Case presentation
A 30-year-old male patient, non-diabetic, non-hypertensive, smoker
presented to our facility complaining of a recent onset dyspnea grade
III, orthopnea and paroxysmal nocturnal dyspnea since 3 weeks. Three
days before admission he was complaining of atypical left sided chest
pain and worsening of dyspnea from grade III to IV. On examination, he
appeared tachypneic with bilateral congested pulsating neck veins. Vital
signs, 110/70mmHg, heart rate of 110 beats per minute. His laboratory
tests were unremarkable. His ECG was unremarkable except for a wide QRS
complex and interventricular conduction delay. Echocardiography (Figure
1, Panel A, Videos 1,2,3,4) showed dilated dimensions with global
hypokinesia mostly at the septum with marked trabeculations of the
apical inferior and lateral walls. Coronary angiography revealed ectatic
vessels with slow flow but no obstructive lesions. CMR (Figure 1, Panel
B,C,D,E,F, Videos 5,6) confirmed the presence of biventricular NC, in
the LV, involved 11/17 segments notably the lateral wall and to a lesser
extent the anterior and inferior walls. The ratio of non-compacted to
compacted layer at end diastole was 4.2. Hypertrophied RV with extensive
trabeculations was also noted. Marked global biventricular hypokinesia
with nearly akinetic septum and very poor biventricular function
(LVEF=15%, RVEF=27%). On late gadolinium enhancement (LGE) images,
extensive fibrosis was found representing 30% of the total myocardial
mass. Different patterns of fibrosis were found in the form of
basal/midventricular mid-wall fibrosis in the septum, subepicardial to
mid wall fibrosis in the anterior and inferior walls (mounting to near
transmural) and mid-ventricular subendocardial to mid wall fibrosis in
the lateral wall as well as transmural fibrosis of all apical segments.
No thrombi were found. So, the diagnosis of biventricular NC with
extensive fibrosis was reported. Accordingly, the patient was maintained
on anti-failure measures and anticoagulation. In our case, CMR confirmed
the diagnosis of biventricular NC with accurate measurement of the
biventricular volumes and function. It also added the presence of
extensive myocardial fibrosis (which is correlated to clinical
manifestations) with the ability of its quantification. The previously
reported most common LGE patterns of fibrosis are subendocardial and
transmural distribution in non-compacted segments and mid-wall
distribution in compacted segments. (1,2) However, in
our case, there was extensive subendocardial, subepicardial, transmural
and mid wall fibrosis within the compacted layer with no fibrosis at the
non-compacted layer. The pathophysiological mechanisms of fibrosis in
isolated NC are still uncertain. Subendocardial and transmural
distribution of the non-compacted layer might be explained by the
defects in the coronary microcirculation which affects the
vascularization of the abnormal myocardium. (2,3) The
mid-wall enhancement of the compacted layer (mainly at the septum) is
thought to be the result of many factors such as genetic predisposition,
microvascular ischemia and the maladaptive processes related to
increased wall stress caused by progressive LV remodeling that may
result in focal myocyte necrosis, preferentially affecting the middle,
circumferential layer. (4)