422. Diagnosis of Transthyretin Amyloid Cardiomyopathy (ATTR-CM) with Dr. Venkatesh Murthy

Drs. Rick Ferraro and Sneha Nandy discuss ‘Diagnosis of ATTR Cardiac Amyloidosis’ with Dr. Venkatesh Murthy. In this episode, we explore the diagnosis of ATTR cardiac amyloidosis, a condition once considered rare but now increasingly recognized due to advances in imaging and the availability of effective therapies. Dr. Venkatesh Murthy, a leader in multimodality imaging, discusses key clinical and laboratory features that should raise suspicion for the disease. We also examine the role of nuclear imaging and genetic testing in confirming the diagnosis, as well as the importance of early detection. Tune in for expert insights on navigating this challenging diagnosis and look out for our next episode on treatment approaches for cardiac amyloidosis! Audio editing for this episode was performed by CardioNerds Intern, Julia Marques Fernandes.

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Pearls: - Diagnosis of Transthyretin amyloid cardiomyopathy

1. Recognizing the Red Flags – ATTR cardiac amyloidosis often presents with subtle but telling signs, such as bilateral carpal tunnel syndrome, low-voltage ECG, and a history of lumbar spinal stenosis or biceps tendon rupture. If you see these features in a patient with heart failure symptoms, think amyloidosis!

2. “Vanilla Ice Cream with a Cherry on Top” – On strain echocardiography, apical sparing is a classic pattern for cardiac amyloidosis. While helpful, it’s not foolproof—multimodal imaging and clinical suspicion are key!

3. Nuclear Imaging is a Game-Changer – When suspicion for cardiac amyloidosis is high à a positive PYP scan with SPECT imaging (grade 2 or 3 myocardial uptake) in the absence of monoclonal protein (ruled out by SPEP, UPEP, and free light chains) is diagnostic for ATTR amyloidosis—no biopsy needed!

4. Wild-Type vs. Hereditary? Know the Clues – Older patients (70+) are more likely to have wild-type ATTR, while younger patients (40s-60s), especially those with neuropathy and a family history of heart failure, should raise suspicion for hereditary ATTR. Genetic testing is crucial for distinguishing between the two. Note that some ATTR variants may predispose to a false negative PYP scan!

5. Missing Amyloidosis = Missed Opportunity – With multiple disease-modifying therapies now available, early diagnosis is critical. If you suspect cardiac amyloidosis, don’t delay the workup—early treatment improves outcomes!

Notes - Diagnosis of Transthyretin amyloid cardiomyopathy

What clinical features should raise suspicion for ATTR cardiac amyloidosis?

ATTR cardiac amyloidosis is underdiagnosed because symptoms overlap with other forms of heart failure.

Red flags include bilateral carpal tunnel syndrome (often years before cardiac symptoms), low-voltage ECG despite increased LV wall thickness, heart failure with preserved ejection fraction (HFpEF) with a restrictive pattern, and history of lumbar spinal stenosis, biceps tendon rupture, and/or peripheral neuropathy, including possible autonomic dysfunction (e.g., orthostatic hypotension).

Remember: If an older patient presents with heart failure and unexplained symptoms like neuropathy or musculoskeletal issues, think amyloidosis!

What is the differential diagnosis for a thick left ventricle (LVH) and how does ATTR amyloidosis fit into it?

Hypertension: Most common cause of LVH, typically with a history of uncontrolled high blood pressure.

Aortic stenosis: May present with concentric LVH.

Hypertrophic cardiomyopathy (HCM): Genetic disorder typically presenting with asymmetric LVH, especially in younger patients.

Infiltrative cardiomyopathy: Often due to amyloidosis, sarcoidosis, or hemochromatosis.

Storage disorder: Fabry’s, Danon, Pompe, etc.

What are the key imaging modalities used t