(13) Additional Cardiac Examination Techniques

What is the definition of Point-of-Care Ultrasound (POCUS)?

Limited, focused ultrasound performed at the bedside to evaluate acute cardiac symptoms such as chest pain or shortness of breath.

What specific cardiac features are commonly evaluated using POCUS?

Pericardial effusion, LV global function, and LV regional/segmental function.

What is the primary purpose of Exercise Stress Testing with EKG?

To evaluate myocardial ischemia with exercise.

Which patients are offered pharmacologic testing instead of treadmill testing?

Patients who are unable to exercise.

Name three common pharmacologic agents used in stress testing.

Dobutamine, persantine, and adenosine.

List five abnormal findings during a stress EKG.

$ST$ elevation/depression, R-wave changes, chest pain, hypotension, and arrhythmia.

In which scenarios may a Stress EKG be unreliable?

Certain arrhythmias, prior CABG, or a history of MI.

What is the primary use of Stress Echo and how does its sensitivity compare to resting echo?

CAD screening; it is more sensitive than resting echo testing.

How does a Stress Echo assist when resting exams are normal?

It helps avoid unnecessary heart catheterization.

What are the two absolute contraindications for Stress Echo related to acute ischemic events?

Unstable angina or acute myocardial infarction.

What rest blood pressure levels are absolute contraindications for Stress Echo?

Systolic $>200$ or diastolic $>100\,mmHg$.

What rest systolic blood pressure level is a baseline absolute contraindication for hypotension?

Baseline systolic BP $<90\,mmHg$.

Which valvular conditions are absolute contraindications for a Stress Echo?

Severe valvular heart disease or symptomatic moderate-to-severe aortic stenosis.

What LVOT finding in hypertrophic cardiomyopathy is an absolute contraindication for Stress Echo?

A significant LVOT gradient at rest.

Name four relative contraindications for Stress Echo that require physician consultation.

Significant LV dysfunction/borderline hypotension, asymptomatic severe aortic stenosis, $ST$ elevation on resting ECG, and rapid atrial fibrillation.

Why is it important to confirm if beta-blockers were discontinued before a stress test?

To ensure the patient can reach their target heart rate.

When should systemic blood pressure be measured during a stress test?

Supine and standing at rest, and again at the end of each stress stage.

What cuff sizes are used for average and large patients during blood pressure assessment?

$10\,cm$ cuff for average patients and $12\,cm$ cuff for large patients.

Where specifically is the BP cuff placed on the arm?

$2.5\,cm$ above the palpated brachial artery with the bladder centered over the artery.

To what pressure should the BP cuff be inflated?

$20-30\,mmHg$ above the estimated radial pressure.

What is the recommended release rate for blood pressure cuff deflation?

$2-3\,mmHg/sec$.

How are systolic and diastolic pressures defined by Korotkoff sounds?

The first beat is the systolic pressure; the last beat before disappearance is the diastolic pressure.

What causes false high blood pressure readings?

Cuff too small or cuff too loose.

What causes false low blood pressure readings during assessment?

Arm not level with the heart or inaudible arterial pulsations.

How many electrodes are used to create a standard 12-lead EKG?

$10$ electrodes.

Where are arm and leg electrodes moved during an exercise EKG?

To the torso.

List four patient instructions or preparations to improve EKG trace quality.

Relax shoulders, keep legs uncrossed, remove electrical devices, and dry/prepare skin.

What areas should be avoided when placing EKG electrodes?

Bones or high-motion/muscle areas.

Where is the V1 lead placed and which wall does it evaluate?

$4^{th}$ intercostal space, right sternal border; evaluates the Septal wall.

Where is the V2 lead placed and which wall does it evaluate?

$4^{th}$ intercostal space, left sternal border; evaluates the Septal wall.

Where is the V3 lead placed and which wall does it evaluate?

Midway between V2 and V4; evaluates the Anterior wall.

Where is the V4 lead placed and which wall does it evaluate?

$5^{th}$ intercostal space, midclavicular line; evaluates the Anterior wall.

Where is the V5 lead placed and which wall does it evaluate?

Anterior axillary line at the same level as V4; evaluates the Lateral wall.

Where is the V6 lead placed and which wall does it evaluate?

Midaxillary line at the same level as V4/V5; evaluates the Lateral wall.

Where are the RA/LA electrodes placed on the torso during exercise stress testing?

Below the clavicles.

Where are the RL/LL electrodes placed on the torso during exercise stress testing?

Above the iliac crest.

What regions do RL/LL electrodes evaluate as a reference?

Inferior/lateral.

Besides systolic function, what else can Exercise Stress Echo technique assess?

Diastolic dysfunction.

What is the most common protocol used to evaluate LV wall motion changes with exercise?

The Bruce protocol.

Which four resting images are standard for Exercise Stress Echo?

PLAX, PSAX, apical $4$ chamber, and apical $2$ chamber.

In what patient position are resting echo images typically obtained?

Left lateral decubitus.

How often do speed and incline increase during the Bruce protocol?

Every $3$ minutes.

What is the target heart rate percentage for a stress test?

$85-90\%$ of $220$ minus age.

Within what timeframe must post-exercise images be obtained after the treadmill stops?

Within $60$ seconds.

What is the label for post-exercise images in a stress echo study?

IMPOST.

What is the minimum number of cardiac cycles per clip for stress echo?

At least $3$ cardiac cycles.

What happens if images are obtained more than $2$ minutes post-exercise?

The study should be reported as likely nondiagnostic.

What are the four normal echo responses to exercise regarding heart volumes and function?

EDV increases, EF% increases, ESV decreases, and wall motion becomes hyperdynamic.

What does a Wall Motion Score of $1$ indicate?

Normal or hyperdynamic.

What does a Wall Motion Score of $2$ indicate?

Hypokinesis.

What does a Wall Motion Score of $3$ indicate?

Akinesis.

What does a Wall Motion Score of $4$ indicate?

Dyskinesis/aneurysmal.

Which parameters are evaluated during a Diastolic Stress Echo?

E velocity and E-prime at rest and after exercise.

What do you record from multiple windows during the rest portion of a diastolic stress test?

Mitral E, annular E-prime, and TR peak velocity.

If evaluating both systolic and diastolic function, when should Doppler be performed?

After the $2D$ post-exercise images.

Why is the supine bike preferred for diastolic dysfunction evaluation?

It allows imaging during exercise.

What is the starting wattage for a supine bike stress test and how often does it increase?

Starts at $25\,watts$ and increases every $2-3$ minutes.

List four abnormal findings in a diastolic stress echo.

New/worsening regional wall motion abnormality, $E/e-prime > 15$, pulmonary HTN, or new ischemic MR.

What common agents are used to simulate exercise in patients unable to perform physical exercise?

Dobutamine and atropine.

How does dobutamine affect oxygen demand and LV contractility?

It increases oxygen demand and LV contractility.

What is the effect of dobutamine on venous return?

It decreases venous return.

Differentiate the effects of low dose vs. high dose dobutamine.

Low dose improves contractility without tachycardia; higher doses increase systolic pressure and heart rate.

At which four stages are images obtained during a dobutamine stress echo?

Rest, low dose, pre-peak, and peak stress.

What is the typical starting dose and incremental schedule for dobutamine?

$5\,mcg/kg/min$ starting dose, increased every $3$ minutes to $10, 20, 30, \text{ and } 40\,mcg/kg/min$.

When is Atropine typically added to a dobutamine stress echo protocol?

If target HR is not reached with the maximum dobutamine dose.

List the five endpoints for stopping a dobutamine infusion.

$85\%$ max calculated HR; max dose received; wall motion abnormality in $2$ or more adjacent segments; Systolic BP $>200$ or $<100\,mmHg$; Diastolic BP $>120\,mmHg$.

When are the post-infusion images taken after dobutamine is stopped?

About $5$ minutes after the infusion stops.

How does dobutamine help identify hibernating myocardium?

Low dose improves function, whereas higher doses may return segments to a nonfunctional state.

Which arm vein is preferred for IV setup during cardiac procedures?

A vein in the non-dominant arm, specifically the antecubital vein.

Why is the antecubital vein avoided for contrast-enhanced exercise stress echo?

Contrast flow issues can occur if the arm bends during exercise.

What gauge catheter is most commonly used for IV setup in stress echo?

$18\text{-gauge}$ catheter.

At what angle should a catheter be inserted into the skin?

$15-20$ degrees parallel to the skin.

What indicates that the IV needle has successfully entered the vein?

A flashback of blood.

What specific blood pressure data must be reported in a stress echo study?

Baseline BP and BP at maximum stress.

What does Myocardial Strain Imaging/Speckle Tracking evaluate?

Deformation of myocardial segments to assess systolic and diastolic ventricular function.

Why is strain imaging recommended for chemotherapy patients?

To follow those at risk for chemotherapy-related LV systolic dysfunction.

List four conditions besides chemotherapy where strain imaging is helpful.

Amyloidosis, hypertrophic cardiomyopathy, hypertensive heart disease, and severe aortic stenosis.

How is Doppler strain imaging performed technicaly?

Tissue Doppler samples are taken from several sites and the strain rate is calculated.

On what physical phenomenon is speckle tracking based?

Soundwave interference during reflection, which produces bright echoes in the myocardium.

What is the 'kernel' in speckle tracking context?

The tracked region on each frame.

What are the three directions in which strain measures regional function?

Longitudinal, circumferential, and radial.

Which types of strain are normally negative?

Longitudinal and circumferential strain.

Which type of strain is normally positive?

Radial strain.

What is the definition of GLS?

Global Longitudinal Strain: maximal LV myocardial deformation at peak systole averaged over the entire ventricle.

What is the normal range for GLS?

$-17\%$ to $-26\%$.

What does a GLS value less negative than $-17\%$ suggest?

Abnormal systolic function.

What does a positive GLS number indicate?

Paradoxical motion of that wall segment.

What is the normal range for radial strain?

$50-70\%$.

What is the normal range for circumferential strain?

$-21\%$ to $-28\%$.

What is the normal strain rate?

$1.0-1.4/s$.

What are the limitations of $2D$ strain imaging?

Inability to record off-axis $3D$ motion, low frame rate, suboptimal quality, and degraded temporal resolution at high heart rates.

What is the 'amyloidosis pattern' in strain imaging?

GLS may be normal apically with abnormal midventricular and basal levels.

What is the purpose of Myocardial Dyssynchrony Testing?

To evaluate dual-chamber pacer therapy/cardiac resynchronization therapy.

In dyssynchrony testing, what difference in IVCT is considered abnormal?

$>40\,ms$ difference between LVOT and RVOT.

Why is agitated saline contrast only used for right heart evaluation?

The salt solution bubbles are too large to pass through the pulmonary bed to the left heart.

What is the standard mixture for agitated saline contrast?

$9\,mL$ saline and $1\,mL$ air mixed between two syringes.

Which echo view is preferred for suspected septal defect evaluation with saline contrast?

Apical $4$ chamber.

In a PFO/ASD study, when should bubbles appear in the LA after injection?

Within $1-3$ beats.

What does bubble visualization in the LA after $5$ or more beats suggest?

Possible pulmonary AV malformation.

How is a persistent left SVC confirmed with contrast echo?

Inject UEA in the left arm; contrast appears in the coronary sinus before the right heart.