Isolated ventricular non-compaction (IVNC) is congenital cardiomyopathy defined by the appearance of prominent ventricular trabeculae and deep intertrabecular recesses on cardiac imaging . Although biventricular non-compaction (BiVNC) has been reported rarely , its strict diagnostic criteria remain unclear. In the study by Lutokhina et al. , a combination of IVNC with arrhythmogenic right ventricular cardiomyopathy (ARVC) was found in 14.8% of the patient subset. The current report presents a challenging case of the biventricular hypertrabeculation phenotype and its unforeseen consequences.
A 36-year-old Caucasian man without prior medical history presented with dyspnea at rest and, on admission, angiographically documented intermediate-high risk pulmonary embolism (PE) complicated by pulmonary and renal infarction and pneumonia. Reperfusion treatment was not considered due to the patient’s hemodynamic stability. Laboratory examination revealed C-reactive protein level 369 mg/l (normal range [NR] <6 mg/l); D-dimer 4.5 mg/l (NR <0.5 mg/l); creatinine 0.97 mg/dl (NR, 0.6–1.6 mg/dl); N-terminal pro-B-type natriuretic peptide 8649 pg/ml (NR <125 ng/l); high-sensitivity cardiac troponin T 203 ng/l (NR <14 ng/l). An electrocardiogram on admission showed a right bundle branch block with epsilon wave (Supplementary material, Figure S1).
Transthoracic echocardiogram on admission showed right ventricular (RV) systolic function at a lower range limit (Tricuspid Annular Plane Systolic Excursion 17 mm, S’ 10 cm/s), lack of tricuspid regurgitation, severely reduced left ventricular ejection fraction (LVEF) by as much as 15%, increased left ventricular (LV) trabeculation, and a thrombus 22 × 17 mm in the LV apex (Figure 1A, Supplementary material, Video S1). Cardiac magnetic resonance confirmed LV non-compaction with a non-compacted/compacted (NC/C) ratio of 4.2 and revealed right ventricular non-compaction with an NC/C ratio of 4.2, left and right ventricular EF impairment (14% and 32%, respectively), and the presence of a thrombus in the LV apex 20 × 12 mm (Figure 1B–C, Supplementary material, Video S2). Moreover, biventricular circumferential subendocardial distribution of late gadolinium enhancement, less common than mid-myocardial , was observed (Figure 1D). The late gadolinium enhancement pattern may result from connective tissue diseases but is also highly specific for coexisting dilated cardiomyopathy. A complete package of rheumatological tests was performed, and connective tissue diseases were excluded. The course of BiVNC was complicated with prehospital thromboembolic events diagnosed during hospitalization deriving both from RV (PE) and LV (pulmonary infarction, clinically silent renal infarction) (Figure 1E–F).
Initial treatment included β-blocker, mineralocorticoid receptor antagonist, diuretics, ivabradine, broad-spectrum antibiotic therapy, anticoagulation primarily with low molecular weight heparin, and then vitamin K antagonist, resulting in the resolution of the LV apex thrombus. Sacubitril/valsartan and a sodium-glucose co-transporter 2 inhibitor were initiated early after acute decompensation of heart failure, resulting in LVEF improvement of up to 25% and concomitant symptom reduction (New York Heart Association class IV to II) within the next 3 months. Chronic anticoagulation with dabigatran was subsequently introduced. The patient was registered as a potential heart transplant recipient and electively implanted with a cardiac resynchronization therapy defibrillator.
Reported complications in IVNC are heterogeneous and poorly understood . The present case study shows that IVNC may include both ventricles and present as thromboembolic events deriving from both sides of the heart. This unusual case of BiVNC shows the borderline features of ARVC  (regional RV akinesia, RVEF ≤40%, and epsilon wave), which should be considered while managing the patient.
Supplementary material is available at https://journals.viamedica.pl/kardiologia_polska.
Conflict of interest: None declared.
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