OUR PROCEDURES
Invasive Cardiology
- Cardiac catheterisation / Coronary angiography
- Percutaneous Transluminal Coronary Angioplasty (PTCA -balloon treatment) and stenting
- Flow Reserve studies
- Rotational atherectomy (Rot ablation)
- Patent Foramen Ovale occlusion (PFO closure)
- Single and dual chamber pacemaker implantation
- Electro Physiological studies (EPS)
- Ablation for cardiac arrhythmias
- Atrial fibrillation (AF) ablation
- Cardiac Resynchronization Therapy (CRT heart faliure devices) pacemaker implantation
- Implantable cardioverter defibrillator (ICD) implantation
Cardiac catheterisation / Coronary angiography
Cardiac catheterisation is an invasive procedure which involves having a fine hollow tube (catheter) placed into an artery or vein under local anaesthetic. The tube is then passed along the blood vessels and guided to the heart under X-ray imaging. The test is carried out most commonly for coronary angiography., although is sometimes performed to measure blood pressures and oxygen readings in different parts of the heart. The procedure can be carried out as a day case or as an inpatient procedure. Coronary angiography is of the tests used to diagnose the degree and severity of coronary artery heart disease. The tip of the catheter is positioned at the opening of the coronary artery, contrast medium is then injected into the artery which produces a clear X-ray image of the very fine network of arteries which make up the blood supply in the heart muscle, any narrowing's or blockages are normally very easily detected. Contrast medium is also injected into the main pumping chamber of the heart (left ventricle). This can sometimes cause a hot or flushing sensation which is transient and passes very quickly. The whole test can take between 10 minutes to one hour.
Coronary angiography is a relatively safe procedure, though complications such as stroke and heart attack can occur during and are estimated at approximately 1:1000. A detailed discussion of the risks versus benefits with the cardiologist will provide an individual guide.
Percutaneous Transluminal Coronary Angioplasty (PTCA -balloon treatment) and stenting
A PTCA is often carried out if narrowing's or blockages are found in the coronary arteries, it may be possible to open the narrowing using a tiny fluid filled balloon which is guided into the narrowed artery using an extremely fine catheter. The catheter is placed in an artery, commonly the femoral artery; this catheter has a small deflated balloon at the tip. Under X-ray guidance, the cardiologist advances this catheter into the narrowed or blocked artery of the heart. When it is in position, the cardiologist inflates the balloon, thereby opening up the blocked artery and blood can then flow through the artery again. Sometimes the Cardiologist may decide to implant a small reinforced metal spring called a stent to help to keep the artery open after the procedure. The stent is mounted on a PTCA balloon catheter which is then inflated inside the artery. The stent expands and is left in place as the balloon is deflated and the catheter is withdrawn. Occasionally the artery can block again over time to cause a condition called restenosis. If this happens, the cardiologist may have to repeat the procedure. Stents used to be made from bare metal. Unfortunately, these had a high probability of restenosis. Recent advances in stent technology are having an impact on restenosis. These new stents are called drug eluting stents. As the name suggests, they have a drug impregnated into them that helps stop the restenosing process.
Patients come in for the procedure and go home the next day. During the procedure the ECG and blood pressure are very carefully monitored. Patients usually have some sedative medication to help them relax during the procedure as it may take up to 1 to 2 hours. They may also experience some angina type symptoms as the balloon is inflated but this soon passes. For any coronary invasive intervention, there are associated risks. The artery may become completely blocked and depending on the importance of this artery, it may be necessary to undergo an immediate bypass graft operation. This is a rare event, with approximately one out of every two hundred people undergoing PTCA converting to coronary artery bypass graft surgery (CABG). A detailed discussion of the risks versus benefits with the cardiologist will provide an individual guide prior to the procedure.
Flow Reserve studies
This is a quick procedure which is carried out in the cath lab to assess the severity of any narrowing's which cannot otherwise be assessed radiographically. A very fine catheter with a sensitive blood pressure detector mounted at its tip is guided through the narrowed vessel. A drug which dramatically increases the workload of the heart is then administered to the patient. The effects of the drug are very short lasting but last long enough to let us know whether enough blood flow is getting passed the narrowing under stressful conditions and therefore whether it is necessary to carry out a PTCA to the narrowing.
Rotational atherectomy (Rotablation)
Chronic narrowing's or blockages may become calcified or have a lot of atheroma in them making them very difficult to treat with just a balloon. Rotablation is a procedure where, once again, a very fine wire is guided through the narrowing and then a catheter with a small device called a burr, similar to drill, mounted at its tip is guided to the beginning of the narrowing. The burr is connected to an external device which when activated by the cardiologist causes the burr to spin at very high speeds inside the narrowing, thereby creating a channel wide enough for a balloon or stent to then be used.
Patent Foramen Ovale occlusion (PFO closure)
Atrial Septal Defect (ASD) is a hole in the heart, specifically in the wall separating the left and right atria. There are 3 main types of ASD, the most commonly seen is called a Patent Foramen Ovale and can exist in adults with no symptoms. ASDs are the 4th most common congenital defect. A more serious defect (Ostium secundumcum) where the septum has failed to grow properly in the foetus, leads to blood shunting from the left side of the heart (high pressure) to the right side (low pressure). This can lead to volume overload, high blood pressure in the lungs and arrhythmias. There is a known link between ASDs' and strokes. In recent years there have also been a number of studies carried out which show that there may also be a link to migraine. Clinical findings normally show up in the 2nd, 3rd decade of life. Closures of ASDs are more commonly carried out in childhood or at the time of the diagnosis later in life. Patients need to have a full echo study to assess their cardiac status and to measure the ASD in multiple views.
Surgical closure is very effective but carries higher risks of morbidity and other complications related to surgery as well as increased hospital stays. Closure can also be performed trans luminally using a catheter device called a Septal Occluder. The device is a self expanding double disc made of a nickel and titanium wire mesh and looks a bit like an umbrella. The device is delivered into the heart through a long introducer sheath which is positioned across the ASD. The septal occluder(or umbrella) is positioned on one side of the septum and one of the discs is opened out, the catheter is then pulled back across the ASD to stent the defect. The 2nd disc is then opened out and deployed on the other side of the septum. During the procedure a Trans Oesophageal Echo probe is positioned in the Oesophagus just behind the heart providing the cardiologist with a good view of the septum and the device as it is deployed. If a good position is confirmed then the device is released from the delivery system and the delivery system and sheath are removed. A whole range of sizes are required for the procedure as sizing the defect occurs at the time of the cardiac cath using a low pressure dilation balloon.
Single and dual chamber pacemaker implantation
Despite the different types of pacemaker, essentially they all have the same function - to detect and act as the hearts pacemaker if an abnormality in rhythm is detected. There are specific abnormal heart rhythms that will require a pacemaker to be inserted - if the heart beat is too slow (bradycardia) or too fast (tachycardia), if there is a irregular heart rate, heart failure, or when the heart does not receive the normal signals sent out by the sinoatrial (SA) node. This is termed heart block. Sometimes electrical impulses generated by the heart's normal pacemaker are not transmitted to the ventricles quickly enough. This is often referred to as a conduction abnormality. Heart failure can cause this, as well as some drugs and cardiac surgery. Heart block has various well defined stages with the last stage resulting in complete heart block. In this stage, no information from the heart's normal pacemaker reaches the ventricles. Luckily, the ventricles have their own built in pacemaker, though this is insufficient in providing the amount of blood the body needs to function adequately. As a result, fainting is a common problem with this form of heart disease. Pacemakers therefore provide an adequate pulse rate when the heart's rate is abnormal.
There are 3 different types of pacemaker - single chamber, dual chamber and biventricular chamber. The implantation procedure is normally carried out under local anaesthetic in the cardiac cath lab. The ECG, blood pressure and Oxygen level in the blood are all very closely monitored throughout. For the single chamber pacemaker, an electrode wire is inserted into a large vein, normally a vein near the shoulder. This wire is the guided under X-ray by a cardiologist into the right atria or ventricle of the heart. Once positioned in the heart the wire is tested by the cardiac physiologist through an external device called a pacing system analyzer. This measures the amount of energy the heart muscle needs to cause it to contract, the size, in millivolts, of the hearts own electrical impulses and whether the electrode is in a satisfactory position for it to be connected to the implantable pacemaker. During the testing of the wire/s, the patient may be aware of their heart beating slightly faster than usual or palpitations. The wire at the skin is then "tunneled" away from the insertion point, and a small pocket is made under the skin where it is attached to the actual pacemaker box. For a dual chamber pacemaker, the same technique is used but there are 2 leads. One lead is guided to the right atria and the other to the right ventricle. A biventricular pacemaker has 3 leads or electrodes that are guided into the right atria and right and left ventricle. Depending on the type of rhythm or severity of heart disease, the cardiologist will choose the most appropriate one.
Electro Physiological studies (EPS)
In the normal heart, electrical impulses flow through the specialized conductive cells in an ordered fashion causing the heart to beat in a regular way and at appropriate rates. Any disturbance or interruption of the normal electrical system can give rise to heart rhythm disturbances or ARRYTHMIAS. An ECG is the first test on the path to diagnosing an arrhythmia, however, if the arrhythmia happens only occasionally, a normal ECG may not be enough to diagnose and therefore treat the arrhythmia properly. An Electrophysiological study (EPS) is an invasive procedure carried out in our specially designed cardiac cath labs kitted out with the most advanced EP technology and equipment. The procedure is performed by a highly specialized rhythm management cardiologist. The procedure involves passing catheter electrodes in to the vein in the groin under local anesthetic and guiding them into position around the heart under X Ray imaging. The electrode catheters are then connected to a large external EP device and electrical data is gathered from the small complex signals generated from various locations' inside the heart. During this procedure, the cardiologist may be able to provoke arrhythmias and therefore analyze the 'map' of electrical signals during the event. This provides the cardiologists with diagnostic information and will help her decide on the appropriate treatment for the specific arrhythmia. Depending on the type of arrhythmia, some patients may be referred for an ablation procedure.
Ablation for cardiac arrhythmias
The ablation procedure is similar in set up to an EPS. Long flexible wires or "catheter electrodes" are introduced from a peripheral blood vessel into the heart and navigated to critical areas responsible for causing cardiac rhythm disorders.
Delivery of a focal energy source from the tip of the catheter, either high frequency radio waves causing heating of tissue or freezing cryo ablation can be delivered at the tip of these catheters causing small discrete (4-5mm) irreversible areas of tissue destruction which render these abnormal areas of electrical activity non functional.
The rest of the heart function is unaffected and the lesions created are usually permanent. A curative catheter ablation approach is preferred by many patients who have recurrent symptoms which cannot be controlled by drugs or who do not wish to take drugs long term. This is an extremely effective form of treatment for arrhythmia, with long term studies showing successful ablation treatment is persistent over time, and that late recurrence of aberrant conduction is a rare event.
Atrial fibrillation (AF) ablation
Atrial fibrillation (AF) is the commonest arrhythmia in man, with an estimated prevalence of 1% under 60 years and increases rapidly with age to more than 10% in those over 80 years AF is the commonest arrhythmic cause for hospitalizations, and is associated with increased morbidity (adverse events) and mortality (risk of death). Despite the prevalence of this condition, it was not until 1998 that the primary cause of AF was discovered. There are some areas of the heart muscle, usually located around the pulmonary veins which deliver oxygen rich blood back to the heart from the lungs, which, for some reason have retained autonomous and inappropriate rapid firing electrical activity and is capable of sending the whole of the atrium into a completely chaotic rhythm resulting in clinical symptoms. During ablation for AF, in order to record the electrical signals and apply the ablation treatment to the appropriate area, the catheter electrodes have to be passed through a thin section of the heart which separates the right from the left side of the heart. This is called a Trans septal puncture. The electrodes are then placed around the openings of the 4 pulmonary veins and ablation treatment applied to the muscle. This has the effect of electrically isolating each pulmonary vein from the left atrium. Consequently, any abnormal electrical signals arising from the pulmonary veins cannot be conducted to the atrium and cause Atrial fibrillation. The duration of the procedure may be slightly longer than for other types of ablation and a CT scan of may be required before coming to have the ablation as we have a particularly advance piece of equipment which allows extremely precise electrical mapping of a 3D image of the left atrium and pulmonary veins.
Cardiac Resynchronization Therapy (CRT heart failure devices) pacemaker implantation
This is a new type of pacemaker which attempts to resynchronize the right and the left ventricles if they are found to be beating in co-ordinately (dysynchrony). The procedure is similar to that of a normal pacemaker implantation; however, as well as an electrode being positioned within the right ventricle, an extra pacemaker electrode is introduced into a large blood vessel running around the heart which allows the electrode to be in close proximity to the left ventricle. The biventricular pacemaker, or CRT device, can sense signals from both ventricles' and decide to pace both ventricles if the signals are found to be too far apart to produce an adequately coordinated contraction of the heart and thereby a forceful enough ejection of blood around the body. These devices have been shown to improve cardiac function, patient quality of life, improve exercise distance and reduce heart failure events. Not all patients with heart failure are suitable for this treatment, but it is thought that up to 30% of this population may benefit from CRT.
Patients will often undergo an echocardiogram for assessment or confirmation of dysynchrony before the implant procedure and often afterwards to optimise the settings of the device to produce the greatest amount of improvement in cardiac function.
Implantable cardioverter defibrillator (ICD) implantation
There are many types of heart rhythm; some can be tolerated by the body reasonably and others cannot. 2 types of rhythm which are not well tolerated are Ventricular tachycardia (VT) and Ventricular fibrillation (VF).
VT is a rhythm whose origin is initiated somewhere in the ventricles, instead of the atria. This causes the heart to beat very rapidly. The heart cannot fill adequately in this rhythm, making the patient feel light headed and weak. This can lead to fainting if not corrected promptly. It can also lead to death if not treated at all.
VF is more serious than VT. In VF, the heart has no coordinated activity. There are a multitude of signals sent out in all directions across the heart. Due to the chaotic activity, the pumping mechanism is totally ineffective. This is a medical emergency, and if not treated promptly, results in death.
The ICD is a device, similar to a pacemaker, which can be fully implanted within the body under local anesthetic taking approximately an hour. The procedure is similar to that of a pacemaker implantation but the patient will have some additional ECG electrodes connected before the procedure and they may receive slightly more sedative medication. A wire electrode is inserted in a vein near the shoulder, in a similar way to a pacemaker wire. This is introduced into the correct position in the heart by a cardiologist. A small pocket is then made underneath the muscle high up on the chest, commonly the pectoral muscle. The ICD is placed here and the electrode tunneled from its insertion point and attached.
The ICDs can be programmed specifically to suit the patients individual needs and are used in some patients who are at risk of developing the life threatening arrhythmias VT or VF. The ICD can terminate some rapid heart rhythms by use of the pacemaker function of the device, which is painless and is successful in 80% of cases. But when the heart is so rapid or irregular that it has stopped pumping, (VF) the device will deliver a shock to reset the heart and restore a normal rhythm.
Patients undergoing ICD implantation should have consulted a Cardiac Rhythm Specialist who will fully assess the suitability and benefit of such a device.