Background. A novel tissue tracking system (TTS) allows the determination of two-dimensional strain from gray scale digital echocardiographic images. We used TTS to measure myocardial strain of the left ventricle (LV) in healthy children. Methods. The study group consisted of 40 healthy children (2 months to 18 years old). The radial and circumferential strain of the interventricular septum (IVS) and the posterior wall (PW) of the left ventricle were measured using the short axis LV view, and the longitudinal strain of the IVS and lateral wall were calculated from the apical four-chamber view. Results. Large differences were seen in the strain of different cardiac regions. Radial strain was largest in the PW (49.1±12.9%), and longitudinal strain was smallest in the IVS (27.5±8.0%). There were no significant relationships between any of the measured peak systolic strain values and heart rate or age. Bland-Altman analysis showed inter- and intra-observer standard deviations of 4.7% and 4.9%, respectively. Conclusions: TTS is able to measure three directional strain of the myocardium in a pediatric population. Our data can be used as normal pediatric cardiac myocardial strain values.
Objective. Mitral apparatus geometry changes during ischemic mitral regurgitation (MR) play an important role in finding mechanisms for ischemic MR. Live three-dimensional echocardiography (L3DE) is a new technique providing cardiac full-volume image in a very short time. We applied this technique to evaluate mitral apparatus geometry changes during acute ischemic MRs. Methods. After baseline two-dimensional echocardiography (2DE) and L3DE image acquiring, the left circumflex (LCX) coronary artery distal to the first obtuse marginal artery origin was ligated in order to produce an acute ischemic MR in 10 canines. When significant ischemic MR occurred, 2DE and L3DE imagings were repeated. PM tethering distance and mitral annular geometric dilation were measured by L3DE. Results. Acute ischemic MR was successfully produced by LCX ligation in 8 canines. MR grade increased from 0.5±0.2 at baseline to 2.4±0.2 during ischemic MR in scale, P<0.05. Mitral annulus dilated asymmetrically; anterior mitral annular perimeter length increased 10.0±3.2%, and posterior mitral annular perimeter length increased 19.4%±5.1% at mid-systole. The mitral annular configuration also somewhat distorted. The posterior annulus near anterior lateral commissure and that near posterior medial commissure could not be shown at the same level if we adjusted the anterior annulus and two commissures at the same level. The posterior papillary muscle (PPM) tethering length increased 1.3 ±0.2mm (p<0.05). The multiple linear regression analysis results showed that increase of PPM tethering distance was the only independent factor determining proximal MR jet cross-section area (r2=0.77). Conclusions. Live three-dimensional echocardiography can show mitral annulus spatial configuration and can be used to address questions related to mitral apparatus. Mitral apparatus geometry changes are contributed to acute ischemic MR.
In a 17-year-old man complaining of exertional chest pain, computed tomography and magnetic resonance imaging showed a mass originating from the right atrium invading the pulmonary artery compatible with malignant lymphoma. However, its invasion to the left ventricular myocardium was not evident. Conventional echocardiography only identified the thickened left ventricular posterior wall. However, transmural myocardial strain distribution obtained by myocardial strain imaging clearly demonstrated abnormal myocardium at the posterior wall suggesting myocardial invasion. The abnormal finding disappeared after chemotherapy. Assessment of transmural myocardial strain profile using myocardial strain imaging was useful to differentiate normal and abnormal myocardium, leading to a correct diagnosis of myocardial invasion.
A 45-year-old woman was admitted to our hospital because of exertional dyspnea. At the age of 26, she was diagnosed with corrected transposition of the great arteries (CTGA) and mild left atrioventricular valve (LAVV) regurgitation. On admission, transthoracic echocardiography revealed severe LAVV regurgitation related to CTGA. The appropriate timing of LAVV replacement in CTGA patients remains unclear. In this case, severe LAVV regurgitation was demonstrated; the anatomic right ventricle had gradually enlarged; systolic function of the anatomic right ventricle was slightly reduced; and sinus rhythm was still maintained, so we opted for valve replacement.
We describe a family in which five members had hypertrophic cardiomyopathy (HCM) with a similar distribution of left ventricular (LV) hypertrophy and LV filling pattern. All five family members had myocardial hypertrophy localized between the anterior LV wall and ventricular septum, in addition to having a triphasic transmitral flow (TMF) velocity pattern with a mid-diastolic wave. The HCM patients with this TMF velocity pattern exhibit decreased LV compliance and delayed LV relaxation, suggesting that the features of diastolic failure may be specific. Thus, these findings may provide an important clue to elucidating the relationship between the pathophysiology and mode of inheritance in patients with HCM.