Acute Coronary Syndromes (Myocardial Ischemia and Infarction)

7/29/2019 Acute Coronary Syndromes (Myocardial Ischemia and Infarction)

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MI 1

Acute Coronary Syndromes


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Objectives Identify patients with acute coronary syndromes

Outline acute management of unstable angina,

non-Q wave and Q-wave myocardial infarction

Identify patients who are candidates forrevascularization interventions

Recognize high-risk patients and early

complications of myocardial infarction

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Acute Coronary Syndromes Overlapping clinical conditions

Unstable angina

Non-Q-wave myocardial infarction (MI)

Q-wave (ST-segment elevation) myocardialinfarction

Variable degrees of coronary artery occlusion

Process of inflammation, platelet activation/

aggregation, thrombus formation, microembolization

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Chest Pain Algorithm

Patient with chest pain

History, physical examination, ECG, chest radiograph

MI with ST-segment elevation present? Yes To MI algorithmNo

Unstable angina presentNo

Consider alternative evaluation


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Unstable Angina and Non-Q-

Wave Myocardial Infarction Evaluation and management similar

Preliminary diagnosis

Clinical symptomsRisk factors

Electrocardiogram

Cardiac enzymes Assess short-term risks


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Unstable angina presentAdmit, monitor ECG, O2

Aspirin

Sublingual or spray nitroglycerin

Intravenous nitroglycerinHeparin (unfractionated, low molecular weight)-blocker

GP IIb/IIIa inhibitor (high-risk patients)Symptoms relieved? Yes Elective evaluation

No (next slide)


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Symptoms relieved?No

Adjust dose of nitroglycerin, -blockerConsider calcium channel blocker

Symptoms relieved? Yes Elective evaluationNo

Emergency consultation/transfer


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Cautions

Nitroglycerin

Avoid decrease in blood pressure 10% Adjust unfractionated heparin infusion

-blocker contraindications Heart rate < 60 beats/min Moderate-severe heart failure

Atrioventricular block > first degree

Systolic blood pressure < 100 mm Hg

Peripheral hypoperfusion

Bronchospastic disease


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Q-Wave (ST-segment elevation)

Myocardial Infarction

Occlusion of coronary artery by thrombus

Progression of necrosis with time

DiagnosisClinical symptoms

Electrocardiogram

Cardiac enzymes


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Admit, O2Aspirin

Sublingual, spray and/or iv nitroglycerin

Morphine

Heparin (unfractionated, low molecular weight)-blockerCandidate for thrombolytic?

NoEmergency consultation/transfer for primary PTCA




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Definite Indications for

Thrombolytic Therapy

Consistent Clinical Syndrome

Chest pain, new arrhythmia, unexplained

hypotension or pulmonary edema

Diagnostic ECG

ST elevation 1 mm in 2 contiguousleads or new left bundle-branch block

Less than 12 hours since onset of pain


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Relative Indications for


Consistent Clinical Syndrome

Chest pain, new arrhythmia, unexplained

hypotension or pulmonary edema

Nondiagnostic ECG

Left bundle-branch block of unknown

duration


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Absolute Contraindications for

Thrombolytic Therapy History of hemorrhagic stroke

Stroke or CVA within 1 year

Allergy to the agent

Surgery or trauma in past 2 wks

Known intracranial neoplasm

Suspected aortic dissection

Active internal bleeding(except menstruation)


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Relative Contraindications for


Severe uncontrolled hypertension

(>180/110 mm Hg)

History of chronic severe hypertension

CVA or intracerebral pathology > 1 yr ago

Current anticoagulant use

Recent trauma (within 2-4 weeks)

Allergy or prior exposure to streptokinase


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Relative Contraindications for

Thrombolytic Therapy Active peptic ulcer disease

Significant hepatic dysfunction

Recent (2-4 weeks) internal bleeding

Bleeding diathesis

Noncompressible arterial or central

venous puncture

Pregnancy


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Candidate for thrombolytic? No Emergency consultation/transferYes for primary PTCA

Thrombolytic agent givenComplications of MI Yes Emergency consultation/transfer

NoElective evaluation


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Continuing Therapy Heparin infusion after thrombolysis

(except after streptokinase)

Aspirin daily

Nitroglycerin for 24- 48 hours -blocker unless contraindicated Angiotensin-converting enzyme (ACE)

inhibitor within first 24 hours

Cardiology consultation and/or transfer


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Complications of Myocardial

Infarction Heart failure: Systolic BP >100 mm Hg

Vasodilators

Nitroglycerin

Nitroprusside

Inotropes

Dobutamine

Milrinone

Loop diuretics


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Heart failure: Systolic BP < 90 mm Hg

Vasopressors initially

Norepinephrine Dopamine

Inotropes when BP stable

Consider PTCA or intra-aortic balloon pump

Cardiology consultation


Infarction


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Infarction Recurrent ischemia or infarction

Follow unstable angina algorithm

Cardiology consultation

Consider repeat thrombolysis with

non-streptokinase agent

Angioplasty or bypass


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Infarction

Arrhythmias

Prophylactic drugs notrecommended

Follow ACLS guidelines


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Perioperative Myocardial

Infarction

Peak occurrence on third postoperative day

May be painless or other pain may

obscure diagnosis New or worsening arrhythmias

Pulmonary edema

Thrombolysis may be contraindicated

Consider primary PTCA


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Key Points

Acute Coronary Syndromes (Myocardial Ischemia and Infarction)

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