Transcript What Does This 12-Lead ECG Show?

Case 6
Acute Coronary
Syndromes
© 2001 American Heart Association
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Learning Objectives
At the end of Case 6 be able to
 Define acute coronary syndromes
 Use the Ischemic Chest Pain Algorithm
 Consider the Why? (actions), When? (indications),
How? (dose), and Watch Out! (precautions) of
medications for ischemic chest pain patients
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Learning Objectives (cont’d)
At the end of Case 6 be able to
 Recognize significant ST-segment changes
 Know how to measure ST-segment elevation
and depression
 Know basic principles of anatomic localization of
infarct, injury, and ischemia
 Know how to use the ECG to risk-stratify patients
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Case 1
A 55-year-old man presents with a chief complaint
of severe (10 of 10) substernal chest pain. He has
pain radiating down his left arm and up into his jaw,
nausea, and a profound sense of impending doom.
He is covered with small beads of sweat.
Vital signs: TEMP = 37.2°C; HR = 110 bpm;
BP = 150/100 mm Hg; RESP = 12
Describe your immediate assessment.
Describe your immediate general treatment.
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Ischemic Chest Pain Algorithm
Chest pain
suggestive of ischemia
Immediate assessment (<10 minutes)
• Measure vital signs (automatic/standard BP cuff)
• Measure oxygen saturation
• Obtain IV access
• Obtain 12-lead ECG (physician reviews)
• Perform brief, targeted history and physical exam;
focus on eligibility for fibrinolytic therapy
• Obtain initial serum cardiac marker levels
• Evaluate initial electrolyte and coagulation studies
• Request, review portable chest x-ray (<30 minutes)
Immediate general treatment
• Oxygen at 4 L/min
• Aspirin 160 to 325 mg
• Nitroglycerin SL or spray
• Morphine IV (if pain not relieved with
nitroglycerin)
Memory aid: “MONA” greets
all patients (Morphine, Oxygen,
Nitroglycerin, Aspirin)
EMS personnel can
perform immediate
assessment and treatment (“MONA”),
including initial 12-lead
ECG and review for
fibrinolytic therapy
indications and
contraindications.
Assess initial 12-lead ECG
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Items of Immediate Assessment (<10 min)
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Check vital signs with automatic or standard BP cuff
Determine oxygen saturation
Obtain IV access
Obtain 12-lead ECG
Obtain a brief, targeted history and perform a physical
examination; use checklist (yes-no); focus on eligibility
for fibrinolytic therapy
 Obtain blood sample for initial cardiac marker levels
 Initiate electrolyte and coagulation studies
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Immediate General Treatment
 Oxygen at 4 L/min
 Aspirin 160 to 325 mg
 Nitroglycerin SL or spray
 Morphine IV (if pain not relieved
with nitroglycerin)
Review the Why? (actions), When? (indications), How?
(dose), and Watch Out! (precautions) of these medications
to consider in patients with ischemic chest pain.
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Medications Used in ACLS
 Why? (Actions)
 When? (Indications)
 How? (Dose)
 Watch Out! (Precautions)
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Oxygen Used in
Acute Coronary Syndromes
Why?
 Increases supply of oxygen to ischemic tissue
When?
 Always when AMI is suspected
How?
 Start with nasal cannula at 4 L/min
 Remember one word: oxygen-IV-monitor
Watch Out!
 Rarely COPD patients with hypoxic
ventilatory drive will hypoventilate
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Nitroglycerin: Actions
 Decreases pain of ischemia
 Increases venous dilation
 Decreases venous blood return to heart
 Decreases preload and cardiac
oxygen consumption
 Dilates coronary arteries
 Increases cardiac collateral flow
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Nitroglycerin: Indications
 Class I: First 24 to 48 hours in patients with
ST-segment elevation or depression including
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•
LV failure (acute pulmonary edema or CHF)
Elevated BP (especially with signs of LV failure)
Large anterior infarction
Persistent ischemia
 Suspected ischemic chest pain
 Unstable angina (change in angina pattern)
 Acute pulmonary edema (if BP >90 mm Hg systolic)
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Nitroglycerin: Dose
 Sublingual: 0.3 to 0.4 mg; repeat every 5 minutes
 Spray inhaler: 2 metered doses at 5-minute intervals
 IV infusion: 12.5 to 25 g bolus, 10 to 20 g/min
infusion, titrated
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Nitroglycerin: Precautions
 Use extreme caution if systolic BP <90 mm Hg
 Use extreme caution in RV infarction
– Suspect RV infarction with inferior ST changes
 Limit BP drop to 10% if patient is normotensive
 Limit BP drop to 30% if patient is hypertensive
 Watch for headache, drop in BP, syncope,
tachycardia
 Tell patient to sit or lie down during administration
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Morphine Sulfate:
Actions, Indications
 Why? (Actions)
• To reduce pain of ischemia
• To reduce anxiety
• To reduce extension of ischemia by reducing
oxygen demands
 When? (Indications)
• Continuing pain
• Evidence of vascular congestion (acute pulmonary edema)
• Systolic blood pressure >90 mm Hg
• No hypovolemia
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Morphine Sulfate:
Dose, Precautions
 How? (Dose)
• 2 to 4 mg titrated to effect
• Goal: Eliminate pain
 Watch out for (Precautions)
• Drop in blood pressure, especially in patients with
– Volume depletion
– Increased systemic resistance
– RV infarction
• Depression of ventilation
• Nausea and vomiting (common)
• Bradycardia
• Itching and bronchospasm (uncommon)
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Aspirin: Actions
 Why? (Actions)
• Blocks formation of thromboxane A2
(thromboxane A2 causes platelets to aggregate and
arteries to constrict)
 These actions will reduce
• Overall mortality from AMI
• Nonfatal reinfarction
• Nonfatal stroke
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Aspirin:
Indications, Dose, Precautions
 When? (Indications) As soon as possible!
• Standard therapy for all patients with new pain suggestive
of AMI
• Give within minutes of arrival
 How? (Dose) 160- to 325-mg tablet taken as soon as possible
 Watch Out! (Precautions)
• Relatively contraindicated in patients with active peptic ulcer
disease or asthma
• Contraindicated in patients with known aspirin hypersensitivity
• Bleeding disorders
• Severe hepatic disease
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Assess Initial 12-Lead
ECG Findings
• ST elevation or new or
presumably new LBBB:
strongly suspicious for
injury
• ST-elevation AMI
• ST depression or dynamic
T-wave inversion:
strongly suspicious
for ischemia
• High-risk unstable angina/
non–ST-elevation AMI
• Nondiagnostic ECG:
absence of changes
in ST segment or
T waves
• Intermediate/low-risk
unstable angina
Classify patients with acute ischemic chest pain into
1 of the 3 groups above within 10 minutes of arrival.
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Recognition of AMI
 Know what to look for—
• ST elevation >1 mm
• 3 contiguous leads
 Know where to look
• Refer to 2000 ECC
Handbook
J point plus
0.04 second
PR baseline
ST-segment deviation
= 4.5 mm
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How to Measure
ST-Segment Deviation
J point plus
0.04 second
PR baseline
ST-segment deviation
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12-Lead ECG Variations
in AMI and Angina
Baseline
Ischemia—tall or inverted T wave (infarct),
ST segment may be depressed (angina)
Injury—elevated ST segment, T wave may invert
Infarction (Acute)—abnormal Q wave,
ST segment may be elevated and T wave
may be inverted
Infarction (Age Unknown)—abnormal Q wave,
ST segment and T wave returned to normal
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AMI Localization
I lateral
aVR
V1 septal
V4 anterior
II inferior
aVL lateral
V2 septal
V5 lateral
III inferior
aVF inferior
V3 anterior
V6 lateral
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Anterior Septal AMI
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ß-Blockers
 Mechanism of action
• Blocks catecholamines from binding to
ß-adrenergic receptors
• Reduces HR, BP, myocardial contractility
• Decreases AV nodal conduction
• Decreases incidence of primary VF
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ß-Blockers
Absolute
Contraindications
 Severe CHF/PE
 SBP <100 mm Hg
 Acute asthma
(bronchospasm)
 2nd- or 3rd-degree
AV block
Cautions
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Mild/moderate CHF
HR <60 bpm
History of asthma
IDDM
Severe peripheral
vascular disease
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Heparin
 Mechanism of action
• Indirect thrombin inhibitor (with AT III)
 Indications
• PTCA or CABG
• With fibrin-specific lytics
• High risk for systemic emboli
– Conditions with high risk for systemic emboli,
such as large anterior MI, atrial
fibrillation, or LV thrombus
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ACE Inhibitors
 Mechanism of action
• Reduces BP by inhibiting angiotensin-converting
enzyme (ACE)
• Alters post-AMI LV remodeling by inhibiting
tissue ACE
• Lowers peripheral vascular resistance
by vasodilatation
• Reduces mortality and CHF from AMI
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Fibrinolytic Therapy
 Breaks up the fibrin network that binds clots together
 Indications: ST elevation >1 mm in 2 or more contiguous
leads or new LBBB or new BBB that obscures ST
• Time of symptom onset must be <12 hours
• Caution: fibrinolytics can cause death from brain
hemorrhage
 Agents differ in their mechanism of action, ease of preparation
and administration; cost; need for heparin
 5 agents currently available: alteplase (tPA, Activase),
anistreplase (Eminase), reteplase (Retavase), streptokinase
(Streptase), tenecteplase (TNKase)
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Antiplatelet Agents
 Blocks glycoprotein IIb/IIIa receptors on platelets
 Blocked receptors cannot attach to fibrinogen
 Fibrinogen cannot aggregate platelets to platelets
 Indications: ACS with NO ST-segment elevation:
• Non–Q-wave MI
• Unstable angina managed medically
• UA undergoing PCI
 Examples: abciximab (ReoPro), eptifibitide (Integrilin),
tirofiban (Aggrastat)
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Percutaneous Transluminal
Coronary Angioplasty
 Direct treatment
 Mechanical reperfusion
of infarct-related
coronary artery
 Best outcome achieved for
patients with AMI plus
cardiogenic shock
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What Does This 12-Lead ECG Show?
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What Does This 12-Lead ECG Show?
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