Is a cardiac MRI warranted for a 60-year-old male with CAD, MI, reduced ejection fraction, hypertension, obstructive sleep apnea, and gastroesophageal reflux disease, presenting with shortness of breath, palpitations, and chest pressure upon exertion, with concern for HCM?

Cardiac MRI is Warranted for Suspected HCM in This Patient

Yes, cardiac MRI is indicated for this patient with concern for HCM, particularly given the clinical context of CAD, prior MI, reduced ejection fraction, and exertional symptoms where echocardiography may be inconclusive or insufficient for definitive diagnosis and risk stratification. 1

Primary Indication: Diagnostic Clarification

For patients suspected to have HCM in whom echocardiography is inconclusive, cardiac MRI imaging is indicated for diagnostic clarification (Class I recommendation, Level B-NR evidence). 1 This is particularly critical in your patient because:

• The presence of CAD with prior MI and reduced ejection fraction creates diagnostic complexity, as distinguishing HCM from ischemic cardiomyopathy with regional hypertrophy requires precise tissue characterization 1
• MRI is superior to echocardiography in recognizing areas of segmental hypertrophy that may be missed or underestimated, particularly at the LV apex, RV anterior free wall, and LV inferoseptum 1
• MRI provides more accurate quantification of myocardial thickness, which is an important prognostic indicator 1

Critical Role in Risk Stratification

For patients with HCM who are not otherwise identified as high risk for sudden cardiac death, or in whom ICD decision remains uncertain, CMR imaging is beneficial to assess maximum LV wall thickness, ejection fraction, LV apical aneurysm, and extent of myocardial fibrosis with late gadolinium enhancement (Class I recommendation, Level B-NR evidence). 1

Late Gadolinium Enhancement (LGE) for Mortality Risk

• LGE is seen in 50-80% of HCM patients, with extent correlating directly with adverse prognosis 1
• HCM patients with LGE have a 7-fold risk for nonsustained ventricular tachycardia 1
• Extensive LGE >15% of LV mass is a marker for sudden death 1
• Native T1 mapping has demonstrated 100% sensitivity, 96% specificity, and 98% accuracy in distinguishing healthy from diseased myocardium, including HCM 1

High-Risk Morphologic Features

• Apical aneurysm and massive hypertrophy >30 mm are high-risk factors for sudden cardiac death 1
• MRI is superior for detecting apical aneurysms, which may be missed in approximately 10% of cases by conventional echocardiography 2
• These findings directly impact ICD candidacy and mortality reduction 1

Distinguishing HCM from Alternative Diagnoses

For patients with left ventricular hypertrophy in whom there is suspicion of alternative diagnoses including infiltrative or storage disease, CMR imaging is useful (Class I recommendation, Level B-NR evidence). 1

Given your patient's multiple comorbidities, MRI can differentiate:

Hypertensive Heart Disease vs. HCM

• Hypertension typically shows milder thickening (<1.6 cm), lower EF, dilated LV, absent or minimal LGE, and lower T1 and ECV values compared to HCM 1
• HCM often produces hyperdynamic high EF with normal or small chamber size 1

Infiltrative Diseases

• Anderson-Fabry disease shows mid-myocardial or subepicardial LGE in the basal inferolateral segment with low native T1 values due to sphingolipid deposition 1
• Cardiac amyloidosis demonstrates diffuse subendocardial LGE with elevated ECV 1
• These diagnoses require fundamentally different management strategies affecting morbidity and mortality 1

Planning for Potential Septal Reduction Therapy

For patients with obstructive HCM in whom the anatomic mechanism of obstruction is inconclusive on echocardiography, CMR imaging is indicated to inform selection and planning of septal reduction therapy (Class I recommendation, Level B-NR evidence). 1

• MRI evaluates papillary muscle abnormalities (anomalous chordal attachment, double bifid muscles, apical displacement), which require different surgical management 1
• Accurate assessment of LVOT obstruction mechanism directly impacts procedural success and quality of life outcomes 1

Common Pitfalls to Avoid

Relying Solely on Echocardiography

• Adult-onset HCM may not be detected by echocardiogram alone, as demonstrated in case reports of patients with repeated dyspnea on exertion where TTE showed only mild LVH and diastolic dysfunction, but MRI revealed definitive HCM 3
• Echocardiography has limited acoustic windows in patients with obesity, OSA, or GERD (all present in your patient) 4, 2

Missing Apical Variants

• Apical HCM and apical aneurysms are particularly difficult to visualize with conventional echocardiography 1, 2
• Contrast-enhanced echocardiography may be reasonable only when CMR is unavailable or contraindicated 1

Timing and Follow-Up Considerations

• Perform cardiac MRI promptly to establish diagnosis and baseline risk stratification 4
• Repeat contrast-enhanced CMR on a periodic basis (every 3-5 years) may be considered for SCD risk stratification to evaluate changes in LGE and morphologic changes including EF, development of apical aneurysm, or LV wall thickness (Class IIb recommendation, Level C-EO evidence) 1

Alternative Only if MRI Unavailable

Cardiac CT may be considered for diagnosis if echocardiogram is not diagnostic and CMR imaging is unavailable (Class IIb recommendation, Level C-LD evidence). 1 However, CT provides inferior tissue characterization compared to MRI and cannot assess for myocardial fibrosis with the same accuracy 1