STRESS ECHO FINAL

What is the order of ISCHEMIC CASCADE?

Sequence of events that occurs after the onset of myocardial ischemia

Main echocardiographic sign of ischemia: thickening and focal or global systolic dysfunction

What should we do before doing a stress echo; Name 7 or less findings you should look for?

List 4 things to do a quix check in PLAX and PSAX List 3 things checked in Apicals

Mini Echo: Should be assessed before taking baseline images:

Valvular abnormalities

Indications of HF

HCM or any other obstructive diseases

CAD

EKG abnormalities

Acute PE

Aortic dissection

QUICK CHECK ONLY PLAX and PSAX

Effusion •

Wall thickness •

Function/CAD assessment •

Sweep with color through all valves

Apical

Function

Valvular abnormalities

CW/PW if needed

Whats the Normal VS Abnormal response to Stress

Regional Normal response: Hyperkinesis post exercise compared to rest

Global normal response: Decrease in ESV , Increase in EF (at minimum > 5% increase)

Abnormal stress response:

Regional ischemic response: Reduction in wall motion relative to resting function in the same region or relative to other regions with normal blood supply

Global ischemic response: Increase in EDV and/or increase in ESV and Decrease in EF in LM or multivessel disease

DUKE TREADMILL SCORE Intergrates what 3 things

Functional capacity

Exertional angina

Ischemic changes on ECG

Numerical index used to predict the risk of CAD and future cardiac events based on the stress test results

What does METS stand for and does it mean?

Metabolic Equivalents of Task

mean’s how much harder the body has to work compared to sitting or standing still

How do calcuate the Target HR and what is the % of the Target HR

Maximal heart rate = 220 – age

85% of max HR is target HR

What minimum HR should a sonography student (22 y/o) achieve?

MODIFIED BRUCE PROTOCOL (vs normal?)

Lower initial workload

Fewer stages

Safer for low-tolerance patients

List 2 Limitations to stress echo imaging

Poor imaging windows •

User dependent •

Respiratory interference •

Translational motion •

Acquisition of identical views •

Time post exercise •

Medications (beta blockers)

Wall motion score Index calculation & List the RWMA Scores and what’s a normal WMSI vs abnormal # mean?

Indexed by taking the sum of the segments divided by the total number of segments

1- normal or hyperkinesis •

2 - hypokinesis •

3 - akinesis •

4 - dyskinesis •

5 - aneurysmal

Normal WMSI Less then 1 normal regional function

Abnormal greater then or equal to 1 RWMA are present

DOBUTAMINE STRESS ECHO

Whats the dosage ?

Given starting at 5 mcg/kg/min and increasing at 3-minute intervals • 5,10, 20, 30, 40 mcg/kg/min • Maximum dose 40 mcg/kg/min

Directly stimulates the heart’s beta-1 receptors to increase myocardial contractility and stroke volume → raises cardiac output • Used when a patient is unable to exercise • Most used modality for myocardial viability assessment by stress echo

whats the dosage for For low dose dobutamine

2.5 mcg/kg/min and increasing at 3-minute intervals • 2.5, 5, 7.5, 10 mcg/kg/min • Maximum dose 10-20 mcg/kg/min

ATROPINE dosage ? & Contraindicated in what pt?

• Blocks M2 receptors located on the SA and AV nodes •

Increases HR and improves AV nodal conduction •

Delivered in doses of 0.25 to 0.50 mg at 1-minute intervals •

Contraindicated in patients with glaucoma due to risk of increased intraocular pressure

Reversing Dobutamine Vs Reversing Atropine

For reversing Dobutamine •

Esmolol (0.5 mg/kg over 1 minute) •

Metoprolol (5 mg IV)

For reversing Atropine •

First line reversal is physostigmine (0.5-1.0 mg IV over 1-2 minutes) •

Restores vagal tone and slows the HR

(REVERSAL MEDICATION • Should be used if the patient experiences: • Severe arrythmias • Severe hypotension/ hypertension uncontrolled by other measures • Severe chest pain, dyspnea, or ischemic ST changes • Signs of decompensation or hemodynamic instability)

Whats the advantages and disavantages of using dobutamine Vs Exercise

Exercise Stress Echo vs. Dobutamine Stress Echo

Both tests are used to evaluate myocardial ischemia (reduced blood flow to the heart) by identifying new or worsening regional wall motion abnormalities.

1. Exercise Stress Echocardiography

How it works: The patient exercises on a treadmill or bicycle, which increases heart rate, blood pressure, and myocardial oxygen demand.

Advantages:

• Evaluates the patient's actual exercise capacity and tolerance.

• Assesses symptoms during exercise, such as chest pain and shortness of breath.

• Evaluates heart rate and blood pressure responses to exercise.

• More physiologic because it mimics everyday physical activity.

• Does not require medication to stress the heart.

Disadvantages:

• Patient must be physically capable of exercising.

• Poor exercise tolerance may prevent the patient from reaching an adequate stress level.

• With treadmill testing, images must be obtained quickly after exercise (ideally within 60–90 seconds).

• Heavy breathing and patient movement can make imaging difficult.

• Ischemic wall motion abnormalities may disappear quickly during recovery.

2. Dobutamine Stress Echocardiography

How it works: Dobutamine is administered intravenously to stimulate beta-1 receptors, increasing heart rate and myocardial contractility, which increases myocardial oxygen demand.

Advantages:

• Ideal for patients who cannot exercise adequately.

• Patient remains lying down, allowing easier image acquisition.

• Images can be obtained throughout the different stages of medication infusion.

• Can assess myocardial viability using low-dose dobutamine.

• Can achieve an adequate stress level without physical exercise.

Disadvantages:

• May cause arrhythmias, palpitations, chest discomfort, or blood pressure abnormalities.

• Requires IV access and medication administration.

• Does not evaluate the patient's actual exercise capacity.

• Requires close monitoring throughout the examination.

• Has medication-related contraindications, including certain significant arrhythmias and uncontrolled hypertension.

Diagnostic EKG leads

Anterior infarct- V1-V4 (Anteroseptal- V1 V2, Anterolateral V3 V4)

Lateral infarct- I & AVL V5 & V6

Inferior infarct- II, III, AVF

Serum Cardiac Markers List 4

Molecules that are released into the blood stream due to compromise of a cell membrane

Troponin

Creatine Kinase

Myoglobin

Lactate Dehydrogenase

Troponin- what is it, this is the gold standrad for what? when does it rise and peaks? whats the normal lab values for Troponin I and Troponin T

Protein that regulates interaction between actin and myosin filaments in both cardiac and skeletal muscle •

Gold standard for detecting heart muscle injury •

Rises 2-4 hours after injury, Peaks at 12-24 hours •

Normal Lab value for Troponin I <0.04 ng/mL •

Normal Lab value for Troponin T < 0.01 ng/mL

Creatine Kinase- what is it, helpful in detecting what and why, what are the normal lab values

Enzyme that helps convert ATP to ADP (for muscles to produce energy) •

Less specific than Troponin but still used •

Helpful in detecting reinfarction because it returns to normal faster •

Normal lab value for CK-MB < 5 ng/mL

Myoglobin - what is it, when is it found / detected, what is the normal values for men vs women?

Protein released in the blood stream due to myocardial injury •

Very early marker but not specific to the heart (arises with skeletal muscle damage too) • Detected within the first few hours after the onset of an MI (1-4) •

Normal value for men 20-90 ng/mL •

Normal value for women 12-75 ng/mL

Lactate Dehydronase - what is it and helps in what detection

Enxyme that assists in the conversion of pyruvate and lactate for ATP in anaerobic cellular respiration

Helps in late detection of MI Appears 1-2 days after the onset of MI

Other imaging list a few

Nuclear medicine, Cardiac cath, Nuclear Medicine, Chest X ray, CT , EKG

EKG- Detects heart electrical activity from electrodes on the surface of the skin •

Provides information on: Electrical activity & Heart structure and function

Nuclear Imaging

Evaluate the physiology and function of the heart •

Eval myocardial perfusion • Rest • Exercise •

Pharmacologic stress agents •

Evaluation of resting regional and global function • MUGA= radionuclide imaging

Cardiac cath,

Involves insertion of hollow tubes or catheters under fluoroscopic guidance into peripheral artery or vein • Injection of radiographic contrast agents •

Helps distinguish severity or extent of pathology •

Helps decide appropriate plan for medical, surgical, or interventional purposes

Chest X RAY

Assess cardiac size and location • Assess pulmonary changes • Pulmonary edema • Pulmonary HTN

Advantages • Inexpensive • Portable • Easily repeated and compared Disadvantages • Repeated radiation exposure

CT

Obtain cross sectional images of the heart • Used to evaluate • Aortic dissection (gold standard) • Pericardial effusion • Detect masses or anatomical abnormalities • May be used to eval coronary artery calcification

RIGHT CORONARY ARTERY Branch supply

The 1st branch which the what supplys ?

List 2 node branch

RV marginal branches feeds what walls

what does the PDA supply list 2

Branch supply •

1st branch, Conus: RVOT

SA node branch

AV Node Branch

RV marginal branches: RV free wall •

PDA: RV inferior wall and 1/3 IVS

LAD supplies what list 2 and list 2 septal perforators supplying

Supplies anterolateral myocardium and apex and the septal perforators supplying the anterior 2/3 of the IVS

CIRCUMFLEX feeds what walls list 2

Feeds the lateral and posterolateral walls of the LV

CORONARY DOMINANCE

Most hearts (70%) have right heart dominance which means PDA branches off the RCA •

If PDA arises from both RCA and cx this is co-dominant circulation (20%) •

If PDA arises from the cx this is left dominance (10%

arrythmias when when can reversal happen

Rupture and remodling

Ventricular Reperfusion

• Early reperfusion (15-20 min) may prevent all necrosis & salvage myocardium •

Reperfusion later (3-6 hrs) may salvage some myocardium •

Myocardial infarct progressive (endo-epicardium) •

Not all regions myocardium equally ischemic •

Reperfusion after 6 hours may not decrease size of infarct: may prevent infarct expansion

Cornoary anatomy and ecg leads

Go study the the different Drugs SLides know the names and what they do and examples of the drug names and study the powerpoint given class sent through email