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Hiroyuki Iwano
Hiroyuki Iwano

Public Documents 3
Prediction of development of tricuspid regurgitation in atrial fibrillation: what do...
Hiroyuki Iwano

Hiroyuki Iwano

May 19, 2025
A document by Hiroyuki Iwano. Click on the document to view its contents.
Right ventricular pressure-volume loop produced with simultaneous application of thre...
Toshitaka Nakaya
Ichizo Tsujino

Toshitaka Nakaya

and 4 more

February 19, 2021
Accurate assessment of right ventricular (RV) function is drawing a growing attention. Pressure-volume (PV) loop analysis is the gold standard method for evaluating RV function; however, it is not widely employed due to its invasive nature and complexity. The present report is the first to have drawn a RV PV loop in a patient with pulmonary hypertension, with a simultaneous recording of RV pressure and volume using high fidelity micromanometry and 3D echocardiography. This allows for less invasive and simple assessment of RV function, potentially promoting better understanding and management of pulmonary hypertension and other cardiovascular diseases.
Functional significance of intra-left ventricular vortices on energy efficiency in no...
Miwa Sarashina
Hiroyuki Iwano

Miwa Sarashina

and 12 more

April 14, 2020
Purpose: To investigate the influence of changes in intra left ventricular (LV) vortices on LV energy efficiency (EE) in normal and diseased hearts. Methods: Vector flow mapping echocardiography was performed in 36 normal subjects (N), 36 patients with dilated cardiomyopathy (D), and 36 patients with LV hypertrophy (H). The circulation of main anterior vortex was measured as a parameter of vortex strength and EE was calculated as energy loss divided by LV stroke work. Results: Circulation increased in the order of N, H, and D (N: 15±4, D: 19±8, H: 17±6 10-3m2/s; analysis of variance [ANOVA], P<0.01). Conversely, EE increased in the order of N, D, and H (N: 0.22±0.07, D: 0.26±0.16, H: 0.30±0.16 10-5J/mmHg·mL·m·s; ANOVA, P=0.04), suggesting worst EE in group H. We found a positive correlation between circulation and stroke work only in group N and positive correlation between circulation and EE only in diseased groups (D: R=0.55, P<0.01; H: R=0.44, P<0.01). Multivariable analyses revealed that circulation was the independent determinant of EE in both of groups D and H. Conclusions: Enhanced vortices could work effectively to increase LV external work without loss of EE in normal hearts, while in failing hearts only to worse EE, regardless of the LV morphology.

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