Stress echocardiography is an important alternative to exercise electrocardiography for the diagnosis of coronary artery disease, especially when there are baseline ECG abnormalities or an inability to exercise or other situations that would preclude exercise testing, Indications for stress echocardiography include diagnosis of ischemic heart disease, evaluation of patients with known ischemic disease, and assessment of valvular heart disease.
There are two main modalities for performing stress echocardiography:
- Exercise stress echocardiography performed either during upright or supine bicycle exercise or immediately following treadmill exercise, and
- Pharmacologic stress echocardiography, most commonly performed using an intravenous infusion of dobutamine at a dose ranging from 5 mcg per kg per min to a maximum of 40 to 50 mcg per kg per min. Atropine is added at peak infusion dose if needed to achieve at least 85% of target heart rate.
Stress echocardiography can also be performed with spectral and color Doppler for the hemodynamic evaluation of patients with valvular heart disease. Ultrasonic contrast agents are used to improve endocardial border detection when clinically indicated.
Minimum Knowledge Requirements for Performance and Interpretation
Competence in performing and/or interpreting stress echocardiograms in adult patients requires all of the basic knowledge of ultrasound physics; instrumentation; and cardiac anatomy, physiology and pathology described in the section on general principles.
In addition, the requirements for stress echocardiography contain 2 distinct components:
- stress testing supervision
- performance and interpretation of the echocardiographic images for wall motion analysis
Stress testing supervision requires the ability to safely monitor stress in an individual with potentially severe cardiovascular disease. Skills needed to perform and supervise the stress portion of the test are recognized to be different from those needed to perform and interpret the echocardiographic images, and proficiency in stress echo will require both components to learn. Recognition and treatment of life-threatening arrhythmias is particularly relevant with dobutamine stress echocardiography (DSE). Assessment of segmental wall motion remains one of the most challenging aspects of echocardiographic interpretation.
Thus, intensive training in echocardiography with a minimum of Level 2 training or equivalent is a prerequisite for acquiring the skills necessary to perform and interpret stress echocardiography studies.
Opportunities are also available for fellows to participate in the performance and interpretation of stress echocardiographic procedures. Instruction in the procedure and indications and contraindications are incorporated into the didactic lecture series and interpretation is provided during the daily reading sessions.
Training Requirements
Specific recommendations for training in stress echocardiography consist of achieving Level 2 training in echocardiography plus a minimum of 100 stress studies performed under the supervision of an echocardiographer with Level 3 training and expertise in stress echocardiography.
Proof of Competence
A letter from the program director is provided after verification from the echo lab director that stress echo training and competence by performing a minimum of 100 stress echocardiograms under the direct supervision of an echocardiographer with Level 3 training and expertise in stress echocardiography was obtained.
Certification by the NBE is highly desirable. Certification requires successful completion of the Adult Special Competence Examination in Echocardiography as well as documentation of training and maintenance of skills.
Echocardiography in Special Settings
The echocardiography lab at Montefiore Medical Center provides a strong foundation in echocardiography. The use of contrast agents has been discussed above. There is also the availability of 3D echo with real-time acquisition at both campuses. In addition, special clinical cases that prove to be challenging but require expertise in echocardiography such as diagnostic echo in congenital heart disease (CHD) is available.
3D echo is an important resource used in the evaluation of adults with CHD. In the case of CHD, echo has become a mainstay in daily clinical use. A comprehensive anatomic diagnosis along with the assessment of associated flow disturbances obtained noninvasively is part of fellows’ clinical training. Shunt detection and calculation, complex congenital anatomy and post-surgical features are part of the echo teaching.
It is, however, recognized that advanced training in CHD is beyond the scope of our lab due to the requirement of a relatively high number of CHD echocardiograms and TEEs needed as outlined in the 32nd Bethesda Conference. For individuals eager to acquire competence at an advanced level, additional training can be pursued.
Board Certification
The National Board of Echocardiography offers certification in echocardiography. Minimum requisites for board certification can be found on the NBE website (www.echoboards.org).
COCATS Training Requirements for Stress Echocardiography
- Understanding of the basic principles, indications, applications, and technical limitations of echocardiography. Exercise stress testing (ACGME minimum = 50)
- Level 2 training in transthoracic echocardiography
- Specialized training in stress echocardiography with performance and interpretation of 100 stress studies under appropriate supervision by a Level III echocardiographer