-Myocardial Infar

8/8/2019 -Myocardial Infar

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Presentation onPresentation on

myocardial infarctionmyocardial infarction

ByBy-- Dr.Vinay VatsayanDr.Vinay Vatsayan


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Presenting Symptoms of Acute

MI Pain-

*typical-crushing substernal chest pain

*atypical - jaw, neck, shoulder, back pain,

indigestion*painless - silent

Dyspnea-

systolic and/or diastolic dysfunction

Dizziness-hypotension, arrhythmia

Nausea, vomiting

Elderly patients: Failure to thrive

Anxiety, restlessness, sense of impending doom


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Presenting Signs in Acute MI

Appearance: Pallor, diaphoretic, anxious

Vital Signs: Normal or abnormal BP and P

Hypertension and tachycardia: SNS

Hypotension and tachycardia:

Cardiogenic shock

Myocardial rupture

Tachyarrhythmia

Hypotension and bradycardia

vagal stimulation

Bradyarhythmia


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Presenting Signs in Acute MI

(Cont.)

Lungs: Rales - CHF

Heart: Displaced LV impulse

S3

S4

Murmur of mitral regurgitation

Murmur of ventricular septal

rupture

Pericardial rub


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Evolution of ECG changes in acute MI


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Cardiac enzymes


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Natural History of Acute

Myocardial Infarction Death-

Arrhythmia: VT/VF

Asystole Myocardial rupture

Cardiogenic shock

ChronicHeart Disease -

LV dysfunction - remodeling

Papillary muscle dysfunction: MR

RV dysfunction


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Natural History of Acute

Myocardial Infarction, (Cont.)

Stabilizationpcompensated LV

dysfunction Post-infarction angina/ischemia

(spontaneous or induced)

Recurrent MI Post-infarction ventricular

tachycardia


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Treatment of Acute Myocardial

Infarction: Acute Phase Prevent/resuscitate from sudden

death: monitor, admit to CCU

Re-establish coronary flow

Thrombolytic therapy

Primary infarct angioplasty/stent


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Major Contraindications To the Use of

Thrombolytic Therapy

Any previous history of hemorrhagic stroke

History of stroke, dementia, or central nervous system

damage within 1 year

Head trauma or brain surgery within 6 months Known intracranial neoplasm

Suspected aortic dissection

Internal bleeding within 6 weeks

Active bleeding or known bleeding disorder

Major surgery, trauma, or bleeding within 6 weeks

Traumatic cardiopulmonary resuscitation within 3

weeks


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Treatment of acute MI:

acute phase (cont.) Decrease myocardial oxygen demand

Pain relief/anxiolytics (Morphine sulfate)

SlowH

R, control BP (beta blockers) Increase myocardial oxygen supply

Oxygen

Prevent platelet aggregation/coronarythrombus (aspirin, IIbIIIa inhibitors,

clopidigrel/heparin) Prevent spasm (nitrates)

Augment collateral flow (nitrates)


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Infarction: Acute Phase (C

ont.)

Stabilize plaques, restore endothelialfunction

?HMGCoA reductase inhibitors (statins)

Prevent ventricular remodeling

ACE inhibitors

Prevent mural thrombus/embolization

Heparin

Coumadin for patients at high risk forthrombus (anterior wall akinesis).


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Infarction - Intermediate Phase Monitor/treat arrhythmias

Monitor/treat heart failure: systolic,

diastolic, MR

Monitor/treat recurrent ischemia/infarction

Watch for pericarditis, Dresslers Syndrome

Monitor for myocardial rupture (free wall,VSD, MR)

Monitor for stroke


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Determinants or Prognosis

after Acute MI

LV function (ejection fraction)

Inducible ischemia/coronary anatomy Arrhythmia potential


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Tests for LV function

Echocardiogram

Radionuclide ventriculogram(MUGA)

Contrast left ventriculogram (cath)


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Echocardiogram in Acute

Myocardial Infarction

Wall motion abnormalities

Ejection fraction

Thrombus

Right ventricular MI

Papillary muscle dysfunction- mitral

regurgitation

Free wall rupture/ventricular septal

defect/papillary muscle rupture


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Test for Inducible ischemia:

Stress Test 1. Positive: Ischemic ST segment

depression - u1mm horizontal or

downsloping ST depression

2. Negative: Patient reaches 85%

maximum predicted heart rate (MPHR)

without #1

3. Nondiagnostic: No ischemia but patient

fails to reach 85% MPHR


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Test to Define Coronary

Anatomy: Coronary

Angiogram

Controversy: Should all patients

undergo coronary angiogram after anMI?

Definite indications for coronary

angiogram after MI:

Recurrent chest pain

Positive stress test

High risk features: CHF, low EF, prior MI


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Risks ofCoronary

Angiography: (all are rare)

Stroke

Myocardial infarction Arrhythmia

Renal failure

Allergic reaction to contrast agent


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Tests to Determine Arrhythmia

Risk:

Monitoring throughout

hospitalization Stress test

Electrophysiologic testing

Controversy: Who should undergo EPstudy after MI?

Sustained VT

Nonsustained VT with depressed ejection

fraction


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Treatment of Acute Myocardial Infarction

Late Phase (Post-Hospital)

Risk factor reduction:

Smoking

Hypertension

Diabetes

Dyslipidemia

Obesity/sedentary life style

Hyperhomocysteinemia

Stress/depression

Monitor for recurrent ischemia

Monitor for LV remodeling/CHF


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ABCs of Treatment and

Secondary Prevention of AMI Aspirin-prophylactic Rx for recurrent ischemic events;

give for at least 3 mo. after AMI, probably indefinitely

Beta blockers-prophylactic, for reduction of cardiac

mortality; Rx for 2 yr-indefinitely

Converting enzyme inhibitors-all pts with LV

dysfunction to reduce risk of progressive heart failure

and death.

Diet and lipid lowering Rx-statins have been shown

to reduce risk of subsequent MI, need for

revascularization and mortality (4S, Care)

Exercise and rehabilitation-essential in restoration of

confidence and improvement in quality of life


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Creatine Phosphokinase (CK)

Rises within 4-8 hours, rapidly cleared by 24-24 hours

Other Sources:

Skeletal

Hypothyroidism Renal failure

Stroke

Isoenzymes

MM skeletal muscle

BB brain

MB cardiac

CKMBu 4% suggests acute myocardial infarction+++


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Cardiac Specific Troponins

(cTnT, cTnI)

Rise within 4-8 hours, remain elevated7-14 days (T>I)

30% of patients with UAP show o

levels cTnT or I, indicating increased

risk of adverse outcome


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Relative Contraindications To the Use of

Thrombolytic Therapy

Oral anticoagulant therapy

Acute pancreatitis

Pregnancy or within 1 week postpartum

Active peptic ulceration

Transient ischemic attack within 6 months

Dementia

Infective endocarditis

Active cavitating pulmonary tuberculosis

Advanced liver disease

Intracardiac thrombi

Uncontrolled hypertension (systolic blood Pressure >180 mm Hg, diastolic blood

pressure > 110 mm Hg

Puncture of noncompressible blood vessel within 2 weeks

Previous streptokinase therapy

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