Cardiac Surgery Flashcards
Describe the electrical activity of the heart?
SA node initiates an electrical impulse. This is propagated through the left and right atria and picked up by the AV node. (atrial systole) The AV node then sends the electrical impulse down through the bundle of his and up through the purkinje fibres causing ventricular systole.
Name the following scar and the surgeries it may be associated with?
Left: Midline stenotomy scar, traditional cardiac scar used in CABG, valve replacements.
Middle and right: Minimally invasive scars used for certain valvular surgery and single CABG. It is a relatively new procedure.
Name the following scar and the procedure it is used for?
Pacemaker scar (or implantable cardioverter-defibrillator)
Name the following scar and the most likely surgery?
Thorocotomy: Usually for pneumenectomy/lobectomy
What is the difference between open and closed cardiac surgery?
Open surgery involves major incisions being made usually a stenotomy or a pacemaker scar.
Surgeries include: CABG, Valve Repair and Replacement, Pacemaker
Closed surgeries are where there are no open incisions and instead the procedure is done vascularly.
Surgeries include: Coronary aa stenting, PCI, Carotid aa stenting, central lines and aortic aneurysm repair.
What is cardiopulmonary bypass?
It is a technique that is used to temporarily take over the function of the heart and lungs.
It is usually used during cardiac surgery to avoid the difficulty of operating on a beating heart.
A cannula is inserted into the vena cava, right atria or femoral vein, this cannula is connected to the heart lung machine which oxygenates the blood, it is then reinserted to the ascending aorta or femoral aa via another cannula.
The blood is usually cooled so as to cool the core body temoerature of the patient as this reduces oxygen requirements.
ECMO (Extrcorpeal membrane oxygenation) is a simplified version of this used in ITU, in tose with severe cardiac/respiratory failure.
Describe the principles behind CABG?
Coronary aa bypass graft.
The aim of the surgery is to bypass sections of coronary aa’s that have become critically narrowed due to the atherosclerosis.
The graft is harvested from one of the patients other vessels this is usually the: greater saphenous vein, the radial aa or the internal mammary aa.
Describe the principles behind coronary angioplasty and stent insertion/PCI?
Percutaneous coronary intervention also known as coronary angioplasty.
This is where a catheter is inserted through the femoral aa, it is directed towards the coronary aa via xray video guidance.
When the narrowed vessel is identified a balloon with a surrounding stent is inflated. This widens the aa, the stent is the left inplace to keep the aa widened.
This procedure is done under local anaesthetic.
Describe the principles behind valvular surgery?
Repair faulty valves or remove and replace faulty valves.
Valves can be repaired by:
Ring annuloplasty. The surgeon tightens the valve by sewing a ring of metal, cloth, or tissue around the valve.
Valve repair. The surgeon trims, shapes, or rebuilds one or both of the flaps that open and close the valve.
Replaced valves can either be mechanical or tissue (usually pig valves).
The procedure usually involves a midline stenotomy scar but may now be done with minimally invasive surgery. The patient is then put on cardio-pulmonary bypass and the surgeon opens up the heart to either replace or repair the valve.
What are the advantages of tissue/mechanical heart valves?
Tissue valves only last 10-15 years therefore in younger patinets it is likely they will need revisions. However there is no need for anticoagualtion therapy.
Mechanical valves last longer but require lifelong anticoagulation.
What are the general risks involved in cardiac surgery?
Wound infection.
Reaction to anaesthesia.
Peicarditis +/- pericardial effusion (rare)
MI
Death
What are the complications of blunt cardiac trauma?
Blunt trauma can cause any of the following:
- Myocardial contusion (may be assymptomatic but may cause some arrhyythmias)
- Ventricular rupture causing cardiac tamponade and usually death.
- Valve disruption
- Septal rupture (will cause breathlessness and heart failure eventually)
- Commotio cordis (sudden cardiac arrest)
How should penetrating cardiac injury be managed?
Call trauma team.
Contact cardiac surgery.
Emergency thorocotomy only if patient has arrested.
Resus until cardiac surgeon has arrived.
How does an atrial myxoma present?
It is a benign connective tissue tumour of the atrium usually affecting the atrial septum in the left atria.
Symptoms can include:
Orthopnea.
Paroxysmal nocturnal dyspnoea.
Exertional dysopnea.
Chest pain.
How is an atrial myoxoma treated?
Surgical removal often with mitral valve replacement as it is damaged in the removal.
