IMBUS-Fundamentals

About The Exam

Screening Heart Exam with Advanced IMBUS

Point-of-care-ultrasound (POCUS) was developed in Emergency and Critical Care Medicine when ultrasound devices became portable and cheaper, and the 2021 edition of the American Society of Echocardiography’s textbook listed the characteristics of POCUS echocardiography as follows:

1. Performed by the physician at the bedside during clinical evaluation
2. Limited number of findings sought, usually brief (<5 minutes)
3. Can encompass more than one organ system
4. Has indication and value to immediately affect diagnosis, management, or triage
5. Uses small, inexpensive portable devices with limited data entry and measurements.
6. Limited reporting, often semiquantitative
7. Often repeated by subsequent physicians and used for monitoring or follow-up.
8. Often lacks characterization of incidental findings
9. Variable imaging and training for each physician

Our Advanced IMBUS clinic physicians have patients that fit these POCUS criteria, but also care for patients without focused complaints such as new clinic patients, annual preventive visits, and preoperative exams for major surgery. These patients have traditionally received a hands/eyes/stethoscope screening exam of the heart, which is suboptimal for most heart pathology.

The ASE textbook does not discuss a screening echocardiogram with advanced devices but describes a LIMITED echocardiogram as a formal imaging test with imaging standards, study archiving, and an all-inclusive interpretation and report in which the user is responsible for all diagnoses. Our screening heart exam with Venue meets these criteria.

We published a study in 2021 that added a screening ultrasound exam with Venue to the Medicare Wellness visits of 108 patients and an important part was a heart exam. (J Ultrasound Med 2021: http://dx.doi.org/10.1002/jum.15788).  We found frequent previously unknown heart abnormalities and the primary physicians graded the benefits of this information as mildly to moderately positive and rarely negative.

We do not use all parts of the heart exam from the preceding chapters because a limited heart screen must be efficient. It uses nine views of the heart and can be completed in 10-15 minutes on a reasonably normal heart with good views but can take twice as long when multiple abnormalities are present. Each view is visually assessed (VA) and Color Doppler is applied to each valve. The VA follows a logical pattern that becomes a habit, reducing the chance of missing something important. There are only 5 measurements that are routine during the exam. If abnormalities are noted, additional views and measurements may be added.

PLAX: clockwise from the top

  • Begin cephalad to find and measure the distal ascending aorta diameter
  • Move caudad to a standard PLAX
  • Have enough initial depth to note posterior effusions, then decrease the depth
  • VA the proximal right ventricular outflow tract (RVOT)
  • VA the proximal ascending aorta and aortic valve (AV) (apply Color)
  • VA the left atrium (LA)
  • VA the coronary sinus location and MV annulus movement
  • VA the mitral valve (MV) (apply Color)
  • VA the basal left ventricle (LV)

PLAXR: follow the blood flow

  • VA the right atrium (RA)
  • VA the tricuspid valve (TV) (apply Color)
  • VA the right ventricle (RV)

PSAX: with a successful PLAXR only two structures need to be imaged

  • VA the LV doughnut
  • VA the AV

 

An apical4 is rarely optimal simultaneously for the right and left hearts. It is better to divide the analysis into separate left and right heart components and optimize views for each. We begin with the left heart.

APICAL4 (Left): follow the blood flow

  • VA the LA
  • VA the septal and lateral MV annulus movement
  • VA the MV leaflets (apply Color)
  • VA the LV
  • Obtain Auto-EF
  • Apply Color to the LV inflow and obtain E and A
  • Use TDI on the septal mitral annulus to obtain s’, e’, and a’

APICAL5

  • VA the left ventricular outflow tract (LVOT) and AV
  • Apply Color and get the plane with best flow through LVOT and AV
  • Obtain Auto-VTI

APICAL4 (Right): follow the blood flow

  • VA the RA
  • VA the TV annulus movement
  • VA the TV (apply Color)
  • VA the RV

APICAL2: follow the blood flow

  • VA the LA
  • VA the MV (apply Color)
  • VA the LV

APICAL3: follow the blood flow

  • VA the LA
  • VA the MV (apply Color)
  • VA the LV
  • VA the LVOT and AV (apply Color)

APICAL3R: follow the blood flow

  • VA the RA
  • VA the TV (apply Color)
  • VA the RV

SUBCOSTAL4: follow the blood flow

  • VA the RA
  • VA the TV
  • VA the RV
  • VA the LA and apply Color to interatrial septum
  • VA the MV
  • VA the LV
  • Fan to subcostal5 and VA the LVOT, AV, and AscA