Cardiac Index

Cardiac output/body surface area; helpful for hemodynamic assessment in amyloid patients.

LV Wall Thickness ≥ 12 mm

Echo threshold suggesting infiltrative disease when hypertensive or athletic hypertrophy is absent.

Low-Voltage ECG

Disproportionately small QRS amplitudes despite thick myocardium; classic but not universal finding in amyloidosis.

Basal Posterior Wall Thickening

Echo clue to amyloid; often accompanied by right-ventricular free-wall thickening.

Periorbital Purpura

Characteristic raccoon-eye bruising linked to AL amyloidosis.

Carpal Tunnel Syndrome

Median nerve entrapment frequently preceding TTR amyloid diagnosis.

TAVR and Amyloid

≈15 % of severe AS patients undergoing TAVR have coexistent TTR amyloid; TAVR still indicated and beneficial.

Serum & Urine Immunofixation Electrophoresis

First-line laboratories to exclude AL amyloid by detecting monoclonal light chains.

Endomyocardial Biopsy

Gold standard when imaging and labs are inconclusive or monoclonal protein present.

Tafamidis

Oral TTR tetramer stabilizer reducing mortality and hospitalizations in ATTR cardiomyopathy (Class I guideline).

AG10 (Acoramidis)

Next-generation oral TTR stabilizer currently in late-phase trials.

Patisiran & Inotersen

RNA-silencing agents that inhibit hepatic TTR production; approved for neuropathic ATTR and being studied in cardiac disease.

TTR Gene Silencers vs Stabilizers

Silencers reduce protein synthesis (injectable, infrequent dosing); stabilizers prevent tetramer dissociation (oral, daily).

NYHA Class and Prognosis

Early-stage (Class I–II) ATTR patients on therapy show ~60 % 82-month survival vs ~25 % when treated at Class III.

Anticoagulation in Amyloid

AFib carries high stroke risk; DOAC or warfarin recommended regardless of CHA₂DS₂-VASc score.

Echocardiographic Response Criteria

≥5 % change in EF or ≥5 mL change in stroke volume considered significant during follow-up.

Cardiac MRI (CMR)

Provides tissue characterization (T1 mapping, ECV) and functional data; useful for diagnosis and potentially for early detection.

Bone Scintigraphy Limitations

Useful for TTR, not AL; false positives occur with coexistent MGUS—biopsy required.

Right-Ventricular Free-Wall Thickening

Additional echo sign raising suspicion for infiltrative amyloid when seen with LV thickening.

Pericardial Effusion

Small effusion commonly accompanies amyloid due to stiff ventricles and elevated right-sided pressures.

Cherry-on-Top Positive Predictive Value

In a single-center study, apical sparing strain pattern predicted amyloid in only 39 % of patients—imaging must be correlated clinically.

Dimer vs Tetramer Misfolding

TTR normally circulates as a tetramer; misfolding/monomer dissociation leads to amyloid formation.