Asynchrony of left ventricular relaxation in normal volunteers: A study using high frame rate echocardiography

Left ventricular relaxation time constant, Tau, is the best index to evaluate left ventricular diastolic function. The measurement is only available traditionally in catheter lab. In Echo lab, several methods of non-invasive measurement of Tau have been tried since 1992, however almost all the methods are still utilizing the same formula to calculate Tau as in catheter lab, which makes them inconvenient, time-consuming and sometimes not very accurate. A simple method to calculate Tau in patients with mitral regurgitation has been developed just based on Weiss’ formula and simplified Bernoulli’s equation. Similarly, formulas are developed here by pure mathematical derivative to calculate Tau by continuous-wave Doppler in patients with aortic regurgitation.

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Calculation of Left Ventricular Relaxation Time Constant-Tau in Humans by Continuous-Wave Doppler

The Open Cardiovascular Medicine Journal ◽

10.2174/1874192400802010009 ◽

2008 ◽

Vol 2 (1) ◽

pp. 9-11 ◽

Cited By ~ 5

Author(s):

Xufang Bai

Keyword(s):

Relaxation Time ◽

Time Constant ◽

Continuous Wave ◽

Left Ventricular Diastolic Function ◽

Left Ventricular ◽

Simple Method ◽

Relaxation Time Constant ◽

Left Ventricular Relaxation ◽

Ventricular Relaxation ◽

Continuous Wave Doppler

Left ventricular relaxation time constant, Tau, is the best index to evaluate left ventricular diastolic function, but the measurement is only available traditionally in catheter lab. In Echo lab, several methods of non-invasive measurement of Tau have been tried since 1992, however almost all the methods are still utilizing the same formula to calculate Tau as in catheter lab, which makes them inconvenient, time-consuming and sometimes not very accurate. Based on Weiss’ formula and simplified Bernoulli’s equation, a simple method is developed by pure mathematical derivative to calculate Tau by continuous-wave Doppler in patients with mitral regurgitation.

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Speckle-Tracking Echocardiography With Novel High Frame-Rate Imaging

10.20944/preprints202104.0403.v1 ◽

2021 ◽

Author(s):

Kana Fujikura ◽

Mohammed Makkiya ◽

Muhammad Farooq ◽

Yun Xing ◽

Wayne Humphrey ◽

...

Keyword(s):

Temporal Resolution ◽

Speckle Tracking ◽

Speckle Tracking Echocardiography ◽

Myocardial Strain ◽

Left Ventricular ◽

Frame Rate ◽

High Frame Rate ◽

Echocardiographic Images ◽

The Impact ◽

Normal Lvef

Background: global longitudinal strain (GLS) measures myocardial deformation and is a sensitive modality for detecting subclinical myocardial dysfunction and predicting cardiac outcomes. The accuracy of speckle-tracking echocardiography (STE) is dependent on temporal resolution. A novel software enables relatively high frame rate (Hi-FR) (~200 fps) echocardiographic images acquisition which empowers us to investigate the impact of Hi-FR imaging on GLS analysis. The goal of this pilot study was to demonstrate the feasibility of Hi-FR for STE. Methods: In this prospective study, we acquired echocardiographic images using clinical scanners on patients with normal left ventricular systolic function using Hi-FR and conventional frame rate (Reg-FR) (~50 FPS). GLS values were evaluated on apical 4-, 2- and 3-chamber images acquired in both Hi-FR and Reg-FR. Inter-observer and intra-observer variabilities were assessed in Hi-FR and Reg-FR. Results: There were 143 resting echocardiograms with normal LVEF included in this study. The frame rate of Hi-FR was 190 ± 25 and Reg-FR was 50 ± 3, and the heart rate was 71 ± 13. Strain values measured in Hi-FR were significantly higher than those measured in Reg-FR (all p < 0.001). Inter-observer and intra-observer correlations were strong in both Hi-FR and Reg-FR. Conclusions: We demonstrated that strain values were significantly higher using Hi-FR when compared with Reg-FR in patients with normal LVEF. It is plausible that higher temporal resolution enabled the measurement of myocardial strain at desired time point. The result of this study may inform clinical adoption of the novel technology. Further investigations are necessary to evaluate the value of Hi-FR to assess myocardial strain in stress echocardiography in the setting of tachycardia.

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