Background. Although second harmonic (2H) imaging is utilized to minimize the tissue signals in myocardial contrast echocardiography (MCE), the native tissue harmonic signal is sufficiently high enough to cause a misreading of myocardial opacification when high mechanical index (MI) is used.
Purpose. The backscattered signal from microbubbles at high MI is broadband, while it is narrowband at low MI. Therefore, the bubble/tissue signal ratio is expected to be high between the fundamental signal and 2H frequencies at high MI. Our aim was to elucidate the efficacy of a new imaging method using an in-between frequency, denoted as 1.5 harmonic (1.5H) imaging.
Methods. Six open-chest dogs were examined using Toshiba APLIO with 1.5H and conventional 2H system. The transmitting/receiving frequencies were 2.3/3.3 MHz for 1.5H and 1.4/2.8MHz for 2H imaging, respectively. Intermittent MCE was performed at a MI of 1.6 after injection of Levovist®, and baseline intensity and peak intensity of opacification of the ventricular septum were measured.
Results. While baseline intensity of the septum was significantly lower using 1.5H than 2H (26±4 vs. 43±14 gray level, p<0.001), the opacification after Levovist was significantly higher using 1.5H than 2H (91±32 vs. 51±38, p<0.001). Due to the combination of these effects, visual recognition of myocardial opacification was quite superior with 1.5H imaging.
Conclusion. The 1.5H imaging system provides superb contrast opacification when using high MI.

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Background. Restrictive or pseudonormalized mitral flow velocity pattern (MFVP) is observed not only in patients with heart failure but also in patients with severe mitral regurgitation (MR). It is important to assess the restrictive MFVP which is primarily due to functional deterioration of the left ventricle or due to MR in individual patients. We hypothesized that left atrial (LA) geometry may be used to estimate restrictive MFVP due to heart failure or MR.
Methods. In addition to MFVP and LA chamber size, LA eccentricity index was determined as LA superior-inferior dimension ×2/(LA antero-posterior dimension + LA medio-lateral dimension) using 2-dimensional echocardiography in 61 sinus rhythm patients with LA volume of 35 ml or greater. Ten patients had congestive heart failure (CHF group), and 9, severe organic MR (MR group). LV diastolic dysfunction was the most likely explanation for the LA enlargement in the remaining 42 patients (DDF group).
Results. There was no difference in mitral E/A ratio (peak early diastolic flow velocity/peak flow velocity at atrial contraction) or in LA chamber size between the MR and CHF groups, but the LA eccentric index was greater in the CHF and DDF groups than in the MR group indicating that LA geometry was spherical in the MR group and elongated in the CHF and DDF groups.
Conclusions. Two-dimensional echocardiographic assessment of the LA geometry is useful to determine whether the pseudonormalized or restrictive MFVP is due to functional deterioration of the left ventricle or due to MR.

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We present a case with posterior mitral valve prolapse exhibiting early closure of the aortic valve and protodiastolic extrasound. It seems that the forward stroke volume suddenly reduced during late-systole because of a late-systolic increase in severe mitral regurgitation and the aortic valve closing early in timing. The simultaneous observations of sound, mitral valve, and mitral inflow recordings suggest that the protodiastolic sound may be related to the rapidly returning motion of the posterior mitral leaflet and recoaptation with the anterior mitral leaflet.

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A 16-year-old male with a history of surgically-closed atrial septal defect (ASD) 2 years before was admitted to our hospital for lung congestion caused by severe mitral regurgitation (MR). Before the closure of the ASD, his echocardiographic findings showed mild prolapse of the anterior mitral leaflet (AML) with the hypoplastic posterior mitral leaflet (PML), but only mild MR. On admission, severe MR was observed by echocardiography in association with an increase in mitral anural size and the progression of AML prolapse. It was assumed that the worsening of MR was due to increased blood volume in the left-side of the heart after closing the ASD combined with cardiac growth. After mitral valvuloplasty, MR and heart failure disappeared.

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We report a case with a large calcified mass on the posterior annulus of the mitral valve. Transthoracic echocardiography (TTE) showed a large, round, and echo-dense mass with central echolucencies resembling liquefaction. TTE was useful in establishing the diagnosis of caseous calcification of the mitral annulus.

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Paradoxical embolism may occur in patients with acute pulmonary thromboembolism when patent foramen ovale (PFO) coexists with pulmonary hypertension (right-to-left shunt). There have been few case reports of paradoxical embolism in arteries coincident with acute pulmonary thromboembolism. We report two cases with acute pulmonary thromboembolism associated with paradoxical embolism. Transesophageal echocardiography revealed a giant thrombus trapped in the foramen ovale, and right-to-left shunt was detected by contrast echocardiography.

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