Book Text

M-mode and Two-Dimensional Echocardiography

Because the propagation velocity of ultrasound in tissue is constant, the distance between the transducer and the reflective structure will be determined by the time that it takes the initial signal to go and come back. This information can be displayed different ways. The first echocardiograms, "motion" or "M-mode" studies, were one-dimensional views of cardiac structures produced by single-crystal transducers with the results traced on moving photosensitive paper. Today, M-mode echocardiography is used principally to view rapidly moving structures,

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**TABLE 33-2** -- Recommended training objectives for basic and advanced perioperative echocardiography
Basic Training
Cognitive Skills
1. Knowledge of the physical principles of echocardiographic image formation and blood velocity measurement
2. Knowledge of the operation of ultrasonographs, including all controls that affect the quality of data displayed
3. Knowledge of equipment handling, infection control, and electrical safety associated with the techniques of perioperative echocardiography
4. Knowledge of the indications, contraindications, and potential complications of perioperative echocardiography
5. Knowledge of the appropriate alternative diagnostic techniques
6. Knowledge of the normal tomographic anatomy as revealed by perioperative echocardiographic techniques
7. Knowledge of commonly encountered blood flow velocity profiles as measured by Doppler echocardiography
8. Knowledge of the echocardiographic manifestations of native valvular lesions and dysfunction
9. Knowledge of the echocardiographic manifestations of cardiac masses, thrombi, cardiomyopathies, pericardial effusions, and lesions of the great vessels
10. Detailed knowledge of the echocardiographic manifestations of myocardial ischemia and infarction
11. Detailed knowledge of the echocardiographic manifestations of normal and abnormal ventricular function
12. Detailed knowledge of the echocardiographic manifestations of air embolization
Technical Skills
1. Ability to operate ultrasonographs, including the primary controls affecting the quality of the displayed data
2. Ability to insert a TEE probe safely in an anesthetized, tracheally intubated patient
3. Ability to perform a comprehensive TEE examination and differentiate normal from markedly abnormal cardiac structures and function
4. Ability to recognize marked changes in segmental ventricular contraction indicative of myocardial ischemia or infarction
5. Ability to recognize marked changes in global ventricular filling and ejection
6. Ability to recognize air embolization
7. Ability to recognize gross valvular lesions and dysfunction
8. Ability to recognize large intracardiac masses and thrombi
9. Ability to detect large pericardial effusions
10. Ability to recognize common echocardiographic artifacts
11. Ability to communicate echocardiographic results effectively to health care professionals, the medical record, and patients
12. Ability to recognize complications of perioperative echocardiography
Advanced Training
Cognitive Skills
1. All the cognitive skills defined under Basic Training
2. Detailed knowledge of the principles and methodologies of qualitative and quantitative echocardiography
3. Detailed knowledge of native and prosthetic valvular function, including valvular lesions and dysfunction
4. Knowledge of congenital heart disease (if congenital heart disease practice is planned, this knowledge must be detailed)
5. Detailed knowledge of all other diseases of the heart and great vessels that is relevant in the perioperative period (if pediatric practice is planned, this knowledge may be more general than detailed)
6. Detailed knowledge of the techniques, advantages, disadvantages, and potential complications of commonly used cardiac surgical procedures for the treatment of acquired and congenital heart disease
7. Detailed knowledge of other diagnostic methods appropriate for correlation with perioperative echocardiography
Technical Skills
1. All the technical skills defined under Basic Training
2. Ability to acquire or direct the acquisition of all necessary echocardiographic data, including epicardial and epiaortic imaging
3. Ability to recognize subtle changes in segmental ventricular contraction indicative of myocardial ischemia or infarction
4. Ability to quantify systolic and diastolic ventricular function and to estimate other relevant hemodynamic parameters
5. Ability to quantify normal and abnormal native and prosthetic valvular function
6. Ability to assess the appropriateness of cardiac surgical plans
7. Ability to identify inadequacies in cardiac surgical interventions and the underlying reasons for the inadequacies
8. Ability to aid in clinical decision making in the operating room
From Cahalan MK, Abel M, Goldman M, et al: American Society of Echocardiography and Society of Cardiovascular Anesthesiologists task force guidelines for training in perioperative echocardiography. Anesth Analg 94:1384–1388, 2002.

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**TABLE 33-3** -- Numbers of examinations and other key training recommendations for basic and advanced perioperative echocardiography
	Basic^*	Advanced^*
Minimum number of examinations^†	150	300
Minimum number personally performed^‡	50	150
Program director qualifications	Advanced perioperative echocardiography training	Advanced perioperative echocardiography training plus at least 150 additional perioperative TEE examinations
Program qualifications	Wide variety of perioperative applications of echocardiography	Full spectrum of perioperative applications of echocardiography
From Cahalan MK, Abel M, Goldman M, et al: American Society of Echocardiography and Society of Cardiovascular Anesthesiologists task force guidelines for training in perioperative echocardiography. Anesth Analg 94:1384–1388, 2002.

*Totals for basic training may be counted toward advanced training provided that the basic training was completed in an advanced training environment. See the text for additional details and explanation of training environments and program director qualifications.
†Complete echocardiographic examinations interpreted and reported by the trainee under appropriate supervision. Transthoracic studies recorded by qualified individuals other than the trainee may be included.
‡Comprehensive intraoperative TEE examinations personally performed, interpreted, and reported by the trainee under appropriate supervision.

such as valve leaflets, because M-mode transducers can produce up to 1800 images per second ( Fig. 33-1 ). However, M-mode images reveal only a small portion of the heart at one time, thus making orientation and interpretation of spatial relationships difficult.

By using multiple crystals (linear or phased-array transducers) or rapidly moving a single crystal (mechanical transducer), multiple views can be obtained and collated into a two-dimensional image. Although two-dimensional techniques produce only about 30 images per second, definition in two dimensions provides an enormous advantage in recognizing anatomic and pathologic landmarks ( Fig. 33-2 ). Images are displayed in "real time" on a monitor screen and recorded on videotape or digital format for later review. By altering the position or angle of the ultrasound beam, the operator produces multiple cross-sectional (tomographic) images revealing the external and internal anatomy and function of the heart and great vessels.