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John Gorcsan, MD ( USA ) 

John-Gorcsan 博士在做报告

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Tissue Doppler imaging (TDI) has emerged in routine clinical practice for specific applications.  Although the concept of TDI has been introduced over 13 years ago, most applications have focused on research topics. A few specific applications have gained widespread clinical acceptance, and can be translated into daily patient care. 

 

The first is the measurement of the mitral annular velocity as a marker of diastolic function as a means to estimate left ventricular (LV) filling pressures.  This is applied using pulsed-TDI where the region of interest is usually applied to the lateral mitral annular site using the apical 4-chamber view.  This peak mitral annular velocity in early diastole is usually referred to as the E' velocity.  The mitral inflow velocity or E velocity is measured from the apical 4-chamber view at the tips of the mitral leaflets.  The simple ratio of E/E' is then used as an estimate of LV filling, with E/E' > 10 indicating an abnormally high LV diastolic filling pressure > 15 mmHg.  Variations in the E/E' ratio have been used including the septal site, and the average of septal and lateral wall sites.  Situations in which the E/E' may not be useful include acute volume depletion, prosthetic mitral valves, mitral stenosis, and constrictive pericarditis.  In general, this reproducible non-invasive estimation of LV filling pressures may have an impact of the clinical care of patients in daily practice. 

 

The second application is to aide in the differentiation of constrictive pericarditis from restrictive cardiomyopathy.  Mitral inflow Doppler data are very useful, with respiratory variation typically observed with constriction and a restrictive pattern, characterized by a short E deceleration time < 150 ms, typically seen in restrictive cardiomyopathy, such as amlyoidosis.   Hepatic vein patterns with respiratory variation also support constrictive pericardidits.  However, these routine Doppler data may be confusing.  A mitral annular velocity < 8 cm /sec by pulsed TDI is supportive of restrictive cardiomyopathy.  A normal mitral annular velocity is usually > 10 cm/sec, and it may be exaggerated further by pericardial constriction.  A third application of TDI is in determining the athletic heart from hypertrophic cardiomyopathy.  It is potentially dangerous to allow persons with hypertrophic cardiomyopathy engage in competitive athletics, but trained athletes have structural alterations in their heart that may be thought to represent disease. 

 

A pulsed Doppler recording of the athlete's heart is usually > 10 cm/sec, whereas, those with forms of hypertrophic cardiomyopathy have diminished E' velocities, usually < 10 cm/sec. These specific applications of TDI have a favorable impact on patient care.