Common cardiac symptoms include shortness of breath, fatigue, reduced exercise tolerance, peripheral edema, abdominal swelling, dizziness, syncope, and palpitations.¹˒² Primary care physicians should also ask about extracardiac manifestations such as bilateral carpal tunnel syndrome, lumbar spinal stenosis, spontaneous biceps tendon rupture, peripheral neuropathy, and autonomic dysfunction, which may precede overt cardiac disease.¹˒³
FAQ #1
How should primary care physicians explain ATTR-CM?
ATTR-CM is a progressive disease in which the transthyretin protein becomes unstable, misfolds, and accumulates as amyloid deposits in the myocardium. These deposits infiltrate the myocardium, producing increased ventricular wall thickness and stiffness and impairing cardiac filling. Over time, ATTR-CM may contribute to heart failure, arrhythmias, and conduction abnormalities.¹˒²
ATTR-CM may be hereditary, resulting from a pathogenic variant in the TTR gene, or wild-type, occurring without an identifiable pathogenic TTR variant and associated with aging. After ATTR-CM is confirmed, genetic testing is recommended to distinguish hereditary from wild-type disease and identify potential implications for family members.¹˒⁴
FAQ #2
How should PCPs discuss the outlook and prognosis of ATTR-CM?
Primary care physicians should explain that ATTR-CM is progressive, but its clinical course varies with disease stage, extent of cardiac involvement, functional status, comorbidities, and treatment response.¹˒³ Prognosis should therefore not be based solely on the diagnosis or presented as a fixed timeline.
Current FDA-approved therapies primarily stabilize transthyretin or reduce its production to slow disease progression and reduce clinical events. They have not been shown to reliably clear existing myocardial amyloid deposits.³˒⁵⁻⁷ Earlier diagnosis may allow treatment to begin before advanced cardiac dysfunction or substantial functional decline develops.¹˒³
Counseling should balance realism with the recognition that the ATTR-CM treatment landscape has expanded. Primary care physicians can reinforce the importance of regular follow-up, medication adherence, symptom monitoring, caregiver involvement, and prompt reporting of worsening dyspnea, edema, dizziness, syncope, or palpitations.¹˒³ Discussions may also include functional goals, caregiver needs, genetic counseling when hereditary ATTR is identified, and advance care planning based on the patient’s disease stage and preferences.¹˒³
FAQ #3
When should PCPs suspect ATTR-CM?
ATTR-CM should be considered in patients with otherwise unexplained heart failure, increased left ventricular wall thickness, atrial arrhythmias, conduction disease, low-flow, low-gradient aortic stenosis, or intolerance of conventional heart failure medications.¹˒³ Clinical suspicion should increase when cardiac findings occur alongside bilateral carpal tunnel syndrome, lumbar spinal stenosis, spontaneous biceps tendon rupture, peripheral neuropathy, or autonomic dysfunction.¹˒³
Primary care physicians should look for a constellation of findings rather than expect every patient to have a classic presentation. Low electrocardiographic voltage is not present in all patients, and its absence does not exclude cardiac amyloidosis.¹
ATTR-CM may also be underrecognized in women. Because women generally have smaller cardiac dimensions and thinner ventricular walls, early amyloid-associated increases in wall thickness may be less conspicuous or may not meet fixed diagnostic thresholds.⁸ Primary care physicians should therefore not dismiss unexplained heart failure symptoms or relevant extracardiac clues solely because a woman lacks marked ventricular wall thickening.⁸
FAQ #4
What diagnostic evaluation should PCPs initiate when ATTR-CM is suspected?
Initial evaluation may include a detailed cardiac, neurologic, and musculoskeletal history; physical examination; electrocardiography; echocardiography; cardiac biomarkers; and assessment of renal and hepatic function.¹˒³ Cardiac magnetic resonance imaging may strengthen suspicion for cardiac amyloidosis but cannot reliably determine whether the amyloid is caused by transthyretin or immunoglobulin light chains.¹˒³
Before ATTR-CM is diagnosed noninvasively, clinicians should evaluate for monoclonal protein by measuring serum free light chains and performing serum and urine immunofixation. Serum or urine protein electrophoresis without immunofixation is not sufficient to exclude a monoclonal protein.¹
If all components of the monoclonal protein screen are negative, characteristic myocardial uptake on technetium-labeled bone-avid tracer scintigraphy may establish ATTR-CM without biopsy in the appropriate clinical setting.¹˒³ If any monoclonal protein testing is abnormal, tissue biopsy with accurate amyloid typing is generally required because scintigraphy alone cannot reliably distinguish ATTR-CM from immunoglobulin light-chain, or AL, amyloidosis in that setting.¹˒³
Patients with abnormal monoclonal protein testing should receive prompt hematology evaluation because AL amyloidosis may progress rapidly and requires fundamentally different treatment.¹ Once ATTR-CM is confirmed, genetic testing should be performed to distinguish hereditary from wild-type disease.¹˒³
FAQ #5
What role should PCPs play in managing and treating ATTR-CM?
The selection of disease-modifying therapy should generally be made in collaboration with a cardiologist or amyloidosis specialist. FDA-approved disease-modifying options include the transthyretin stabilizers tafamidis and acoramidis, as well as the transthyretin-silencing therapy vutrisiran.³˒⁵⁻⁷ These therapies have distinct mechanisms, administration requirements, safety considerations, and labeled clinical outcomes; treatment selection should account for the approved indication, available evidence, comorbidities, patient preferences, access, and cost.³˒⁵⁻⁷
Primary care physicians remain central to longitudinal management. Their responsibilities may include monitoring symptoms, body weight, blood pressure, renal function, volume status, medication adherence, adverse effects, functional decline, and comorbid conditions.¹˒³ They may also identify worsening congestion, arrhythmia symptoms, orthostatic hypotension, falls, neuropathic complications, and barriers to treatment access.
Loop diuretics are commonly used to control congestion, but both fluid overload and excessive volume reduction may be poorly tolerated.¹˒³ Conventional heart failure therapies—including beta-blockers, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and angiotensin receptor–neprilysin inhibitors—may contribute to hypotension, fatigue, bradycardia, or low-output symptoms in some patients with ATTR-CM.¹˒³ These medications are not universally contraindicated, but their use should be individualized according to the clinical indication, hemodynamics, renal function, and tolerability rather than applied as a uniform regimen.¹˒³
Primary care physicians can also coordinate care among cardiology, hematology, neurology, genetics, pharmacy, and advanced heart failure specialists.¹˒³ Medication reconciliation, management of noncardiac comorbidities, caregiver support, vaccination, fall-risk assessment, and communication across the care team remain important components of comprehensive ATTR-CM care.¹˒³