Yu Izawa

The differences between bisecting and off‐center cuts of the aortic root: The three‐dimensional anatomy of the aortic root reconstructed from the living heart

It is axiomatic that the diameter of the virtual basal ring of the aortic root, which is elliptical rather than circular, will differ when assessed using between bisecting as opposed to off‐center cuts. Such differences, however, which pertain directly to echocardiographic assessments of the so‐called valvar annulus, have yet to be systematically explored.

Diversity and Determinants of the Three-dimensional Anatomical Axis of the Heart as Revealed Using Multidetector-row Computed Tomography

The location of the heart within the thorax varies significantly between individuals. The resultant diversity of the anatomical cardiac long axis, however, and its determinants, have yet to be systematically investigated. We enrolled 100 consecutive patients undergoing coronary arterial computed tomographic angiography, decomposing the vector of the anatomical cardiac long axis by projecting it to horizontal, frontal, and sagittal planes. The projected vectors on each plane were then converted into three rotation angles using coordinate transformation. We then measured the extent of aortic wedging, using the vertical distance between the inferior margins of the non‐adjacent aortic sinus and the epicardium. We took the aortic root rotation angle to be zero when an “en face” view of the right coronary aortic sinus was obtained in the frontal view, defining leftward rotation to be positive. The mean horizontal, frontal, and sagittal rotation angles were 48.7° ± 9.5°, 52.3° ± 12.0°, and 34.0° ± 11.2°, respectively. The mean extent of aortic wedging, and the aortic root rotation angle, were 42.7 ± 9.8 mm, and 5.3° ± 16.4°. Horizontal rotation of the anatomical axis was associated with leftward and ventral rotation, and vice versa. Multivariate analysis showed aortic root rotation to be associated with horizontal cardiac rotation, while aortic wedging is associated with frontal and sagittal cardiac rotation. We have quantified the marked individual variation observed in the anatomical axis of the living heart, identifying the different mechanisms involved in producing the marked three‐dimensional diversity of the living heart. Anat Rec, 300:1083–1092, 2017.

Optimal reconstruction of left ventricular outflow tract obstruction before surgical myectomy in a case with hypertrophic obstructive cardiomyopathy

We present optimally reconstructed three‐dimensional computed tomography images of left ventricular outflow obstruction, comprehensive left ventriculography, and comparable intraoperative transesophageal echocardiography, as well as serial operative pictures, to facilitate the understanding of live‐heart anatomy of hypertrophic obstructive cardiomyopathy. As shown in this case, detailed morphological analysis around the left ventricular outflow tract using preoperative computed tomography would be feasible and useful. The present case highlights the importance of obtaining complete three‐dimensional information present in the acquired computed tomography dataset because computed tomography is not entirely noninvasive or free of radiation exposure and contrast material.

Serial observation of electrocardiographic responses to corticosteroid therapy in a patient with right ventricular-predominant cardiac sarcoidosis

Predominant or isolated right ventricular involvement in cardiac sarcoidosis is uncommon, but should always be considered in a case of right ventricular hypertrophy combined with ventricular arrhythmia and/or conduction disturbance. Although improvement in right ventricular hypertrophy and atrioventricular conduction disturbance following corticosteroid therapy has been reported, the detailed serial electrocardiographic responses during corticosteroid therapy, as well as temporal changes in the electrocardiographic, biochemical, and morphological responses, have not been reported. We describe the clinical course and supportive imaging findings of reversible right ventricular hypertrophy and cardiac conduction disturbance in a case of right ventricular-predominant cardiac sarcoidosis.

Relationship between the membranous septum and the virtual basal ring of the aortic root in candidates for transcatheter implantation of the aortic valve: Variation in the Membranous Septum in TAVI

Knowledge of the anatomy of the membranous septum, as a surrogate to the location of the atrioventricular conduction axis, is a prerequisite for those undertaking transcatheter implantation of the aortic valve (TAVI). Equally important is its relationship of the virtual basal ring. This feature, however, has yet to be adequately described in the living heart. We analyzed computed tomographic angiographic datasets from 107 candidates (84.1 ± 5.2 years, 68% women) for TAVI. Using multiplanar reconstructions, we measured the height and width of the membranous septum, and the distances of its superior and inferior margins from the virtual basal ring plane. We also assessed the extent of wedging of the aortic root between the mitral valve and the ventricular septum. Mean heights and widths of the membranous septum were 6.6 ± 2.0, and 10.2 ± 3.1 mm, respectively, with its size significantly associated with that of the aortic root (P < 0.05). Its superior and inferior margins were 4.5 ± 2.3 and 2.1 ± 2.1 mm, respectively, from the plane of the basal ring. The inferior distance, the surrogate for the adjacency of the atrioventricular conduction axis, was ≤ 5mm in 91% of the patients. Deeper wedging of the aortic root was independently correlated with a shorter inferior distance (β = 0.0569, P = 0.0258). The membranous septum is appreciably closer to the virtual basal ring than previously appreciated. These findings impact on estimations of the risk of damage to the atrioventricular conduction axis during TAVI. Clin. Anat. 31:525–534, 2018.

Extracardiac compression of the inferolateral branch of the coronary vein by the descending aorta in a patient with dilated cardiomyopathy

Extracardiac structures can cause distortion of cardiac anatomy particularly in patients presenting with a significantly dilated heart, and/or thoracic deformities. We present the case of a 69‐year‐old woman with dilated cardiomyopathy who underwent cardiac resynchronization therapy. Preoperative electrocardiography‐gated contrast‐enhanced computed tomography revealed the inferolateral wall of her significantly dilated and leftward‐rotated heart was close to the descending aorta, and the descending aorta compressed the sandwiched inferolateral branch of the coronary vein. Retrograde coronary venography performed at the time of device implantation confirmed focal stenosis of the inferolateral branch of the coronary vein.

Optimal image reconstruction using multidetector‐row computed tomography to facilitate cardiac resynchronization therapy

Preprocedural recognition of the segment of latest mechanical contraction along with the anatomy of the coronary venous system is important for successful and effective cardiac resynchronization therapy. We present a case of ischemic cardiomyopathy who underwent implantation of a cardiac resynchronization therapy device with a defibrillator, which was facilitated by preprocedural computed tomographic images reconstructed to visualize the left ventricular slab and the coronary venous system simultaneously on the cardiac contour. The present reconstruction method using computed tomography is optimal and feasible method to incorporate the echocardiographic findings into the procedure performed under fluoroscopy appropriately.

Cardiac apical swinging detected by computed tomography

In cases with significant pericardial effusion, cardiac apical swinging is a characteristic finding, usually detected by echocardiography and electrocardiography. We present a case showing typical cardiac apical swinging, initially detected by routine computed tomography as a cardiac swinging artifact. The present case highlights the importance of multidisciplinary interpretation of cardiac images, specifically focusing on the difference between static images obtained by computed tomography and dynamic images visualized by echocardiography.

Reversed Rivero‐Carvallo's sign confirmed by blood flow analysis using cardiac magnetic resonance imaging in a patient with straight back syndrome

An asymptomatic 45‐year‐old man was referred to our hospital for detailed evaluation of a systolic ejection murmur. The intensity of the murmur increased on deep expiration and decreased on deep inspiration, showing so‐called reversed Rivero‐Carvallos sign. Using cardiac magnetic resonance imaging, we demonstrated a characteristic respiratory‐induced change in peak flow velocity in the right ventricular outflow tract, which was the basic mechanism of the reversed Rivero‐Carvallos sign in a case with straight back syndrome. Concomitant anatomical changes in the entire heart in relation to the thoracic cage were also clarified.