Prime time use of tissue Doppler echocardiography: what have we gained?
In daily practice, Tissue Doppler Echocardiography (TDI) is used to estimate left ventricular filling pressures, categorize diastolic dysfunction, identify patients with heart failure (HF) with normal ejection fraction, differentiate constrictive pericarditis from restrictive cardiomyopathy, to prognosticate acute coronary syndrome, valvular heart disease syndrome of HF etc, correlate exercise capacity and symptoms, differentiate physiological versus pathological hypertrophy, assessment of intraventricular dyssynchrony, regional and global systolic and diastolic properties, detection of right ventricular function and possible carriers of genetic cardiomyopathies like Fabry's disease and hypertrophic cardiomyopathy, etc. Its role in adding incremental value to stress echocardiography, subclinical dysfunction evaluation, cardiac transplant rejection, cardiotoxicity of anti-cancer drugs, predicting occurrence and reversion of atrial fibrillation, predicting aortic catastrophies etc, although very encouraging has not found many users. It was intuitively considered invaluable in detecting subclinical myocarditis, acute rheumatic fever, Chaga's disease and localization of atrioventricular accessory pathways with manifest conduction, but could not find prime time readiness. In a similar manner, tissue-velocity derived deformation parameters have not found prime time use, despite making great inroads into the mysteries of muscle mechanics. Part of the problem lies in their emphasis on unidirectional information of a structure which is essentially multidimensional. The other problems have been angle-dependency and low signal-to-noise ratio in deformation imaging which has restricted its use to highly experienced operators rather than more democratic use. Validation studies did indicate its great potential. TDI-derived imaging paved the way for non-Doppler multidimensional deformation imaging which is slowly gaining ground.
Mohan
Jagdish C
JC
Department of Cardiology, Ridge Heart Centre, Sunder Lal Jain Hospital, Ashok Vihar-III, Delhi-52, India. jcmohan@vsnl.com
Tomar
Deepak
D
Mohan
Vipul
V
D003937:Diagnosis, Differential; D015150:Echocardiography, Doppler / Q000379:methods*; D006331:Heart Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D009200:Myocardial Contraction / Q000502:physiology*; D015203:Reproducibility of Results; D013318:Stroke Volume / Q000502:physiology*