Redbud Medical Systems, Inc.
Custom-made beds for Supine bike stress echo, Post treadmill imaging exercise echo, & Resting echo

Redbud home

About us

Models:
     1000
     400
     500

Features & accessories

Delivery, installation, & warranty

Factors to consider when purchasing an echocardiography bed

Stress Echo techniques & literature

Contact us
(design your bed & obtain a bid)

[ The following is excerpted, with permission, from the Manual for Stress Echo by Larry DeBord. ]

Chapter 14
The Five Orthographic Planes -
Imaging Techniques and Interpretation
of the Stress Echo Images

Coronary Artery Territories 
Scoring and Evaluation Parameters 
Echocardiographic Criteria for Positive Diagnosis 
Post Treadmill Imaging 
Peak Imaging with Upright Bike 
Peak Imaging with Supine Bike 
Notes on Identifying the Regional Wall Motion Abnormality 
Reading Suggestions
Parasternal Long Axis
Parasternal Short Axis
Apical Four chamber
Apical Two Chamber
Apical Three Chamber

Now that the patient has triumphed over the exercise, the images of his heart must be put into order. These walls might be called hyperkinetic, hypokinetic, akinetic, dyskinetic, aneurysmic or normal. We may wax poetic and call them tardikinetic, slow, lazy, out, gone to lunch, struggling or dead. We may say they suffered a hit. Or the circ is shot. Or the septum is struggling, limping or gimpy. The wall motion may be described as being tugged, dragged or moving like gang busters. Or we may sink to the dreary level of merely entering numeric scores through the keyboard. Whatever your style, this is the moment you caress the Truth. So take your time and be honest, but also, regardless of what you may think about the nature of science and the role of objective observation, remember that it takes imagination to read stress echoes. Stress Echo is but one palette of the Medical Arts.

I cannot over-emphasize the importance of cardiologists reading together in their early days of stress echo. Consensus and disagreement are the best tools to improve your reading skills. Even if you have been reading conventional echoes for years, you will discover that identifying endocardium and comparing wall motion is a new game that requires hours of retraining. You will be surprised at how often one man’s akinesia is another man’s normal. Neglecting to hold joint reading sessions and failure to define and to agree upon reading criteria or guidelines, encourages the growth of bad reading habits and weakens the group’s credibility. These early reading sessions should include the sonographer. He should be encouraged to teach the physicians what he knows about imaging. If the technologist’s skills and viewpoints are considered unimportant, perhaps the group needs a new technologist. Or perhaps the technologist needs a new group.

Coronary artery distribution is variable, but until documented by the angiogram, every new patient’s coronary architecture is assumed to be as illustrated below. Individual variation and collateralization cannot be accounted for in such schema, nor can they be dealt with in any logical fashion in scoring. The sonographer and the physician must be familiar with the typical coronary territories in each orthographic plane.

Figure 14—1. Coronary artery territories. Note that the borders between areas are not discrete lines. Distributions will overlap and will vary from patient to patient. In some cases, the basal segment of the septum in the PSLA and the basal septal segment of the Ap-4 will be supplied by the RCA.

Scoring and Evaluation Parameters
The terms "inferior" "posterior" and "infero-posterior" and "postero-lateral" are used in slightly different ways by different clinicians. We assign the names in reference to coronary artery territories. We consider the "inferior wall" to be RCA territory and the "posterior," "postero-lateral" and the "lateral" walls to be Cfx territory.
We score each segment’s performance at REST, at PEAK and at IMPOST as:

non-diagnostic
hyperkinetic
normal
mildly hypokinetic
moderately hypokinetic
severely hypokinetic
akinetic
dyskinetic
aneurysmic

Grading the degree of hypokinesia is important to the study of ischemia. Some labs elect to use measurement and scoring packages integrated into their systems, others choose only to identify and describe the walls that show provoked hypokinesia and others may elect to predict the suspected culprit artery: +RCA, +LAD and/or +Cfx. In general, regardless of the scoring schematic chosen, in the final analysis the most that stress echocardiography will allow us is to say is that coronary artery disease is most likely in the LAD, the Cfx, and/or the RCA or coronary artery disease probably is not in the LAD, the LCx, or the RCA. Honing the interpretation any finer is attempting to approach Truth through faith, self-delusion, or, worse yet, an unseemly eagerness to publish. Nevertheless, these predictions can be quite accurate as evidenced by the numbers in the literature.

A normal stress response is considered to be augmentation, or, at least, no decline in contractility. Positive echocardiographic indicators of coronary artery disease are as follows:

1. Resting wall motion abnormality - Interpreting myocardium with resting abnormalities presents a dilemma for the reader. For one, not all resting wall motion abnormalities are due to prior MI or ischemia. Non-ischemic wall motion abnormalities have been reported by others [Robertson 1983; Armstrong 1986]. A thin, scarred site obviously represents prior MI and coronary artery disease in that region, but the difficulty is interpreting areas of hypokinesis. Does that segment augment, stay the same or get worse with exercise? What would that same segment do with dobutamine?

A hypokinetic segment that worsens with exercise is considered to have some viable though ischemic myocardium. An akinetic segment that becomes dyskinetic is considered to be infarcted, and is not entitled to a debate on its perfusion. The problem is fully appreciated only when you attempt to judge the motion of a small discrete area, compromised at rest, in the neighborhood of healthy, hyperdynamic myocardium. The surrounding tissue exerts its peer pressure and pulls the unhealthy regions right along with it. It’s a tough call. (See Sawada 1989.)

2. Exercise-induced reduction in ejection fraction (increased end-systolic volume). The normal response to exercise in young healthy individuals is an increase in ejection fraction. But it has been demonstrated that healthy people over the age of 60 may fail to increase EF and may even show a decrease with exercise [Port 1980]. It should be noted that a drop in ejection fraction is not specific for coronary artery disease; it is also seen in patients with hypertension, aortic stenosis and cardiodmyopathies. Other studies have demonstrated that a peak exercise drop in ejection fraction of more than 5% compared to resting ejection fraction identifies the presence of coronary artery disease [Port 1980; Caldwell 1980]. Limacher [1983] evaluated the utility of stress echo to detect this EF drop. The mean EF of normals increased from 66% at rest to 73% after exercise. In CAD patients the mean resting ejection fraction was 56%, dropping to 53% after exercise. Crawford, Petru, Amon [1984] compared stress echo with radionuclide angiography in identifying CAD by ejection fraction drop. Echo correctly identified 72% of the CAD patients; radionuclide angiography correctly identified only 44% of the patients.

3. Exercise-induced regional wall motion abnormality ("segmental wall motion abnormality" or "SWMA" or "asynergy") This is the most important parameter and is the chief concern of this chapter.

Crouse and Kramer [1991] explained "if resting contraction is normal, the only normal response is a hyperdynamic one: any other response, even if there is some improvement, is abnormal." But in those areas of resting wall motion abnormalities, any improvement predicts freedom from regional coronary insufficiency. The resting abnormality that neither improves or becomes worse has unclear implications. Thus, their criteria for a positive study is a segment (normal at rest) that fails to augment with exercise.

Ryan [1993], using upright bike, defined a normal study as normal wall motion at rest, with all segments demonstrating normal or hyperdynamic wall motion during and after exercise. The development of hyperkinesis was not an absolute requirement of normalcy. Preservation of function was considered a negative test. A positive test required the worsening of segmental contraction. A segment that was slow at rest but did not worsen was not considered ischemic.

Using the PEAK images of Supine bike stress echo, a segment must move worse at exercise than at REST to be scored positive for ischemia..

Some readers score SWMAs as resting, induced or induced with rapid recovery [Presti 1988; Ryan 1993]. Rapid recovery refers to a SWMA that is seen during PEAK but has resolved by the time the IMPOST images are acquired.

The reader must be sensitive to the lack of "thickening" of the myocardium. Walls are frequently seen to move "inward" when, in fact, they are merely being pulled inward by the surrounding normally-contracting myocardium, or appear to move inward because of cardiac motion or respiratory motion.

Look for myocardium that is being pulled or "tugged" at right angles to the direction of normal contraction. In RCA disease, the inferior wall of the Ap-2 may be seen to be tugged toward the apex, moving parallel to the plane of the wall rather than moving toward the center of the chamber. Distal LAD disease often causes the (Ap-2, Ap-4) endocardium to be pulled around the apex like rope over a pulley. LCx disease may cause the lateral wall of the Ap-4 to be pulled upward toward the apex. Often the mid- and basal-lateral wall will not be seen, and only a small segment of the distal lateral wall can be seen to be moving toward the apex, revealing a Cfx lesion. This tugging can also be seen in the PSSA view, the myocardium pulling radially.

The reader must constantly remind himself that this is an exercise in comparison. The PEAK and IMPOST loops are not analyzed in isolation. Each loop is compared to the equivalent REST loop. A segment at PEAK is not called hypokinetic if it moves slowly, but only if it moves slower than it did at REST. If it moves slowly at PEAK but it moved just as slowly at REST, it is not scored as ischemic. If a region is mildly hypokinetic at REST, determine if it becomes moderately or severely hypokinetic at PEAK. If so, it will be scored ischemic.

It is important that the reader simultaneously see all phases of exercise on the screen at the same time. This is critically important to accurate reading because comparing the IMPOST to the PEAK is often nearly as important as comparing the PEAK to the REST.

Consider a study with typical poor imaging and consequent uncertainty about the exact location and behavior of the endocardium, and consider that one of the fuzzy walls seems to become worse with exercise. The reader will feel greater confidence in calling this wall if he sees that at IMPOST it appears to improve or normalize. This will provide the reader increased confidence that the perceived abnormality was not simply a result of a bad cut, cardiac motion or other imaging artifact, but was a real provoked abnormality.

This same confidence is provided in the case of a poorly visualized wall motion abnormality that persists into IMPOST. If another loop acquired 2 or 3 minutes later in FINAL shows normalization of that segment, the reader feels confident that the motion he saw was indeed a persistent provoked abnormality.

It is for this reason that we do not use the LV function and scoring program in our Tom-Tec frame grabber - The program does not permit simultaneous viewing of the REST-PEAK-PEAK-IMPOST format.

Reading Suggestions

ø Do not mistake drop-out for akinesia. You will be tempted. Some areas are especially problematic: Ap-2 basal inferior wall. Ap-4 basal lateral wall. PSLA posterior wall. PSSA lateral wall.

ø Be very cautious reading off-axis imaging. If an imaging cut is off to the side, of an Ap-2 for instance, the side walls can move into view at systole, mimicking contracting endocardium. A hypokinetic inferior wall suddenly looks good. Similarly, a truncated Ap-4 can make a severely hypokinetic apex look normal. In this case it is not the apex that is seen, but an impostor - the distal anterior wall moving in and out of view. If you see the apex moving conspicuously downward with contraction, toward the center of the LV, you probably are not seeing the apex. It just doesn’t move that way.

ø Watch for volume changes. A dilated LV at exercise is an unmistakable announcement of bad news.

ø Do not mistake muscle bands, chords or pericardial reflections for endocardium. In the PSSA a bouncing postero-medial pap muscle can make an akinetic inferior wall look hyperkinetic.

ø Be careful with too proximal PSSA views. The inferior wall here is normally stiff in many patients, even at rest.

ø Verify suspect abnormalities in different imaging planes and in different loops of the same plane. If you cannot see the problem in at least two views, it is probably artifact.

ø Bundle branch blocks can make the septum look hypokinetic or even dyskinetic, but with care, you can identify the mis-timed myocardial thickening.

ø Be careful with pacemakers. The insertion of a pacemaker wire can affect the distal septum’s motion.

ø If the left ventricle becomes globally hypokinetic and the EF falls conspicuously with exercise, consider cardiomyopathy or severe AI.

ø Use the terms "tardikinesia" and "early release" only in well-imaged studies. Readers sometimes describe wall segments as moving in more slowly than is normal. That is, they may thicken, but appear to thicken more slowly or begin to thicken later than neighboring segments. Some refer to this as "tardikinesia." This phenomenon is reported to be more obvious if only the first half of systole is observed by limiting the digital playback loop to the first four frames only. [Feigenbaum 1988]. Similarly, a segment may appear to prematurely cease contracting and return to its diastolic position before its neighbors - "early release," some have termed it. I often question whether these are real phenomenon that can be reliably read in echo. The appearance of tardikinesia is easily and often emulated by imaging artifact. If you wish to call tardikinesia or early release, make sure you are not merely seeing different segments of the endocardium moving in and out of the imaging plane and/or seeing a segment alternately drop-out and drop-in, producing the effect artificially. The basal inferior wall is most famous for this. Such artifacts are easier to identify by the one holding the transducer.

ø Do not mistake poor triggering and improper interim delays for hypo- or hyperkinesia. Failure to capture end systole makes the walls look more hypokinetic than they are, and capturing too much diastole after the end systolic frame makes the walls look more hyperkinetic than they are. (Demonstrate this to yourself!)

ø Do not be in a hurry at this critical time of reading. Take the time to pull the previous studies for comparison. If a reading is equivocal, comparing it to the patient’s previous study can be useful. If the previous study is obviously normal, you may feel more confident in calling today’s "equivocal" study positive. If the two-year old study moves exactly like today’s, you may feel more confidence in calling it negative..

ø Reading the previous study is a good way to determine if you now read the walls the same as you did last year.

ø Very Important: When you receive the angiographic results of a positive study, take the time to pull up those loops and re-examine them. If the cath results confirmed your diagnosis, toot your horn. If the cath was negative, determine how and why you read the echo incorrectly. Without this feedback, you won’t learn. Upon re-reading many of your false-positive cases you will agree with your previous conclusion: "that wall stops moving!" It happens. This is an imperfect technology and an art of broad strokes.

Apparent differences in myocardial contraction should be attributed to the following causes and in this order:

Stone, et. al [1995], recalling that scintigraphy studies suggested that coronary collaterals can protect against the development of stress-induced perfusion abnormalities, studied the effect of collaterals on wall motion in stress echo. They concluded that coronary collaterals can protect against the development of stress-induced wall motion abnormalities despite the presence of a high-grade coronary artery obstruction, and that the lack of a stress-induced wall motion abnormality in a stress echo in the perfusion territory of an obstructed vessel may suggest the presence of adequate collateral perfusion.

Lu, Picano et. al. [1995] attempted to assess the relation between stenosis lesion morphology and dipyridamole stress echocardiographic results. Two groups of patients with proven nonoccluding single-vessel disease, with similar degrees of stenosis (about 60% diameter reduction) were studied. One group had simple coronary lesions and the other had "complex" lesions. An angiographic lesion was considered complex when irregular borders and/or intraluminal lucencies suggestive of ulcer and/or thrombus were present. They reported that those patients with single-vessel disease without coronary occlusion or previous myocardial infarction, coronary lesion morphology of the complex type is associated with a higher dipyridamole stress echocardiographic sensitivity and with a greater prevalence of low-dose, positive responses. Presence of irregular plaque contours, not only plaque geometry, is important in modulating stress responses in the presence of angiographically assessed coronary artery disease.

Parasternal Long Axis
(PSLA)

 The PSLA is conventionally imaged at the fourth intercostal space. But often the only window is at the fifth and rarely at the third intercostal. This view is for scoring the middle and basal segments of the septum of the proximal LAD distribution and the middle and basal posterior wall, usually the circumflex distribution. Occasionally the RCA is seen to serve these posterior segments. See Figure 14 - 1.

While having the septum imaged perpendicular to the beam axis is ideal, the window for this view is not always open. The exact orientation of the long axis of this view is less important than having a good cut showing the widest diameter of the LV at the mid- and basal areas, showing endocardium, and having the REST, PEAK and IMPOST images at the same orientation. The open aorta, the pap muscles, the mitral valve, and the shape of the septum are the interior landmarks to judge similarity of cuts. The sonographer must attempt to "open" the LV as much as possible, especially toward the apex. Any cut outside the plane of center will exaggerate septal and posterior wall motion.

 The myocardial contraction and the endocardial edge of the PSLA’s septum is easily misrepresented by cursory imaging. The septum in the PSLA view is not a smooth-surfaced structure of uniform thickness. Its borders are often camouflaged by trabeculations, by valve apparatus from the right side and by superficial structures from the left side. It is not unusual to see an ectopic chord inserting at the proximal segment of the septum or a muscle band inserting at the mid-septum. These can easily be mistaken for the endocardial edge, making the septum appear thicker than it really is. This irregularity or "two-faced" septum can sometimes be clarified by the PSSA. Bright linear echodensities within the septal myocardium can be mistaken for the endocardial border, making the septum appear more narrow than it is. The sonographer must exercise judgment in these cases. If he can alter the apparent thickness of the septum by altering the image plane, which image does he select to represent REST? The loop with the "thick" septum or the loop with the "thin" one? The problem arises when, for instance, the "thick" septum image is chosen for the REST and the "thin" septum image is chosen for the PEAK. The result is apparent provoked hypokinesia - a false positive call.

Sweep the sector back and forth perpendicular to the image plane. He should image first in the antero-septal region, then sweeping to the anterior and finally into the more antero-lateral zones. Use alternate windows. Acquire loops in each of these planes at REST and at PEAK and then match up complimentary views for comparison.

In older patients, the proximal septum often comes equipped with a "knuckle," a localized hypertrophy that is familiar to all sonographers. Its contractions are difficult to analyze within the context of evaluating wall motion and are probably best ignored. An occasional dissonant sight is the mid- and distal septum moving well, but with this basal segment being akinetic. This may be due to lesion in the first septal perforator, but I have seen two instances of this akinesia resulting from a rotoblator accidentally severing this artery.

 The PSLA posterior wall (circumflex territory), while seldom considered a problem in resting echocardiography, is a difficult segment when attempting to judge wall motion. While the proximal segment (#3) will usually show a faint endocardium, the mid-section curves anteriorly and is frequently dominated by the postero-medial papillary muscle and is obscured by artifact and drop-out. We sometimes must judge its performance reluctantly on "general impression" rather than on the motion of the discreet endocardial edge (a violation of our own rules!)

The papillary muscle is usually located medial enough that with very slight angulation, it can be partially omitted from view, making interpretation easier. This pap muscle is most often a problem when it is out of the plane in the first half of a loop but then barges into view in the last half of the loop. This can fool the reader into thinking a hypodynamic posterior wall is very hyperdynamic. Step through this loop frame at a time to determine if the pap moves in and out of the imaging plane.

Caution is advised in reading the basal segment of the posterior wall, especially when the neighboring mitral annulus is calcified or when the wall is hypertrophied. These conditions depress the motion of that wall segment so take care not to confuse this with ischemia.

All the wall segments of the PSLA are also seen in the Ap-3 ("long-axis"). The posterior wall of the Ap-3, enigmatically, is often much more clearly displayed than in the PSLA. For those using post-treadmill imaging, use either the PSLA or the Ap-3, whichever presents the better view.

Seductively bright chords languishing along the posterior wall without movement can be mistaken for slow endocardium and become the cause of a false positive. Chords strung just below the septum can conceal true septal wall motion: these chords, when moving upward at systole, can present an image that looks like dyskinetic septal endocardium, while, in fact, the very faint (invisible) endocardium is moving downward, normally.

The posterior pericardium is very bright and can often dominate the myocardium of the posterior wall. Adjust the TGCs, dynamic range and/or post-processing to minimize this.

Except in very unusual cases, the apex cannot be seen in the PSLA. Dropping to a lower intercostal or moving laterally may bring it into view. Imaging somewhere in between the PSLA and Ap-3 is perfectly acceptable as long as the PEAK and IMPOST images match the orientation of the REST.

Phasic cardiac swing is less of a problem in the parasternal views, but nevertheless, more stable images are obtained with the patient holding his breath. Most frequently, the PSLA view is best obtained with complete exhalation, but use trial and error to find the best respiratory tactic in each plane at each phase.

"WNL," usually meaning within normal limits, 
may also conveniently substitute for we never looked.

Parasternal Short Axis
(PSSA)

 The parasternal short axis is comprised of the antero-septal and anterior walls (LAD distribution), the lateral, postero-lateral and lateral walls (Cfx distribution) and the inferior and inferior septal walls (RCA distribution). While many workers have praised this view because it allows visualization of all three coronary artery territories, we usually regard this to be the least useful of the views because it is so susceptible to imaging error. With transducer slight-of-hand, this Houdini-view magically can show almost any wall motion abnormality you wish and can make real ones vanish.

Window choice - Choosing too low a window or over-rotating or under-rotating can change the whole PSSA picture. Very commonly the only window that will allow an imaging cut perpendicular to the septum (usually the fourth intercostal) is lost at PEAK exercise so the transducer is necessarily moved to the lower intercostal.

It is still useful to view the long axis from this low window, even if the chamber is tilted with the apex pointing upward on the sector, for the contractility of the posterior and septal walls can still be accurately assessed. But the short axis musty not be obtained from this site. The PSSA must be obtained with the beam path perpendicular to the long axis of the septum or the image will be less than useful — it will be misleading. If the chamber shape is distorted - egg-shaped instead of round - wall motion is equally distorted.

Image in the most superior and medial window that you can find, striving for the image of a round chamber. Be cautioned, however, that not all LVs are round. A pair of large paps can create a keyhole-shaped PSSA. And of course, any infarcted wall can produce an odd shape and motion.

When all other windows fail, the short axis view can be obtained from the subcostal window, but I am seldom completely successful here, especially during pedaling, when belly-bouncing reaches its glory.

If it is impossible to get a round PSSA, even when you are perpendicular to the septum, and it is egg-shaped and leaning toward the anterior septum, look at the apical-4 to see if the septum bulges toward the right side due to a previous infarct. If the inferior wall seems too "loose," perhaps the basal inferior segment of the apical-2 view will reveal an old infarct site.

The PSSA is usually taken at the mid-section of the LV. Attempt to make the cut at the plane of the tips of the pap muscles. Memorize the appearance of the pap muscles and look for this same image during PEAK and IMPOST to duplicate the cut. The PSSA may be imaged more proximally, so that the mitral valve apparatus is in view. At this plane, the basal segments come into view. The basal infero-septal wall will often contract conspicuously less than more distal segments, even in the healthy heart. This plane may be useful in showing a basal inferior infarct zone, usually fed by the RCA (posterior descending coronary artery).

A common PSSA problem is as follows: the REST PSSA images are captured at the level of pap muscle where wall motion appears normal, but it overlooks a basal akinesia in the infero-posterior wall. The PEAK images are then captured not in this same plane, but moving down into the basal akinetic area. Comparing the more distal (normal) REST with the more proximal and akinetic base will read out as provoked wall motion abnormality and ischemia, rather than as a fixed wall motion abnormality.

Rotation - I check my images by rotating from the PSSA to the PSLA with an imaginary M-mode cursor vertically bisecting the image to judge the validity of the PSSA cut. I then rotate back to PSSA, over-rotate and under-rotate to estimate the correct rotational position.

Multiple views - In some poor-imaging patients, one transducer position will not clearly show all the walls. In these instances you may have to acquire a series of PSSA loops - one loop to show the anterior wall, another loop to concentrate on the inferior wall, and a third loop to show the lateral and posterior walls. In those instances when there are no apical views, it may be useful to capture several cuts of the PSSA, ranging from the basal segments to mid-LV to the apex. These short axis views may provide the only information about the other arteries.

Translation - Cardiac motion, also termed translation and displacement refers to the normal cardiac motion. During systole the annulus moves toward the apex and rotates slightly. This is seen in all hearts to some extent, and it is exaggerated in others, particularly in many post CABG patients. The effects of translation take a heavy toll on the PSSA view (particularly when the window is low as described above) because the segments imaged will not be those of the mid-LV throughout systole. As systole progresses and the heart moves apically, the more proximal septal segments come into the plane of the sector. The angled orientation of the septum (especially if it is sigmoid in shape with a "knuckle" of localized septal hypertrophy at the base) greatly exaggerates the apparent anterior wall motion. In such instance, a completely akinetic septum can be made to look like it is contracting vigorously. This is a problem well known to those who carefully look at M-mode scans of this area. Very often a valid M-mode is completely impossible because of this cardiac motion.

• Respiration Control - While complete exhalation is sometimes the best, I usually ask the patient to " . . .breathe in . . . now slowly breathe out until I say stop." At the instant the lateral wall appears out of the fog of the left lung (the right side of the sector) I say "Hold it!" Continued exhalation beyond this point often degrades the image. During PEAK and IMPOST images, it is generally best with total exhalation. I repeat, this is not predictable and every patient, every view, every position at every stage should be expected to be different. Experiment. No matter what techniques are used, the endocardium of the lateral wall (segment #6) is usually very difficult to image.

As described in the PSLA section, muscle bands, chordae and pap muscles can camouflage the endocardial edges. And the diaphanous anterior wall may be so "silent" that a bright line, commonly seen within the more anterior myocardium, may be mistaken for the margin.

It is often a surprise to visitors to our lab that good images are frequently obtained from supine patients. Particularly with obese patients, you may find the best PSSA in the supine position.

Apical Four Chamber
(Ap - 4)

 The Ap-4 view consists of the anterior septal wall and apex (LAD), and the lateral wall (Cfx). The most proximal portion of the septum is considered to be fed by the RCA though this is seldom considered or noticed unless a patient has severe RCA disease or has suffered an RCA infarct. The Ap-4 is usually the most important view for assessing the apex.

It is tempting to choose a high window because it is often prettier, but this sacrifices the apex. It is far more important to have a good cut than to have a pretty image. To image the Ap-4, first get the widest LV, widest RV and show the true apex. The septum usually comes in quite clearly with little help, so put your efforts into visualizing the lateral wall. The antero-lateral pap muscle will often dominate the lateral wall, making the reading difficult, so attempt to eliminate it from the view by a very slight rotation. Obviously, if you rotate too much, you will leave the plane of view, so use judgment. To bring out the basal segment of the lateral wall, it may help to lower the focus. To get the best appreciation of the apical wall motion, set the ROI box to show the entire apex, slightly beyond the pericardium. It is hard to appreciate thickening unless the entire myocardium and pericardium are in view.

Some hearts do not conform to ASE-approved shape. They are curved, or bent. In these instances it will be necessary to include the aorta, in what is technically a "5- chamber" view, in order to include the apex and/or the widest dimensions of the ventricles. You may be required to acquire loops in two planes: one with the apex clearly defined, the other to show the mid- and basal regions. Save several views - some with and some without the aorta.

The basal lateral segment (#14) is one of the most difficult segments in the heart to image. As mentioned above, it may be necessary to save two different cuts of the Ap-4 - one to show the apex and one to show the lateral wall and basal segments, changing windows and focus to optimize each. And remember to also grab these different cuts during PEAK so they can be matched with the "apical" and "basal" REST cuts. Remember: when grabbing the PEAK images, do not merely capture the Ap-4 pattern and go on. You must examine the lateral wall, decide if it is imaged correctly and if it is moving normally. Then continue to the apex. Can you see all of it, clear down to the very tip? Is it moving? Now look at the septum’s images and motion before continuing to the next view.

Septum - There are many rather futile discussions about whether the Ap-4 septum is "anterior" or "inferior" and how or if this changes with the inclusion of the aorta in the view. In stress echo it is never useful to consider the mid- and distal Ap-4 septum to be anything other than LAD territory unless the angiogram demonstrates otherwise.

Atrial fibrillation can cause extremely irregular and often bizarre contraction patterns, expecially in the septum. With a patient in a-fib, digitize many extra heartbeats so that you can choose several that best represent "normal" contraction.

The insertion of a pacemaker wire almost always causes hypokinesia of the distal septum. Make sure you document this in your REST images so that the hypokinesia seen here during PEAK is not mistakenly considered an ischmia- provoked wall abnormality.

Of course LBBB causes unusual septal motion and requires careful consideration.

You may notice in those hearts suffering with an infarct in the RCA territory, that the entire septum in the Ap-4 moves in a peculiar manner. This orthographic plane is cutting through myocardial tissue that is supplied primarily by the LAD, but the contraction is affected by the adjacent akinetic tissue formerly supplied by the now occluded RCA. The result is a contraction that appears irregular or "snakey." Words fail me.

In a CABG heart the septum may move in a jerky, inelegant fashion. Make sure you understand this and ar able to distinguish it from an ischemia- provoked WMA.

Tricuspid regurgitation, if severe enough, can affect septal motion. [D’Arcy, B. and Nanda, N.C.: Two dimensional echocardiographic features of right ventricular infarction. Circulation, 65:167, 1982.]

Apex-Hypertrophy, especially apical hypertrophy, seriously limits apical motion. It is as if the myocardium simply has no room for thickening and consequently looks hypokinetic. Be aware of ectopic chords, trabeculations, and muscle bands near the apex that can obscure or be mistaken for the endocardium. These same chords can be mistaken for or obscure thrombi in a dilated apex.

The apical views are also very dependent upon patient position. Roll the patient far up onto his left side. If this does not improve the image, allow him to return to a more comfortable position. The right arm should rest on the right hip. Holding it up by the head only occasionally improves the images.

If the Ap-4 window shifts too far medial, the Ap-4 image will slant with the apex to the (monitor’s) right. This usually brings in the lateral wall quite nicely, but if the image is tipped too far (apex at 2 o’clock), the walls are no longer reliably readable. They seem to move differently from the same heart imaged with the apex at noon. Try to match the tipped PEAK view with a tipped REST view, and then read it with reservation.

Respiratory Control - Asking the patient to take a deep inhalation may produce a new, clearer window in a more medial position. Ask the patient to breathe in, and quickly search for this transient, elusive window. It may be better to say,

" . . . breathe in, hold it, now slowly breathe out until I ask you to stop."

At some point during exhalation the window may pop in and then, with continued exhalation, just as quickly disappear. The trick is to stop exhalation at the right point. Occasionally this view is best at complete exhalation, particularly at PEAK. And at other times, this view can be obtained only when the patient is actively breathing. For some reason, when these patients hold their breath, they strain . . . or something . . . and the window immediately disappears. Again, I stress the importance of the patient being relaxed. Continually assess the patient for muscle tenseness and encourage relaxation. Some patients attempt to "help" you by holding themselves in a rigid pose. Relax them. Use the Bundle Block support pillow. Talk about the weather. Grandchildren. Pets. Florida. quilting clubs.

Apical Two Chamber
(Ap - 2)

 The Ap-2 is comprised of the anterior wall (LAD territory), and the inferior wall (RCA territory) This view is similar to the standard right anterior oblique angiogram. Remember, the lines drawn between the coronary artery distributions in Figure 14-1 are rather arbitrary. There is variation between patients where, for instance, he Cfx takes over from the LAD near the apex on the inferior wall of the Ap-2.

The Ap-2 and Ap-3 views can be obtained from slightly higher windows than the apical 4 and still show the entire chamber and apex. This view is usually better with a small inhalation. But not always. It is not unusual for a rib shadow or lung smudge to conceal the anterior wall. But a small inhalation will sometimes push the heart medial and the anterior wall pops into view. As with the other cuts, it may be best to allow the patient to breathe normally and while using multi-loop capture, just wait until that clear image flashes by.

If the anterior and inferior walls cannot both be brought into view at the same time, forget the anterior and concentrate on the inferior, for this is the only good view of the RCA distribution. It can be read from good PSSA views, but these are rare. The (normal) anterior wall may often appear to move less dynamically than the antero-septal walls of the Ap-4 and the PSLA.

    The inferior wall of the right ventricle is the "flattest," "straightest" wall in the heart, so attempt to make the image appear that way. If the inferior wall is curved to the left, and if the image of the apex comes to a point, giving the chamber a "dog-toothed" shape, you are off-axis. Try to eliminate the inferior wall’s pap muscle from view, but not at the risk of getting out of plane and getting into the Cfx distribution of the posterior wall. Sometimes the lack of features require you to locate the right cut by finding the plane central to the Ap-4 and the AP-3 — two views with more identifiable landmarks. But I find it safer to begin in the Ap-4,and rotate CCW until the moment the RV leaves the view. Rotating more risks getting into LCx territory.

The basal inferior segment (#3) is more subject to drop-out than any other area. It will be very tempting to call this positive when you see nothing but a black hole there. Be careful.

Earlier workers described their difficulty in accurately distinguishing coronary artery distributions in the posterior/lateral walls and the inferior septum/inferior walls [Armstrong 1987]. Some studies chose to combine these territories and merely read them as the Cfx/RCA region [Sawada, Judson, Ryan 1989]. Because we routinely include the apical three in our imaging protocol, collect images during PEAK, and save multiple views of each plane, we have not noticed this to be such a persistent problem and continue to read and score the two territories separately. Our sensitivity for detecting CAD in the Cfx and in the RCA is 79% and 90% respectively.

RCA Disease - When the proximal portion of the right coronary artery is obstructed, blood flow to the posterior descending coronary artery is decreased, and the inferior wall of the left ventricle is affected. An infarct here would typically show an akinetic wall in the lower left sector of the PSSA, the corresponding wall in the Ap-2 and perhaps in the basal septal segment of the Ap-4. Additionally, this obstruction reduces flow in the right ventricular branches and may result in akinesia in the right ventricle. The right ventricle is not easily visualized, but if the RCA is the vessel of primary concern, attempt to show the right ventricular free wall. Is it akinetic? (In every study, look at the RV free wall at rest. Contraction here is less obvious than in the LV, making provoked hypokinesia less obvious.) Is the RV dilated? Dilatation is more obvious in apical region.

Apical Three Chamber
(Ap - 3)

The Ap-3 chamber, commonly called the "long axis", is theoretically in the same orthographic plane as the PSLA, showing the same walls but from a different vantage point: the antero-septal and apex of LAD territory and the posterior wall of the Cfx distribution. It also provides another important opportunity to look at the apex. The Ap-3 is used to confirm or to cast suspicion upon the judgment levied on the PSLA. Surprisingly, this view, which is typically excluded in most stress echo labs, has proven itself to be of great value and is included as an important component of the Preferred Protocol. In more than half the studies the posterior wall is shown here better than in the PSLA. This appears to violate ultrasound physics as the AP-3 posterior wall is parallel to the beam and may be farther from the probe, but nevertheless, the image is usually better. The septum and the apex also frequently image quite well in this view. 

The postero-medial pap muscle frequently obscures the posterior wall. Often, with a very small rotation, it can be omitted from the view, making the endocardium more readable. The critical landmarks that distinguish the Ap-3 view from the Apical-2 are the aorta and a portion of the RV. Without these landmarks, you may be looking at RCA territory. (It is interesting to note that the Freeland User’s Manual illustrates this Ap-3 view, clearly with Ao and RV and labels it the Apical 2 chamber. Wrong walls. Wrong arteries.) The literature reports that the circumflex distribution is the most difficult to call [Ryan 1993]. One reason proposed for this is that its territory is smaller. This is another argument for including PEAK images that are more likely to reveal this subtle wall motion abnormality that is likely to be disguised by the post exercise rebound. And having this extra view, the Ap-3, provides one more look at the Cfx.

Redbud home | Contact Us
Model 1000 | Model 400 | Model 500
Email: sales@redbudmedical.com Web address: http://www.redbudmedical.com

Content revised: January 24, 2004