Defibrillation is a procedure performed when the heart stops beating or the heart rhythm becomes dangerously irregular and cannot support life. It is a procedure only performed when a patient is unconscious. Defibrillation pads are positioned on the chest and an electrical charge is delivered by a defibrillation device so the natural pacemaker in the heart can restore the heart’s electrical rhythm.  

Defibrillation is delivered

  • In an emergency cardiac arrest.
  • Electively as a cardioversion.
  • Via an internal defibrillator which is inserted under the skin and wired into the heart.

Elective cardioversion

Defibrillation is delivered in a controlled situation when the patient has an irregular heartbeat (arrhythmia) such as atrial fibrillation and the cardiologist deems it appropriate to try rhythm control via defibrillation. The patient will be to reduce the risk of any clot located in the atrium being flicked off during cardioversion causing heart attack or stroke. Sedation is administered and an electrical current is delivered to restore normal rhythm (sinus). In many instances, anti-arrhythmia (irregular heartbeat) medications are needed indefinitely to keep the heart’s rhythm and rate in the most appropriate range. It often successfully restores regular heart rhythm, but for some patients their atrial fibrillation may return1.  

Internal automated defibrillator

Also called an implantable cardioverter defibrillator, an automated internal defibrillator is a small battery-powered device that treats life-threatening irregular heartbeats (arrhythmias), including those that cause sudden cardiac arrest. The device is implanted under the skin of the chest with wires that connect to the heart. If the device detects an irregular heart rhythm, it sends electrical impulses to restore a normal rhythm2.  

Artificial pacemaker

A small battery-operated device that helps the heart beat in a regular. There are two parts; a generator and wires (leads).

  • The generator is a small battery-powered unit.
  • It produces the electrical impulses that stimulate your heart to beat.
  • The generator may be implanted under your skin through a small incision.
  • The generator is connected to your heart through tiny wires that are implanted at the same time.
  • The impulses flow through these leads to your heart and are timed to flow at regular intervals just as impulses from your heart's natural pacemaker would.
  • Some pacemakers are external and temporary, not surgically implanted3.


Coronary angioplasty and stents (PCI Percutaneous Coronary Intervention)

A coronary angioplasty is performed to increase the amount of blood delivered to the heart. Following a coronary angioplasty there is an option to insert a stent. A stent is an expandable metal mesh tube that can be placed in an artery permanently to keep the artery expanded, and promote blood flow. This procedure does not remove heart disease, and it is essential to continue to take heart medications prescribe by your doctor and to continue to reduce heart disease risk factors. Angioplasty requires a short hospital stay and fasting is required. Sedation may be used.

In the cath lab (examination room in a hospital specially designed to examine hearts) a doctor numbs an area in the groin or arm and inserts a small tube (catheter) into an artery. The catheter is threaded through the artery until it reaches a coronary (heart) artery. Watching on an X-ray screen, the doctor moves a very thin wire through the catheter and across the blockage. Over this wire, a catheter with a thin, expandable balloon on the end is passed to the blockage. The balloon is inflated. It pushes plaque to the side and stretches the artery open, so blood can flow more easily. This may be done more than once.

In many patients a collapsed wire mesh tube (stent) mounted on a special balloon, is moved over the wire to the blocked area.  As the balloon is inflated, it opens the stent and imbeds this into the artery walls. The stent locks in this position and helps keep the artery open.  The balloon and catheters are removed.

Direct pressure for 15 minutes or longer will be applied to the place where the catheter was inserted to ensure there’s no internal bleeding.  If angioplasty is done through the leg, for several hours you’ll lie quietly on your back and the doctors and nurses will check for any signs of bleeding or chest discomfort. If the procedure is performed through the arm, lying flat is not required. Bruising at the site is common5.


Drug eluting or bare metal stents

Drug-eluting stents (expandable metal mesh tubes) are specially designed stents that slowly release medication to reduce the chance of re-narrowing, or restenosis, of the blood vessel.

Because re-narrowing (restenosis) within the stented region of a heart artery is caused by tissue growth, some stents (called drug-eluting stents) have medication on them to prevent this tissue growth. Drug-eluting stents are placed in a fashion similar to other stents; however, their use markedly reduces the rate of re-narrowing. About 1 in 10 patients develops re-narrowing in the several years after drug-eluting stent implantation, a rate about half of that seen for stents without medication.

Because stents expose foreign material to the blood stream, a small risk exists that a blood clot may develop in the stent, a process called stent thrombosis. These blood clots can occur many months and even years after stent implantation and may lead to a heart attack or death. All stents can potentially be affected by stent thrombosis. For this reason, most patients with stents are instructed to take anticlotting medication, usually a combination of aspirin and clopidogrel. Each of these medications stops platelets (particles in the blood that help clots to form) from functioning to their full capacity. The precise duration of anticlotting medication depends on the type of stent placed by your doctor and your overall medical condition. If you have been prescribed anticlotting medications, you should not stop them (even for a few days) unless instructed to do so by your doctor7.  

Coronary artery bypass graft (CABG) surgery

A CABG is a major surgical procedure performed through the sternum (breastbone), which is performed in order to promote blood flow to your heart muscle and minimise angina. It is performed by removing a blood vessel (either artery or vein) from elsewhere in the body (e.g. leg, arm) and attached to the heart muscle to bypass (graft) the narrowed diseased arteries. A patient may undergo one, two, three or more bypass grafts, depending on how many coronary arteries are blocked. A period of time will be spent in hospital and rehabilitation will be necessary. This is an effective procedure to manage blockage of blood to the heart muscle, improve the supply of blood and oxygen to the heart, relieve chest pain (angina), reduce risk of heart attack, and improve ability for physical activity.    

Valve Replacement

The four heart valves are:

  • The tricuspid valve is between the right atrium and right ventricle.
  • The pulmonary or pulmonic valve is between the right ventricle and the pulmonary artery.
  • The mitral valve is between the left atrium and left ventricle.
  • The aortic valve is between the left ventricle and the aorta.

Each valve has a set of flaps (also called leaflets or cusps). When working properly, the heart valves open and close fully.

Valve issues include congenital heart defect, damage from infections such as infective endocarditis, rheumatic fever and changes in valve structure in the elderly

A defective heart valve is one that fails to fully open or close.

  • A stenotic heart valve can't open completely, so blood is pumped through a smaller-than-normal opening.
  • A valve also may not be able to close completely. This leads to regurgitation (blood leaking back through the valve when it should be closed).

People with congenital heart valve defects may need treatment with drugs. Some valve defects may be repaired with surgery. Artificial heart valves are used to replace damaged or diseased heart valves that can't be repaired. Patients own tissue can sometimes be used for appropriate patients.  
People with artificial heart valves are at higher risk for developing an infection of the valve (endocarditis) and are also in the highest risk category for having poor outcomes from endocarditis. Some patients will need to take antibiotics before dental procedures.

After valve surgery patients will require anticoagulation to help prevent clot formation and risk of Deep vein thrombosis (DVT), stroke or heart attack. This will require ongoing blood tests to monitor clotting times 11.  



  1. American Heart Association, ‘Non-surgical procedures for atrial fibrillation (Fib or AF),’ viewed 12 June 2013,
  2. American Heart Association, ‘Heart and stroke encyclopaedia’, viewed 12 June 2013’,
  3. WedMD 2013, ‘Heart valve disease’, viewed 12 June 2013,
  4. 2013, ‘Pacemaker maze procedure after heart valve’, viewed 12 June 2013,
  5. American Heart Association, ‘Cardiac catheterization’, viewed 12 June 2013,
  6. American Heart Association, ‘Angioplasty’, viewed 12 June 2013
  7. Maisel, W.H & Laskey, W.K 2007, ‘Drug eluting stents’, Circulation, vol. 115, pp. 426-7
  8. American Heart Association 2012, ‘Stents’, viewed 12 June 2013,
  9. Meltzer, LE, Pinneo, R & Roderick, KJ 1983, Intensive coronary care: A manual for nurses, 4th edn, RJ Brady Co
  10. American Heart Association 2012, ‘Coronary bypass’, viewed 12 June 2013,
  11. American Heart Association 2013, ‘Options for heart valve replacement’, viewed 13 June 2013,
  12. University of Maryland Medical Centre, ‘Heart valve surgery’, viewed 13 June 2013