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PENETRATING CARDIAC INJURIES

Although the cardiac injuries are known from the ancient times, first successful operation on the heart was performed by Dr.Rhen, who sutured one of the walls of the heart. Later many attempts were made for the creation of precise and delicate techniques in the surgery of the heart.
Penetrating cardiac trauma may be due to stab wound and or missile injury. Stab wounds are the most common. Factors that influence the mortality rate are:
  • Coronary artery injury
  • Multiple chamber injuries or isolated injuries of left atrium and left ventricle
  • Comminuted tear of single chamber
  • Separate right sided injuries
  • Tangential injuries of the heart
Any kind of the wound in the chest and back region must be suspected as penetrating injuries of the heart. Anxious chest pain, tachycardia, tachypnoea and hypotension are common signs of penetrating cardiac injuries. The consequences after the cardiac penetration are:
  • Cardiac temponade
  • Haemorrhagic shock
These consequences are highly dependant on the size of the penetration in the pericardium. If the size is small, then cardiac temponade occurs as the small amount of blood may cause cardiac temponade because of little distensibilty of the pericardium. In the case of large orifice, haemorrhagic shock results.

ECG and chest films have no great values in these events, but echocardiography has great capability in the evaluation of cardiac penetrating injuries. By Pericardiocentesis we often receive false negative or false positive results.

Surgical treatment is a method of choice here. In this surgery, first we perform left anterior sternostomy then we suppress the penetrated wall with the digit control (applying pressure with the help of fingers). Here main coronary branches should be prevented from ligation and pericardium must be sutured not thoroughly and drainage should be inserted in the pericardial cavity. If there is any evidence of some inter-connection between the cardiac chambers, then little fistulas less than 1cm should be left in place but the larger fistulas should be restored. If there is no possibility to restore the main fistulas then the surgeon must perform restoration after some time of surgery when the patient’s life is out of danger.

PATENT DUCTUS ARTERIOSUS

It is the emryogenic structure, which is derived from the left sixth aortic arch. Under normal circumstances it connects left or common pulmonary artery and the descending aorta near its arch near the orifice of the left subclavian artery. The size of the ductus is variable but the aortic orifice is larger than the pulmonic one. During the gestation, ductus arteriosus plays an important role, when the lungs are collapsed and make high resistance for the blood from the right chambers. So the blood flows from the right ventricle via the ductus arteriosus and passes to the left chamber and then finally to the extremities. After the birth when distension of the lungs occurs, so the resistance also decreases and high oxygen concentration promotes the fibrotic closure of the ductus arteriosus.

Functional closure in the normal neonate occurs within the 10-15 hours after birth and structural closure occurs after eight weeks, but in some infants the sensivity of the ductal fibers to oxygen is low and anatomic closure occurs lately or doesn’t occur at all. After some times the symptoms of left to right shunt appear.

Results of surgery are gratifying with practically no risk of mortality. Ligation of the ductus is the standard procedure and chances of recanalization are rare. Non-absorbable sutures are used – one at either end of the ductus and a central transfixion suture.

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This article has been written by Dr. M. Javed Abbas.
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19:05 09/02/2003