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IMAGING VIGNETTE

LV Noncompaction Cardiomyopathyor Just a Lot of Trabeculations?

Nay Aung, MD, Filip Zemrak, MD, Saidi A. Mohiddin, MBCHB, MD, Steffen E. Petersen, MD, DPHIL, MPH

LEFT VENTRICULAR NONCOMPACTION (LVNC) IS CHARACTERIZED BY THE PRESENCE OF AN EXTENSIVE

noncompacted myocardial layer lining the cavity of the left ventricle (LV) and potentially leads to cardiacfailure, thromboembolism, and malignant arrhythmias (1). LVNC is a heterogeneous clinical condition, whichoften shows an overlap with other forms of established cardiomyopathy (2). Whether it is a distinct cardio-myopathy or a morphological variant of other types of nonischemic cardiomyopathy is still debated. There areuncertainties regarding its prevalence and incidence, natural history including prognosis, best diagnosticapproaches, and management. Most published data on LVNC is likely to include a significant publication bias.Nonetheless, the reported morbidity and mortality of LVNC patients is high for both pediatric and adultsubjects. LVNC may be familial in 30% to 50% of cases with autosomal dominant and X-linked recessive beingthe preponderant modes of inheritance. Even though the role of sarcomeric mutations in the pathogenesis ofLVNC is recognized, the genotype-phenotype correlation is poor. Both echocardiogram and cardiac magneticresonance (CMR) are widely utilized as imaging modalities to diagnose LVNC. In addition to superior spatialresolution and reproducibility, contrast-enhanced CMR can also assess late gadolinium enhancement patternas a surrogate marker for myocardial fibrosis. Due to the risk of over-diagnosis of LVNC based on imagingcriteria alone, interpretation of imaging findings in the clinical context is recommended.

We report 2 short cases of related individuals (Figures 1 to 3, Online Videos 1, 2, 3, and 4) with increased LVtrabeculations. The key learning points highlight the importance of LV systolic function and pre-testprobability in formulating the management plan (Figure 4).

From the Barts Heart Centre, William Harvey Research Institute, NIHR Cardiovascular Biomedical Research Unit at Barts, Queen

Mary University of London, London, United Kingdom. Dr. Petersen is a consultant to Circle Cardiovascular Imaging. All other

authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Manuscript received March 2, 2016; revised manuscript received March 21, 2016, accepted March 24, 2016.

FIGURE 1 CMR Images of Case 1 Demonstrating Prominent LV Trabeculations

Case 1: A 51-year-old Caucasian woman with no previous medical history presented with a 10-min episode of severe dizziness while sitting. She had no other cardiac

symptoms. Cardiac magnetic resonance (CMR) showed a dilated left ventricle (LV) with severe global systolic impairment (left ventricular end-diastolic volume

[LVEDV] 233 ml; left ventricular end-systolic volume [LVESV] 166 ml; left ventricular stroke volume [LVSV] 67 ml; left ventricular ejection fraction [LVEF] 29%)

and features of LV noncompaction based on the diastolic noncompaction to compaction ratio in the long-axis steady-state free precession cines of 4:1 (yellow arrow)

(Online Videos 1 and 2). A diagnosis of dilated cardiomyopathy with features of left ventricular noncompaction (LVNC) was made, and she was treated with conventional

heart failure medical therapy. An interval CMR 2 years later demonstrated progressive LV disease (LVEDV 210 ml, LVESV 155 ml, LVSV 55 ml, LVEF 26%). She

subsequently received a primary prevention implantable cardioverter-defibrillator.

J A C C : C A R D I O V A S C U L A R I M A G I N G , V O L . 1 0 , N O . 6 , 2 0 1 7 Aung et al.J U N E 2 0 1 7 : 7 0 4 – 7 Significance of Left Ventricular Trabeculations

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FIGURE 2 Baseline CMR Images of Case 2

Case 2: A 32-year-old Caucasian man was referred to the cardiology clinic with palpitations and a family history of LVNC. He had no other cardiac symptoms. Baseline

CMR showed a nondilated LV with good systolic function (LVEDV 180 ml, LVESV 75 ml, LVSV 105 ml, LVEF 58%) (Online Video 3). Hypertrabeculation of the LV

myocardium was noted with a noncompaction to compaction (NC/C) ratio of 2.3:1, and there was no late gadolinium enhancement. In the absence of any cardiac

symptoms or LV impairment, no therapy was introduced at this point. A second CMR 2 years later demonstrated an increase in LV internal dimensions and decline in LV

systolic function (LVEDV 219 ml, LVESV 128 ml, LVSV 91 ml, LVEF 48%) (Online Video 4). The maximal NC/C ratio was 3.4:1. In view of these interval changes in CMR

findings, a diagnosis of LVNC was made and a long-term follow-up was offered. Abbreviations as in Figure 1.

Aung et al. J A C C : C A R D I O V A S C U L A R I M A G I N G , V O L . 1 0 , N O . 6 , 2 0 1 7

Significance of Left Ventricular Trabeculations J U N E 2 0 1 7 : 7 0 4 – 7

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28 Years “Viral Myocarditis

Age 2 Weeks”

III.4III.3

II.3

III.2

II.2

I.2

III.1

II.1

I.1

Palpitations

2 YearsHeart FailureAs Neonate

IV.1

MI Age 72 PPM

FIGURE 3 Family Pedigree

Case 1 is Patient #II.2. Case 2 is Patient #III.2.

deriapmIlamroN LV Function?

Patient ManagementAccording to

Clinical Needsand Guidelines

Reassure, No Follow-up

Screening of Relatives

No

Increased Pre-test Probability?

• Arrhythmia• Syncope• Thromboembolic event• Family history of cadiomyopathy• Neuromuscular disorder

YesYes

Increased LV Trabeculation(any criteria, any imaging modality)

FIGURE 4 Clinical Algorithm Guiding Management of Patients With

Increased LV Trabeculations

Case 1 follows the path of impaired LV systolic function (pink boxes)

where the diagnosis is clear cut, but this case report highlights the

current lack of evidence on whether the treatment should be different

from the conventional management of dilated cardiomyopathy. Case

2’s palpitations, along with normal systolic function would, in isolation,

not have suggested a diagnosis of LVNC. However, Case 2 (III.2 in

Figure 3) is the son of Case 1, and the follow-up CMR detected adverse

cardiac remodeling over time. Case 2 illustrates the importance of a

thorough family history and of pre-test probability. CMR is excellent at

quantifying LV volumes, systolic function, and the extent of LV tra-

beculations. However, if marked LV trabeculations are not accompa-

nied by suggestive clinical features or other CMR abnormalities

associated with nonischemic cardiomyopathies, a diagnosis of LVNC

should not be assumed, and patients should not be managed as having

this poorly understood condition. Abbreviations as inFigure 1. (Zemrak F,

Petersen SE. Spot the difference: LV trabeculation vs. LV non-

compaction. Cardiology Today, February 2015. Reproduced with

permission from SLACK Incorporated.)

J A C C : C A R D I O V A S C U L A R I M A G I N G , V O L . 1 0 , N O . 6 , 2 0 1 7 Aung et al.J U N E 2 0 1 7 : 7 0 4 – 7 Significance of Left Ventricular Trabeculations

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ADDRESS FOR CORRESPONDENCE: Dr. Steffen E. Petersen, Barts Heart Centre, William Harvey ResearchInstitute, NIHR Cardiovascular Biomedical Research Unit at Barts, Charterhouse Square, London, EC1M 6BQ,United Kingdom. E-mail: s.e.petersen@qmul.ac.uk.

R EF E RENCE S

1. Arbustini E, Weidemann F, Hall JL. Left ven-tricular noncompaction: a distinct cardiomyopathyor a trait shared by different cardiac diseases?J Am Coll Cardiol 2014;64:1840–50.

2. Oechslin E, Jenni R. Left ventricular non-compaction revisited: a distinct phenotype with

genetic heterogeneity? Eur Heart J 2011;32:1446–56.

KEY WORDS cardiac magnetic resonance,left ventricular noncompaction, leftventricular trabeculations

APPENDIX For accompanying videos andtheir legends, please see the online version ofthis article.