Below is a description of the 6 most common cardiac issues we treat in our surgical practise. It is in no way everything that we can and will do for patients at the Royal Jubilee Hospital.

1. Coronary Bypass 4. Atrial Fibrillation

2. Heart Valve Repair / Replacement 5. Adult Congenital Heart Problems - Bicuspid Aortic Valve/ ASD / VSD

3. Aortic Aneurysm Repair 6. Pace Maker / Defibrillator Implantation

1. Coronary Artery Disease (C.A.D.)

Coronary Arteries are the fuel lines that supply oxygen and nutrients to your heart muscle. Coronary artery disease (C.A.D.) is the build-up of lipid, calcium and abnormal cells within the walls of the coronary arteries. We call this build-up plaque or a blockage. As this plaque increases, it can narrow these fuel lines, which in turn impairs the supply of oxygen-rich blood to the heart muscle. Poor fuel supply to the heart muscle can result in symptoms such as chest pressure or tightness, discomfort up into the neck / jaw / teeth or arms, shortness of breath, or poor exercise capacity. We call these symptoms angina. If one of these areas of plaque ruptures, blood clot can form totally blocking blood flow to an area of heart muscle and this leads to muscle dying. This we call a myocardial infarction or a heart attack. Muscle that dies goes on to form scar tissue and this is irreversible. If a large area of muscle is affected then the heart’s pumping function becomes impaired, which can lead to Congestive Heart Failure (C.H.F.) or death.

Coronary Artery Bypass Grafting (C.A.B.G.)

Coronary artery bypass grafting  surgery (C.A.B.G.) is a procedure used to treat coronary artery disease (C.A.D.). First, a piece of a healthy blood vessel is taken from somewhere elsewhere in your body. We call this new fuel line a graft. One end of this graft is attached to the aorta, which is the major blood supply for your body. The other end is attached beyond the blockage in your coronary artery.  Blood bypasses the blockage by going through the new fuel line to reach the heart muscle. This process improves the fuel supply to your heart muscle.

Blood vessels (grafts) used for the bypass procedure may include an artery from inside your chest wall (Internal Mammary or Thoracic Artery), pieces of a vein from your legs (Saphenous Vein) and an artery from your forearm (Radial Artery). The number of grafts you receive depends on how many blockages you have and their locations.

Coronary Artery Bypass Grafting does not cure Coronary Artery Disease. It does however decrease or eliminate angina, lowers the risk of a heart attack and, in most people we operate on, improves their chances of living longer.

2. Heart Valve Disease

The heart has four chambers and each of these has a valve at its outlet. Heart valves open and close with everyone of our heart beats, typically 100,000 times a day. The best way to think about a valve is that it is a one way door. Blood should easily pass through a valve in one direction, and then because the valve closes, blood is prevented from returning to the previous chamber.

Heart valves can be affected by many types of diseases resulting in their leaking (regurgitation) or narrowing (stenosis). Both regurgitation and stenosis impair the normal flow of blood through the heart. If this condition becomes severe blood congests in the heart resulting in symptoms of shortness of breath on exertion / when lying flat / waking you from sleep, fatigue and tiredness, development of ankle swelling, and poor exercise capacity. We call these symptoms Congestive Heart Failure (C.H.F.). Patient can also experience chest discomfort (angina) and light headedness.

The two hearts valves most commonly diseased are the aortic and the mitral. The aortic more commonly become narrowed (Aortic Stenosis). The mitral more commonly becomes leaky (Mitral Regurgitation). Both valves however can get a combination of stenosis and regurgitation at the same time.

Heart Valve Repair or Replacement ?

Heart Valve Repair

Repair of a valve is much more commonly done if the valve is leaky (regurgitant). Today we have many techniques to repair the vast majority of mitral and tricuspid valve that have isolated regurgitation.

Heart Valve Replacement

When a valve is narrowed (stenotic) the calcified scarring cannot be removed and thus the valve must be replaced. When a valve must be replaced, most patients will have the choice of having either a Tissue or a Mechanical one.

• Tissue valves are made of natural tissue that comes from either a cow (Bovine) or pig (porcine) heart. The body accepts this type of valve because this tissue is specially treated to prevent its rejection. Most patients with this kind of valve are put on an aspirin (ASA) for the rest of their life. Tissue valves however do not last indefinitely and may wear out after some years. This may result in a patient needing another operation. The average lifespan of a tissue valve is around 10 years.

• Mechanical valves are man-made of a special steel compound. These valves are very structurally sound and effectively will last an entire lifetime (100+ years). With a mechanical valve however a patient must take a medication called an anticoagulant. This drug (presently warfarin) which is taken to reduce the risk of blood clot forming on the surface of the valve. In the near future we expect new anticoagulant medications to be approved for use in patients with mechanical heart valves thus avoiding the need of regular blood testing that is needed in the case of warfarin.

• Pulmonic Autograft (Ross Procedure) is a operation where by the patient's own pulmonary artery with its intact pulmonary valve is used to replace the aortic valve and the first part of the ascending aorta. That same section of pulmonary artery / valve (allograft) from another human donor (cadaver) is then used to replace the transferred pulmonary artery. This is a very complicated operation that is typically reserved for young patients who want to avoid the implantation of a mechanical valve and hope to have longer term function of a replacement tissue valve. It has the advantages of using natural tissue and thus avoids the need of anticoagulation. It has the downside of leaving a patient with 2 tissue valves that in time can deteriorate and require further cardiac surgery.

3. Aortic Aneurysms

The aorta is the major arterial blood vessel in the body that carries oxygenated blood. It begins just above the aortic valve and travels through the chest and finally into the abdomen. This blood vessel is usually the size of your thumb (20 - 25 m.m. in diameter)

An aneurysm is a blood vessel that is dilated larger than it should be. Just like a balloon, as an aneurysm grows larger the vessel wall becomes thinner and then at a certain dimension it will rupture. When this occurs it is a life threatening event. Most people who suffer an acute rupture will die shortly after it happens.

In the chest an aneurysm can affect the aorta in a localised area or it can involve its entire length all the way through to the diaphragm. Some will even extend into the abdomen.

Many aneurysms are caused by long standing histories of Smoking and High Blood Pressure (Hypertension). Over many years these can cause damage to the support layers of the blood vessel wall weakening them.

Repair of Aortic Aneurysms

When an aortic aneurysm grows beyond a certain dimension its risk of rupture starts to increase. We call this the surgical threshold. At this size generally the risk of the aneurysm rupturing in the next year is higher than the risk a patient would face of getting it surgically repaired. The surgical threshold can vary depending on the patient’s body size, location of the aneurysm, rate at which the aneurysm has expanded as well as associated medical issues. If you have an aneurysm your surgeon will give you more information about what they feel is the surgical threshold of your particular aorta.

An aortic aneurysm is repaired in order to remove it from the body so that it is no longer at risk of rupturing.

Repair of an aneurysm is done by cutting out the diseased aorta and replacing it with a special man made tube called a graft. This graft is made out of a special polyester material and it will last 50+ years. This tube takes over the function of the aorta itself by providing a new conduit for blood to travel in.

4. Atrial Fibrillation

Atrial fibrillation is an abnormal heart rhythm (dysrhythmia) that occurs when the heart's two upper chambers (the atria) beat chaotically resulting in its loss of coordination with the two lower chambers (the ventricles) of the heart. This dyrthythmia can result in a rapid, irregular heart rate. Atrial fibrillation symptoms often include heart palpitations, shortness of breath and weakness.

If atrial fibrillation is not controlled it can lead to a persistent, irregular, rapid heart rate which in turn can increase the risk of stroke and heart failure.

Surgical Treatments for Atrial Fibrillation

Two types of surgical treatments are available for Atrial Fibrillation.

1. Ligation of the Left Atrial Appendage. The appendage is a part of the atrium that has no know function. When a patient is in atrial fibrillation for a prolonged period of time blood clot can form inside this appendage and this can lead to stroke. The appendage is over-sewn (ligated) to reduce the chances of stroke long term. Unfortunately this procedure does not completely eliminate the risk of stroke with atrial fibrillation so most patients still require anti-coagulation to minimise the risk of this occurring.

2. Pulmonary Vein Ablation. Many of the abnormal heart muscle cells that cause atrial fibrillation reside in the area of the pulmonary veins (These are the veins that return blood from your lungs to the left side of the heart). Pulmonary vein ablation is a procedure used to stop the electrical signals from these abnormal muscle cells that cause atrial fibrillation. It is done to try to keep a patient in a normal heart rhythm and prevent the return of atrial fibrillation.

5. Adult Congenital Heart Conditions

Bicuspid Aortic Valve.

A Bicuspid Aortic Valve (B.A.V.) is the most common congenital heart valve problem seen in humans, occurring in roughly 1% of the general population. The normal structure of the aortic valve has three cusps (doors). A bicuspid valve occurs when two cusps become fused resulting in a valve that has two unequal sized cusps. When a person is younger this valve usually works in a normal fashion but as people get older it can undergo degenerative changes resulting in deterioration of its function.

Younger patients that present for surgery more often have regurgitation of their valve. Older patients typically develop dense scarring and calcification of their valve so they present with stenosis.

A common abnormality associated with B.A.V. is aneurysm formation of the thoracic aorta. An aneurysm is a blood vessel that is dilated larger than it should be. In these patient who have an aneurysm the aorta is typically repaired at the same time of valve replacement.

If you have a bicuspid aortic valve then your biological children have an increased chance of having one too (about 5%).

Treatment of a Bicuspid Aortic Valve

A bicuspid aortic valve is usually replaced like any other abnormal heart valve. Repair of this is unlikely and if done typically doesn’t have good long-term results.

Atrial and Ventricular Septal Defects

Atrial Septal ( A.S.D.). and Ventricular Septal (V.S.D.) Defects occur when the wall that separates the left and right side of the heart does not form completely. As a result there is an abnormal communication through this defect. If the defect is large enough they can result in large amounts of blood traveling through them into the wrong chamber of the heart. This can lead to Congestive Heart Failure. Stroke can also be seen if debris from the venous system crosses over to the left heart and it gets sent out to the brain.

Treatment is by way of repair of the A.S.D. or V.S.D.

Many of these abnormal defects are closed by simple suturing. If very large they sometimes need an tissue patch to fill in the gap.

6. Pacemakers and Implantable Cardiac Defibrillators (I.C.D.)

Pacemakers

If a patient develops an abnormal heart rhythm where their heart rate is too slow, we call this bradycardia. When your heart rate is too slow the heart does not pump enough blood flow to your body and as a result your blood pressure can drop. This can lead to fatigue and tiredness, poor exercise capacity, heart failure, and loss of consciousness (syncope). In order to correct this a pacemaker is installed.

The pacemaker has one or two wires (leads) that are placed into the heart and they are connected to a battery control unit (generator). The pacemaker senses if there is an adequate heart rate and if not then it will stimulate the heart to beat. New versions of pacemakers can even sense activity so that if a patient is walking / running / swimming / etc. it will speed up their heart rates so they will have better exercise capacity.

Implantable Cardiac Defibrillators (I.C.D.)

When a patient develops an abnormal heart rhythm in the ventricles (big pumping chambers) it can result in their heart rate becoming extremely fast and chaotic. This can lead to a cardiac arrest. Two common rhythms that occur like this are Ventricular Tachycardia (V.T.) and Ventricular Fibrillation (V.F.). These generally occur in patients that have some other underlying cardiac disease such as Coronary Artery Disease which has caused a prior heart attack or Congestive Heart Failure. An implantable cardiac defibrillator (I.C.D.) is used to treat both V.T. and V.F.. They are also inserted in some patients who have very low heart pump function because these patients are at high risk of developing V.T. or V.F. in the future and dying of a cardiac arrest.

An I.C.D. consists of 2 components. The first is a regular pacemaker which will monitor the patients heart rate and pace it if it is too slow. The second component is a monitoring system that watches for V.T. or V.F. and if it occurs it will deliver energy impulses to the heart to shock it back to a more normal rhythm.

Technique of Device insertion. Pacemakers and I.C.D.’s are implanted in a similar manner. They are typically done using a local anaesthetic and very mild sedation. A small 10 - 12 cm. (2 - 3 inch) incision is made below the collar bone and then one / two leads are placed into the heart. These wires are guided into position using a special x-ray system to visualize them. The pacemaker or I.C.D. generator is then buried under the skin. They usually takes 30 - 60 minutes to insert. Most patient are walking within 4 hours and discharged home shortly thereafter.

Patients must avoid strenuous activity and heavy lifting for 6 weeks after their device is inserted. If they do too much the leads can move out of position and the system does not work properly. This requires another trip back to the operating room to reposition them.