Cardiac MRI — practice case: suspected amyloidosis with a pacemaker

Presentation

Practice case (not a real patient). A 74-year-old man in Australia has heart failure and increased LV wall thickness on echocardiography. His ECG shows low QRS voltage relative to LV thickness.^[3] Two years ago he received a dual-chamber pacemaker for AV conduction disease; the generator and both leads are from the same manufacturer and are labelled MRI conditional, and no other leads, adaptors or extenders are present. His eGFR is 48 mL/min/1.73 m².^[3][9][1]

Step 1 — Why suspect amyloidosis?

Discussion:

• ESC 2026 HF says cardiac amyloidosis should be suspected in patients with HF and increased LV wall thickness in the presence of specific red flags, particularly in patients aged >65 years.^[3]
• His low QRS voltage relative to LV thickness and his AV conduction disease are both ECG red flags in ESC 2026 HF Table 20, marked for TTR and AL amyloidosis.^[3]

Step 2 — Can he have CMR with his pacemaker?

• ESC 2021 says the entire CIED system, generator and leads from the same manufacturer, determines MRI conditionality; his whole system is MRI conditional.^[9]
• In patients with MRI-conditional pacemaker systems (an MRI-conditional generator and lead(s) from the same manufacturer), MRIs can be performed safely following the manufacturer's instructions (ESC 2021, Class I, Level A).^[9]
• ESC 2021 says that, in general, MRIs should always be performed within a rigorously applied standardised institutional workflow, following the appropriate conditions of use (including programming); in its CMR section, ESC 2025 myocarditis and pericarditis says programming before and after the scan is warranted in all cases, as well as patient monitoring.^[9][2]
• In the same section, ESC 2025 says ferromagnetic objects such as implants cause artefacts on CMR, and that the same holds true for active MR-conditional devices such as pacemakers, but dedicated techniques are now available to achieve better diagnostic image quality in many cases.^[2]
• With an eGFR of 48, gadolinium-based contrast agents can be safely administered (ESC 2023: eGFR >30 mL/min/1.73 m²).^[1]

Step 3 — Reading his CMR

• His CMR shows global subendocardial LGE, elevated native T1 values and increased extracellular volume.^[3]
• All three are CMR red flags for cardiac amyloidosis in ESC 2026 HF Table 20, and the table footnote says CMR can be diagnostic for cardiac amyloidosis.^[3]
• ESC 2023 describes often global, subendocardial or segmental LGE with a highly specific pattern of myocardial and blood-pool gadolinium kinetics in cardiac amyloidosis.^[1]

Step 4 — What comes next?

• Among investigations for underlying aetiology in patients with HFpEF or HFrEF, ESC 2026 HF recommends initial diagnostic testing with serum and urine immunofixation, a serum free light chains assay, and DPD/PYP/HMDP bone scintigraphy in patients with HF and a suspicion of cardiac amyloidosis (Class I, Level B).^[3]
• ESC 2026 HF says invasive diagnostic criteria apply to all forms, whereas non-invasive criteria are accepted only for transthyretin amyloidosis (ATTR).^[3]
• ESC 2023 non-invasive criteria: typical echocardiographic/CMR findings combined with grade 2 or 3 myocardial radiotracer uptake on bone scintigraphy and exclusion of a clonal dyscrasia.^[1]
• ESC 2023 invasive criteria, which apply to all forms of cardiac amyloidosis: amyloid fibrils within cardiac tissue or, alternatively, amyloid deposits in an extracardiac biopsy accompanied by characteristic features on echocardiography or CMR.^[1]

Step 5 — Follow-up imaging

• ESC 2023: contrast-enhanced CMR should be considered for the serial follow-up and assessment of therapeutic response in patients with cardiac amyloidosis, Anderson–Fabry disease, sarcoidosis, inflammatory cardiomyopathies, and haemochromatosis with cardiac involvement (Class IIa, Level C).^[1]
• ESC 2023 gives ECV evaluation in amyloidosis as an example of how serial CMR, every 2–5 years depending on initial severity and clinical course, can assist in evaluating progression and the benefits of therapy.^[1]
• Treatment of the confirmed subtype is covered in the cardiac amyloidosis topic.

Marking (Pass/Fail)

• Pass: recognises the ESC 2026 HF suspicion setting and red flags; confirms whole-system MRI conditionality before scanning and states the ESC 2021 Class I row and the programming and monitoring steps; reads the CMR red flags; orders immunofixation, free light chains and bone scintigraphy (Class I, Level B); and states that non-invasive criteria apply only to ATTR.^[3][9][2]
• Fail: treats CMR as typing the amyloid on its own, or scans without checking the whole pacemaker system.^[3][9]