Non-compaction cardiomyopathy is a congenital disorder of the myocardium that causes cardiomyopathy, a variety of arrhythmias, conduction disorders, and an increased risk of sudden death. Diagnosis includes ECG, cardiac imaging, and genetic testing. Treatment is usually an implantable cardioverter-defibrillator (ICD), antiarrhythmic medications, and standard measures for heart failure.
Non-compaction cardiomyopathy is a rare cardiomyopathy resulting from failure of the embryonic ventricular myocardial compaction process, such that the ventricular myocardium consists of an outer layer of normally compact myocardium and an inner non-compacted layer that has retained embryonal characteristics (1). The inner layer is spongy and markedly trabeculated with deep intertrabecular recesses usually most prominent at the left ventricular apex, then elsewhere in the left ventricle, and least commonly in the right ventricle. Although there are likely acquired cases, most cases result from inherited mutations in genes encoding sarcomeric proteins, cytoskeletal proteins, or mitochondrial proteins. Inherited cases are most commonly autosomal dominant or X-linked. Increased left ventricular trabeculation incidentally found on cardiac imaging in athletes and during pregnancy is often reversible and non-pathologic rather than a true noncompaction cardiomyopathy. (2). (See also Overview of Arrhythmogenic Cardiomyopathies and Overview of Arrhythmias.)
In non-compaction cardiomyopathy, the disordered myocardial architecture and associated microvascular abnormalities lead to myocardial fibrosis. The fibrosis predisposes to both systolic and diastolic heart failure and to ventricular tachyarrhythmias, cardiac arrest, and sudden death (1, 3). The deep intertrabecular recesses produce areas of blood flow stasis predisposing to thromboembolic events, including stroke. Some forms also are associated with atrial tachyarrhythmias (eg, atrial fibrillation, Wolff-Parkinson-White syndrome), conduction system blocks, early repolarization pattern or long QT interval on the ECG, other congenital heart disorders, or skeletal muscular dystrophies (2).
General references
1. Filho DCS, do Rêgo Aquino PL, et al. Left Ventricular Noncompaction: New Insights into a Poorly Understood Disease. Curr Cardiol Rev. 2021;17(2):209-216. doi: 10.2174/1573403X16666200716151015
2. Martínez-Tittonel LE, Ciorba FR, Bayona-Huguet X, Kaplinsky E. Left Ventricular Non-Compaction Cardiomyopathy: A Review of the Pathophysiology, Epidemiology, Diagnosis, Genetics, and Clinical Management. J Pers Med. 2025;15(10):484. doi:10.3390/jpm15100484
3. Pittorru R, De Lazzari M, Migliore F, et al. Left Ventricular Non-Compaction: Evolving Concepts. J Clin Med. 2024;13(19):5674. Published 2024 Sep 24. doi:10.3390/jcm13195674
Symptoms and Signs of Non-Compaction Cardiomyopathy
Patients may be asymptomatic.
Initial symptoms are usually those of heart failure (eg, exertional dyspnea, fatigue, peripheral edema), although some patients present with symptoms of conduction blocks and/or arrhythmias, including palpitations and/or syncope, or sometimes cardiac arrest. Ventricular tachyarrhythmias may be triggered by exercise.
Diagnosis of Non-Compaction Cardiomyopathy
Cardiac imaging (eg, echocardiography, MRI with late gadolinium enhancement)
Genetic testing
Screening of first-degree relatives
Diagnosis of non-compaction cardiomyopathy is suspected in patients with manifestations of arrhythmias or conduction disorders in whom standard evaluation (eg, echocardiography) shows ventricular wall abnormalities, including hypertrophy, distinct layers, and deep trabeculae. However, it is frequently difficult to distinguish the findings in non-compaction cardiomyopathy from normal variations, particularly in patients with physiological or pathological left ventricular hypertrophy, those with other cardiomyopathies, and pregnant patients. Cardiac MRI with late gadolinium enhancement is usually also performed and is more sensitive than echocardiography (1, 2).
Each imaging technique uses measurement cutoff criteria to enhance discrimination. Several different consensus criteria (eg, by echocardiography [3, 4] or by MRI [5, 6]) have been developed to facilitate diagnosis. Imaging criteria typically use the ratio of non-compacted (trabeculated) and compacted myocardium, among other factors. Patients with decreased left ventricular ejection fraction or significant levels of myocardial fibrosis have a worse prognosis (7).
In patients with non-compaction cardiomyopathy, ECG and ambulatory cardiac rhythm monitoring are performed to assess current rhythm status and are repeated annually to guide antiarrhythmic medication or device therapies. Imaging is repeated as clinically indicated once the diagnosis is made.
Patients with findings suggestive of the disorder should be offered genetic testing.
First-degree relatives of patients should have clinical evaluation (ie, to detect symptoms suggestive of arrhythmia, and/or heart failure), ECG, and echocardiography initially and repeated every 1 to 3 years (8). Genetic testing is performed if the index case has a causative mutation identified; family members who are not carriers of that mutation do not require ongoing testing.
Diagnosis references
1. Patel AR, Kramer CM. Role of Cardiac Magnetic Resonance in the Diagnosis and Prognosis of Nonischemic Cardiomyopathy. JACC Cardiovasc Imaging. 2017;10(10 Pt A):1180-1193. doi:10.1016/j.jcmg.2017.08.005
2. Thuny F, Jacquier A, Jop B, et al. Assessment of left ventricular non-compaction in adults: side-by-side comparison of cardiac magnetic resonance imaging with echocardiography. Arch Cardiovasc Dis. 2010;103(3):150-159. doi:10.1016/j.acvd.2010.01.002
3. Chin TK, Perloff JK, Williams RG, et al. Isolated noncompaction of left ventricular myocardium. A study of eight cases. Circulation. 1990;82(2):507-513. doi:10.1161/01.cir.82.2.507
4. Jenni R, Oechslin E, Schneider J, et al. Echocardiographic and pathoanatomical characteristics of isolated left ventricular non-compaction: a step towards classification as a distinct cardiomyopathy. Heart. 2001;86(6):666-671. doi: 10.1136/heart.86.6.666
5. Jacquier A, Thuny F, Jop B, et al. Measurement of trabeculated left ventricular mass using cardiac magnetic resonance imaging in the diagnosis of left ventricular non-compaction. Eur Heart J. 2010;31(9):1098-1104. doi:10.1093/eurheartj/ehp595
6. Petersen SE, Selvanayagam JB, Wiesmann F, et al. Left ventricular non-compaction: Insights from cardiovascular magnetic resonance imaging. J Am Coll Cardiol. 2005;46(1):101-105. doi 10.1016/j.jacc.2005.03.045
7. Casas G, Limeres J, Oristrell G, et al. Clinical Risk Prediction in Patients With Left Ventricular Myocardial Noncompaction. J Am Coll Cardiol. 2021;78(7):643-662. doi:10.1016/j.jacc.2021.06.016
8. Arbustini E, Weidemann F, Hall JL. Left ventricular noncompaction: a distinct cardiomyopathy or a trait shared by different cardiac diseases? J Am Coll Cardiol. 2014;64(17):1840-1850. doi:10.1016/j.jacc.2014.08.030
Treatment of Non-Compaction Cardiomyopathy
Sometimes moderation of physical activity
Sometimes an implantable cardioverter-defibrillator (ICD)
Usually a beta-blocker
Sometimes other antiarrhythmic medications (particularly sotalol or amiodarone)
Heart failure therapy (including transplantation) as required
Sometimes chronic anticoagulation
Exercise restriction may be appropriate if ventricular dysfunction, LV hypertrophy, LV dilation or wall thinning, ventricular arrhythmia, or thromboembolism is present (1). Restriction is not generally recommended for LV hypertrabeculation alone.
Prevention of sudden death is by an ICD (see also table ). An ICD is recommended for patients with (2):
Prior ventricular tachycardia with syncope
Resuscitated cardiac arrest
Severe left ventricular systolic dysfunction (left ventricular ejection fraction < 35%) and symptoms on guideline-directed medical therapy for heart failure (3)
Placement of an ICD is reasonable for patients with non-compaction cardiomyopathy who have (2):
Both nonsustained ventricular tachycardia and reduced left ventricular ejection fraction
Beta-blockers and other antiarrhythmic medications are used to treat tachyarrhythmias as they occur.
Anticoagulation is used for patients with atrial fibrillation or stroke who meet standard criteria (see also table ). Antithrombotic therapy is reasonable in patients with evidence of ventricular dysfunction and/or trabecular thrombi (2).
Standard measures for treatment of heart failure are used (see also Treatment of Dilated Cardiomyopathy).
Treatment references
1. Kim JH, Baggish AL, Levine BD, et al. Clinical Considerations for Competitive Sports Participation for Athletes With Cardiovascular Abnormalities: A Scientific Statement From the American Heart Association and American College of Cardiology. Circulation. 2025;151(11):e716-e761. doi:10.1161/CIR.0000000000001297
2. Towbin, JA, McKenna WJ, Abrams DJ, et al. 2019 HRS expert consensus statement on evaluation, risk stratification, and management of arrhythmogenic cardiomyopathy. Heart Rhythm. 2019;16(11):e301-e372. doi: 10.1016/j.hrthm.2019.05.007
3. Heidenreich PA, Bozkurt B, Aguilar D, et al. 2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation. 2022;145(18):e895-e1032. doi:10.1161/CIR.0000000000001063
Key Points
Non-compaction cardiomyopathy is a genetic cardiac disorder that causes heart failure, arrhythmias, heart blocks, and thromboembolic disease.
Diagnosis is based on clinical factors, arrhythmias, cardiac imaging, and genetic testing.
First-degree relatives have a significant risk of disease and require screening.
Treatment may require an implantable cardioverter-defibrillator (ICD), antiarrhythmic medications, anticoagulation, and/or heart failure medications.
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