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| What are the Frontal Leads? |
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Definition
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| What are the six precordial leads "chest leads"? |
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| The leads which have the “best view” of the septum are leads... |
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| The criteria for normal septal Q waves are: |
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Definition
• ≤ .04 seconds wide (one small ECG box)
• ≤ 25% the height of the R wave
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| An abnormal Q wave has the following criteria: |
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Definition
• ≥ .04 seconds wide
• ≥ 25% the height of the R wave
• Permanent (do not go away) on the ECG recording
Abnormal Q waves are an indication that the heart has been damaged and cannot conduct normally. Abnormal Q waves reflect that there has been a loss of electrical activity resulting from damaged myocardial tissue. Abnormal Q waves are a permanent marker of damage and never go away. Abnormal Qs can be found in any of the 12 leads. Generally speaking, the larger the number of leads with abnormal Qs, the greater the amount of heart damage!
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| More information about Q waves: |
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Definition
| Abnormal Qs are wider and deeper than the normal “petite” Q wave. Abnormal Q waves tell the story that at some time in the past, this person has experienced heart damage and as a result, there is a loss of electrical conduction (due to old tissue damage). These Q waves are permanent and typically do not go away with time. |
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| There should be an R wave in each of the 12 leads except in lead ___. Normal R waves become progressively higher in amplitude from___ then stabilize or gradually become smaller again through____ |
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Definition
| aVR.: V1 through V4: V6. Some people call this “Normal R Wave Progression.” |
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| The J-point is located at the end of the QRS where the ___ begins |
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Definition
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Step 1: Examine all 12 leads closely with exception of aVR. The aVR lead is not useful in the detection of ischemia, injury, or infartction. You
Step 2: Q waves should be < or = .04 seconds and < = 25% the height of the R waves. These normal septal q waves are typically seen best in leads I aVL, and V6. Circle all Q waves which do not meet this criteria. |
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Definition
Step 3: Go on an “R wave search”
•11 out of the 12 leads should have an “R wave.” The only lead which does not have an R wave is aVR. Some leads have tiny R waves… for example in V1, the R wave is very small, but if there is an upright deflection after the PR interval, so we call it an R wave. Circle all leads which do not have an R wave, as this would be abnormal
Step 4: Examine the ST segment… does it live on the isoelectric line?
•With the exception of V1, all eleven leads should have the ST segment begin and end on the isoelectric baseline. Mark any leads that have a ST segment that does not begin and end on the isoelectric line.
Step 5: Examine the T wave… |
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| Ischemia (lack of oxygenation to the heart but no damage yet) may present on the EKG as ____, and _____. |
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Definition
ST inversion (depression), T-wave inversion.
In ischemia, no damage is actually done to the heart, so you will not have cardiac enzymes if you are able to reverse the ischemia in time before actual damage(infarction) occurs. |
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Term
| Case Scenerio 1Your patient is experiencing midsternal chest pressure; an eight (8) on a scale of 0-10. Per your unit standing protocol, you obtain a 12 lead ECG. You note that several of the T waves are inverted on this ECG tracing. You ask the patient to remain supine; apply oxygen at 2 liters per nasal cannula, attach a cardiac monitor, and obtain IV access. You are thinking to yourself, “How can I decrease oxygen demands and increase oxygen supply to my patient? |
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Definition
| The healthcare provider orders nitroglycerine (NTG) .4mg sublingual and this“makes sense” as you know NTG dilates coronary arteries and increases myocardial oxygen delivery. The patient’s blood pressure is 146/90, so you proceed with administering the nitroglycerine. A few minutes later, the patient’s chest pain is gone and blood pressure is stable. You obtain a second, follow- up 12 lead ECG. The T waves have returned to their upright, normal position. This is an example of ischemia… not a MI, but clearly a warning sign. If the ischemia is not resolved, it can progress into an acute MI |
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Scenario Two:Your patient has left your unit to undergo a diagnostic stress test on a treadmill. After increasing the speed and incline on the treadmill, the technician, nurse, and MD note new ST segment depression and T wave inversion on the concurrent 12 lead ECG recording. The treadmill is immediately stopped. The patient rests and oxygen is applied. The abnormal ST-T waves return upright to the normal position. This is obviously an abnormal treadmill stress and this person will likely need ?
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Definition
| a coronary angiogram (cardiac catheterization) to determine the extent of predicted coronary artery disease. This patient may ultimately need a percutaneous coronary intervention (angioplasty/stent type of procedure) or may need coronary artery bypass grafting surgery (CABG). |
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| Acute myocardial injury is characterized by ST segment elevation due to acute damage of myocardial tissues. The formal name for this type of heart damage is called “ST Elevation Myocardial Infarction” or STEMI. |
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Definition
| With myocardial injury, the greater the number of leads with ST elevation, the larger the infarct size. With acute ST elevation, myocardial tissue destruction is occurring right before your very eyes!! You need to get very excited!! Again, think about your principles of oxygen supply and demand. How can you decrease demand and increase supply? |
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| For MI immediate treatment typically includes? |
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Definition
| Morphine 2 – 4 mg IV repeated at 5- to 15-minute intervals until pain is relieved Oxygen Nitroglycerin patients with ongoing ischemic discomfort should receive sublingual nitroglycerin (0.4 mg) every 5 minutes for a total of 3 doses, after which an assessment should be made about the need for intravenous nitroglycerin. Most physicians prefer nurses to begin treating chest pain with nitro. If unrelieved after 3 doses, most hospital units have protocols to progress to treating the pain with morphine sulfate AspirinThe initial dose should be 162 mg which is more effective than the dose of 325 mg. |
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| In addition to MONA, evidence based practice shows there is great benefit from adding a ____________. |
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Definition
Beta Blocker.If not contraindicated (low b/p or heart rate), immediate beta-blocker therapy appears to reduce the magnitude of infarction and reduces life threatening ventricular tachyarrhythmias.-----Additional treatment includes continuous ECG monitoring, ST-segment monitoring (if available) and rest. Stay in close communication with your patient’s MD.
The MD will consider the appropriateness of:
• Percutaneous coronary intervention (i.e. angioplasty/stent insertion) versus
• Systemic thrombolytic treatment versus
• Medical management (i.e. Heparin, nitroglycerine drip, beta blocker therapy).
If the acute injury is not stopped, the patient will have an acute STEMI as evidenced by acute ECG changes and positive cardiac lab markers. |
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| the best way to assess cardiac function (and damaged areas) is with a ______. |
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Definition
| two- dimensional echocardiogram (2 D-Echo). |
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Term
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Definition
- AV node in 90% of the population
- the Bundle of His
- SA node in 55% of people.
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Term
The Right Coronary Artery
supplies blood to |
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Definition
1 Right atrium 2 Right ventricle 3 SA Node in 55% of population 4 AV Node in 90% of population.
5 Posterior wall in 90% of population (described as “right dominant”. 6RCA feeds into the PDA (posterior descending artery) in 85% of population. PDA feeds inferior wall. |
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| Inferior Wall MIs related to RCA occlusion is seen in which leads? |
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Definition
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| Potential clinical complications of RCA occlusion with resulting inferior wall STEMI include: |
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Definition
| 1.Sinus node disturbances: watch for sinus bradycardia, sinus arrest, and sinus exit blocks. 2.AV block: parasympathetic hyperactivity is common with IWMI so watch for first, second (usually Mobitz I), third degree conduction delays or “blocks” that may occur within hours or up through the first two days. AV conduction disturbances occur two to three times more frequently in inferior infarctions compared with anterior infarctions. Patients with second or third degree AV block have higher mortality rates. |
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| Potential clinical complications of RCA occlusion with resulting inferior wall STEMI include (continued): RCA Occlusion: Suspect RV damage: The RCA also supplies the blood to the right ventricle (RV) in many individuals. Approximately 1/3 of all inferior wall MI patients also have damage to the RV. Early detection of RV infarction is important because therapy for right-sided HF is very different from therapy for LVI. RV failure is usually treated with volume loading versus left VF which is treated with preload reduction (i.e. diuretics, afterload reducing drugs). |
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Definition
| RV infarction can be diagnosed with the ECG by using three leads placed on the right side of the chest or “right precordial leads,” V4R, V5R, V6R, creating a 15 lead ECG. Many experts feel patients with inferior wall MIs should routinely receive right precordial lead monitoring with ECGs to detect potential RV infarction. The 15 lead ECG tracing is the standard of care at many hospitals. Other facilities may use 2-D echocardiograms to assess RV function. |
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| In an inferior STEMI which lead do you want to look at for optimal viewing of potential heart blocks? |
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Definition
| Monitor in Lead II; a good lead to assess for “P waves” for optimal viewing of potential heart blocks. |
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Term
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Definition
| 1. Anterior wall LV 2. Interventricular septum 3. Right Bundle Branch 4. Anterior devision of Left Bundle Branch 5.Papillary muscles to mitral valve |
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| Anterior wall damage is evidenced by abnormal ST segment elevation, followed by development of abnormal Q waves in leads __ |
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Definition
| V1 through V4 (or possibly just V2, V3 and V4) |
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Term
| The prognosis of patients with anterior wall MI (AWMI) is significantly worse than patients with inferior wall MI. Anterior MI is associated with more myocardial damage than inferior infarction; this damage affects LV function, a major determinant in prognostic outcome after acute MI. An infarction involving 40% or more of left ventricular myocardium is generally associated with cardiogenic shock. |
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Definition
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| Clinical complications of left coronary artery occlusion include (1 of 3): |
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Definition
| Pump disturbances: weak cardiac output, low B/P, weaker pulses, lower urinary output which may lead to CHF. Unless the infarction is massive, signs and symptoms of CHF generally do not occur until a few days after the infarction. However, acute pulmonary edema may occur within the first few hours. Despite advances in medical technology, cardiogenic shock continues to have a high mortality rate. |
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Clinical complications of left coronary artery occlusion include (2 of 3):
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Definition
| Arrhythmias: sinus tachycardia (compensatory mechanism for lower cardiac output), PVCs (which might progress to Ventricular Tachycardia), PACs, Mobitz II heart block. |
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Term
Clinical complications of left coronary artery occlusion include (3 of 3):
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Definition
| BBB: New bundle branch blocks: either right or left BBB may result from occlusion to the LAD. You may also know this ECG abnormality as an intraventricular conduction delay (IVCD). When one of the two bundle branches in not conducting normally, the QRS is widened. If you are the first person to identify the widened QRS, please notify the MD. If this problem worsens, your patient may need a pacemaker. |
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Medical and Nursing Management for acute
Anterior Wall STEMI
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Definition
| Similar to the inferior wall MI patient, the nurse must collaborate with the MD for candidacy for thrombolytic therapy or PCI. Assess for signs and symptoms of right heart failure, left heart failure or biventricular failure. A third heart sound (S3) is more common in patients with an anterior wall MI than with other types of MIs. In patients with a third heart sound during the acute phase of infarction, the mortality is 40%, as compared with 15% in patients without a third heart sound. |
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| In an anterior MI montior lead ___, because ____. |
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Definition
| Monitor in the V1 lead. This lead will help you differentiate SVT versus VT (should they be having lots of ventricular arrhythmias). Patients with AWMIs might also lose blood flow to the Right Bundle Branch (supplied by the LAD coronary artery) and could develop a new RBBB. You can only diagnose a RBBB in leads V1 and V6, thus another good reason to use V1 as your bedside lead! |
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L Circumflex (LCx) supplies blood to:
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• Lateral wall LV
•Posterior wall LV (10% of population described as "left dominant")
•SA Node in 45% of the population |
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| What are the features on the 12 lead EKG and labs for Non-STEMI? |
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Definition
Regional or Global ST segment depression and/or T wave inversion
No abnormal Q waves
No loss of R wave voltage
Elevated cardiac marker labs (CK-MB, Troponin I) |
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| Treatment priorities for Non-Stemi: |
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Definition
| Antiplatlet, anticoagulate (heparin), Administer a platelet glycoprotein (GP) IIb-IIIa antagonist (in addition to heparin and aspirin). Examples of these drugs are: Abciximab (ReoPro), Eptifibatide (Integrilin) and Tirofiban (Aggrestat), send to cardiac cath within 24 to 48 hours. |
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