Myasthenia gravis echocardiography or ultrasound
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Overview
Transthoracic echocardiography (TTE) is a second-line, problem-solving study in myasthenia gravis (MG) used to characterize suspected cardiac involvement rather than to screen unselected patients.[1] In a large Medicare cohort, cardiovascular disorders were the leading cause of death in MG patients with a cause-specific mortality proportion comparable to matched controls (15.3% vs 15.7%; all-cause mortality was higher in MG but non-significant after comorbidity adjustment), and functional imaging typically reveals only minor, subclinical dysfunction.[2] Clinically overt cardiac involvement is rare, but a spectrum of disease exists—including subclinical diastolic dysfunction, myocarditis, dilated and Takotsubo cardiomyopathy, and reduced ejection fraction—that carries prognostic significance and requires targeted management.[1][3]
Echocardiography or Ultrasound
Role and Indications
- TTE is indicated when clinical features (unexplained fatigue, dyspnea, heart failure signs), ECG abnormalities, or elevated cardiac biomarkers (troponin, BNP/NT-proBNP) raise concern for myocarditis, cardiomyopathy, or heart failure.[3]
- Routine echocardiographic screening in asymptomatic MG patients is not recommended.[1][3]
- In a cohort of MG patients without pre-existing cardiovascular disease, an abnormal ECG predicted echocardiographic cardiac damage (ejection fraction <55% or E/e′ >8) with high discrimination, whereas systolic impairment was observed exclusively in patients with ECG abnormalities—supporting an ECG-first diagnostic pathway.[3]
Echocardiographic Findings
- Diastolic Dysfunction: The most consistently reported echocardiographic abnormality. Features include reduced peak filling rate, reduced E velocity, increased A velocity, and a reduced E/A ratio with preserved ejection fraction (EF). Mean E/e′ is mildly elevated (10.5 ± 3.2), with significantly higher ratios observed in patients with baseline ECG abnormalities.[4][3]
- Systolic Dysfunction: Left ventricular ejection fraction (LVEF) <55% is uncommon; when present, it carries a worse prognosis but may improve with immunosuppressive therapy.[3]
- Deformation Imaging: Global longitudinal strain (GLS) and tissue Doppler imaging demonstrate higher sensitivity than standard LVEF for detecting subtle myocardial injury. In ICI-related myocarditis, reduced GLS predicts major adverse cardiovascular events (MACE) even in patients with preserved LVEF; each 1% absolute reduction in GLS was associated with an approximately 4-fold increase in major adverse cardiovascular events among patients with preserved LVEF.[5][6]
Specific Cardiac Syndromes
Myocarditis
- Reported in up to 10% of MG cohorts in specialized series, primarily associated with thymoma-associated MG and autoantibodies against cardiac antigens (anti-Kv1.4, anti-titin, and anti-ryanodine receptor).[7]
- TTE findings include regional wall motion abnormalities, global systolic dysfunction, or isolated diastolic dysfunction.[8]
- A normal TTE does not exclude early or localized myocarditis; cardiac MRI using the modified Lake Louise criteria (T1/T2 mapping, late gadolinium enhancement) is the reference imaging modality. In ICI-associated myocarditis, late gadolinium enhancement is present in approximately 48% and T2 signal elevation in 28% of confirmed cases; therefore, CMR sensitivity is imperfect, and a negative CMR does not exclude myocarditis, particularly early in its course.[8][6][9][10]
Takotsubo (Stress) Cardiomyopathy
- A recognized complication of myasthenic crisis, characterized by transient left ventricular apical ballooning with basal hyperkinesis extending beyond a single coronary distribution.[11][12]
- LV dysfunction resolves spontaneously on serial echocardiography over days to weeks in most surviving cases.[13][14]
Immune Checkpoint Inhibitor (ICI) "3M" Overlap
- In patients receiving immune checkpoint inhibitors (e.g., anti-PD-1/PD-L1 agents), MG or MG-like syndrome can co-occur with myositis and myocarditis (the "3M" overlap syndrome).[9][15]
- Reduced left ventricular ejection fraction is present in roughly one-third to one-half of ICI myocarditis cases, with the majority—and most fatal cases—showing preserved LVEF; conduction disturbances dominate and are the leading cause of death in fatal presentations. A normal LVEF therefore does not rule out life-threatening myocarditis.[16][6][15]
Physiologic Context: Pyridostigmine Effect
Historical Doppler studies noted acute changes in LV diastolic filling parameters following acetylcholinesterase inhibitor administration.[4] Subsequent tissue Doppler evaluation confirmed lower early-diastolic annular velocity and strain prior to pyridostigmine dosing that normalized post-administration, with no persistent conventional echocardiographic abnormalities after adjusting for blood pressure.[17] These observations reflect acute autonomic and loading alterations rather than reversible structural cardiomyopathy and do not justify serial echocardiographic monitoring.[17]
Summary of Diagnostic Utility
| Clinical Scenario | Recommended Imaging | Key Echocardiographic Findings | Clinical Management Impact |
|---|---|---|---|
| Asymptomatic MG | None (Screen with baseline ECG) | N/A | Avoid unnecessary imaging; evaluate further only if ECG is abnormal.[3] |
| Abnormal ECG or Elevated Troponin/BNP | TTE with GLS | Elevated E/e′, reduced GLS, regional wall motion abnormalities | Identifies subclinical myocarditis or cardiomyopathy; prompts cardiac MRI.[3][8] |
| Myasthenic Crisis with Hemodynamic Instability | Urgent TTE | Apical ballooning with basal hyperkinesis (Takotsubo pattern) | Guides supportive hemodynamic care; tracks serial LV recovery.[11][14] |
| ICI-Induced MG Overlap ("3M" Syndrome) | TTE with strain | Often preserved LVEF; subtle GLS/GCS reduction or pericardial effusion | High-risk overlap; NCCN recommends TTE with strain (if possible); normal LVEF does not exclude severe myocarditis.[9][15] |
References
- ↑ 1.0 1.1 1.2 Gilhus NE (2016). "Myasthenia Gravis". N Engl J Med. 375 (26): 2570–2581. doi:10.1056/NEJMra1602678. PMID 28029925.
- ↑ Li Y, Bruckman D, Schold JD, et al. (2026). "Survival Outcomes of Medicare-Covered Elderly US Population With Myasthenia Gravis". Muscle Nerve. 73 (1): 41–49. doi:10.1002/mus.70045.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 Kato T, Hirose S, Kumagai S, et al. (2016). "Electrocardiography as the First Step for the Further Examination of Cardiac Involvement in Myasthenia Gravis". BioMed Res Int. 2016: 8058946. doi:10.1155/2016/8058946. PMID 27651804.
- ↑ 4.0 4.1 Johannessen KA, Mygland A, Gilhus NE, Aarli J, Vik-Mo H (1992). "Left ventricular function in myasthenia gravis". Am J Cardiol. 69 (1): 129–132. doi:10.1016/0002-9149(92)90688-u. PMID 1729861.
- ↑ Awadalla M, Mahmood SS, Groarke JD, et al. (2020). "Global Longitudinal Strain and Cardiac Events in Patients With Immune Checkpoint Inhibitor-Related Myocarditis". J Am Coll Cardiol. 75 (5): 467–478. doi:10.1016/j.jacc.2019.11.049. PMID 32029135 Check
|pmid=value (help). - ↑ 6.0 6.1 6.2 Schulz-Menger J, Collini V, Gröschel J, et al. (2025). "2025 ESC Guidelines for the Management of Myocarditis and Pericarditis". Eur Heart J. 46 (40): 3952–4041. doi:10.1093/eurheartj/ehaf192.
- ↑ Messina C (2025). "The overlooked side of myasthenia gravis: the non-motor manifestations—a comprehensive review". J Neurol. 272 (12): 764. doi:10.1007/s00415-025-13504-3.
- ↑ 8.0 8.1 8.2 Drazner MH, Bozkurt B, Cooper LT, et al. (2025). "2024 ACC Expert Consensus Decision Pathway on Strategies and Criteria for the Diagnosis and Management Of Myocarditis". J Am Coll Cardiol. 85 (4): 391–431. doi:10.1016/j.jacc.2024.10.080.
- ↑ 9.0 9.1 9.2 Ganatra S, Barac A, Armenian S, et al. (2026). "Diagnosis and Management of Cardiovascular Adverse Effects of Targeted Oncology Therapies: 2025 ACC Concise Clinical Guidance". J Am Coll Cardiol. 87 (5): 654–682. doi:10.1016/j.jacc.2025.10.018.
- ↑ Bloom MW, Vo JB, Rodgers JE, et al. (2025). "Cardio-Oncology and Heart Failure: A Scientific Statement From the Heart Failure Society of America". J Card Fail. 31 (2): 415–455. doi:10.1016/j.cardfail.2024.08.045.
- ↑ 11.0 11.1 Ranellone A, Abraham MG (2022). "Takotsubo Cardiomyopathy in the Setting of a Myasthenic Crisis". Int J Neurosci. 132 (1): 89–94. doi:10.1080/00207454.2020.1797720. PMID 32677485 Check
|pmid=value (help). - ↑ Rathish D, Karalliyadda M (2019). "Takotsubo syndrome in patients with myasthenia gravis: a systematic review of previously reported cases". BMC Neurol. 19 (1): 281. doi:10.1186/s12883-019-1523-z. PMID 31779603.
- ↑ Medina de Chazal H, Del Buono MG, Keyser-Marcus L, et al. (2018). "Stress Cardiomyopathy Diagnosis And Treatment: JACC State-of-the-Art Review". J Am Coll Cardiol. 72 (16): 1955–1971. doi:10.1016/j.jacc.2018.07.072. PMID 30309323.
- ↑ 14.0 14.1 Omiya M, Morii Y, Mukai M, et al. (2024). "Myasthenic Crisis and Concomitant Takotsubo Syndrome Complicated by Shock". Intern Med. 63 (24): 3383–3387. doi:10.2169/internalmedicine.3306-23. PMID 38719601 Check
|pmid=value (help). - ↑ 15.0 15.1 15.2 "Management of Immune Checkpoint Inhibitor-Related Toxicities (Version 1.2025)". National Comprehensive Cancer Network. 2025.
- ↑ Chen YC, Dolladille C, Rao A, et al. (2025). "Immune Checkpoint Inhibitor Myocarditis and Left Ventricular Systolic Dysfunction". JACC CardioOncol. 7 (3): 234–248. doi:10.1016/j.jaccao.2025.01.020. PMID 40246381 Check
|pmid=value (help). - ↑ 17.0 17.1 Furlund Owe J, Skulstad Davidsen E, Eide GE, Gerdts E, Gilhus NE (2008). "Left Ventricular Long-Axis Function in Myasthenia Gravis". J Neurol. 255 (11): 1777–1784. doi:10.1007/s00415-008-0049-x. PMID 18751932.