Hypertrophic cardiomyopathy and left ventricular non-compaction: Distinct diseases or variant phenotypes of a single condition?

Figure 1 Different morphological changes in hypertrophic cardiomyopathy. A: Different cardiomyopathy (CMP) phenotypes. Dilated cardiomyopathy: Dilated CMP with left ventricle (LV) enlargement and hypokinesia. Hypertrophic cardiomyopathy (HCM): With increased LV mass or thickness. Restrictive cardiomyopathy: Restrictive CMP with enlarged atria; B: Morphological changes in mitral apparatus in HCM. Increased number and mass of papillary muscle heads, their atypical location, and elongation of the mitral leaflets; C and E: Different types and localization of LV hypertrophy; D: Phenotypic continuum between normal LV mass and structure, LV hypertrabeculation with normal LV mass [fulfilled diagnostic criteria for LV non-compaction (LVNC)], and hypertrabeculation with increased LV mass (fulfilled diagnostic criteria for LVNC and HCM). DCM: Dilated cardiomyopathy; HCM: Hypertrophic cardiomyopathy; IVS: Intraventricular septum; LV: Left ventricle; LVH: Left ventricular hypertrophy; MV: Mitral valve; PM: Papillary muscle; RCM: Restrictive cardiomyopathy; SAM: Systolic anterior motion.

Figure 2 Images from transthoracic echocardiography and cardiac magnetic resonance imaging of a 58-year-old woman with coexistence of left ventricle hypertrophy and hypertrabeculation leading to intracavitary obstruction with heart failure symptoms, and left ventricle thrombus formation with subsequent transient ischemic attack. A: Pulse-wave Doppler from apical 4-chamber transthoracic echocardiography (TTE) view showing intracavitary obstruction at the level of the papillary muscles (maximal resting gradient of 76 mmHg); B: Left ventricle (LV) apical hypertrophy in apical 4-chamber view in TTE; C and D: LV hypertrabeculation in cardiac magnetic resonance short axis view and 4-chamber view (ratio of thickness of non-compacted to compacted layers 2.1: 13 mm and 6 mm); E and F: LV thrombus entering between the LV trabeculae and recesses in short axis view and 4-chamber view (blue arrow).