Coronary Thrombosis Myocardial Infraction

 

Coronary Thrombosis Myocardial Infraction

 

Definition :

It is a condition characterized by formation of a blood clot in the coronary artery.

 

Pathophysiology

1.      Circulation in the coronary arteries is slowed down due to arteriosclerosis.

2.      Irregularity of the inside of the arterial wall  predisposes to clotting of blood.

3.      If a coronary artery gets totally occluded, due to thrombosis, the blood supply to the part of the heart supplied by that vessel is stopped. Loss of supply of oxygen and nutrients to that part of the heart results in its death ( infraction).

4.      If the main coronary artery gets occluded, the patient dies because the heart cannot function. But if a small branch of the coronary artery is occluded, a small part of the myocardium undergoes infraction. The dead tissue gets absorbed gradually and replaced by fibrous scar tissue. If the scar is small, the patient can lead a normal life. But if the scar is large ventricular failure or congestive cardiac failure.

 

              Clinical Features:

1. The onset is sudden, at any time of the day.

2. The patient may or may not have had angina pectoris in the past.

3. There is a sudden onset of chest pain, as described under ‘angina pectoris’ in the past.

4. There may be breathlessness.

o   Severe pain.

§  Restlessness.

§  Excessive sweating

§  Vomiting.

§  Cold and pale skin.

§  Pulse: Rapid, low volume.

§  Collapse.

§  Unconsciousness and death

                             7.Other features

           - Anxiety.

           - Abdominal distention.

           - Hiccups.

           -Palpitations.

           -Drowsiness.

           -Confusion.

                              8.On auscultation, the heart sounds are muffled. There is tachycardia and systolic murmur  pericardial rub may be heard on the second or third day.                        

Investigations

1.ECG

            . Deep Q-wave.

            . Elevation of ST-Segment and inversion of t-wave.

2.Serum SGPT: It raises 24 hours after the. Infraction and remains elevated for a number of days.

3.WBC count  rises.

 

 

                  Comparison of Angina Pectoris and Myocardial  Infraction

Variable	Angina Pectoris	Myocardial infraction
Precipitating factors	Excessive exercise, cold, heavy food.	There may not be any cause, and it may occur even at rest.
Patient’s condition	He stops all work and remains still	Restless.
Pain -site -Duration -Nature -Spread -Nitrates	-                    -Retrosternal. -<5 minutes. -Intermittent. -Neck, left shoulder and arm. -Relief.	-  -Retrosternal. - > 1hour. -Continuous. -Less than in angina pectoris. -No effect.
Vomiting	Absent.	Present.
Dyspnea	Absent.	Present.
Shock	Absent.	Present.
Sweating	Less.	Profuse.
Fever	Absent	Present.
Heart sounds	Normal.	Abnormal.
Blood Pressure	Normal or raised.	Low.
Cardiac failure	Absent.	Present.
ECG	Elevation of ST-segment and inversion of T-wave.	Q-wave.
SGOT	Normal.	Elevation.
LDH	Normal.	Elevation.

 

 

 

 

 

 

 

        

Comparison of pulmonary Embolism and Myocardial infraction 

variable	Pulmonary	Myocardial infraction
History	Recent major illness.	Angina pectoris.
Pain	Severe, site variable.	Retrosternal, spreading to left shoulder and arm.
Shock	Early	Late.
Cough	Present.	Rare.
Cyanosis	Early, severe.	Late. If at all.
Hemoptysis	Possible.	Absent.
Fever	High.	Mild, after 24 to 36 hours.
ECG	Q-wave is normal.	Deep Q-wave.

 

Prognosis

1.A patient with severe disease may die in a few hours.

2.A patient with a mild attack gets well after variable interval.

3.A patient with a mild attack may not feel the pain, and may not known that, he has had an attack. It is diagnosed only when an ECG is done later.

 

Complication

1.Early

          -Arrhythmias: Atrial fibrillation or flutter, ventricular fibrillation.

          -Cardiogenic shock.

          -Congestive cardiac failure.

          -Rupture or dysfunction of papillary muscle.

          -Pulmonary embolism.

          -Systemic embolism.

          -Cardiac rupture.

2. Late

          -Ventricular aneurysm.

          -post myocardial infraction syndrome.

          -Shoulder hand syndrome.

 

Immediate care

1.The patient is kept in a cardiac intensive care unit.

2.Acardioscope is attached to the patient, so that his pulse and ECG are monitored as required.

3.A sphygmomanometer is attached to the patients, arm so that his  blood pressure can be monitored as required.

4.The following articles are kept ready.

5.Any of the following is given to relieve pain.

          - Pethidine 100mg IM.

          -Morphine 15mg IM.

        -Trifluoperazine 10 mg IM along with pethidine or morphine to prevent or treat vomiting.

6. 5% dextrose slow intravenous infusion.

7. Oxygen if there is cyanosis.

8. Serum electrolytes and SGOT test.

9.Complete bed rest.

10.Diazepam 5mg tablet 8 hourly for relieving anxiety and inducing sleep.

11. Mild laxative to prevent straining for stools.

12.Diet

          -Tea, milk, fruit juice, lime juice etc. are given initially.

          -Light diet is introduced gradually.

          -Normal diet is introduced gradually.

13.Heparin is given 5000 units IV 6 hourly to prevent  vascular thrombosis. Warfarin is given orally later.

14.Hypertension and diabetes are treated appropriately, if present.

15.Streptokinase or urokinase injection is given intravenously to dissolve the blood clot in the coronary artery.

16.Treatment of complication (see the following table).

 

 

                                      Treatment of Complications

Complication	Treatment
Left ventricular failure	Furosemide. Oxygen.
Ventricular ectopic beats	Lignocaine 100mg IV followed by 2 mg/min infusion.
Atrial fibrillation	Digitalis. Procainamide. Proctolol. Phenytoin.
Ventricular fibrillation	Drug therapy (see before) Electric cardioversion, if drug therapy fails.

 

 

Long  term treatment:-

1.The patient’s room should be well lighted and  ventilated.

2.The patient’s bed is made every day.

3.The patient should be made comfortable in bed.

4.His temperature ,pulse, respiration and blood pressure are examined every 4 hours.

5.Oral hygiene is maintained for  every 4 hours . He is given water to gargle every time he eats or drinks anything.

6.Care is given for the back and pressure points every 4 hours. His position is changed frequently.

7.His nails are trimmed every week.

8.Medicines are given at appropriate time every day.

9.Diet is given including green leafy vegetables ,so that he does not get constipated. Low calorie diet is given to reduce weight if the patient is obese. Salt content of the  diet is reduced if the patient has hypertension. Diabetes.

10.The patient is told  not to worry about anything . Nothing should  be  said that  would hurt him.

11.He should be given books to read that would not cause tension and  relieve his anxiety.

12.He may be given indoor games to play.

13.He his given a sponge every day . He is made ready to manage his bath and other work by the time he is discharged from the hospital.

14.Initially he is given exercises  are added under the supervision of a physiotherapist.

15.Preventive measures are explained to the patient before he goes home.

16.He is advised to see his doctor every 15 day.