Acute Myocardial infarction

Priya .M. Vincent & Padma Susan Mathew

ICCU

Definition

•Necrosis to cardiac muscle due to acute occlusion of coronary artery as a result

of plaque rupture and thrombosis

Coronary Atherosclerosis with Thrombus

Risk factors

• Non-modifiable– Age– Race– Sex– Heredity

• Modifiable– Smoking– Hypertension– Diabetes mellitus – Hyperlipidemia.– Obesity– Response to stress

Understanding Myocardial Infarction

Change in the condition of plaque in the coronary artery

Activation of platelets

Formation of thrombus

Ischemia of tissue in the region supplied by the artery

Coronary blood supply < demand

Myocardial cell death

Contractility

Stimulation of the sympathetic nervous system

Altered repolarization of

myocardium

Release of lysosomal enzymes

Anaerobic Glycolysis

Myocardial irritability

Dysrhythmias

ST seg. q wave

CPK-MB LDH

Lactic Acid production

Angina

Contractility

Stimulation of the sympathetic nervous system LV function

Preload Cardiac Output

CVP

PCWP

LVEF

HR O2 NEED After load

Vasoconstricti

on

Continuation….

Normal Myocardium:

Myocardial Infarction - Gross

Myocardial Infarction – 1st week

Post-infarcted Myocardium - CS

2nd week - Myocardial Infarction - 3d

MI 18-24 hours loss of nucleus, contraction bands, coagulative

necrosis

MI 3-4 days – Hemorrhage, inflammation

MI 1st – 2nd week – Granulation tissue

MI 2-4 weeks - Resorption, fibrosis

MI > 4–6 weeks - Collagen Scar

Clinical features

Symptoms:• Prolonged chest pain• Profuse sweating • Nausea & vomiting• Breathlessness• Anxiety• Collapse / Syncope

Physical signs

• Pallor, sweating, vomiting• Tachycardia / Bradycardia• Hypotension, oliguria, cold

periphery • Narrow pulse pressure• Raised JVP in RVMI• Lung crepitation• 3rd and 4th heart sounds• Fever

Diagnostic measures• ECG• Lab Investigations

– Troponin I– Troponin T– CPK-MB– CPK [Total]– SGOT– CBC & ESR

• X-Ray Chest• Echocardiogram• Radioisotope studies - Stress Thallium - Rest Thallium - Multi-gated acquisition scan [MUGA] • Coronary Angiogram• MRI

ECG Patterns

Coronary Arteries

•Left Coronary A.•L.A.Descending•Left Circumflex

•Right Coronary A.

LCx

LAD

Area of myocardium

involved

Coronary artery supply Leads

Anterior Left coronary artery left anterior descending branch

V2,V3,V4

Posterior Right Coronary Artery V1 – V3

Inferior Right Coronary Artery II, III, avf

Anteroseptel Left Coronary Artery left anterior descending branch

V2 & V3

High lateral Circumflex artery, marginal branch or LCA

I, aVL

Apical Usually LCA, left anterior branch may be RCA, posterior descending branch

V5 & V6

Enzyme Normal value

Onset Peak Return to normal

Trop. I & Trop T

<0.2 4-6hrs 24-36 hrs. 10-12days

CPK [Total] 21-232 hrs. 12-24 hrs. 3-5days

CPK – MB <25 . 12-20 hrs. 42-48hrs.

SGOT <40 6-12hrs. 24-48 hrs. 10days

LDH 160 – 410 24hrs. 48-72 hrs. 7-10days

Management

• Seek immediate medical attention

Medical Management

•Major goals:

– Management of the acute attack– Prevention of complications – Rehabilitation

1. Management of Acute attack

• History• ECG• IV access• Routine blood investigations• Continuous cardiac monitoring• Invasive monitoring

General Measures

• Pain control• Aspirin• Clopidogrel• Nitrates• Beta-adrenoreceptor blockers• ACE inhibitors• Bed rest upto 48 hours• Soft diet• Stool softeners

Patients with ischemic type discomfort

ECG

ST elevation ECG strongly suspicious for ischemia ( ST depression, T

wave inversion

Non diagnostic ECG

Eligible for thrombolytic

therapy

Thrombolytic therapy

contraindicated

Admit

Initial antiischemic therapy or treat as unstable angina

Thrombolytic therapy

Primary PTCA

Continue evaluation

Obtain follow up serum cardiac marker levels

ECHO

Evidence of ischemic infarction

Evidence of ischemic infarctionYes

NoInitial reperfusion strategy if ST elevation develops Discharge

Thrombolysis

• Streptokinase• Urokinase• Tissue plasminogen activator

(t-PA)• Acylated plasminogen

streptokinase activator complex (APSAC)

Criteria for thrombolysis in acute MI

Indications:

• Chest pain• ECG changes• Time from onset of symptoms

<6 hrs. : most beneficial6-12 hrs. : lesser but still important benefits>12 hrs. : diminishing benefits but may still be used in selected patients

Absolute contraindications

1. Active internal bleeding (excluding menses)

2. Suspected aortic dissection3. Recent head trauma or known

intracranial neoplasm4. Hemorrhagic CVA5. Major surgery or trauma < 2weeks.

Relative contraindications

• BP>180/110mmHg on at least 2 readings• History of hypertension• Active peptic ulcer• History of CVA• Current use of anticoagulants• Prolonged or traumatic CPR• Diabetic hemorrhagic retinopathy• Pregnancy• Prior exposure to STK & APSAC

Protocol followed in ICCU• Aspirin 150-325mg chewed, 75mg daily thereafter• Clopidogrel 300mg stat & 75mg daily• Pain relief

– Inj. Morphine 3mg + Inj. Phenergan 12.5mg slow IV– Inj. Pethedine 12.5mg IV in patients with asthma

• O2 2-4 lit/min for 2-3 hrs. If saturation <95% continue beyond 3hours.

• 2 IV access if the patient is for thrombolysis• Inj.Avil 2cc + Inj. Hydrocortisone 200mg+Inj.

Ranitidine 50mg IV• Inj.Streptokinase 1.5million /15 lakhs units in 100ml

NS over 1hr.• Inj. Heparin 60 units/kg bolus +

12units/kg/hr.infusion 4 hrs. after STK

• Inj. NTG infusion x 24-48hrs. in LVF, large anti. MI persistent pain

• blockers to all patients unless contraindicatedMetoprolol 12.5mg – 25mg BDuse carvedilol 3.125mg OD for anti. MI, LVF, previous MI

• Statins if LDL >100mg/dL & TGL>150mg/dL• Stool softeners• Hypnotic – Lorazepam 1-2mg HS• NPO till pain relief

Liquid diet x 12 hours.Semisolid diet thereafter, low fat,low cholesterol 1500 calories diet.

• Pulse,BP ½ hourly till stable then hourly.• ECG 90 min,180 min after starting STK &daily thereafter

till transfer out. • Consider IV beta-blockers in young patients with

tachycardia,hypertension(Metoprolol 5mg 3 doses at 5min interval.

2. Prevention of complications

a. Dysrhythmiasb. Cardiogenic shockc. Heart failure & pulmonary edemad. Pulmonary embolisme. Recurrent MIf. Complications due to necrosis of

myocardiumg. Pericarditish. Dressler’s syndrome (late pericarditis)

3. Rehabilitation

Overall goals• Lead a productive life• Remain within the limits of the heart’s ability to respond to

increase in activity and stress

Sub goals• A programme of progressive physical activity• Health teaching• Help to accept the limitations• Aid the client in adjusting to changes in occupational goal• Change the psychological factors • Reduce risk factors

Phase I (in hospital)

• Bed rest for 1 day with liquid diet• When vital signs get stabilized, patient can move in

bed• Passive exercises• As strength is regained - sit on the side of the bed

and dangle the feet.• Once transferred from CCU self-care activities are

encouraged• Brief walks with supervision• Instruct regarding warning signs of over exertion• Client education

Phase II (Intermediate)

• If no complications, discharge at the end of one week

• Sexual intercourse after 4-8 weeks.• Stop smoking completely • Encourage frequent walks• Avoid strenuous activities• Monitored group programmes• Warm up and stretching exercises• Aspirin daily.• Return to work at the end of 8-9 wks.• Follow up in hospital between 8-9 wks.

Phase – III (Long term)

• Periodic evaluation

Interventional Management

[PTCA] Percutaneous Transluminal Coronary Angioplasty

Coronary Artery Bypass Graft Surgery [CABG]

Nursing Management

• Nursing Diagnosis:– Acute chest pain related to myocardial ischemia resulting from

coronary artery occlusion with loss/restriction of blood flow to an area of myocardium and necrosis of the myocardium.

– Dysrhythmias related to electrical instability or irritability secondary to ischemic or infracted tissue.

– Decreased cardiac output related to negative inotropic changes in the heart secondary to myocardial ischemia, injury or infarction.

– Impaired gas exchange related to decreased cardiac output– Powerlessness related to hospital environment and anticipated

life style changes– Fear & anxiety related to hospital admission and fear of death– Altered health maintenance related to MI and implications for

life style changes.

Thank you