Coronary Angioplasty (PCI)
Coronary angioplasty, also called percutaneous coronary intervention (PCI), is a treatment used to deal with tight narrowings in the coronary arteries that are affecting the blood supply to the heart and causing chest pain (angina) or breathlessness. A tiny balloon is inflated in the artery to squash the narrowing out of the way and then a stent (a small metal mesh) is inserted to keep the artery open.
Coronary angioplasty is carried out in a similar way to coronary angiography. In preparation for the procedure the patient must not eat or drink for 4 to 6 hours beforehand but usual medication can be taken with some water. Diabetics and patients on warfarin will be given special advice.
During the procedure itself, under local anaesthetic and sedation a tiny flexible tube is passed up the artery from the groin or wrist to the coronary artery using X-ray guidance. An extremely fine wire is passed along this tube, into and beyond the narrowing in the coronary artery. A very small balloon is then passed over the wire and up to the site of the narrowing where it is inflated. Following this a stent is inserted. Unless there are special circumstances, the stents used are drug-eluting stents, which are coated with drugs to prevent re-narrowing of the artery. The patient will usually need to stay in hospital for one night after the procedure.
After stent implantation it is very important for the patient to take a combination of two blood thinners, aspirin and clopidogrel (or prasugrel) for a year. Following this, patients can usually remain on aspirin alone for the long-term.
Patients who are troubled with symptoms arising from an abnormal heart rhythm (atrial fibrillation) may be suitable for a procedure called cardioversion to restore normal heart rhythm. This involves giving the patient a short general anesthetic for five to ten minutes and then delivering one or more electrical shocks to the chest. This is carried out as a day-case procedure.
It is very important that patients undergoing cardioversion have their blood thinned with warfarin for several weeks prior to the procedure. The effectiveness of warfarin treatment is measure by a blood test called the INR. This needs to be above 2 for the cardioversion to go ahead.
Patients will also sometimes need to have a TOE (Transoesophageal Echocardiogram) immediately prior to the delivery of the shock.
It is important that patients remain on warfarin treatment after the cardioversion until the doctor says that it is fine to stop it.
The normal heartbeat depends upon the electrical current that flows through the heart’s electrical wiring and makes the heart muscle contract. The current normally starts within the Sinus Node which is the heart’s natural pacemaker and flows in one direction from the top chambers (atria) to the bottom chambers (ventricles). Short circuits may develop anywhere along the. electrical wiring giving rise to abnormal heart rhythms. This may result in palpitations, breathlessness, chest pains, dizziness or blackouts.
Catheter ablation is a procedure in which the short circuits are destroyed. It is usually performed by a specialist cardiologist called a Cardiac Electrophysiologist. The procedure is perfomed under local anaesthetic with light or heavy sedation. For the most complex procedures, general anaesthesia is sometimes administered. Patients are able to go home either on the day of the procedure or the following day.
During the procedure, specially designed wires called catheters (figure 1) are passed into the heart from the leg veins under X-ray guidance (figure 2). The short circuits are pinpointed by performing an Electrophysiology Study during which the abnormal heart rhythm is triggered off by delivering electrical impulses to the heart through the catheters. Once localised, the short circuits are destroyed either by heating (radiofrequency ablation) or freezing (cryoablation) the critical bits of heart muscle.
In complex ablation procedures for abnormal rhythms like Atrial Fibrillation (AF), the catheters are guided using a 3 dimensional mapping computer that minimises the need for X-rays.(Figure 3) Movie showing an image of the left atrium in a patient undergoing catheter ablation for Atrial Fibrillation (AF). Each brown dot represents an ablation site. In this patient, the AF stopped during ablation and the heart went back into a normal rhythm. The patient remains in a normal rhythm 1 year after the procedure and is not taking any rhythm control drugs.
The overall success rates of catheter ablation are excellent and range from 80% to 95% depending upon the abnormal heart rhythm. The risk of serious complications such as stroke or damage to the heart is usually 1% or less. Catheter ablation is a permanent solution for abnormal heart rhythms and is more effective than drug therapy.
What is a Pacemaker and who needs one?
The normal heartbeat is produced by electrical impulses that begin inside a specialised part of the heart’s electrical system called the Sinus Node, which sits at the top of the right atrium. The electrical impulses then spread to all of the heart’s chambers through specialised electrical wiring and make the heart muscle contract. This ensures that enough blood and oxygen are pumped around the body to meet its demands. Any problems that affect the sinus node or the wiring may result in a slow heartbeat and cause symptoms like palpitations, breathlessness, tiredness, dizziness and blackouts. A pacemaker may then be required to restore the normal heartbeat and relieve the symptoms.
Pacemaker insertion is a minor surgical procedure that is performed under local anaesthetic with mild sedation. It takes about 60 minutes to do and most patients go home on the same day. There is a 1% risk of infection for which intravenous antibiotics are given.
A small, 3-cm cut is made under the collar bone (usually the left side). The pacemaker consists of one or two wires called “leads” that are positioned inside the chambers on the right side of the heart. They are introduced through the veins that run under the collar bone and guided into the heart using X-rays. The leads are connected to a small generator that sits under the skin below the collar bone and is the size of a large wristwatch. The generator is a small computer with a battery, electrical circuits and a memory chip. The battery lasts 10 to 15 years during which the pacemaker is constantly monitoring the heart’s electrical activity. Whenever the heart slows below a certain rate, the pacemaker switches on immediately and stimulates the heart muscle through the leads increasing the heart rate again. The generator also contains a motion sensor that tells the pacemaker to increase the heart rate in response to exercise.
The pacemaker is checked at least once a year in a special clinic to make sure it is working properly and to check the remaining battery life. This is done by either placing a sensor on the skin overlying the generator or by a wireless connection much like a mobile phone. A special computer called a programmer then checks the pacemaker and can adjust the pacemaker’s settings if necessary. When the battery starts to run down the old generator is removed and the leads reconnected to a new one.
Modern pacemakers are sophisticated devices that allow patients to lead full, active lives with few restrictions.
What is an Implantable Cardioverter Defibrillator and who needs it?
Some patients are at high risk for dangerous heart rhythms that come from either of the bottom two chambers of the heart called the ventricles. The dangerous rhythms are fast and may cause palpitations, chest pains, breathlessness, dizzy spells or blackouts. In the worst case scenario, the heart may stop completely, which is called a Cardiac Arrest and maybe fatal. Most patients will have some form of heart failure caused by a previous heart attack or a heart muscle problem called a Cardiomyopathy e.g. Hypertrophic Cardiomyopathy. Other patients however, have defects in the proteins that give rise to the heart’s electrical activity causing problems like the Brugada and Long QT Syndromes.
In these conditions, an Implantable Cardioverter Defibrillator or ICD gives the best protection together with drug therapy. If the heart goes into cardiac arrest, the ICD immediately delivers a lifesaving shock to the heart that restores the normal rhythm. ICDs have repeatedly been shown to significantly improve lifespan in such situations.
ICD insertion is a minor surgical procedure that is performed under local anaesthetic with heavy sedation. It takes about 60 to 90 minutes to do and most patients go home on the same day. There is a 1% risk of infection for which intravenous antibiotics are given.
A 5-cm cut is made under the collar bone (usually the left side). The ICD consists of one or two wires called “leads” that are positioned inside the chambers on the right side of the heart. They are introduced through the veins that run under the collar bone and guided into the heart using X-rays. The leads are connected to a generator that sits under the skin below the collar bone and is the size of a business card. The generator is a small computer with a battery, electrical circuits and a memory chip. The battery lasts 7 to 10 years during which the ICD is constantly monitoring the heart’s electrical activity. Whenever the heart goes into a fast, dangerous rhythm the ICD switches on immediately and stimulates the heart muscle through the leads or delivers a shock to restore the normal rhythm again. The ICD also works like a pacemaker to treat slow heart rates if necessary.
The ICD is checked at least once a year in a special clinic to make sure it is working properly and to check the remaining battery life. This is done by either placing a sensor on the skin overlying the generator or by a wireless connection much like a mobile phone. A special computer called a programmer then checks the ICD and can adjust the settings if necessary. When the battery starts to run down the old generator is removed and the leads reconnected to a new one.